- 10 Jul, 2017 40 commits
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Joe Perches authored
For consistency, MAINTAINERS entries should be an upper case letter, then a colon, then a tab, then the value. Warn when an entry doesn't have this form. --fix it too. Link: http://lkml.kernel.org/r/9aaaf03ec10adf3888b5e98dd2176b7fe9b5fad8.1496343345.git.joe@perches.comSigned-off-by:
Joe Perches <joe@perches.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Joe Perches authored
Use the context around a patch to avoid missing some candidates. Link: http://lkml.kernel.org/r/865e874fbae5decc331a849bd8d71c325db6bc80.1496343345.git.joe@perches.comSigned-off-by:
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Sergey Senozhatsky authored
There is a slightly faster way (in terms of the number of instructions being used) to calculate the position of a middle element, preserving integer overflow safeness. ./scripts/bloat-o-meter lib/bsearch.o.old lib/bsearch.o.new add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-24 (-24) function old new delta bsearch 122 98 -24 TEST INT array of size 100001, elements [0..100000]. gcc 7.1, Os, x86_64. a) bsearch() of existing key "100001 - 2": BASE ==== $ perf stat ./a.out Performance counter stats for './a.out': 619.445196 task-clock:u (msec) # 0.999 CPUs utilized 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 133 page-faults:u # 0.215 K/sec 1,949,517,279 cycles:u # 3.147 GHz (83.06%) 181,017,938 stalled-cycles-frontend:u # 9.29% frontend cycles idle (83.05%) 82,959,265 stalled-cycles-backend:u # 4.26% backend cycles idle (67.02%) 4,355,706,383 instructions:u # 2.23 insn per cycle # 0.04 stalled cycles per insn (83.54%) 1,051,539,242 branches:u # 1697.550 M/sec (83.54%) 15,263,381 branch-misses:u # 1.45% of all branches (83.43%) 0.620082548 seconds time elapsed PATCHED ======= $ perf stat ./a.out Performance counter stats for './a.out': 475.097316 task-clock:u (msec) # 0.999 CPUs utilized 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 135 page-faults:u # 0.284 K/sec 1,487,467,717 cycles:u # 3.131 GHz (82.95%) 186,537,162 stalled-cycles-frontend:u # 12.54% frontend cycles idle (82.93%) 28,797,869 stalled-cycles-backend:u # 1.94% backend cycles idle (67.10%) 3,807,564,203 instructions:u # 2.56 insn per cycle # 0.05 stalled cycles per insn (83.57%) 1,049,344,291 branches:u # 2208.693 M/sec (83.60%) 5,485 branch-misses:u # 0.00% of all branches (83.58%) 0.475760235 seconds time elapsed b) bsearch() of un-existing key "100001 + 2": BASE ==== $ perf stat ./a.out Performance counter stats for './a.out': 499.244480 task-clock:u (msec) # 0.999 CPUs utilized 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 132 page-faults:u # 0.264 K/sec 1,571,194,855 cycles:u # 3.147 GHz (83.18%) 13,450,980 stalled-cycles-frontend:u # 0.86% frontend cycles idle (83.18%) 21,256,072 stalled-cycles-backend:u # 1.35% backend cycles idle (66.78%) 4,171,197,909 instructions:u # 2.65 insn per cycle # 0.01 stalled cycles per insn (83.68%) 1,009,175,281 branches:u # 2021.405 M/sec (83.79%) 3,122 branch-misses:u # 0.00% of all branches (83.37%) 0.499871144 seconds time elapsed PATCHED ======= $ perf stat ./a.out Performance counter stats for './a.out': 399.023499 task-clock:u (msec) # 0.998 CPUs utilized 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 134 page-faults:u # 0.336 K/sec 1,245,793,991 cycles:u # 3.122 GHz (83.39%) 11,529,273 stalled-cycles-frontend:u # 0.93% frontend cycles idle (83.46%) 12,116,311 stalled-cycles-backend:u # 0.97% backend cycles idle (66.92%) 3,679,710,005 instructions:u # 2.95 insn per cycle # 0.00 stalled cycles per insn (83.47%) 1,009,792,625 branches:u # 2530.660 M/sec (83.46%) 2,590 branch-misses:u # 0.00% of all branches (83.12%) 0.399733539 seconds time elapsed Link: http://lkml.kernel.org/r/20170607150457.5905-1-sergey.senozhatsky@gmail.comSigned-off-by:Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by:
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Thomas Meyer authored
[thomas@m3y3r.de: v3: fix arch specific implementations] Link: http://lkml.kernel.org/r/1497890858.12931.7.camel@m3y3r.deSigned-off-by:
Thomas Meyer <thomas@m3y3r.de> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by:
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Michal Hocko authored
bucket_table_alloc() can be currently called with GFP_KERNEL or GFP_ATOMIC. For the former we basically have an open coded kvzalloc() while the later only uses kzalloc(). Let's simplify the code a bit by the dropping the open coded path and replace it with kvzalloc(). Link: http://lkml.kernel.org/r/20170531155145.17111-3-mhocko@kernel.orgSigned-off-by:
Michal Hocko <mhocko@suse.com> Cc: Thomas Graf <tgraf@suug.ch> Cc: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by:
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Davidlohr Bueso authored
... such that a user can specify visiting all the nodes in the tree (intersects with the world). This is a nice opposite from the very basic default query which is a single point. Link: http://lkml.kernel.org/r/20170518174936.20265-5-dave@stgolabs.netSigned-off-by:
Davidlohr Bueso <dbueso@suse.de> Signed-off-by:
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Davidlohr Bueso authored
Add a 'max_endpoint' parameter such that users may easily limit the size of the intervals that are randomly generated. Link: http://lkml.kernel.org/r/20170518174936.20265-4-dave@stgolabs.netSigned-off-by:
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Davidlohr Bueso authored
Allows for more flexible debugging. Link: http://lkml.kernel.org/r/20170518174936.20265-3-dave@stgolabs.netSigned-off-by:
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Davidlohr Bueso authored
Patch series "lib/interval_tree_test: some debugging improvements". Here are some patches that update the interval_tree_test module allowing users to pass finer grained options to run the actual test. This patch (of 4): It is a tristate after all, and also serves well for quick debugging. Link: http://lkml.kernel.org/r/20170518174936.20265-2-dave@stgolabs.netSigned-off-by:
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Alexey Dobriyan authored
gcc does generates stupid code sign extending data back and forth. Help by using "unsigned int". add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-61 (-61) function old new delta _parse_integer 128 123 -5 It _still_ does generate useless MOVSX but I don't know how to delete it: 0000000000000070 <_parse_integer>: ... a0: 89 c2 mov edx,eax a2: 83 e8 30 sub eax,0x30 a5: 83 f8 09 cmp eax,0x9 a8: 76 11 jbe bb <_parse_integer+0x4b> aa: 83 ca 20 or edx,0x20 ad: 0f be c2 ===> movsx eax,dl <=== useless b0: 8d 50 9f lea edx,[rax-0x61] b3: 83 fa 05 cmp edx,0x5 Patch also helps on embedded archs which generally only like "int". On arm "and 0xff" is generated which is waste because all values used in comparisons are positive. Link: http://lkml.kernel.org/r/20170514194720.GB32563@avx2Signed-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by:
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Alexey Dobriyan authored
Standard "while (*s)" test is unnecessary because NUL won't pass valid-digit test anyway. Save one branch per parsed character. Link: http://lkml.kernel.org/r/20170514193756.GA32563@avx2Signed-off-by:
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Matthew Wilcox authored
Commit 7dd96816 ("bitmap: bitmap_equal memcmp optimization") was rather more restrictive than necessary; we can use memcmp() to implement bitmap_equal() as long as the number of bits can be proved to be a multiple of 8. And architectures other than s390 may be able to make good use of this optimisation. [arnd@arndb.de: fix build: add a memcmp() declaration] Link: http://lkml.kernel.org/r/20170630153908.3439707-1-arnd@arndb.de Link: http://lkml.kernel.org/r/20170628153221.11322-5-willy@infradead.orgSigned-off-by:
Matthew Wilcox <mawilcox@microsoft.com> Signed-off-by:
Arnd Bergmann <arnd@arndb.de> Acked-by:
Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by:
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Matthew Wilcox authored
Several callers have constant 'start' and an 'nbits' that is a multiple of 8, so we can turn them into calls to memset. We don't need the entirety of 'start' and 'nbits' to be constant, we just need to know whether they're divisible by 8. Link: http://lkml.kernel.org/r/20170628153221.11322-4-willy@infradead.orgSigned-off-by:
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Matthew Wilcox authored
We have eight users calling bitmap_clear for a single bit and seventeen calling bitmap_set for a single bit. Rather than fix all of them to call __clear_bit or __set_bit, turn bitmap_clear and bitmap_set into inline functions and make this special case efficient. Link: http://lkml.kernel.org/r/20170628153221.11322-3-willy@infradead.orgSigned-off-by:
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Matthew Wilcox authored
Patch series "Bitmap optimisations", v2. These three bitmap patches use more efficient specialisations when the compiler can figure out that it's safe to do so. Thanks to Rasmus's eagle eyes, a nasty bug in v1 was avoided, and I've added a test case which would have caught it. This patch (of 4): This version of the test is actually a no-op; the next patch will enable it. Link: http://lkml.kernel.org/r/20170628153221.11322-2-willy@infradead.orgSigned-off-by:
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Luis R. Rodriguez authored
We poke at proc sysctl enough that really we should declare it maintained. We'll just be Cc'd and sending updates / ACK'ing changes through akpm's tree. Link: http://lkml.kernel.org/r/20170524231305.8649-1-mcgrof@kernel.orgSigned-off-by:
Luis R. Rodriguez <mcgrof@kernel.org> Acked-by:
Kees Cook <keescook@chromium.org> Signed-off-by:
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Masahiro Yamada authored
'all_var' looks like a variable, but is actually a macro. Use IS_ENABLED(CONFIG_KALLSYMS_ALL) for clarification. Link: http://lkml.kernel.org/r/1497577591-3434-1-git-send-email-yamada.masahiro@socionext.comSigned-off-by:
Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by:
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Rasmus Villemoes authored
setgroups is not exactly a hot path, so we might as well use the library function instead of open-coding the sorting. Saves ~150 bytes. Link: http://lkml.kernel.org/r/1497301378-22739-1-git-send-email-linux@rasmusvillemoes.dkSigned-off-by:
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Arvind Yadav authored
attribute_groups are not supposed to change at runtime. All functions working with attribute_groups provided by <linux/sysfs.h> work with const attribute_group. So mark the non-const structs as const. File size before: text data bss dec hex filename 1120 544 16 1680 690 kernel/ksysfs.o File size After adding 'const': text data bss dec hex filename 1160 480 16 1656 678 kernel/ksysfs.o Link: http://lkml.kernel.org/r/aa224b3cc923fdbb3edd0c41b2c639c85408c9e8.1498737347.git.arvind.yadav.cs@gmail.comSigned-off-by:
Arvind Yadav <arvind.yadav.cs@gmail.com> Acked-by:
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Bart Van Assche authored
The global variable 'rd_size' is declared as 'int' in source file arch/arm/kernel/atags_parse.c and as 'unsigned long' in drivers/block/brd.c. Fix this inconsistency. Additionally, remove the declarations of rd_image_start, rd_prompt and rd_doload from parse_tag_ramdisk() since these duplicate existing declarations in <linux/initrd.h>. Link: http://lkml.kernel.org/r/20170627065024.12347-1-bart.vanassche@wdc.comSigned-off-by:
Bart Van Assche <bart.vanassche@sandisk.com> Acked-by:
Russell King <rmk+kernel@armlinux.org.uk> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Jason Yan <yanaijie@huawei.com> Cc: Zhaohongjiang <zhaohongjiang@huawei.com> Cc: Miao Xie <miaoxie@huawei.com> Signed-off-by:
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Ian Abbott authored
Including <linux/bug.h> pulls in a lot of bloat from <asm/bug.h> and <asm-generic/bug.h> that is not needed to call the BUILD_BUG() family of macros. Split them out into their own header, <linux/build_bug.h>. Also correct some checkpatch.pl errors for the BUILD_BUG_ON_ZERO() and BUILD_BUG_ON_NULL() macros by adding parentheses around the bitfield widths that begin with a minus sign. Link: http://lkml.kernel.org/r/20170525120316.24473-6-abbotti@mev.co.ukSigned-off-by:
Ian Abbott <abbotti@mev.co.uk> Acked-by:
Michal Nazarewicz <mina86@mina86.com> Acked-by:
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Ian Abbott authored
Correct these checkpatch.pl errors: |ERROR: space required before that '-' (ctx:OxO) |#37: FILE: include/linux/bug.h:37: |+#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); })) |ERROR: space required before that '-' (ctx:OxO) |#38: FILE: include/linux/bug.h:38: |+#define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); })) I decided to wrap the bitfield expressions that begin with minus signs in parentheses rather than insert spaces before the minus signs. Link: http://lkml.kernel.org/r/20170525120316.24473-5-abbotti@mev.co.ukSigned-off-by: -
Ian Abbott authored
Correct this checkpatch.pl error: |ERROR: "(foo*)" should be "(foo *)" |#19: FILE: include/linux/bug.h:19: |+#define BUILD_BUG_ON_NULL(e) ((void*)0) Link: http://lkml.kernel.org/r/20170525120316.24473-4-abbotti@mev.co.ukSigned-off-by:
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Ian Abbott authored
Correct these checkpatch.pl warnings: |WARNING: Block comments use * on subsequent lines |#34: FILE: include/linux/bug.h:34: |+/* Force a compilation error if condition is true, but also produce a |+ result (of value 0 and type size_t), so the expression can be used |WARNING: Block comments use a trailing */ on a separate line |#36: FILE: include/linux/bug.h:36: |+ aren't permitted). */ Link: http://lkml.kernel.org/r/20170525120316.24473-3-abbotti@mev.co.ukSigned-off-by:
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Ian Abbott authored
This series of patches splits BUILD_BUG related macros out of "include/linux/bug.h" into new file "include/linux/build_bug.h" (patch 5), and changes the pointer type checking in the `container_of()` macro to deal with pointers of array type better (patch 6). Patches 1 to 4 are prerequisites. Patches 2, 3, 4, and 5 have been inserted since the previous version of this patch series. Patch 6 here corresponds to v3 and v4's patch 2. Patch 1 was a prerequisite in v3 of this series to avoid a lot of warnings when <linux/bug.h> was included by <linux/kernel.h>. That is no longer relevant for v5 of the series, but I left it in because it was acked by a Arnd Bergmann and Michal Nazarewicz. Patches 2, 3, and 4 are some checkpatch clean-ups on "include/linux/bug.h" before splitting out the BUILD_BUG stuff in patch 5. Patch 5 splits the BUILD_BUG related macros out of "include/linux/bug.h" into new file "include/linux/build_bug.h" because including <linux/bug.h> in "include/linux/kernel.h" would result in build failures due to circular dependencies. Patch 6 changes the pointer type checking by `container_of()` to avoid some incompatible pointer warnings when the dereferenced pointer has array type. 1) asm-generic/bug.h: declare struct pt_regs; before function prototype 2) linux/bug.h: correct formatting of block comment 3) linux/bug.h: correct "(foo*)" should be "(foo *)" 4) linux/bug.h: correct "space required before that '-'" 5) bug: split BUILD_BUG stuff out into <linux/build_bug.h> 6) kernel.h: handle pointers to arrays better in container_of() This patch (of 6): The declaration of `__warn()` has `struct pt_regs *regs` as one of its parameters. This can result in compiler warnings if `struct regs` is not already declared. Add an empty declaration of `struct pt_regs` to avoid the warnings. Link: http://lkml.kernel.org/r/20170525120316.24473-2-abbotti@mev.co.ukSigned-off-by:
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Heiner Kallweit authored
The code can be much simplified by switching to ida_simple_get/remove. Link: http://lkml.kernel.org/r/8d1cc9f7-5115-c9dc-028e-c0770b6bfe1f@gmail.comSigned-off-by:
Heiner Kallweit <hkallweit1@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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Will Deacon authored
FRV supports 64-bit cmpxchg, which is provided by the arch code as __cmpxchg_64 and subsequently used to implement atomic64_cmpxchg. This patch hooks up the generic cmpxchg64 API using the same function, which also provides default definitions of the relaxed, acquire and release variants. This fixes the build when COMPILE_TEST=y and IOMMU_IO_PGTABLE_LPAE=y. Link: http://lkml.kernel.org/r/1499084670-6996-1-git-send-email-will.deacon@arm.comSigned-off-by:
Will Deacon <will.deacon@arm.com> Reported-by:
kbuild test robot <fengguang.wu@intel.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: David Howells <dhowells@redhat.com> Signed-off-by:
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Tobias Klauser authored
The arch uses a verbatim copy of the asm-generic version and does not add any own implementations to the header, so use asm-generic/fb.h instead of duplicating code. Link: http://lkml.kernel.org/r/20170517083307.1697-1-tklauser@distanz.chSigned-off-by:
Tobias Klauser <tklauser@distanz.ch> Reviewed-by:
David Howells <dhowells@redhat.com> Signed-off-by:
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Tobias Klauser authored
frv's asm/device.h is merely including asm-generic/device.h. Thus, the arch specific header can be omitted and the generic header can be used directly. Link: http://lkml.kernel.org/r/20170517124915.26904-1-tklauser@distanz.chSigned-off-by:
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Colin Ian King authored
The helper function get_wild_bug_type() does not need to be in global scope, so make it static. Cleans up sparse warning: "symbol 'get_wild_bug_type' was not declared. Should it be static?" Link: http://lkml.kernel.org/r/20170622090049.10658-1-colin.king@canonical.comSigned-off-by:
Colin Ian King <colin.king@canonical.com> Acked-by:
Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Signed-off-by:
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Joonsoo Kim authored
They return positive value, that is, true, if non-zero value is found. Rename them to reduce confusion. Link: http://lkml.kernel.org/r/20170516012350.GA16015@js1304-desktopSigned-off-by:
Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by:
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Andrey Ryabinin authored
KASAN doesn't happen work with memory hotplug because hotplugged memory doesn't have any shadow memory. So any access to hotplugged memory would cause a crash on shadow check. Use memory hotplug notifier to allocate and map shadow memory when the hotplugged memory is going online and free shadow after the memory offlined. Link: http://lkml.kernel.org/r/20170601162338.23540-4-aryabinin@virtuozzo.comSigned-off-by:
Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Alexander Potapenko <glider@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Ingo Molnar <mingo@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by:
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Andrey Ryabinin authored
We used to read several bytes of the shadow memory in advance. Therefore additional shadow memory mapped to prevent crash if speculative load would happen near the end of the mapped shadow memory. Now we don't have such speculative loads, so we no longer need to map additional shadow memory. Link: http://lkml.kernel.org/r/20170601162338.23540-3-aryabinin@virtuozzo.comSigned-off-by:
Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
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Andrey Ryabinin authored
We used to read several bytes of the shadow memory in advance. Therefore additional shadow memory mapped to prevent crash if speculative load would happen near the end of the mapped shadow memory. Now we don't have such speculative loads, so we no longer need to map additional shadow memory. Link: http://lkml.kernel.org/r/20170601162338.23540-2-aryabinin@virtuozzo.comSigned-off-by:
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Andrey Ryabinin authored
For some unaligned memory accesses we have to check additional byte of the shadow memory. Currently we load that byte speculatively to have only single load + branch on the optimistic fast path. However, this approach has some downsides: - It's unaligned access, so this prevents porting KASAN on architectures which doesn't support unaligned accesses. - We have to map additional shadow page to prevent crash if speculative load happens near the end of the mapped memory. This would significantly complicate upcoming memory hotplug support. I wasn't able to notice any performance degradation with this patch. So these speculative loads is just a pain with no gain, let's remove them. Link: http://lkml.kernel.org/r/20170601162338.23540-1-aryabinin@virtuozzo.comSigned-off-by:
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Joonsoo Kim authored
There is missing optimization in zero_p4d_populate() that can save some memory when mapping zero shadow. Implement it like as others. Link: http://lkml.kernel.org/r/1494829255-23946-1-git-send-email-iamjoonsoo.kim@lge.comSigned-off-by:
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Jerome Marchand authored
Commit 40f9fb8c ("mm/zsmalloc: support allocating obj with size of ZS_MAX_ALLOC_SIZE") fixes a size calculation error that prevented zsmalloc to allocate an object of the maximal size (ZS_MAX_ALLOC_SIZE). I think however the fix is unneededly complicated. This patch replaces the dynamic calculation of zs_size_classes at init time by a compile time calculation that uses the DIV_ROUND_UP() macro already used in get_size_class_index(). [akpm@linux-foundation.org: use min_t] Link: http://lkml.kernel.org/r/20170630114859.1979-1-jmarchan@redhat.comSigned-off-by:
Jerome Marchand <jmarchan@redhat.com> Acked-by:
Minchan Kim <minchan@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Mahendran Ganesh <opensource.ganesh@gmail.com> Signed-off-by:
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Arvind Yadav authored
attribute_groups are not supposed to change at runtime. All functions working with attribute_groups provided by <linux/sysfs.h> work with const attribute_group. So mark the non-const structs as const. File size before: text data bss dec hex filename 8293 841 4 9138 23b2 drivers/block/zram/zram_drv.o File size After adding 'const': text data bss dec hex filename 8357 777 4 9138 23b2 drivers/block/zram/zram_drv.o Link: http://lkml.kernel.org/r/65680c1c4d85818f7094cbfa31c91bf28185ba1b.1499061182.git.arvind.yadav.cs@gmail.comSigned-off-by:
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Michal Hocko authored
early_pfn_to_nid will return node 0 if both HAVE_ARCH_EARLY_PFN_TO_NID and HAVE_MEMBLOCK_NODE_MAP are disabled. It seems we are safe now because all architectures which support NUMA define one of them (with an exception of alpha which however has CONFIG_NUMA marked as broken) so this works as expected. It can get silently and subtly broken too easily, though. Make sure we fail the compilation if NUMA is enabled and there is no proper implementation for this function. If that ever happens we know that either the specific configuration is invalid and the fix should either disable NUMA or enable one of the above configs. Link: http://lkml.kernel.org/r/20170704075803.15979-1-mhocko@kernel.orgSigned-off-by:
Vlastimil Babka <vbabka@suse.cz> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Yang Shi <yang.shi@linaro.org> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by:
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Thomas Gleixner authored
Andrey reported a potential deadlock with the memory hotplug lock and the cpu hotplug lock. The reason is that memory hotplug takes the memory hotplug lock and then calls stop_machine() which calls get_online_cpus(). That's the reverse lock order to get_online_cpus(); get_online_mems(); in mm/slub_common.c The problem has been there forever. The reason why this was never reported is that the cpu hotplug locking had this homebrewn recursive reader writer semaphore construct which due to the recursion evaded the full lock dep coverage. The memory hotplug code copied that construct verbatim and therefor has similar issues. Three steps to fix this: 1) Convert the memory hotplug locking to a per cpu rwsem so the potential issues get reported proper by lockdep. 2) Lock the online cpus in mem_hotplug_begin() before taking the memory hotplug rwsem and use stop_machine_cpuslocked() in the page_alloc code to avoid recursive locking. 3) The cpu hotpluck locking in #2 causes a recursive locking of the cpu hotplug lock via __offline_pages() -> lru_add_drain_all(). Solve this by invoking lru_add_drain_all_cpuslocked() instead. Link: http://lkml.kernel.org/r/20170704093421.506836322@linutronix.deReported-by:
Thomas Gleixner <tglx@linutronix.de> Acked-by:
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