- 04 Jan, 2019 40 commits
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Qian Cai authored
unreferenced object 0xffff808ec6dc5a80 (size 128): comm "swapper/0", pid 1, jiffies 4294938063 (age 2560.530s) hex dump (first 32 bytes): ff ff ff ff 00 00 00 00 6b 6b 6b 6b 6b 6b 6b 6b ........kkkkkkkk 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk backtrace: [<00000000476dcf8c>] kmem_cache_alloc_trace+0x430/0x500 [<000000004f708d37>] platform_device_register_full+0xbc/0x1e8 [<000000006c2a7ec7>] acpi_create_platform_device+0x370/0x450 [<00000000ef135642>] acpi_default_enumeration+0x34/0x78 [<000000003bd9a052>] acpi_bus_attach+0x2dc/0x3e0 [<000000003cf4f7f2>] acpi_bus_attach+0x108/0x3e0 [<000000003cf4f7f2>] acpi_bus_attach+0x108/0x3e0 [<000000002968643e>] acpi_bus_scan+0xb0/0x110 [<0000000010dd0bd7>] acpi_scan_init+0x1a8/0x410 [<00000000965b3c5a>] acpi_init+0x408/0x49c [<00000000ed4b9fe2>] do_one_initcall+0x178/0x7f4 [<00000000a5ac5a74>] kernel_init_freeable+0x9d4/0xa9c [<0000000070ea6c15>] kernel_init+0x18/0x138 [<00000000fb8fff06>] ret_from_fork+0x10/0x1c [<0000000041273a0d>] 0xffffffffffffffff Then, faddr2line pointed out this line, /* * This memory isn't freed when the device is put, * I don't have a nice idea for that though. Conceptually * dma_mask in struct device should not be a pointer. * See http://thread.gmane.org/gmane.linux.kernel.pci/9081 */ pdev->dev.dma_mask = kmalloc(sizeof(*pdev->dev.dma_mask), GFP_KERNEL); Since this leak has existed for more than 8 years and it does not reference other parts of the memory, let kmemleak ignore it, so users don't need to waste time reporting this in the future. Link: http://lkml.kernel.org/r/20181206160751.36211-1-cai@gmx.usSigned-off-by:Qian Cai <cai@gmx.us> Reviewed-by:
Andrew Morton <akpm@linux-foundation.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J . Wysocki" <rafael.j.wysocki@intel.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Nikolay Borisov authored
Multiple filesystems open code lru_to_page(). Rectify this by moving the macro from mm_inline (which is specific to lru stuff) to the more generic mm.h header and start using the macro where appropriate. No functional changes. Link: http://lkml.kernel.org/r/20181129104810.23361-1-nborisov@suse.com Link: https://lkml.kernel.org/r/20181129075301.29087-1-nborisov@suse.comSigned-off-by:
Nikolay Borisov <nborisov@suse.com> Acked-by:
Michal Hocko <mhocko@suse.com> Reviewed-by:
David Hildenbrand <david@redhat.com> Reviewed-by:
Mike Rapoport <rppt@linux.ibm.com> Acked-by:
Pankaj gupta <pagupta@redhat.com> Acked-by: "Yan, Zheng" <zyan@redhat.com> [ceph] Signed-off-by:
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Davidlohr Bueso authored
This is already done for us internally by the signal machinery. [akpm@linux-foundation.org: fix fs/buffer.c] Link: http://lkml.kernel.org/r/20181116002713.8474-7-dave@stgolabs.netSigned-off-by:
Davidlohr Bueso <dave@stgolabs.net> Reviewed-by:
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Davidlohr Bueso authored
This is already done for us internally by the signal machinery. Link: http://lkml.kernel.org/r/20181116002713.8474-5-dave@stgolabs.netSigned-off-by:
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Davidlohr Bueso authored
This is already done for us internally by the signal machinery. Link: http://lkml.kernel.org/r/20181116002713.8474-4-dave@stgolabs.netSigned-off-by:
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Davidlohr Bueso authored
This is already done for us internally by the signal machinery. Link: http://lkml.kernel.org/r/20181116002713.8474-3-dave@stgolabs.netSigned-off-by:
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Davidlohr Bueso authored
This is already done for us internally by the signal machinery. Link: http://lkml.kernel.org/r/20181116002713.8474-2-dave@stgolabs.netSigned-off-by:
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Joel Fernandes (Google) authored
Moving page-tables at the PMD-level on x86 is known to be safe. Enable this option so that we can do fast mremap when possible. Link: http://lkml.kernel.org/r/20181108181201.88826-4-joelaf@google.comSigned-off-by:
Joel Fernandes (Google) <joel@joelfernandes.org> Suggested-by:
Kirill A. Shutemov <kirill@shutemov.name> Acked-by:
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Joel Fernandes (Google) authored
Android needs to mremap large regions of memory during memory management related operations. The mremap system call can be really slow if THP is not enabled. The bottleneck is move_page_tables, which is copying each pte at a time, and can be really slow across a large map. Turning on THP may not be a viable option, and is not for us. This patch speeds up the performance for non-THP system by copying at the PMD level when possible. The speedup is an order of magnitude on x86 (~20x). On a 1GB mremap, the mremap completion times drops from 3.4-3.6 milliseconds to 144-160 microseconds. Before: Total mremap time for 1GB data: 3521942 nanoseconds. Total mremap time for 1GB data: 3449229 nanoseconds. Total mremap time for 1GB data: 3488230 nanoseconds. After: Total mremap time for 1GB data: 150279 nanoseconds. Total mremap time for 1GB data: 144665 nanoseconds. Total mremap time for 1GB data: 158708 nanoseconds. If THP is enabled the optimization is mostly skipped except in certain situations. [joel@joelfernandes.org: fix 'move_normal_pmd' unused function warning] Link: http://lkml.kernel.org/r/20181108224457.GB209347@google.com Link: http://lkml.kernel.org/r/20181108181201.88826-3-joelaf@google.comSigned-off-by:
William Kucharski <william.kucharski@oracle.com> Cc: Julia Lawall <Julia.Lawall@lip6.fr> Cc: Michal Hocko <mhocko@kernel.org> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by:
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Joel Fernandes (Google) authored
Patch series "Add support for fast mremap". This series speeds up the mremap(2) syscall by copying page tables at the PMD level even for non-THP systems. There is concern that the extra 'address' argument that mremap passes to pte_alloc may do something subtle architecture related in the future that may make the scheme not work. Also we find that there is no point in passing the 'address' to pte_alloc since its unused. This patch therefore removes this argument tree-wide resulting in a nice negative diff as well. Also ensuring along the way that the enabled architectures do not do anything funky with the 'address' argument that goes unnoticed by the optimization. Build and boot tested on x86-64. Build tested on arm64. The config enablement patch for arm64 will be posted in the future after more testing. The changes were obtained by applying the following Coccinelle script. (thanks Julia for answering all Coccinelle questions!). Following fix ups were done manually: * Removal of address argument from pte_fragment_alloc * Removal of pte_alloc_one_fast definitions from m68k and microblaze. // Options: --include-headers --no-includes // Note: I split the 'identifier fn' line, so if you are manually // running it, please unsplit it so it runs for you. virtual patch @pte_alloc_func_def depends on patch exists@ identifier E2; identifier fn =~ "^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$"; type T2; @@ fn(... - , T2 E2 ) { ... } @pte_alloc_func_proto_noarg depends on patch exists@ type T1, T2, T3, T4; identifier fn =~ "^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$"; @@ ( - T3 fn(T1, T2); + T3 fn(T1); | - T3 fn(T1, T2, T4); + T3 fn(T1, T2); ) @pte_alloc_func_proto depends on patch exists@ identifier E1, E2, E4; type T1, T2, T3, T4; identifier fn =~ "^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$"; @@ ( - T3 fn(T1 E1, T2 E2); + T3 fn(T1 E1); | - T3 fn(T1 E1, T2 E2, T4 E4); + T3 fn(T1 E1, T2 E2); ) @pte_alloc_func_call depends on patch exists@ expression E2; identifier fn =~ "^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$"; @@ fn(... -, E2 ) @pte_alloc_macro depends on patch exists@ identifier fn =~ "^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$"; identifier a, b, c; expression e; position p; @@ ( - #define fn(a, b, c) e + #define fn(a, b) e | - #define fn(a, b) e + #define fn(a) e ) Link: http://lkml.kernel.org/r/20181108181201.88826-2-joelaf@google.comSigned-off-by: -
David Engraf authored
Unpacking an external initrd may fail e.g. not enough memory. This leads to an incomplete rootfs because some files might be extracted already. Fixed by cleaning the rootfs so the kernel is not using an incomplete rootfs. Link: http://lkml.kernel.org/r/20181030151805.5519-1-david.engraf@sysgo.comSigned-off-by:
David Engraf <david.engraf@sysgo.com> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> Signed-off-by:
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Du Changbin authored
A bug is present in GDB which causes early string termination when parsing variables. This has been reported [0], but we should ensure that we can support at least basic printing of the core kernel strings. For current gdb version (has been tested with 7.3 and 8.1), 'lx-version' only prints one character. (gdb) lx-version L(gdb) This can be fixed by casting 'linux_banner' as (char *). (gdb) lx-version Linux version 4.19.0-rc1+ (changbin@acer) (gcc version 7.3.0 (Ubuntu 7.3.0-16ubuntu3)) #21 SMP Sat Sep 1 21:43:30 CST 2018 [0] https://sourceware.org/bugzilla/show_bug.cgi?id=20077 [kbingham@kernel.org: add detail to commit message] Link: http://lkml.kernel.org/r/20181111162035.8356-1-kieran.bingham@ideasonboard.com Fixes: 2d061d99 ("scripts/gdb: add version command") Signed-off-by:
Du Changbin <changbin.du@gmail.com> Signed-off-by:
Kieran Bingham <kbingham@kernel.org> Acked-by:
Jan Kiszka <jan.kiszka@siemens.com> Cc: Jan Kiszka <jan.kiszka@siemens.com> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by:
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Anders Roxell authored
Since __sanitizer_cov_trace_const_cmp4 is marked as notrace, the function called from __sanitizer_cov_trace_const_cmp4 shouldn't be traceable either. ftrace_graph_caller() gets called every time func write_comp_data() gets called if it isn't marked 'notrace'. This is the backtrace from gdb: #0 ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:179 #1 0xffffff8010201920 in ftrace_caller () at ../arch/arm64/kernel/entry-ftrace.S:151 #2 0xffffff8010439714 in write_comp_data (type=5, arg1=0, arg2=0, ip=18446743524224276596) at ../kernel/kcov.c:116 #3 0xffffff8010439894 in __sanitizer_cov_trace_const_cmp4 (arg1=<optimized out>, arg2=<optimized out>) at ../kernel/kcov.c:188 #4 0xffffff8010201874 in prepare_ftrace_return (self_addr=18446743524226602768, parent=0xffffff801014b918, frame_pointer=18446743524223531344) at ./include/generated/atomic-instrumented.h:27 #5 0xffffff801020194c in ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:182 Rework so that write_comp_data() that are called from __sanitizer_cov_trace_*_cmp*() are marked as 'notrace'. Commit 903e8ff8 ("kernel/kcov.c: mark funcs in __sanitizer_cov_trace_pc() as notrace") missed to mark write_comp_data() as 'notrace'. When that patch was created gcc-7 was used. In lib/Kconfig.debug config KCOV_ENABLE_COMPARISONS depends on $(cc-option,-fsanitize-coverage=trace-cmp) That code path isn't hit with gcc-7. However, it were that with gcc-8. Link: http://lkml.kernel.org/r/20181206143011.23719-1-anders.roxell@linaro.orgSigned-off-by:
Anders Roxell <anders.roxell@linaro.org> Signed-off-by:
Arnd Bergmann <arnd@arndb.de> Co-developed-by:
Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by:
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Feng Tang authored
So that we can also runtime chose to print out the needed system info for panic, other than setting the kernel cmdline. Link: http://lkml.kernel.org/r/1543398842-19295-3-git-send-email-feng.tang@intel.comSigned-off-by:
Feng Tang <feng.tang@intel.com> Suggested-by:
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Feng Tang authored
Kernel panic issues are always painful to debug, partially because it's not easy to get enough information of the context when panic happens. And we have ramoops and kdump for that, while this commit tries to provide a easier way to show the system info by adding a cmdline parameter, referring some idea from sysrq handler. Link: http://lkml.kernel.org/r/1543398842-19295-2-git-send-email-feng.tang@intel.comSigned-off-by:
Kees Cook <keescook@chromium.org> Acked-by:
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Tigran Aivazian authored
Strengthen validation of BFS superblock against corruption. Make in-core inode bitmap static part of superblock info structure. Print a warning when mounting a BFS filesystem created with "-N 512" option as only 510 files can be created in the root directory. Make the kernel messages more uniform. Update the 'prefix' passed to bfs_dump_imap() to match the current naming of operations. White space and comments cleanup. Link: http://lkml.kernel.org/r/CAK+_RLkFZMduoQF36wZFd3zLi-6ZutWKsydjeHFNdtRvZZEb4w@mail.gmail.comSigned-off-by:
Tigran Aivazian <aivazian.tigran@gmail.com> Reported-by:
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Signed-off-by:
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Oleg Nesterov authored
get_arg_page() checks bprm->rlim_stack.rlim_cur and re-calculates the "extra" size for argv/envp pointers every time, this is a bit ugly and even not strictly correct: acct_arg_size() must not account this size. Remove all the rlimit code in get_arg_page(). Instead, add bprm->argmin calculated once at the start of __do_execve_file() and change copy_strings to check bprm->p >= bprm->argmin. The patch adds the new helper, prepare_arg_pages() which initializes bprm->argc/envc and bprm->argmin. [oleg@redhat.com: fix !CONFIG_MMU version of get_arg_page()] Link: http://lkml.kernel.org/r/20181126122307.GA1660@redhat.com [akpm@linux-foundation.org: use max_t] Link: http://lkml.kernel.org/r/20181112160910.GA28440@redhat.comSigned-off-by:
Oleg Nesterov <oleg@redhat.com> Acked-by:
Guenter Roeck <linux@roeck-us.net> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by:
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Oleg Nesterov authored
load_script() simply truncates bprm->buf and this is very wrong if the length of shebang string exceeds BINPRM_BUF_SIZE-2. This can silently truncate i_arg or (worse) we can execute the wrong binary if buf[2:126] happens to be the valid executable path. Change load_script() to return ENOEXEC if it can't find '\n' or zero in bprm->buf. Note that '\0' can come from either prepare_binprm()->memset() or from kernel_read(), we do not care. Link: http://lkml.kernel.org/r/20181112160931.GA28463@redhat.comSigned-off-by:
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Yi Wang authored
We get a warning when building kernel with W=1: kernel/fork.c:167:13: warning: no previous prototype for `arch_release_thread_stack' [-Wmissing-prototypes] kernel/fork.c:779:13: warning: no previous prototype for `fork_init' [-Wmissing-prototypes] Add the missing declaration in head file to fix this. Also, remove arch_release_thread_stack() completely because no arch seems to implement it since bb9d8126 (arch: remove tile port). Link: http://lkml.kernel.org/r/1542170087-23645-1-git-send-email-wang.yi59@zte.com.cnSigned-off-by:
Yi Wang <wang.yi59@zte.com.cn> Acked-by:
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Carmeli Tamir authored
This patch introduces 3 new inline functions - is_fat12, is_fat16 and is_fat32, and replaces every occurrence in the code in which the FS variant (whether this is FAT12, FAT16 or FAT32) was previously checked using msdos_sb_info->fat_bits. Link: http://lkml.kernel.org/r/1544990640-11604-4-git-send-email-carmeli.tamir@gmail.comSigned-off-by:
Carmeli Tamir <carmeli.tamir@gmail.com> Acked-by:
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Reviewed-by:
Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: Bart Van Assche <bvanassche@acm.org> Cc: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by:
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Carmeli Tamir authored
MAX_FAT is useless in msdos_fs.h, since it uses the MSDOS_SB function that is defined in fat.h. So really, this macro can be only called from code that already includes fat.h. Hence, this patch moves it to fat.h, right after MSDOS_SB is defined. I also changed it to an inline function in order to save the double call to MSDOS_SB. This was suggested by joe@perches.com in the previous version. This patch is required for the next in the series, in which the variant (whether this is FAT12, FAT16 or FAT32) checks are replaced with new macros. Link: http://lkml.kernel.org/r/1544990640-11604-3-git-send-email-carmeli.tamir@gmail.comSigned-off-by:
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Carmeli Tamir authored
The comment edited in this patch was the only reference to the FAT_FIRST_ENT macro, which is not used anymore. Moreover, the commented line of code does not compile with the current code. Since the FAT_FIRST_ENT macro checks the FAT variant in a way that the patch series changes, I removed it, and instead wrote a clear explanation of what was checked. I verified that the changed comment is correct according to Microsoft FAT spec, search for "BPB_Media" in the following references: 1. Microsoft FAT specification 2005 (http://read.pudn.com/downloads77/ebook/294884/FAT32%20Spec%20%28SDA%20Contribution%29.pdf). Search for 'volume label'. 2. Microsoft Extensible Firmware Initiative, FAT32 File System Specification (https://staff.washington.edu/dittrich/misc/fatgen103.pdf). Search for 'volume label'. Link: http://lkml.kernel.org/r/1544990640-11604-2-git-send-email-carmeli.tamir@gmail.comSigned-off-by:
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Carmeli Tamir authored
The FAT file system volume label file stored in the root directory should match the volume label field in the FAT boot sector. As consequence, the max length of these fields ought to be the same. This patch replaces the magic '11' usef in the struct fat_boot_sector with MSDOS_NAME, which is used in struct msdos_dir_entry. Please check the following references: 1. Microsoft FAT specification 2005 (http://read.pudn.com/downloads77/ebook/294884/FAT32%20Spec%20%28SDA%20Contribution%29.pdf). Search for 'volume label'. 2. Microsoft Extensible Firmware Initiative, FAT32 File System Specification (https://staff.washington.edu/dittrich/misc/fatgen103.pdf). Search for 'volume label'. 3. User space code that creates FAT filesystem sometimes uses MSDOS_NAME for the label, sometimes not. Search for 'if (memcmp(label, NO_NAME, MSDOS_NAME))'. I consider to make the same patch there as well. https://github.com/dosfstools/dosfstools/blob/master/src/mkfs.fat.c Link: http://lkml.kernel.org/r/1543096879-82837-1-git-send-email-carmeli.tamir@gmail.comSigned-off-by:
Johannes Thumshirn <jthumshirn@suse.de> Acked-by:
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Ernesto A. Fernández authored
The immutable, append-only and no-dump attributes can only be retrieved with an ioctl; implement the ->getattr() method to return them on statx. Do not return the inode birthtime yet, because the issue of how best to handle the post-2038 timestamps is still under discussion. This patch is needed to pass xfstests generic/424. Link: http://lkml.kernel.org/r/20181014163558.sxorxlzjqccq2lpw@eafSigned-off-by:
Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com> Cc: Viacheslav Dubeyko <slava@dubeyko.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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Ian Kent authored
Commit 092a5345 ("autofs: take more care to not update last_used on path walk") helped to (partially) resolve a problem where automounts were not expiring due to aggressive accesses from user space. This patch was later reverted because, for very large environments, it meant more mount requests from clients and when there are a lot of clients this caused a fairly significant increase in server load. But there is a need for both types of expire check, depending on use case, so add a mount option to allow for strict update of last use of autofs dentrys (which just means not updating the last use on path walk access). Link: http://lkml.kernel.org/r/154296973880.9889.14085372741514507967.stgit@pluto-themaw-netSigned-off-by:
Ian Kent <raven@themaw.net> Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by:
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Ian Kent authored
Change the superblock info. catatonic setting to be part of a flags bit field. Link: http://lkml.kernel.org/r/154296973142.9889.17275721668508589639.stgit@pluto-themaw-netSigned-off-by:
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Ian Kent authored
The parse_options() function uses a long list of parameters, most of which are present in the super block info structure already. The mount parameters set in parse_options() options don't require cleanup so using the super block info struct directly is simpler. Link: http://lkml.kernel.org/r/154296972423.9889.9368859245676473329.stgit@pluto-themaw-netSigned-off-by:
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Ian Kent authored
Al Viro made some suggestions to improve the implementation of commit 0633da48 ("fix autofs_sbi() does not check super block type"). The check is unnecessary in all cases except for ioctl usage so placing the check in the super block accessor function adds a small overhead to the common case where it isn't needed. So it's sufficient to do this in the ioctl code only. Also the check in the ioctl code is needlessly complex. [akpm@linux-foundation.org: declare autofs_fs_type in .h, not .c] Link: http://lkml.kernel.org/r/154296970987.9889.1597442413573683096.stgit@pluto-themaw-netSigned-off-by:
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Alexey Dobriyan authored
Initcall names should not be changed. Link: http://lkml.kernel.org/r/20181124091829.GD10969@avx2Signed-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by:
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Davidlohr Bueso authored
There is no reason why we rearm the waitiqueue upon every fetch_events retry (for when events are found yet send_events() fails). If nothing else, this saves four lock operations per retry, and furthermore reduces the scope of the lock even further. [akpm@linux-foundation.org: restore code to original position, fix and reflow comment] Link: http://lkml.kernel.org/r/20181114182532.27981-2-dave@stgolabs.netSigned-off-by:
Davidlohr Bueso <dbueso@suse.de> Cc: Jason Baron <jbaron@akamai.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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Davidlohr Bueso authored
It is currently called check_events because it, well, did exactly that. However, since the lockless ep_events_available() call, the label no longer checks, but just sends the events. Rename as such. Link: http://lkml.kernel.org/r/20181114182532.27981-1-dave@stgolabs.netSigned-off-by:
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Davidlohr Bueso authored
Upon timeout, we can just exit out of the loop, without the cost of the changing the task's state with an smp_store_mb call. Just exit out of the loop and be done - setting the task state afterwards will be, of course, redundant. [dave@stgolabs.net: forgotten fixlets] Link: http://lkml.kernel.org/r/20181109155258.jxcr4t2pnz6zqct3@linux-r8p5 Link: http://lkml.kernel.org/r/20181108051006.18751-7-dave@stgolabs.netSigned-off-by:
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Davidlohr Bueso authored
This patch aims at reducing ep wq.lock hold times in epoll_wait(2). For the blocking case, there is no need to constantly take and drop the spinlock, which is only needed to manipulate the waitqueue. The call to ep_events_available() is now lockless, and only exposed to benign races. Here, if false positive (returns available events and does not see another thread deleting an epi from the list) we call into send_events and then the list's state is correctly seen. Otoh, if a false negative and we don't see a list_add_tail(), for example, from irq callback, then it is rechecked again before blocking, which will see the correct state. In order for more accuracy to see concurrent list_del_init(), use the list_empty_careful() variant -- of course, this won't be safe against insertions from wakeup. For the overflow list we obviously need to prevent load/store tearing as we don't want to see partial values while the ready list is disabled. [dave@stgolabs.net: forgotten fixlets] Link: http://lkml.kernel.org/r/20181109155258.jxcr4t2pnz6zqct3@linux-r8p5 Link: http://lkml.kernel.org/r/20181108051006.18751-6-dave@stgolabs.netSigned-off-by:
Jason Baron <jbaron@akamai.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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Davidlohr Bueso authored
Insted of just commenting how important it is, lets make it more robust and add a lockdep_assert_held() call. Link: http://lkml.kernel.org/r/20181108051006.18751-5-dave@stgolabs.netSigned-off-by:
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Davidlohr Bueso authored
The ep->ovflist is a secondary ready-list to temporarily store events that might occur when doing sproc without holding the ep->wq.lock. This accounts for every time we check for ready events and also send events back to userspace; both callbacks, particularly the latter because of copy_to_user, can account for a non-trivial time. As such, the unlikely() check to see if the pointer is being used, seems both misleading and sub-optimal. In fact, we go to an awful lot of trouble to sync both lists, and populating the ovflist is far from an uncommon scenario. For example, profiling a concurrent epoll_wait(2) benchmark, with CONFIG_PROFILE_ANNOTATED_BRANCHES shows that for a two threads a 33% incorrect rate was seen; and when incrementally increasing the number of epoll instances (which is used, for example for multiple queuing load balancing models), up to a 90% incorrect rate was seen. Similarly, by deleting the prediction, 3% throughput boost was seen across incremental threads. Link: http://lkml.kernel.org/r/20181108051006.18751-4-dave@stgolabs.netSigned-off-by:
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Davidlohr Bueso authored
The current logic is a bit convoluted. Lets simplify this with a standard list_for_each_entry_safe() loop instead and just break out after maxevents is reached. While at it, remove an unnecessary indentation level in the loop when there are in fact ready events. Link: http://lkml.kernel.org/r/20181108051006.18751-3-dave@stgolabs.netSigned-off-by:
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Davidlohr Bueso authored
Patch series "epoll: some miscellaneous optimizations". The following are some incremental optimizations on some of the epoll core. Each patch has the details, but together, the series is seen to shave off measurable cycles on a number of systems and workloads. For example, on a 40-core IB, a pipetest as well as parallel epoll_wait() benchmark show around a 20-30% increase in raw operations per second when the box is fully occupied (incremental thread counts), and up to 15% performance improvement with lower counts. Passes ltp epoll related testcases. This patch(of 6): All callers pass the EP_MAX_NESTS constant already, so lets simplify this a tad and get rid of the redundant parameter for nested eventpolls. Link: http://lkml.kernel.org/r/20181108051006.18751-2-dave@stgolabs.netSigned-off-by:
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Joe Perches authored
These declarations should generally be static const to avoid poor compilation and runtime performance where compilers tend to initialize the const declaration for every call instead of using .rodata for the string. Miscellanea: - Convert spaces to tabs for indentation in 2 adjacent checks Link: http://lkml.kernel.org/r/10ea5f4b087dc911e41e187a4a2b5e79c7529aa3.camel@perches.comSigned-off-by:
Joe Perches <joe@perches.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by:
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huang.zijiang authored
memblock_alloc() never returns NULL because panic never returns. Link: http://lkml.kernel.org/r/1545640882-42009-1-git-send-email-huang.zijiang@zte.com.cnSigned-off-by:
huang.zijiang <huang.zijiang@zte.com.cn> Acked-by:
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Huang Shijie authored
Some devices may have big memory on chip, such as over 1G. In some cases, the nbytes maybe bigger then 4M which is the bounday of the memory buddy system (4K default). So use vzalloc_node() to allocate the bitmap. Also use vfree to free it. Link: http://lkml.kernel.org/r/20181225015701.6289-1-sjhuang@iluvatar.aiSigned-off-by:
Huang Shijie <sjhuang@iluvatar.ai> Reviewed-by:
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