1. 08 Sep, 2021 40 commits
    • Nathan Chancellor's avatar
      Documentation/llvm: update mailing list · 28f8fc19
      Nathan Chancellor authored
      We are now at llvm@lists.linux.dev.
      
      Link: https://lkml.kernel.org/r/20210825211823.6406-2-nathan@kernel.orgSigned-off-by: default avatarNathan Chancellor <nathan@kernel.org>
      Reviewed-by: default avatarNick Desaulniers <ndesaulniers@google.com>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Masahiro Yamada <masahiroy@kernel.org>
      Cc: Sami Tolvanen <samitolvanen@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      28f8fc19
    • Nathan Chancellor's avatar
      MAINTAINERS: update ClangBuiltLinux mailing list · 726248b6
      Nathan Chancellor authored
      We are now at llvm@lists.linux.dev.
      
      Link: https://lkml.kernel.org/r/20210825211823.6406-1-nathan@kernel.orgSigned-off-by: default avatarNathan Chancellor <nathan@kernel.org>
      Acked-by: default avatarNick Desaulniers <ndesaulniers@google.com>
      Cc: Masahiro Yamada <masahiroy@kernel.org>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Sami Tolvanen <samitolvanen@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      726248b6
    • Pavel Skripkin's avatar
      profiling: fix shift-out-of-bounds bugs · 2d186afd
      Pavel Skripkin authored
      Syzbot reported shift-out-of-bounds bug in profile_init().
      The problem was in incorrect prof_shift. Since prof_shift value comes from
      userspace we need to clamp this value into [0, BITS_PER_LONG -1]
      boundaries.
      
      Second possible shiht-out-of-bounds was found by Tetsuo:
      sample_step local variable in read_profile() had "unsigned int" type,
      but prof_shift allows to make a BITS_PER_LONG shift. So, to prevent
      possible shiht-out-of-bounds sample_step type was changed to
      "unsigned long".
      
      Also, "unsigned short int" will be sufficient for storing
      [0, BITS_PER_LONG] value, that's why there is no need for
      "unsigned long" prof_shift.
      
      Link: https://lkml.kernel.org/r/20210813140022.5011-1-paskripkin@gmail.com
      Fixes: 1da177e4 ("Linux-2.6.12-rc2")
      Reported-and-tested-by: syzbot+e68c89a9510c159d9684@syzkaller.appspotmail.com
      Suggested-by: default avatarTetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
      Signed-off-by: default avatarPavel Skripkin <paskripkin@gmail.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2d186afd
    • Yang Yang's avatar
      kernel/acct.c: use dedicated helper to access rlimit values · 3c91dda9
      Yang Yang authored
      Use rlimit() helper instead of manually writing whole chain from
      task to rlimit value. See patch "posix-cpu-timers: Use dedicated
      helper to access rlimit values".
      
      Link: https://lkml.kernel.org/r/20210728030822.524789-1-yang.yang29@zte.com.cnSigned-off-by: default avatarYang Yang <yang.yang29@zte.com.cn>
      Reported-by: default avatarZeal Robot <zealci@zte.com.cn>
      Cc: Randy Dunlap <rdunlap@infradead.org>
      Cc: sh_def@163.com <sh_def@163.com>
      Cc: Yang Yang <yang.yang29@zte.com.cn>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3c91dda9
    • Daniel Lezcano's avatar
      phy/drivers/stm32: use HZ macros · 18821693
      Daniel Lezcano authored
      HZ unit conversion macros are available in units.h, use them and remove
      the duplicate definition.
      
      Link: https://lkml.kernel.org/r/20210816114732.1834145-11-daniel.lezcano@linaro.orgSigned-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
      Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
      Cc: Chanwoo Choi <cw00.choi@samsung.com>
      Cc: Christian Eggers <ceggers@arri.de>
      Cc: Guenter Roeck <linux@roeck-us.net>
      Cc: Jonathan Cameron <jic23@kernel.org>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Kyungmin Park <kyungmin.park@samsung.com>
      Cc: Lars-Peter Clausen <lars@metafoo.de>
      Cc: Lukasz Luba <lukasz.luba@arm.com>
      Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
      Cc: Miquel Raynal <miquel.raynal@bootlin.com>
      Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
      Cc: Peter Meerwald <pmeerw@pmeerw.net>
      Cc: "Rafael J. Wysocki" <rafael@kernel.org>
      Cc: Zhang Rui <rui.zhang@intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      18821693
    • Daniel Lezcano's avatar
      mtd/drivers/nand: use HZ macros · 9ef347c3
      Daniel Lezcano authored
      HZ unit conversion macros are available in units.h, use them and remove
      the duplicate definition.
      
      Link: https://lkml.kernel.org/r/20210816114732.1834145-10-daniel.lezcano@linaro.orgSigned-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
      Acked-by: default avatarMiquel Raynal <miquel.raynal@bootlin.com>
      Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
      Cc: Chanwoo Choi <cw00.choi@samsung.com>
      Cc: Christian Eggers <ceggers@arri.de>
      Cc: Guenter Roeck <linux@roeck-us.net>
      Cc: Jonathan Cameron <jic23@kernel.org>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Kyungmin Park <kyungmin.park@samsung.com>
      Cc: Lars-Peter Clausen <lars@metafoo.de>
      Cc: Lukasz Luba <lukasz.luba@arm.com>
      Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
      Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
      Cc: Peter Meerwald <pmeerw@pmeerw.net>
      Cc: "Rafael J. Wysocki" <rafael@kernel.org>
      Cc: Zhang Rui <rui.zhang@intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9ef347c3
    • Daniel Lezcano's avatar
      i2c/drivers/ov02q10: use HZ macros · 09704a94
      Daniel Lezcano authored
      HZ unit conversion macros are available in units.h, use them and remove
      the duplicate definition.
      
      Link: https://lkml.kernel.org/r/20210816114732.1834145-9-daniel.lezcano@linaro.orgSigned-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
      Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
      Cc: Chanwoo Choi <cw00.choi@samsung.com>
      Cc: Christian Eggers <ceggers@arri.de>
      Cc: Guenter Roeck <linux@roeck-us.net>
      Cc: Jonathan Cameron <jic23@kernel.org>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Kyungmin Park <kyungmin.park@samsung.com>
      Cc: Lars-Peter Clausen <lars@metafoo.de>
      Cc: Lukasz Luba <lukasz.luba@arm.com>
      Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
      Cc: Miquel Raynal <miquel.raynal@bootlin.com>
      Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
      Cc: Peter Meerwald <pmeerw@pmeerw.net>
      Cc: "Rafael J. Wysocki" <rafael@kernel.org>
      Cc: Zhang Rui <rui.zhang@intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      09704a94
    • Daniel Lezcano's avatar
      iio/drivers/hid-sensor: use HZ macros · 87000e7f
      Daniel Lezcano authored
      HZ unit conversion macros are available in units.h, use them and remove
      the duplicate definition.
      
      Link: https://lkml.kernel.org/r/20210816114732.1834145-8-daniel.lezcano@linaro.orgSigned-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
      Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
      Acked-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Chanwoo Choi <cw00.choi@samsung.com>
      Cc: Christian Eggers <ceggers@arri.de>
      Cc: Guenter Roeck <linux@roeck-us.net>
      Cc: Jonathan Cameron <jic23@kernel.org>
      Cc: Kyungmin Park <kyungmin.park@samsung.com>
      Cc: Lars-Peter Clausen <lars@metafoo.de>
      Cc: Lukasz Luba <lukasz.luba@arm.com>
      Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
      Cc: Miquel Raynal <miquel.raynal@bootlin.com>
      Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
      Cc: Peter Meerwald <pmeerw@pmeerw.net>
      Cc: "Rafael J. Wysocki" <rafael@kernel.org>
      Cc: Zhang Rui <rui.zhang@intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      87000e7f
    • Daniel Lezcano's avatar
      hwmon/drivers/mr75203: use HZ macros · d59eacaa
      Daniel Lezcano authored
      HZ unit conversion macros are available in units.h, use them and remove
      the duplicate definition.
      
      The new macro is an unsigned long.  The code dealing with it is
      considering as an unsigned long also.
      
      Link: https://lkml.kernel.org/r/20210816114732.1834145-7-daniel.lezcano@linaro.orgSigned-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
      Reviewed-by: default avatarChristian Eggers <ceggers@arri.de>
      Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
      Acked-by: default avatarGuenter Roeck <linux@roeck-us.net>
      Cc: Chanwoo Choi <cw00.choi@samsung.com>
      Cc: Jonathan Cameron <jic23@kernel.org>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Kyungmin Park <kyungmin.park@samsung.com>
      Cc: Lars-Peter Clausen <lars@metafoo.de>
      Cc: Lukasz Luba <lukasz.luba@arm.com>
      Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
      Cc: Miquel Raynal <miquel.raynal@bootlin.com>
      Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
      Cc: Peter Meerwald <pmeerw@pmeerw.net>
      Cc: "Rafael J. Wysocki" <rafael@kernel.org>
      Cc: Zhang Rui <rui.zhang@intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d59eacaa
    • Daniel Lezcano's avatar
      iio/drivers/as73211: use HZ macros · 55c653e0
      Daniel Lezcano authored
      HZ unit conversion macros are available in units.h, use them and remove
      the duplicate definition.
      
      Link: https://lkml.kernel.org/r/20210816114732.1834145-6-daniel.lezcano@linaro.orgSigned-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
      Reviewed-by: default avatarChristian Eggers <ceggers@arri.de>
      Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
      Acked-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Chanwoo Choi <cw00.choi@samsung.com>
      Cc: Guenter Roeck <linux@roeck-us.net>
      Cc: Jonathan Cameron <jic23@kernel.org>
      Cc: Kyungmin Park <kyungmin.park@samsung.com>
      Cc: Lars-Peter Clausen <lars@metafoo.de>
      Cc: Lukasz Luba <lukasz.luba@arm.com>
      Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
      Cc: Miquel Raynal <miquel.raynal@bootlin.com>
      Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
      Cc: Peter Meerwald <pmeerw@pmeerw.net>
      Cc: "Rafael J. Wysocki" <rafael@kernel.org>
      Cc: Zhang Rui <rui.zhang@intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      55c653e0
    • Daniel Lezcano's avatar
      devfreq: use HZ macros · 04c8984a
      Daniel Lezcano authored
      HZ unit conversion macros are available in units.h, use them and remove
      the duplicate definition.
      
      The new macro has an unsigned long type.
      
      All the code is dealing with unsigned long and the code using the macro is
      doing a coercitive cast to unsigned long.
      
      Link: https://lkml.kernel.org/r/20210816114732.1834145-5-daniel.lezcano@linaro.orgSigned-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
      Reviewed-by: default avatarChristian Eggers <ceggers@arri.de>
      Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
      Acked-by: default avatarChanwoo Choi <cw00.choi@samsung.com>
      Cc: Guenter Roeck <linux@roeck-us.net>
      Cc: Jonathan Cameron <jic23@kernel.org>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Kyungmin Park <kyungmin.park@samsung.com>
      Cc: Lars-Peter Clausen <lars@metafoo.de>
      Cc: Lukasz Luba <lukasz.luba@arm.com>
      Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
      Cc: Miquel Raynal <miquel.raynal@bootlin.com>
      Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
      Cc: Peter Meerwald <pmeerw@pmeerw.net>
      Cc: "Rafael J. Wysocki" <rafael@kernel.org>
      Cc: Zhang Rui <rui.zhang@intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      04c8984a
    • Daniel Lezcano's avatar
      thermal/drivers/devfreq_cooling: use HZ macros · 73b718c6
      Daniel Lezcano authored
      HZ unit conversion macros are available in units.h, use them and remove
      the duplicate definition.
      
      The new macro uses a unsigned long type which is already the type in the
      current code via the 'freq' variable.
      
      Link: https://lkml.kernel.org/r/20210816114732.1834145-4-daniel.lezcano@linaro.orgSigned-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
      Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
      Reviewed-by: default avatarChristian Eggers <ceggers@arri.de>
      Cc: Chanwoo Choi <cw00.choi@samsung.com>
      Cc: Guenter Roeck <linux@roeck-us.net>
      Cc: Jonathan Cameron <jic23@kernel.org>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Kyungmin Park <kyungmin.park@samsung.com>
      Cc: Lars-Peter Clausen <lars@metafoo.de>
      Cc: Lukasz Luba <lukasz.luba@arm.com>
      Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
      Cc: Miquel Raynal <miquel.raynal@bootlin.com>
      Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
      Cc: Peter Meerwald <pmeerw@pmeerw.net>
      Cc: "Rafael J. Wysocki" <rafael@kernel.org>
      Cc: Zhang Rui <rui.zhang@intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      73b718c6
    • Daniel Lezcano's avatar
      units: add the HZ macros · e2c77032
      Daniel Lezcano authored
      The macros for the unit conversion for frequency are duplicated in
      different places.
      
      Provide these macros in the 'units' header, so they can be reused.
      
      Link: https://lkml.kernel.org/r/20210816114732.1834145-3-daniel.lezcano@linaro.orgSigned-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
      Reviewed-by: default avatarChristian Eggers <ceggers@arri.de>
      Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
      Cc: Chanwoo Choi <cw00.choi@samsung.com>
      Cc: Guenter Roeck <linux@roeck-us.net>
      Cc: Jonathan Cameron <jic23@kernel.org>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Kyungmin Park <kyungmin.park@samsung.com>
      Cc: Lars-Peter Clausen <lars@metafoo.de>
      Cc: Lukasz Luba <lukasz.luba@arm.com>
      Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
      Cc: Miquel Raynal <miquel.raynal@bootlin.com>
      Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
      Cc: Peter Meerwald <pmeerw@pmeerw.net>
      Cc: "Rafael J. Wysocki" <rafael@kernel.org>
      Cc: Zhang Rui <rui.zhang@intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e2c77032
    • Daniel Lezcano's avatar
      units: change from 'L' to 'UL' · c9221919
      Daniel Lezcano authored
      Patch series "Add Hz macros", v3.
      
      There are multiple definitions of the HZ_PER_MHZ or HZ_PER_KHZ in the
      different drivers.  Instead of duplicating this definition again and
      again, add one in the units.h header to be reused in all the place the
      redefiniton occurs.
      
      At the same time, change the type of the Watts, as they can not be
      negative.
      
      This patch (of 10):
      
      The users of the macros are safe to be assigned with an unsigned instead
      of signed as the variables using them are themselves unsigned.
      
      Link: https://lkml.kernel.org/r/20210816114732.1834145-1-daniel.lezcano@linaro.org
      Link: https://lkml.kernel.org/r/20210816114732.1834145-2-daniel.lezcano@linaro.orgSigned-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
      Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
      Cc: Jonathan Cameron <jic23@kernel.org>
      Cc: Christian Eggers <ceggers@arri.de>
      Cc: Lukasz Luba <lukasz.luba@arm.com>
      Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
      Cc: Kyungmin Park <kyungmin.park@samsung.com>
      Cc: Lars-Peter Clausen <lars@metafoo.de>
      Cc: Peter Meerwald <pmeerw@pmeerw.net>
      Cc: Zhang Rui <rui.zhang@intel.com>
      Cc: Guenter Roeck <linux@roeck-us.net>
      Cc: Miquel Raynal <miquel.raynal@bootlin.com>
      Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
      Cc: "Rafael J. Wysocki" <rafael@kernel.org>
      Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
      Cc: Chanwoo Choi <cw00.choi@samsung.com>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c9221919
    • Andy Shevchenko's avatar
    • Colin Ian King's avatar
    • Ohhoon Kwon's avatar
      connector: send event on write to /proc/[pid]/comm · c2f273eb
      Ohhoon Kwon authored
      While comm change event via prctl has been reported to proc connector by
      'commit f786ecba ("connector: add comm change event report to proc
      connector")', connector listeners were missing comm changes by explicit
      writes on /proc/[pid]/comm.
      
      Let explicit writes on /proc/[pid]/comm report to proc connector.
      
      Link: https://lkml.kernel.org/r/20210701133458epcms1p68e9eb9bd0eee8903ba26679a37d9d960@epcms1p6Signed-off-by: default avatarOhhoon Kwon <ohoono.kwon@samsung.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Christian Brauner <christian.brauner@ubuntu.com>
      Cc: Eric W. Biederman <ebiederm@xmission.com>
      Cc: Alexey Dobriyan <adobriyan@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c2f273eb
    • Christoph Hellwig's avatar
      proc: stop using seq_get_buf in proc_task_name · 8d23b208
      Christoph Hellwig authored
      Use seq_escape_str and seq_printf instead of poking holes into the
      seq_file abstraction.
      
      Link: https://lkml.kernel.org/r/20210810151945.1795567-1-hch@lst.deSigned-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Acked-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
      Cc: Alexey Dobriyan <adobriyan@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8d23b208
    • Greg Kroah-Hartman's avatar
      percpu: remove export of pcpu_base_addr · 3843c50a
      Greg Kroah-Hartman authored
      This is not needed by any modules, so remove the export.
      
      Link: https://lkml.kernel.org/r/20210722185814.504541-1-gregkh@linuxfoundation.orgSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Cc: Dennis Zhou <dennis@kernel.org>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Christoph Lameter <cl@linux.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3843c50a
    • Randy Dunlap's avatar
      alpha: pci-sysfs: fix all kernel-doc warnings · 0a9d991c
      Randy Dunlap authored
      Fix all kernel-doc warnings in arch/alpha/kernel/pci-sysfs.c:
      
        arch/alpha/kernel/pci-sysfs.c:67: warning: No description found for return value of 'pci_mmap_resource'
        arch/alpha/kernel/pci-sysfs.c:115: warning: Function parameter or member 'pdev' not described in 'pci_remove_resource_files'
        arch/alpha/kernel/pci-sysfs.c:115: warning: Excess function parameter 'dev' description in 'pci_remove_resource_files'
        arch/alpha/kernel/pci-sysfs.c:230: warning: Function parameter or member 'pdev' not described in 'pci_create_resource_files'
        arch/alpha/kernel/pci-sysfs.c:230: warning: Excess function parameter 'dev' description in 'pci_create_resource_files'
        arch/alpha/kernel/pci-sysfs.c:232: warning: No description found for return value of 'pci_create_resource_files'
        arch/alpha/kernel/pci-sysfs.c:305: warning: Function parameter or member 'bus' not described in 'pci_adjust_legacy_attr'
        arch/alpha/kernel/pci-sysfs.c:305: warning: Excess function parameter 'b' description in 'pci_adjust_legacy_attr'
      
      Link: https://lkml.kernel.org/r/20210808185249.31442-1-rdunlap@infradead.orgSigned-off-by: default avatarRandy Dunlap <rdunlap@infradead.org>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: Matt Turner <mattst88@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0a9d991c
    • Randy Dunlap's avatar
      alpha: agp: make empty macros use do-while-0 style · 5ecae8f6
      Randy Dunlap authored
      Copy these macros from ia64/include/asm/agp.h to avoid the
      "empty-body" in 'if' statment warning.
      
      drivers/char/agp/generic.c: In function 'agp_generic_destroy_page':
      ../drivers/char/agp/generic.c:1265:42: warning: suggest braces around empty body in an 'if' statement [-Wempty-body]
       1265 |                 unmap_page_from_agp(page);
      
      Link: https://lkml.kernel.org/r/20210809030822.20658-1-rdunlap@infradead.orgSigned-off-by: default avatarRandy Dunlap <rdunlap@infradead.org>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: Matt Turner <mattst88@gmail.com>
      Cc: David Airlie <airlied@linux.ie>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      5ecae8f6
    • SeongJae Park's avatar
      MAINTAINERS: update for DAMON · 75e39b1a
      SeongJae Park authored
      This commit updates MAINTAINERS file for DAMON related files.
      
      Link: https://lkml.kernel.org/r/20210716081449.22187-14-sj38.park@gmail.comSigned-off-by: default avatarSeongJae Park <sjpark@amazon.de>
      Reviewed-by: default avatarMarkus Boehme <markubo@amazon.de>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Amit Shah <amit@kernel.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Brendan Higgins <brendanhiggins@google.com>
      Cc: David Hildenbrand <david@redhat.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: David Woodhouse <dwmw@amazon.com>
      Cc: Fan Du <fan.du@intel.com>
      Cc: Fernand Sieber <sieberf@amazon.com>
      Cc: Greg Kroah-Hartman <greg@kroah.com>
      Cc: Greg Thelen <gthelen@google.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Joe Perches <joe@perches.com>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Leonard Foerster <foersleo@amazon.de>
      Cc: Marco Elver <elver@google.com>
      Cc: Maximilian Heyne <mheyne@amazon.de>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: Shakeel Butt <shakeelb@google.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
      Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      75e39b1a
    • SeongJae Park's avatar
      mm/damon: add user space selftests · b348eb7a
      SeongJae Park authored
      This commit adds a simple user space tests for DAMON.  The tests are using
      kselftest framework.
      
      Link: https://lkml.kernel.org/r/20210716081449.22187-13-sj38.park@gmail.comSigned-off-by: default avatarSeongJae Park <sjpark@amazon.de>
      Reviewed-by: default avatarMarkus Boehme <markubo@amazon.de>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Amit Shah <amit@kernel.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Brendan Higgins <brendanhiggins@google.com>
      Cc: David Hildenbrand <david@redhat.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: David Woodhouse <dwmw@amazon.com>
      Cc: Fan Du <fan.du@intel.com>
      Cc: Fernand Sieber <sieberf@amazon.com>
      Cc: Greg Kroah-Hartman <greg@kroah.com>
      Cc: Greg Thelen <gthelen@google.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Joe Perches <joe@perches.com>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Leonard Foerster <foersleo@amazon.de>
      Cc: Marco Elver <elver@google.com>
      Cc: Maximilian Heyne <mheyne@amazon.de>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: Shakeel Butt <shakeelb@google.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
      Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b348eb7a
    • SeongJae Park's avatar
      mm/damon: add kunit tests · 17ccae8b
      SeongJae Park authored
      This commit adds kunit based unit tests for the core and the virtual
      address spaces monitoring primitives of DAMON.
      
      Link: https://lkml.kernel.org/r/20210716081449.22187-12-sj38.park@gmail.comSigned-off-by: default avatarSeongJae Park <sjpark@amazon.de>
      Reviewed-by: default avatarBrendan Higgins <brendanhiggins@google.com>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Amit Shah <amit@kernel.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: David Hildenbrand <david@redhat.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: David Woodhouse <dwmw@amazon.com>
      Cc: Fan Du <fan.du@intel.com>
      Cc: Fernand Sieber <sieberf@amazon.com>
      Cc: Greg Kroah-Hartman <greg@kroah.com>
      Cc: Greg Thelen <gthelen@google.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Joe Perches <joe@perches.com>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Leonard Foerster <foersleo@amazon.de>
      Cc: Marco Elver <elver@google.com>
      Cc: Markus Boehme <markubo@amazon.de>
      Cc: Maximilian Heyne <mheyne@amazon.de>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: Shakeel Butt <shakeelb@google.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
      Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      17ccae8b
    • SeongJae Park's avatar
      Documentation: add documents for DAMON · c4ba6014
      SeongJae Park authored
      This commit adds documents for DAMON under
      `Documentation/admin-guide/mm/damon/` and `Documentation/vm/damon/`.
      
      Link: https://lkml.kernel.org/r/20210716081449.22187-11-sj38.park@gmail.comSigned-off-by: default avatarSeongJae Park <sjpark@amazon.de>
      Reviewed-by: default avatarFernand Sieber <sieberf@amazon.com>
      Reviewed-by: default avatarMarkus Boehme <markubo@amazon.de>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Amit Shah <amit@kernel.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Brendan Higgins <brendanhiggins@google.com>
      Cc: David Hildenbrand <david@redhat.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: David Woodhouse <dwmw@amazon.com>
      Cc: Fan Du <fan.du@intel.com>
      Cc: Greg Kroah-Hartman <greg@kroah.com>
      Cc: Greg Thelen <gthelen@google.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Joe Perches <joe@perches.com>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Leonard Foerster <foersleo@amazon.de>
      Cc: Marco Elver <elver@google.com>
      Cc: Maximilian Heyne <mheyne@amazon.de>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: Shakeel Butt <shakeelb@google.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
      Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c4ba6014
    • SeongJae Park's avatar
      mm/damon/dbgfs: support multiple contexts · 75c1c2b5
      SeongJae Park authored
      In some use cases, users would want to run multiple monitoring context.
      For example, if a user wants a high precision monitoring and dedicating
      multiple CPUs for the job is ok, because DAMON creates one monitoring
      thread per one context, the user can split the monitoring target regions
      into multiple small regions and create one context for each region.  Or,
      someone might want to simultaneously monitor different address spaces,
      e.g., both virtual address space and physical address space.
      
      The DAMON's API allows such usage, but 'damon-dbgfs' does not.  Therefore,
      only kernel space DAMON users can do multiple contexts monitoring.
      
      This commit allows the user space DAMON users to use multiple contexts
      monitoring by introducing two new 'damon-dbgfs' debugfs files,
      'mk_context' and 'rm_context'.  Users can create a new monitoring context
      by writing the desired name of the new context to 'mk_context'.  Then, a
      new directory with the name and having the files for setting of the
      context ('attrs', 'target_ids' and 'record') will be created under the
      debugfs directory.  Writing the name of the context to remove to
      'rm_context' will remove the related context and directory.
      
      Link: https://lkml.kernel.org/r/20210716081449.22187-10-sj38.park@gmail.comSigned-off-by: default avatarSeongJae Park <sjpark@amazon.de>
      Reviewed-by: default avatarFernand Sieber <sieberf@amazon.com>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Amit Shah <amit@kernel.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Brendan Higgins <brendanhiggins@google.com>
      Cc: David Hildenbrand <david@redhat.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: David Woodhouse <dwmw@amazon.com>
      Cc: Fan Du <fan.du@intel.com>
      Cc: Greg Kroah-Hartman <greg@kroah.com>
      Cc: Greg Thelen <gthelen@google.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Joe Perches <joe@perches.com>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Leonard Foerster <foersleo@amazon.de>
      Cc: Marco Elver <elver@google.com>
      Cc: Markus Boehme <markubo@amazon.de>
      Cc: Maximilian Heyne <mheyne@amazon.de>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: Shakeel Butt <shakeelb@google.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
      Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      75c1c2b5
    • SeongJae Park's avatar
      mm/damon/dbgfs: export kdamond pid to the user space · 429538e8
      SeongJae Park authored
      For CPU usage accounting, knowing pid of the monitoring thread could be
      helpful.  For example, users could use cpuaccount cgroups with the pid.
      
      This commit therefore exports the pid of currently running monitoring
      thread to the user space via 'kdamond_pid' file in the debugfs directory.
      
      Link: https://lkml.kernel.org/r/20210716081449.22187-9-sj38.park@gmail.comSigned-off-by: default avatarSeongJae Park <sjpark@amazon.de>
      Reviewed-by: default avatarFernand Sieber <sieberf@amazon.com>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Amit Shah <amit@kernel.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Brendan Higgins <brendanhiggins@google.com>
      Cc: David Hildenbrand <david@redhat.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: David Woodhouse <dwmw@amazon.com>
      Cc: Fan Du <fan.du@intel.com>
      Cc: Greg Kroah-Hartman <greg@kroah.com>
      Cc: Greg Thelen <gthelen@google.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Joe Perches <joe@perches.com>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Leonard Foerster <foersleo@amazon.de>
      Cc: Marco Elver <elver@google.com>
      Cc: Markus Boehme <markubo@amazon.de>
      Cc: Maximilian Heyne <mheyne@amazon.de>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: Shakeel Butt <shakeelb@google.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
      Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      429538e8
    • SeongJae Park's avatar
      mm/damon: implement a debugfs-based user space interface · 4bc05954
      SeongJae Park authored
      DAMON is designed to be used by kernel space code such as the memory
      management subsystems, and therefore it provides only kernel space API.
      That said, letting the user space control DAMON could provide some
      benefits to them.  For example, it will allow user space to analyze their
      specific workloads and make their own special optimizations.
      
      For such cases, this commit implements a simple DAMON application kernel
      module, namely 'damon-dbgfs', which merely wraps the DAMON api and exports
      those to the user space via the debugfs.
      
      'damon-dbgfs' exports three files, ``attrs``, ``target_ids``, and
      ``monitor_on`` under its debugfs directory, ``<debugfs>/damon/``.
      
      Attributes
      ----------
      
      Users can read and write the ``sampling interval``, ``aggregation
      interval``, ``regions update interval``, and min/max number of monitoring
      target regions by reading from and writing to the ``attrs`` file.  For
      example, below commands set those values to 5 ms, 100 ms, 1,000 ms, 10,
      1000 and check it again::
      
          # cd <debugfs>/damon
          # echo 5000 100000 1000000 10 1000 > attrs
          # cat attrs
          5000 100000 1000000 10 1000
      
      Target IDs
      ----------
      
      Some types of address spaces supports multiple monitoring target.  For
      example, the virtual memory address spaces monitoring can have multiple
      processes as the monitoring targets.  Users can set the targets by writing
      relevant id values of the targets to, and get the ids of the current
      targets by reading from the ``target_ids`` file.  In case of the virtual
      address spaces monitoring, the values should be pids of the monitoring
      target processes.  For example, below commands set processes having pids
      42 and 4242 as the monitoring targets and check it again::
      
          # cd <debugfs>/damon
          # echo 42 4242 > target_ids
          # cat target_ids
          42 4242
      
      Note that setting the target ids doesn't start the monitoring.
      
      Turning On/Off
      --------------
      
      Setting the files as described above doesn't incur effect unless you
      explicitly start the monitoring.  You can start, stop, and check the
      current status of the monitoring by writing to and reading from the
      ``monitor_on`` file.  Writing ``on`` to the file starts the monitoring of
      the targets with the attributes.  Writing ``off`` to the file stops those.
      DAMON also stops if every targets are invalidated (in case of the virtual
      memory monitoring, target processes are invalidated when terminated).
      Below example commands turn on, off, and check the status of DAMON::
      
          # cd <debugfs>/damon
          # echo on > monitor_on
          # echo off > monitor_on
          # cat monitor_on
          off
      
      Please note that you cannot write to the above-mentioned debugfs files
      while the monitoring is turned on.  If you write to the files while DAMON
      is running, an error code such as ``-EBUSY`` will be returned.
      
      [akpm@linux-foundation.org: remove unneeded "alloc failed" printks]
      [akpm@linux-foundation.org: replace macro with static inline]
      
      Link: https://lkml.kernel.org/r/20210716081449.22187-8-sj38.park@gmail.comSigned-off-by: default avatarSeongJae Park <sjpark@amazon.de>
      Reviewed-by: default avatarLeonard Foerster <foersleo@amazon.de>
      Reviewed-by: default avatarFernand Sieber <sieberf@amazon.com>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Amit Shah <amit@kernel.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Brendan Higgins <brendanhiggins@google.com>
      Cc: David Hildenbrand <david@redhat.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: David Woodhouse <dwmw@amazon.com>
      Cc: Fan Du <fan.du@intel.com>
      Cc: Greg Kroah-Hartman <greg@kroah.com>
      Cc: Greg Thelen <gthelen@google.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Joe Perches <joe@perches.com>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Marco Elver <elver@google.com>
      Cc: Markus Boehme <markubo@amazon.de>
      Cc: Maximilian Heyne <mheyne@amazon.de>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: Shakeel Butt <shakeelb@google.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
      Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4bc05954
    • SeongJae Park's avatar
      mm/damon: add a tracepoint · 2fcb9362
      SeongJae Park authored
      This commit adds a tracepoint for DAMON.  It traces the monitoring results
      of each region for each aggregation interval.  Using this, DAMON can
      easily integrated with tracepoints supporting tools such as perf.
      
      Link: https://lkml.kernel.org/r/20210716081449.22187-7-sj38.park@gmail.comSigned-off-by: default avatarSeongJae Park <sjpark@amazon.de>
      Reviewed-by: default avatarLeonard Foerster <foersleo@amazon.de>
      Reviewed-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
      Reviewed-by: default avatarFernand Sieber <sieberf@amazon.com>
      Acked-by: default avatarShakeel Butt <shakeelb@google.com>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Amit Shah <amit@kernel.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Brendan Higgins <brendanhiggins@google.com>
      Cc: David Hildenbrand <david@redhat.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: David Woodhouse <dwmw@amazon.com>
      Cc: Fan Du <fan.du@intel.com>
      Cc: Greg Kroah-Hartman <greg@kroah.com>
      Cc: Greg Thelen <gthelen@google.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Joe Perches <joe@perches.com>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Marco Elver <elver@google.com>
      Cc: Markus Boehme <markubo@amazon.de>
      Cc: Maximilian Heyne <mheyne@amazon.de>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2fcb9362
    • SeongJae Park's avatar
      mm/damon: implement primitives for the virtual memory address spaces · 3f49584b
      SeongJae Park authored
      This commit introduces a reference implementation of the address space
      specific low level primitives for the virtual address space, so that users
      of DAMON can easily monitor the data accesses on virtual address spaces of
      specific processes by simply configuring the implementation to be used by
      DAMON.
      
      The low level primitives for the fundamental access monitoring are defined
      in two parts:
      
      1. Identification of the monitoring target address range for the address
         space.
      2. Access check of specific address range in the target space.
      
      The reference implementation for the virtual address space does the works
      as below.
      
      PTE Accessed-bit Based Access Check
      -----------------------------------
      
      The implementation uses PTE Accessed-bit for basic access checks.  That
      is, it clears the bit for the next sampling target page and checks whether
      it is set again after one sampling period.  This could disturb the reclaim
      logic.  DAMON uses ``PG_idle`` and ``PG_young`` page flags to solve the
      conflict, as Idle page tracking does.
      
      VMA-based Target Address Range Construction
      -------------------------------------------
      
      Only small parts in the super-huge virtual address space of the processes
      are mapped to physical memory and accessed.  Thus, tracking the unmapped
      address regions is just wasteful.  However, because DAMON can deal with
      some level of noise using the adaptive regions adjustment mechanism,
      tracking every mapping is not strictly required but could even incur a
      high overhead in some cases.  That said, too huge unmapped areas inside
      the monitoring target should be removed to not take the time for the
      adaptive mechanism.
      
      For the reason, this implementation converts the complex mappings to three
      distinct regions that cover every mapped area of the address space.  Also,
      the two gaps between the three regions are the two biggest unmapped areas
      in the given address space.  The two biggest unmapped areas would be the
      gap between the heap and the uppermost mmap()-ed region, and the gap
      between the lowermost mmap()-ed region and the stack in most of the cases.
      Because these gaps are exceptionally huge in usual address spaces,
      excluding these will be sufficient to make a reasonable trade-off.  Below
      shows this in detail::
      
          <heap>
          <BIG UNMAPPED REGION 1>
          <uppermost mmap()-ed region>
          (small mmap()-ed regions and munmap()-ed regions)
          <lowermost mmap()-ed region>
          <BIG UNMAPPED REGION 2>
          <stack>
      
      [akpm@linux-foundation.org: mm/damon/vaddr.c needs highmem.h for kunmap_atomic()]
      [sjpark@amazon.de: remove unnecessary PAGE_EXTENSION setup]
        Link: https://lkml.kernel.org/r/20210806095153.6444-2-sj38.park@gmail.com
      [sjpark@amazon.de: safely walk page table]
        Link: https://lkml.kernel.org/r/20210831161800.29419-1-sj38.park@gmail.com
      
      Link: https://lkml.kernel.org/r/20210716081449.22187-6-sj38.park@gmail.comSigned-off-by: default avatarSeongJae Park <sjpark@amazon.de>
      Reviewed-by: default avatarLeonard Foerster <foersleo@amazon.de>
      Reviewed-by: default avatarFernand Sieber <sieberf@amazon.com>
      Acked-by: default avatarShakeel Butt <shakeelb@google.com>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Amit Shah <amit@kernel.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Brendan Higgins <brendanhiggins@google.com>
      Cc: David Hildenbrand <david@redhat.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: David Woodhouse <dwmw@amazon.com>
      Cc: Fan Du <fan.du@intel.com>
      Cc: Greg Kroah-Hartman <greg@kroah.com>
      Cc: Greg Thelen <gthelen@google.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Joe Perches <joe@perches.com>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Marco Elver <elver@google.com>
      Cc: Markus Boehme <markubo@amazon.de>
      Cc: Maximilian Heyne <mheyne@amazon.de>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
      Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3f49584b
    • SeongJae Park's avatar
      mm/idle_page_tracking: make PG_idle reusable · 1c676e0d
      SeongJae Park authored
      PG_idle and PG_young allow the two PTE Accessed bit users, Idle Page
      Tracking and the reclaim logic concurrently work while not interfering
      with each other.  That is, when they need to clear the Accessed bit, they
      set PG_young to represent the previous state of the bit, respectively.
      And when they need to read the bit, if the bit is cleared, they further
      read the PG_young to know whether the other has cleared the bit meanwhile
      or not.
      
      For yet another user of the PTE Accessed bit, we could add another page
      flag, or extend the mechanism to use the flags.  For the DAMON usecase,
      however, we don't need to do that just yet.  IDLE_PAGE_TRACKING and DAMON
      are mutually exclusive, so there's only ever going to be one user of the
      current set of flags.
      
      In this commit, we split out the CONFIG options to allow for the use of
      PG_young and PG_idle outside of idle page tracking.
      
      In the next commit, DAMON's reference implementation of the virtual memory
      address space monitoring primitives will use it.
      
      [sjpark@amazon.de: set PAGE_EXTENSION for non-64BIT]
        Link: https://lkml.kernel.org/r/20210806095153.6444-1-sj38.park@gmail.com
      [akpm@linux-foundation.org: tweak Kconfig text]
      [sjpark@amazon.de: hide PAGE_IDLE_FLAG from users]
        Link: https://lkml.kernel.org/r/20210813081238.34705-1-sj38.park@gmail.com
      
      Link: https://lkml.kernel.org/r/20210716081449.22187-5-sj38.park@gmail.comSigned-off-by: default avatarSeongJae Park <sjpark@amazon.de>
      Reviewed-by: default avatarShakeel Butt <shakeelb@google.com>
      Reviewed-by: default avatarFernand Sieber <sieberf@amazon.com>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Amit Shah <amit@kernel.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Brendan Higgins <brendanhiggins@google.com>
      Cc: David Hildenbrand <david@redhat.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: David Woodhouse <dwmw@amazon.com>
      Cc: Fan Du <fan.du@intel.com>
      Cc: Greg Kroah-Hartman <greg@kroah.com>
      Cc: Greg Thelen <gthelen@google.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Joe Perches <joe@perches.com>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Leonard Foerster <foersleo@amazon.de>
      Cc: Marco Elver <elver@google.com>
      Cc: Markus Boehme <markubo@amazon.de>
      Cc: Maximilian Heyne <mheyne@amazon.de>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
      Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      1c676e0d
    • SeongJae Park's avatar
      mm/damon: adaptively adjust regions · b9a6ac4e
      SeongJae Park authored
      Even somehow the initial monitoring target regions are well constructed to
      fulfill the assumption (pages in same region have similar access
      frequencies), the data access pattern can be dynamically changed.  This
      will result in low monitoring quality.  To keep the assumption as much as
      possible, DAMON adaptively merges and splits each region based on their
      access frequency.
      
      For each ``aggregation interval``, it compares the access frequencies of
      adjacent regions and merges those if the frequency difference is small.
      Then, after it reports and clears the aggregated access frequency of each
      region, it splits each region into two or three regions if the total
      number of regions will not exceed the user-specified maximum number of
      regions after the split.
      
      In this way, DAMON provides its best-effort quality and minimal overhead
      while keeping the upper-bound overhead that users set.
      
      Link: https://lkml.kernel.org/r/20210716081449.22187-4-sj38.park@gmail.comSigned-off-by: default avatarSeongJae Park <sjpark@amazon.de>
      Reviewed-by: default avatarLeonard Foerster <foersleo@amazon.de>
      Reviewed-by: default avatarFernand Sieber <sieberf@amazon.com>
      Acked-by: default avatarShakeel Butt <shakeelb@google.com>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Amit Shah <amit@kernel.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Brendan Higgins <brendanhiggins@google.com>
      Cc: David Hildenbrand <david@redhat.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: David Woodhouse <dwmw@amazon.com>
      Cc: Fan Du <fan.du@intel.com>
      Cc: Greg Kroah-Hartman <greg@kroah.com>
      Cc: Greg Thelen <gthelen@google.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Joe Perches <joe@perches.com>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Marco Elver <elver@google.com>
      Cc: Markus Boehme <markubo@amazon.de>
      Cc: Maximilian Heyne <mheyne@amazon.de>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
      Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b9a6ac4e
    • SeongJae Park's avatar
      mm/damon/core: implement region-based sampling · f23b8eee
      SeongJae Park authored
      To avoid the unbounded increase of the overhead, DAMON groups adjacent
      pages that are assumed to have the same access frequencies into a
      region.  As long as the assumption (pages in a region have the same
      access frequencies) is kept, only one page in the region is required to
      be checked.  Thus, for each ``sampling interval``,
      
       1. the 'prepare_access_checks' primitive picks one page in each region,
       2. waits for one ``sampling interval``,
       3. checks whether the page is accessed meanwhile, and
       4. increases the access count of the region if so.
      
      Therefore, the monitoring overhead is controllable by adjusting the
      number of regions.  DAMON allows both the underlying primitives and user
      callbacks to adjust regions for the trade-off.  In other words, this
      commit makes DAMON to use not only time-based sampling but also
      space-based sampling.
      
      This scheme, however, cannot preserve the quality of the output if the
      assumption is not guaranteed.  Next commit will address this problem.
      
      Link: https://lkml.kernel.org/r/20210716081449.22187-3-sj38.park@gmail.comSigned-off-by: default avatarSeongJae Park <sjpark@amazon.de>
      Reviewed-by: default avatarLeonard Foerster <foersleo@amazon.de>
      Reviewed-by: default avatarFernand Sieber <sieberf@amazon.com>
      Acked-by: default avatarShakeel Butt <shakeelb@google.com>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Amit Shah <amit@kernel.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Brendan Higgins <brendanhiggins@google.com>
      Cc: David Hildenbrand <david@redhat.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: David Woodhouse <dwmw@amazon.com>
      Cc: Fan Du <fan.du@intel.com>
      Cc: Greg Kroah-Hartman <greg@kroah.com>
      Cc: Greg Thelen <gthelen@google.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Joe Perches <joe@perches.com>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Marco Elver <elver@google.com>
      Cc: Markus Boehme <markubo@amazon.de>
      Cc: Maximilian Heyne <mheyne@amazon.de>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
      Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f23b8eee
    • SeongJae Park's avatar
      mm: introduce Data Access MONitor (DAMON) · 2224d848
      SeongJae Park authored
      Patch series "Introduce Data Access MONitor (DAMON)", v34.
      
      Introduction
      ============
      
      DAMON is a data access monitoring framework for the Linux kernel.  The
      core mechanisms of DAMON called 'region based sampling' and 'adaptive
      regions adjustment' (refer to 'mechanisms.rst' in the 11th patch of this
      patchset for the detail) make it
      
      - accurate (The monitored information is useful for DRAM level memory
        management.  It might not appropriate for Cache-level accuracy,
        though.),
      
      - light-weight (The monitoring overhead is low enough to be applied
        online while making no impact on the performance of the target
        workloads.), and
      
      - scalable (the upper-bound of the instrumentation overhead is
        controllable regardless of the size of target workloads.).
      
      Using this framework, therefore, several memory management mechanisms such
      as reclamation and THP can be optimized to aware real data access
      patterns.  Experimental access pattern aware memory management
      optimization works that incurring high instrumentation overhead will be
      able to have another try.
      
      Though DAMON is for kernel subsystems, it can be easily exposed to the
      user space by writing a DAMON-wrapper kernel subsystem.  Then, user space
      users who have some special workloads will be able to write personalized
      tools or applications for deeper understanding and specialized
      optimizations of their systems.
      
      DAMON is also merged in two public Amazon Linux kernel trees that based on
      v5.4.y[1] and v5.10.y[2].
      
      [1] https://github.com/amazonlinux/linux/tree/amazon-5.4.y/master/mm/damon
      [2] https://github.com/amazonlinux/linux/tree/amazon-5.10.y/master/mm/damon
      
      The userspace tool[1] is available, released under GPLv2, and actively
      being maintained.  I am also planning to implement another basic user
      interface in perf[2].  Also, the basic test suite for DAMON is available
      under GPLv2[3].
      
      [1] https://github.com/awslabs/damo
      [2] https://lore.kernel.org/linux-mm/20210107120729.22328-1-sjpark@amazon.com/
      [3] https://github.com/awslabs/damon-tests
      
      Long-term Plan
      --------------
      
      DAMON is a part of a project called Data Access-aware Operating System
      (DAOS).  As the name implies, I want to improve the performance and
      efficiency of systems using fine-grained data access patterns.  The
      optimizations are for both kernel and user spaces.  I will therefore
      modify or create kernel subsystems, export some of those to user space and
      implement user space library / tools.  Below shows the layers and
      components for the project.
      
          ---------------------------------------------------------------------------
          Primitives:     PTE Accessed bit, PG_idle, rmap, (Intel CMT), ...
          Framework:      DAMON
          Features:       DAMOS, virtual addr, physical addr, ...
          Applications:   DAMON-debugfs, (DARC), ...
          ^^^^^^^^^^^^^^^^^^^^^^^    KERNEL SPACE    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      
          Raw Interface:  debugfs, (sysfs), (damonfs), tracepoints, (sys_damon), ...
      
          vvvvvvvvvvvvvvvvvvvvvvv    USER SPACE      vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
          Library:        (libdamon), ...
          Tools:          DAMO, (perf), ...
          ---------------------------------------------------------------------------
      
      The components in parentheses or marked as '...' are not implemented yet
      but in the future plan.  IOW, those are the TODO tasks of DAOS project.
      For more detail, please refer to the plans:
      https://lore.kernel.org/linux-mm/20201202082731.24828-1-sjpark@amazon.com/
      
      Evaluations
      ===========
      
      We evaluated DAMON's overhead, monitoring quality and usefulness using 24
      realistic workloads on my QEMU/KVM based virtual machine running a kernel
      that v24 DAMON patchset is applied.
      
      DAMON is lightweight.  It increases system memory usage by 0.39% and slows
      target workloads down by 1.16%.
      
      DAMON is accurate and useful for memory management optimizations.  An
      experimental DAMON-based operation scheme for THP, namely 'ethp', removes
      76.15% of THP memory overheads while preserving 51.25% of THP speedup.
      Another experimental DAMON-based 'proactive reclamation' implementation,
      'prcl', reduces 93.38% of residential sets and 23.63% of system memory
      footprint while incurring only 1.22% runtime overhead in the best case
      (parsec3/freqmine).
      
      NOTE that the experimental THP optimization and proactive reclamation are
      not for production but only for proof of concepts.
      
      Please refer to the official document[1] or "Documentation/admin-guide/mm:
      Add a document for DAMON" patch in this patchset for detailed evaluation
      setup and results.
      
      [1] https://damonitor.github.io/doc/html/latest-damon/admin-guide/mm/damon/eval.html
      
      Real-world User Story
      =====================
      
      In summary, DAMON has used on production systems and proved its usefulness.
      
      DAMON as a profiler
      -------------------
      
      We analyzed characteristics of a large scale production systems of our
      customers using DAMON.  The systems utilize 70GB DRAM and 36 CPUs.  From
      this, we were able to find interesting things below.
      
      There were obviously different access pattern under idle workload and
      active workload.  Under the idle workload, it accessed large memory
      regions with low frequency, while the active workload accessed small
      memory regions with high freuqnecy.
      
      DAMON found a 7GB memory region that showing obviously high access
      frequency under the active workload.  We believe this is the
      performance-effective working set and need to be protected.
      
      There was a 4KB memory region that showing highest access frequency under
      not only active but also idle workloads.  We think this must be a hottest
      code section like thing that should never be paged out.
      
      For this analysis, DAMON used only 0.3-1% of single CPU time.  Because we
      used recording-based analysis, it consumed about 3-12 MB of disk space per
      20 minutes.  This is only small amount of disk space, but we can further
      reduce the disk usage by using non-recording-based DAMON features.  I'd
      like to argue that only DAMON can do such detailed analysis (finding 4KB
      highest region in 70GB memory) with the light overhead.
      
      DAMON as a system optimization tool
      -----------------------------------
      
      We also found below potential performance problems on the systems and made
      DAMON-based solutions.
      
      The system doesn't want to make the workload suffer from the page
      reclamation and thus it utilizes enough DRAM but no swap device.  However,
      we found the system is actively reclaiming file-backed pages, because the
      system has intensive file IO.  The file IO turned out to be not
      performance critical for the workload, but the customer wanted to ensure
      performance critical file-backed pages like code section to not mistakenly
      be evicted.
      
      Using direct IO should or `mlock()` would be a straightforward solution,
      but modifying the user space code is not easy for the customer.
      Alternatively, we could use DAMON-based operation scheme[1].  By using it,
      we can ask DAMON to track access frequency of each region and make
      'process_madvise(MADV_WILLNEED)[2]' call for regions having specific size
      and access frequency for a time interval.
      
      We also found the system is having high number of TLB misses.  We tried
      'always' THP enabled policy and it greatly reduced TLB misses, but the
      page reclamation also been more frequent due to the THP internal
      fragmentation caused memory bloat.  We could try another DAMON-based
      operation scheme that applies 'MADV_HUGEPAGE' to memory regions having
      >=2MB size and high access frequency, while applying 'MADV_NOHUGEPAGE' to
      regions having <2MB size and low access frequency.
      
      We do not own the systems so we only reported the analysis results and
      possible optimization solutions to the customers.  The customers satisfied
      about the analysis results and promised to try the optimization guides.
      
      [1] https://lore.kernel.org/linux-mm/20201006123931.5847-1-sjpark@amazon.com/
      [2] https://lore.kernel.org/linux-api/20200622192900.22757-4-minchan@kernel.org/
      
      Comparison with Idle Page Tracking
      ==================================
      
      Idle Page Tracking allows users to set and read idleness of pages using a
      bitmap file which represents each page with each bit of the file.  One
      recommended usage of it is working set size detection.  Users can do that
      by
      
          1. find PFN of each page for workloads in interest,
          2. set all the pages as idle by doing writes to the bitmap file,
          3. wait until the workload accesses its working set, and
          4. read the idleness of the pages again and count pages became not idle.
      
      NOTE: While Idle Page Tracking is for user space users, DAMON is primarily
      designed for kernel subsystems though it can easily exposed to the user
      space.  Hence, this section only assumes such user space use of DAMON.
      
      For what use cases Idle Page Tracking would be better?
      ------------------------------------------------------
      
      1. Flexible usecases other than hotness monitoring.
      
      Because Idle Page Tracking allows users to control the primitive (Page
      idleness) by themselves, Idle Page Tracking users can do anything they
      want.  Meanwhile, DAMON is primarily designed to monitor the hotness of
      each memory region.  For this, DAMON asks users to provide sampling
      interval and aggregation interval.  For the reason, there could be some
      use case that using Idle Page Tracking is simpler.
      
      2. Physical memory monitoring.
      
      Idle Page Tracking receives PFN range as input, so natively supports
      physical memory monitoring.
      
      DAMON is designed to be extensible for multiple address spaces and use
      cases by implementing and using primitives for the given use case.
      Therefore, by theory, DAMON has no limitation in the type of target
      address space as long as primitives for the given address space exists.
      However, the default primitives introduced by this patchset supports only
      virtual address spaces.
      
      Therefore, for physical memory monitoring, you should implement your own
      primitives and use it, or simply use Idle Page Tracking.
      
      Nonetheless, RFC patchsets[1] for the physical memory address space
      primitives is already available.  It also supports user memory same to
      Idle Page Tracking.
      
      [1] https://lore.kernel.org/linux-mm/20200831104730.28970-1-sjpark@amazon.com/
      
      For what use cases DAMON is better?
      -----------------------------------
      
      1. Hotness Monitoring.
      
      Idle Page Tracking let users know only if a page frame is accessed or not.
      For hotness check, the user should write more code and use more memory.
      DAMON do that by itself.
      
      2. Low Monitoring Overhead
      
      DAMON receives user's monitoring request with one step and then provide
      the results.  So, roughly speaking, DAMON require only O(1) user/kernel
      context switches.
      
      In case of Idle Page Tracking, however, because the interface receives
      contiguous page frames, the number of user/kernel context switches
      increases as the monitoring target becomes complex and huge.  As a result,
      the context switch overhead could be not negligible.
      
      Moreover, DAMON is born to handle with the monitoring overhead.  Because
      the core mechanism is pure logical, Idle Page Tracking users might be able
      to implement the mechanism on their own, but it would be time consuming
      and the user/kernel context switching will still more frequent than that
      of DAMON.  Also, the kernel subsystems cannot use the logic in this case.
      
      3. Page granularity working set size detection.
      
      Until v22 of this patchset, this was categorized as the thing Idle Page
      Tracking could do better, because DAMON basically maintains additional
      metadata for each of the monitoring target regions.  So, in the page
      granularity working set size detection use case, DAMON would incur (number
      of monitoring target pages * size of metadata) memory overhead.  Size of
      the single metadata item is about 54 bytes, so assuming 4KB pages, about
      1.3% of monitoring target pages will be additionally used.
      
      All essential metadata for Idle Page Tracking are embedded in 'struct
      page' and page table entries.  Therefore, in this use case, only one
      counter variable for working set size accounting is required if Idle Page
      Tracking is used.
      
      There are more details to consider, but roughly speaking, this is true in
      most cases.
      
      However, the situation changed from v23.  Now DAMON supports arbitrary
      types of monitoring targets, which don't use the metadata.  Using that,
      DAMON can do the working set size detection with no additional space
      overhead but less user-kernel context switch.  A first draft for the
      implementation of monitoring primitives for this usage is available in a
      DAMON development tree[1].  An RFC patchset for it based on this patchset
      will also be available soon.
      
      Since v24, the arbitrary type support is dropped from this patchset
      because this patchset doesn't introduce real use of the type.  You can
      still get it from the DAMON development tree[2], though.
      
      [1] https://github.com/sjp38/linux/tree/damon/pgidle_hack
      [2] https://github.com/sjp38/linux/tree/damon/master
      
      4. More future usecases
      
      While Idle Page Tracking has tight coupling with base primitives (PG_Idle
      and page table Accessed bits), DAMON is designed to be extensible for many
      use cases and address spaces.  If you need some special address type or
      want to use special h/w access check primitives, you can write your own
      primitives for that and configure DAMON to use those.  Therefore, if your
      use case could be changed a lot in future, using DAMON could be better.
      
      Can I use both Idle Page Tracking and DAMON?
      --------------------------------------------
      
      Yes, though using them concurrently for overlapping memory regions could
      result in interference to each other.  Nevertheless, such use case would
      be rare or makes no sense at all.  Even in the case, the noise would bot
      be really significant.  So, you can choose whatever you want depending on
      the characteristics of your use cases.
      
      More Information
      ================
      
      We prepared a showcase web site[1] that you can get more information.
      There are
      
      - the official documentations[2],
      - the heatmap format dynamic access pattern of various realistic workloads for
        heap area[3], mmap()-ed area[4], and stack[5] area,
      - the dynamic working set size distribution[6] and chronological working set
        size changes[7], and
      - the latest performance test results[8].
      
      [1] https://damonitor.github.io/_index
      [2] https://damonitor.github.io/doc/html/latest-damon
      [3] https://damonitor.github.io/test/result/visual/latest/rec.heatmap.0.png.html
      [4] https://damonitor.github.io/test/result/visual/latest/rec.heatmap.1.png.html
      [5] https://damonitor.github.io/test/result/visual/latest/rec.heatmap.2.png.html
      [6] https://damonitor.github.io/test/result/visual/latest/rec.wss_sz.png.html
      [7] https://damonitor.github.io/test/result/visual/latest/rec.wss_time.png.html
      [8] https://damonitor.github.io/test/result/perf/latest/html/index.html
      
      Baseline and Complete Git Trees
      ===============================
      
      The patches are based on the latest -mm tree, specifically
      v5.14-rc1-mmots-2021-07-15-18-47 of https://github.com/hnaz/linux-mm.  You can
      also clone the complete git tree:
      
          $ git clone git://github.com/sjp38/linux -b damon/patches/v34
      
      The web is also available:
      https://github.com/sjp38/linux/releases/tag/damon/patches/v34
      
      Development Trees
      -----------------
      
      There are a couple of trees for entire DAMON patchset series and features
      for future release.
      
      - For latest release: https://github.com/sjp38/linux/tree/damon/master
      - For next release: https://github.com/sjp38/linux/tree/damon/next
      
      Long-term Support Trees
      -----------------------
      
      For people who want to test DAMON but using LTS kernels, there are another
      couple of trees based on two latest LTS kernels respectively and
      containing the 'damon/master' backports.
      
      - For v5.4.y: https://github.com/sjp38/linux/tree/damon/for-v5.4.y
      - For v5.10.y: https://github.com/sjp38/linux/tree/damon/for-v5.10.y
      
      Amazon Linux Kernel Trees
      -------------------------
      
      DAMON is also merged in two public Amazon Linux kernel trees that based on
      v5.4.y[1] and v5.10.y[2].
      
      [1] https://github.com/amazonlinux/linux/tree/amazon-5.4.y/master/mm/damon
      [2] https://github.com/amazonlinux/linux/tree/amazon-5.10.y/master/mm/damon
      
      Git Tree for Diff of Patches
      ============================
      
      For easy review of diff between different versions of each patch, I
      prepared a git tree containing all versions of the DAMON patchset series:
      https://github.com/sjp38/damon-patches
      
      You can clone it and use 'diff' for easy review of changes between
      different versions of the patchset.  For example:
      
          $ git clone https://github.com/sjp38/damon-patches && cd damon-patches
          $ diff -u damon/v33 damon/v34
      
      Sequence Of Patches
      ===================
      
      First three patches implement the core logics of DAMON.  The 1st patch
      introduces basic sampling based hotness monitoring for arbitrary types of
      targets.  Following two patches implement the core mechanisms for control
      of overhead and accuracy, namely regions based sampling (patch 2) and
      adaptive regions adjustment (patch 3).
      
      Now the essential parts of DAMON is complete, but it cannot work unless
      someone provides monitoring primitives for a specific use case.  The
      following two patches make it just work for virtual address spaces
      monitoring.  The 4th patch makes 'PG_idle' can be used by DAMON and the
      5th patch implements the virtual memory address space specific monitoring
      primitives using page table Accessed bits and the 'PG_idle' page flag.
      
      Now DAMON just works for virtual address space monitoring via the kernel
      space api.  To let the user space users can use DAMON, following four
      patches add interfaces for them.  The 6th patch adds a tracepoint for
      monitoring results.  The 7th patch implements a DAMON application kernel
      module, namely damon-dbgfs, that simply wraps DAMON and exposes DAMON
      interface to the user space via the debugfs interface.  The 8th patch
      further exports pid of monitoring thread (kdamond) to user space for
      easier cpu usage accounting, and the 9th patch makes the debugfs interface
      to support multiple contexts.
      
      Three patches for maintainability follows.  The 10th patch adds
      documentations for both the user space and the kernel space.  The 11th
      patch provides unit tests (based on the kunit) while the 12th patch adds
      user space tests (based on the kselftest).
      
      Finally, the last patch (13th) updates the MAINTAINERS file.
      
      This patch (of 13):
      
      DAMON is a data access monitoring framework for the Linux kernel.  The
      core mechanisms of DAMON make it
      
       - accurate (the monitoring output is useful enough for DRAM level
         performance-centric memory management; It might be inappropriate for
         CPU cache levels, though),
       - light-weight (the monitoring overhead is normally low enough to be
         applied online), and
       - scalable (the upper-bound of the overhead is in constant range
         regardless of the size of target workloads).
      
      Using this framework, hence, we can easily write efficient kernel space
      data access monitoring applications.  For example, the kernel's memory
      management mechanisms can make advanced decisions using this.
      Experimental data access aware optimization works that incurring high
      access monitoring overhead could again be implemented on top of this.
      
      Due to its simple and flexible interface, providing user space interface
      would be also easy.  Then, user space users who have some special
      workloads can write personalized applications for better understanding and
      optimizations of their workloads and systems.
      
      ===
      
      Nevertheless, this commit is defining and implementing only basic access
      check part without the overhead-accuracy handling core logic.  The basic
      access check is as below.
      
      The output of DAMON says what memory regions are how frequently accessed
      for a given duration.  The resolution of the access frequency is
      controlled by setting ``sampling interval`` and ``aggregation interval``.
      In detail, DAMON checks access to each page per ``sampling interval`` and
      aggregates the results.  In other words, counts the number of the accesses
      to each region.  After each ``aggregation interval`` passes, DAMON calls
      callback functions that previously registered by users so that users can
      read the aggregated results and then clears the results.  This can be
      described in below simple pseudo-code::
      
          init()
          while monitoring_on:
              for page in monitoring_target:
                  if accessed(page):
                      nr_accesses[page] += 1
              if time() % aggregation_interval == 0:
                  for callback in user_registered_callbacks:
                      callback(monitoring_target, nr_accesses)
                  for page in monitoring_target:
                      nr_accesses[page] = 0
              if time() % update_interval == 0:
                  update()
              sleep(sampling interval)
      
      The target regions constructed at the beginning of the monitoring and
      updated after each ``regions_update_interval``, because the target regions
      could be dynamically changed (e.g., mmap() or memory hotplug).  The
      monitoring overhead of this mechanism will arbitrarily increase as the
      size of the target workload grows.
      
      The basic monitoring primitives for actual access check and dynamic target
      regions construction aren't in the core part of DAMON.  Instead, it allows
      users to implement their own primitives that are optimized for their use
      case and configure DAMON to use those.  In other words, users cannot use
      current version of DAMON without some additional works.
      
      Following commits will implement the core mechanisms for the
      overhead-accuracy control and default primitives implementations.
      
      Link: https://lkml.kernel.org/r/20210716081449.22187-1-sj38.park@gmail.com
      Link: https://lkml.kernel.org/r/20210716081449.22187-2-sj38.park@gmail.comSigned-off-by: default avatarSeongJae Park <sjpark@amazon.de>
      Reviewed-by: default avatarLeonard Foerster <foersleo@amazon.de>
      Reviewed-by: default avatarFernand Sieber <sieberf@amazon.com>
      Acked-by: default avatarShakeel Butt <shakeelb@google.com>
      Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Amit Shah <amit@kernel.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: David Hildenbrand <david@redhat.com>
      Cc: David Woodhouse <dwmw@amazon.com>
      Cc: Marco Elver <elver@google.com>
      Cc: Fan Du <fan.du@intel.com>
      Cc: Greg Kroah-Hartman <greg@kroah.com>
      Cc: Greg Thelen <gthelen@google.com>
      Cc: Joe Perches <joe@perches.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Maximilian Heyne <mheyne@amazon.de>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
      Cc: Brendan Higgins <brendanhiggins@google.com>
      Cc: Markus Boehme <markubo@amazon.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2224d848
    • Marco Elver's avatar
      kfence: test: fail fast if disabled at boot · c40c6e59
      Marco Elver authored
      Fail kfence_test fast if KFENCE was disabled at boot, instead of each test
      case trying several seconds to allocate from KFENCE and failing.  KUnit
      will fail all test cases if kunit_suite::init returns an error.
      
      Even if KFENCE was disabled, we still want the test to fail, so that CI
      systems that parse KUnit output will alert on KFENCE being disabled
      (accidentally or otherwise).
      
      Link: https://lkml.kernel.org/r/20210825105533.1247922-1-elver@google.comSigned-off-by: default avatarMarco Elver <elver@google.com>
      Reported-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
      Tested-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
      Acked-by: default avatarAlexander Potapenko <glider@google.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c40c6e59
    • Marco Elver's avatar
      kfence: show cpu and timestamp in alloc/free info · 4bbf04aa
      Marco Elver authored
      Record cpu and timestamp on allocations and frees, and show them in
      reports.  Upon an error, this can help correlate earlier messages in the
      kernel log via allocation and free timestamps.
      
      Link: https://lkml.kernel.org/r/20210714175312.2947941-1-elver@google.comSuggested-by: default avatarJoern Engel <joern@purestorage.com>
      Signed-off-by: default avatarMarco Elver <elver@google.com>
      Acked-by: default avatarAlexander Potapenko <glider@google.com>
      Acked-by: default avatarJoern Engel <joern@purestorage.com>
      Cc: Yuanyuan Zhong <yzhong@purestorage.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4bbf04aa
    • Jordy Zomer's avatar
      mm/secretmem: use refcount_t instead of atomic_t · 11086054
      Jordy Zomer authored
      When a secret memory region is active, memfd_secret disables hibernation.
      One of the goals is to keep the secret data from being written to
      persistent-storage.
      
      It accomplishes this by maintaining a reference count to
      `secretmem_users`.  Once this reference is held your system can not be
      hibernated due to the check in `hibernation_available()`.  However,
      because `secretmem_users` is of type `atomic_t`, reference counter
      overflows are possible.
      
      As you can see there's an `atomic_inc` for each `memfd` that is opened in
      the `memfd_secret` syscall.  If a local attacker succeeds to open 2^32
      memfd's, the counter will wrap around to 0.  This implies that you may
      hibernate again, even though there are still regions of this secret
      memory, thereby bypassing the security check.
      
      In an attempt to fix this I have used `refcount_t` instead of `atomic_t`
      which prevents reference counter overflows.
      
      Link: https://lkml.kernel.org/r/20210820043339.2151352-1-jordy@pwning.systemsSigned-off-by: default avatarJordy Zomer <jordy@pwning.systems>
      Cc: Kees Cook <keescook@chromium.org>,
      Cc: Jordy Zomer <jordy@jordyzomer.github.io>
      Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
      Cc: Mike Rapoport <rppt@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      11086054
    • Muchun Song's avatar
      mm: introduce PAGEFLAGS_MASK to replace ((1UL << NR_PAGEFLAGS) - 1) · 41c961b9
      Muchun Song authored
      Instead of hard-coding ((1UL << NR_PAGEFLAGS) - 1) everywhere, introducing
      PAGEFLAGS_MASK to make the code clear to get the page flags.
      
      Link: https://lkml.kernel.org/r/20210819150712.59948-1-songmuchun@bytedance.comSigned-off-by: default avatarMuchun Song <songmuchun@bytedance.com>
      Reviewed-by: default avatarRoman Gushchin <guro@fb.com>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Reviewed-by: default avatarShakeel Butt <shakeelb@google.com>
      Cc: Michal Hocko <mhocko@kernel.org>
      Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
      Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      41c961b9
    • Changbin Du's avatar
      mm: in_irq() cleanup · ea0eafea
      Changbin Du authored
      Replace the obsolete and ambiguos macro in_irq() with new macro
      in_hardirq().
      
      Link: https://lkml.kernel.org/r/20210813145245.86070-1-changbin.du@gmail.comSigned-off-by: default avatarChangbin Du <changbin.du@gmail.com>
      Acked-by: Catalin Marinas <catalin.marinas@arm.com>	[kmemleak]
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ea0eafea
    • Sebastian Andrzej Siewior's avatar
      highmem: don't disable preemption on RT in kmap_atomic() · 51386120
      Sebastian Andrzej Siewior authored
      kmap_atomic() disables preemption and pagefaults for historical reasons.
      The conversion to kmap_local(), which only disables migration, cannot be
      done wholesale because quite some call sites need to be updated to
      accommodate with the changed semantics.
      
      On PREEMPT_RT enabled kernels the kmap_atomic() semantics are problematic
      due to the implicit disabling of preemption which makes it impossible to
      acquire 'sleeping' spinlocks within the kmap atomic sections.
      
      PREEMPT_RT replaces the preempt_disable() with a migrate_disable() for
      more than a decade.  It could be argued that this is a justification to do
      this unconditionally, but PREEMPT_RT covers only a limited number of
      architectures and it disables some functionality which limits the coverage
      further.
      
      Limit the replacement to PREEMPT_RT for now.
      
      Link: https://lkml.kernel.org/r/20210810091116.pocdmaatdcogvdso@linutronix.deSigned-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      51386120