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* kmod: remove unecessary explicit wide CPU affinity settingFrederic Weisbecker2015-09-101-3/+0
| | | | | | | | | | | | | | | | | | | | | Khelper is affine to all CPUs. Now since it creates the call_usermodehelper_exec_[a]sync() kernel threads, those inherit the wide affinity. As such explicitly forcing a wide affinity from those kernel threads is like a no-op. Just remove it. It's needless and it breaks CPU isolation users who rely on workqueue affinity tuning. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Rik van Riel <riel@redhat.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Tejun Heo <tj@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kmod: bunch of internal functions renamesFrederic Weisbecker2015-09-101-13/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patchset does a bunch of cleanups and converts khelper to use system unbound workqueues. The 3 first patches should be uncontroversial. The last 2 patches are debatable. Kmod creates kernel threads that perform userspace jobs and we want those to have a large affinity in order not to contend busy CPUs. This is (partly) why we use khelper which has a wide affinity that the kernel threads it create can inherit from. Now khelper is a dedicated workqueue that has singlethread properties which we aren't interested in. Hence those two debatable changes: _ We would like to use generic workqueues. System unbound workqueues are a very good candidate but they are not wide affine, only node affine. Now probably a node is enough to perform many parallel kmod jobs. _ We would like to remove the wait_for_helper kernel thread (UMH_WAIT_PROC handler) to use the workqueue. It means that if the workqueue blocks, and no other worker can take pending kmod request, we can be screwed. Now if we have 512 threads, this should be enough. This patch (of 5): Underscores on function names aren't much verbose to explain the purpose of a function. And kmod has interesting such flavours. Lets rename the following functions: * __call_usermodehelper -> call_usermodehelper_exec_work * ____call_usermodehelper -> call_usermodehelper_exec_async * wait_for_helper -> call_usermodehelper_exec_sync Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Rik van Riel <riel@redhat.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Tejun Heo <tj@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kmod: correct documentation of return status of request_moduleNeilBrown2015-09-101-4/+5
| | | | | | | | | | | | | | | | | | If request_module() successfully runs modprobe, but modprobe exits with a non-zero status, then the return value from request_module() will be that (positive) error status. So the return from request_module can be: negative errno zero for success positive exit code. Signed-off-by: NeilBrown <neilb@suse.com> Cc: Goldwyn Rodrigues <rgoldwyn@suse.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Tejun Heo <tj@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hfs: fix B-tree corruption after insertion at position 0Hin-Tak Leung2015-09-101-9/+11
| | | | | | | | | | | | | | | | | | | | | Fix B-tree corruption when a new record is inserted at position 0 in the node in hfs_brec_insert(). This is an identical change to the corresponding hfs b-tree code to Sergei Antonov's "hfsplus: fix B-tree corruption after insertion at position 0", to keep similar code paths in the hfs and hfsplus drivers in sync, where appropriate. Signed-off-by: Hin-Tak Leung <htl10@users.sourceforge.net> Cc: Sergei Antonov <saproj@gmail.com> Cc: Joe Perches <joe@perches.com> Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com> Cc: Anton Altaparmakov <anton@tuxera.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hfs,hfsplus: cache pages correctly between bnode_create and bnode_freeHin-Tak Leung2015-09-102-8/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pages looked up by __hfs_bnode_create() (called by hfs_bnode_create() and hfs_bnode_find() for finding or creating pages corresponding to an inode) are immediately kmap()'ed and used (both read and write) and kunmap()'ed, and should not be page_cache_release()'ed until hfs_bnode_free(). This patch fixes a problem I first saw in July 2012: merely running "du" on a large hfsplus-mounted directory a few times on a reasonably loaded system would get the hfsplus driver all confused and complaining about B-tree inconsistencies, and generates a "BUG: Bad page state". Most recently, I can generate this problem on up-to-date Fedora 22 with shipped kernel 4.0.5, by running "du /" (="/" + "/home" + "/mnt" + other smaller mounts) and "du /mnt" simultaneously on two windows, where /mnt is a lightly-used QEMU VM image of the full Mac OS X 10.9: $ df -i / /home /mnt Filesystem Inodes IUsed IFree IUse% Mounted on /dev/mapper/fedora-root 3276800 551665 2725135 17% / /dev/mapper/fedora-home 52879360 716221 52163139 2% /home /dev/nbd0p2 4294967295 1387818 4293579477 1% /mnt After applying the patch, I was able to run "du /" (60+ times) and "du /mnt" (150+ times) continuously and simultaneously for 6+ hours. There are many reports of the hfsplus driver getting confused under load and generating "BUG: Bad page state" or other similar issues over the years. [1] The unpatched code [2] has always been wrong since it entered the kernel tree. The only reason why it gets away with it is that the kmap/memcpy/kunmap follow very quickly after the page_cache_release() so the kernel has not had a chance to reuse the memory for something else, most of the time. The current RW driver appears to have followed the design and development of the earlier read-only hfsplus driver [3], where-by version 0.1 (Dec 2001) had a B-tree node-centric approach to read_cache_page()/page_cache_release() per bnode_get()/bnode_put(), migrating towards version 0.2 (June 2002) of caching and releasing pages per inode extents. When the current RW code first entered the kernel [2] in 2005, there was an REF_PAGES conditional (and "//" commented out code) to switch between B-node centric paging to inode-centric paging. There was a mistake with the direction of one of the REF_PAGES conditionals in __hfs_bnode_create(). In a subsequent "remove debug code" commit [4], the read_cache_page()/page_cache_release() per bnode_get()/bnode_put() were removed, but a page_cache_release() was mistakenly left in (propagating the "REF_PAGES <-> !REF_PAGE" mistake), and the commented-out page_cache_release() in bnode_release() (which should be spanned by !REF_PAGES) was never enabled. References: [1]: Michael Fox, Apr 2013 http://www.spinics.net/lists/linux-fsdevel/msg63807.html ("hfsplus volume suddenly inaccessable after 'hfs: recoff %d too large'") Sasha Levin, Feb 2015 http://lkml.org/lkml/2015/2/20/85 ("use after free") https://bugs.launchpad.net/ubuntu/+source/linux/+bug/740814 https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1027887 https://bugzilla.kernel.org/show_bug.cgi?id=42342 https://bugzilla.kernel.org/show_bug.cgi?id=63841 https://bugzilla.kernel.org/show_bug.cgi?id=78761 [2]: http://git.kernel.org/cgit/linux/kernel/git/tglx/history.git/commit/\ fs/hfs/bnode.c?id=d1081202f1d0ee35ab0beb490da4b65d4bc763db commit d1081202f1d0ee35ab0beb490da4b65d4bc763db Author: Andrew Morton <akpm@osdl.org> Date: Wed Feb 25 16:17:36 2004 -0800 [PATCH] HFS rewrite http://git.kernel.org/cgit/linux/kernel/git/tglx/history.git/commit/\ fs/hfsplus/bnode.c?id=91556682e0bf004d98a529bf829d339abb98bbbd commit 91556682e0bf004d98a529bf829d339abb98bbbd Author: Andrew Morton <akpm@osdl.org> Date: Wed Feb 25 16:17:48 2004 -0800 [PATCH] HFS+ support [3]: http://sourceforge.net/projects/linux-hfsplus/ http://sourceforge.net/projects/linux-hfsplus/files/Linux%202.4.x%20patch/hfsplus%200.1/ http://sourceforge.net/projects/linux-hfsplus/files/Linux%202.4.x%20patch/hfsplus%200.2/ http://linux-hfsplus.cvs.sourceforge.net/viewvc/linux-hfsplus/linux/\ fs/hfsplus/bnode.c?r1=1.4&r2=1.5 Date: Thu Jun 6 09:45:14 2002 +0000 Use buffer cache instead of page cache in bnode.c. Cache inode extents. [4]: http://git.kernel.org/cgit/linux/kernel/git/\ stable/linux-stable.git/commit/?id=a5e3985fa014029eb6795664c704953720cc7f7d commit a5e3985fa014029eb6795664c704953720cc7f7d Author: Roman Zippel <zippel@linux-m68k.org> Date: Tue Sep 6 15:18:47 2005 -0700 [PATCH] hfs: remove debug code Signed-off-by: Hin-Tak Leung <htl10@users.sourceforge.net> Signed-off-by: Sergei Antonov <saproj@gmail.com> Reviewed-by: Anton Altaparmakov <anton@tuxera.com> Reported-by: Sasha Levin <sasha.levin@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Vyacheslav Dubeyko <slava@dubeyko.com> Cc: Sougata Santra <sougata@tuxera.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs/coda: fix readlink buffer overflowJan Harkes2015-09-101-3/+3
| | | | | | | | | | | | | | | | | | | | | | | Dan Carpenter discovered a buffer overflow in the Coda file system readlink code. A userspace file system daemon can return a 4096 byte result which then triggers a one byte write past the allocated readlink result buffer. This does not trigger with an unmodified Coda implementation because Coda has a 1024 byte limit for symbolic links, however other userspace file systems using the Coda kernel module could be affected. Although this is an obvious overflow, I don't think this has to be handled as too sensitive from a security perspective because the overflow is on the Coda userspace daemon side which already needs root to open Coda's kernel device and to mount the file system before we get to the point that links can be read. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Jan Harkes <jaharkes@cs.cmu.edu> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* checkpatch: add constant comparison on left side testJoe Perches2015-09-101-0/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | "CONST <comparison> variable" checks like: if (NULL != foo) and while (0 < bar(...)) where a constant (or what appears to be a constant like an upper case identifier) is on the left of a comparison are generally preferred to be written using the constant on the right side like: if (foo != NULL) and while (bar(...) > 0) Add a test for this. Add a --fix option too, but only do it when the code is immediately surrounded by parentheses to avoid misfixing things like "(0 < bar() + constant)" Signed-off-by: Joe Perches <joe@perches.com> Cc: Nicolas Morey Chaisemartin <nmorey@kalray.eu> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* checkpatch: add __pmem to $Sparse annotationsJoe Perches2015-09-101-0/+1
| | | | | | | | | | | | | commit 61031952f4c8 ("arch, x86: pmem api for ensuring durability of persistent memory updates") added a new __pmem annotation for sparse verification. Add __pmem to the $Sparse variable so checkpatch can appropriately ignore uses of this attribute too. Signed-off-by: Joe Perches <joe@perches.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Acked-by: Andy Whitcroft <apw@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* checkpatch: fix left brace warningEddie Kovsky2015-09-101-4/+4
| | | | | | | | | | | | | | Using checkpatch.pl with Perl 5.22.0 generates the following warning: Unescaped left brace in regex is deprecated, passed through in regex; This patch fixes the warnings by escaping occurrences of the left brace inside the regular expression. Signed-off-by: Eddie Kovsky <ewk@edkovsky.org> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* checkpatch: avoid some commit message long line warningsJoe Perches2015-09-101-3/+27
| | | | | | | | | | | | | | | | | Fixes: and Link: lines may exceed 75 chars in the commit log. So too can stack dump and dmesg lines and lines that seem like filenames. And Fixes: lines don't need to have a "commit" prefix before the commit id. Add exceptions for these types of lines. Signed-off-by: Joe Perches <joe@perches.com> Reported-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* checkpatch: emit an error on formats with 0x%<decimal>Joe Perches2015-09-101-2/+6
| | | | | | | | | | | | Using 0x%d is wrong. Emit a message when it happens. Miscellanea: Improve the %Lu warning to match formats like %16Lu. Signed-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>
* checkpatch: make --strict the default for drivers/staging files and patchesJoe Perches2015-09-101-1/+1
| | | | | | | | | | | Making --strict the default for staging may help some people submit patches without obvious defects. Signed-off-by: Joe Perches <joe@perches.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* checkpatch: always check block comment stylesJoe Perches2015-09-101-8/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | Some of the block comment tests that are used only for networking are appropriate for all patches. For example, these styles are not encouraged: /* block comment without introductory * */ and /* * block comment with line terminating */ Remove the networking specific test and add comments. There are some infrequent false positives where code is lazily commented out using /* and */ rather than using #if 0/#endif blocks like: /* case foo: case bar: */ case baz: Signed-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>
* checkpatch: report the right line # when using --emacs and --fileJoe Perches2015-09-101-1/+5
| | | | | | | | | | | commit 34d8815f9512 ("checkpatch: add --showfile to allow input via pipe to show filenames") broke the --emacs with --file option. Fix it. Signed-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>
* checkpatch: add some <foo>_destroy functions to NEEDLESS_IF testsJoe Perches2015-09-101-4/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | Sergey Senozhatsky has modified several destroy functions that can now be called with NULL values. - kmem_cache_destroy() - mempool_destroy() - dma_pool_destroy() Update checkpatch to warn when those functions are preceded by an if. Update checkpatch to --fix all the calls too only when the code style form is using leading tabs. from: if (foo) <func>(foo); to: <func>(foo); Signed-off-by: Joe Perches <joe@perches.com> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Julia Lawall <julia.lawall@lip6.fr> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* checkpatch: Allow longer declaration macrosJoe Perches2015-09-101-1/+1
| | | | | | | | | | | | | | | Some really long declaration macros exist. For instance; DEFINE_DMA_BUF_EXPORT_INFO(exp_info); and DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(name, description) Increase the limit from 2 words to 6 after DECLARE/DEFINE uses. Signed-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>
* checkpatch: improve SUSPECT_CODE_INDENT testJoe Perches2015-09-101-6/+15
| | | | | | | | | | | | | | | | | | | | | Many lines exist like if (foo) bar; where the tabbed indentation of the branch is not one more than the "if" line above it. checkpatch should emit a warning on those lines. Miscellenea: o Remove comments from branch blocks o Skip blank lines in block Signed-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>
* checkpatch: add warning on BUG/BUG_ON useJoe Perches2015-09-101-6/+8
| | | | | | | | | | | | | | | | Using BUG/BUG_ON crashes the kernel and is just unfriendly. Enable code that emits a warning on BUG/BUG_ON use. Make the code emit the message at WARNING level when scanning a patch and at CHECK level when scanning files so that script users don't feel an obligation to fix code that might be above their pay grade. Signed-off-by: Joe Perches <joe@perches.com> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* checkpatch: warn on bare SHA-1 commit IDs in commit logsJoe Perches2015-09-101-3/+12
| | | | | | | | | Commit IDs should have commit descriptions too. Warn when a 12 to 40 byte SHA-1 is used in commit logs. Signed-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>
* lib/test_kasan.c: make kmalloc_oob_krealloc_less more correctlyWang Long2015-09-101-1/+1
| | | | | | | | | | | | | | | In kmalloc_oob_krealloc_less, I think it is better to test the size2 boundary. If we do not call krealloc, the access of position size1 will still cause out-of-bounds and access of position size2 does not. After call krealloc, the access of position size2 cause out-of-bounds. So using size2 is more correct. Signed-off-by: Wang Long <long.wanglong@huawei.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lib/test_kasan.c: fix a typoWang Long2015-09-101-2/+2
| | | | | | | Signed-off-by: Wang Long <long.wanglong@huawei.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lib/string_helpers: rename "esc" arg to "only"Kees Cook2015-09-102-14/+14
| | | | | | | | | | | To further clarify the purpose of the "esc" argument, rename it to "only" to reflect that it is a limit, not a list of additional characters to escape. Signed-off-by: Kees Cook <keescook@chromium.org> Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lib/string_helpers: clarify esc arg in string_escape_memKees Cook2015-09-101-4/+6
| | | | | | | | | | | | | The esc argument is used to reduce which characters will be escaped. For example, using " " with ESCAPE_SPACE will not produce any escaped spaces. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Mathias Krause <minipli@googlemail.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hexdump: do not print debug dumps for !CONFIG_DEBUGLinus Walleij2015-09-101-2/+8
| | | | | | | | | | | | print_hex_dump_debug() is likely supposed to be analogous to pr_debug() or dev_dbg() & friends. Currently it will adhere to dynamic debug, but will not stub out prints if CONFIG_DEBUG is not set. Let's make it do the right thing, because I am tired of having my dmesg buffer full of hex dumps on production systems. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lib/bitmap.c: bitmap_parselist can accept string with whitespaces on head or ↵Pan Xinhui2015-09-101-14/+18
| | | | | | | | | | | | | | | | | | | | tail In __bitmap_parselist we can accept whitespaces on head or tail during every parsing procedure. If input has valid ranges, there is no reason to reject the user. For example, bitmap_parselist(" 1-3, 5, ", &mask, nmaskbits). After separating the string, we get " 1-3", " 5", and " ". It's possible and reasonable to accept such string as long as the parsing result is correct. Signed-off-by: Pan Xinhui <xinhuix.pan@intel.com> Cc: Yury Norov <yury.norov@gmail.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lib/bitmap.c: fix a special string handling bug in __bitmap_parselistPan Xinhui2015-09-101-0/+4
| | | | | | | | | | | | | | If string end with '-', for exapmle, bitmap_parselist("1,0-",&mask, nmaskbits), It is not in a valid pattern, so add a check after loop. Return -EINVAL on such condition. Signed-off-by: Pan Xinhui <xinhuix.pan@intel.com> Cc: Yury Norov <yury.norov@gmail.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lib/bitmap.c: correct a code style and do some, optimizationPan Xinhui2015-09-101-3/+4
| | | | | | | | | | | | | | We can avoid in-loop incrementation of ndigits. Save current totaldigits to ndigits before loop, and check ndigits against totaldigits after the loop. Signed-off-by: Pan Xinhui <xinhuix.pan@intel.com> Cc: Yury Norov <yury.norov@gmail.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: convert to kstrto*()/kstrto*_from_user()Alexey Dobriyan2015-09-101-49/+21
| | | | | | | | | | | | Convert from manual allocation/copy_from_user/... to kstrto*() family which were designed for exactly that. One case can not be converted to kstrto*_from_user() to make code even more simpler because of whitespace stripping, oh well... Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kstrto*: accept "-0" for signed conversionAlexey Dobriyan2015-09-102-6/+2
| | | | | | | | | | | | | | strtol(3) et al accept "-0", so should we. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: David Howells <dhowells@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Joel Becker <jlbec@evilplan.org> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* MAINTAINERS/CREDITS: mark MaxRAID as Orphan, move Anil Ravindranath to CREDITSJoe Perches2015-09-102-2/+5
| | | | | | | | | | Anil's email address bounces and he hasn't had a signoff in over 5 years. Signed-off-by: Joe Perches <joe@perches.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* include/linux/printk.h: include pr_fmt in pr_debug_ratelimitedJason A. Donenfeld2015-09-101-2/+2
| | | | | | | | | | | | | The other two implementations of pr_debug_ratelimited include pr_fmt, along with every other pr_* function. But pr_debug_ratelimited forgot to add it with the CONFIG_DYNAMIC_DEBUG implementation. This patch unifies the behavior. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/cred.c: remove unnecessary kdebug atomic readsJoe Perches2015-09-101-4/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit e0e817392b9a ("CRED: Add some configurable debugging [try #6]") added the kdebug mechanism to this file back in 2009. The kdebug macro calls no_printk which always evaluates arguments. Most of the kdebug uses have an unnecessary call of atomic_read(&cred->usage) Make the kdebug macro do nothing by defining it with do { if (0) no_printk(...); } while (0) when not enabled. $ size kernel/cred.o* (defconfig x86-64) text data bss dec hex filename 2748 336 8 3092 c14 kernel/cred.o.new 2788 336 8 3132 c3c kernel/cred.o.old Miscellanea: o Neaten the #define kdebug macros while there Signed-off-by: Joe Perches <joe@perches.com> Cc: David Howells <dhowells@redhat.com> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/extable.c: remove duplicated includeWei Yongjun2015-09-101-1/+0
| | | | | | | | Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* include/linux/poison.h: remove not-used poison pointer macrosVasily Kulikov2015-09-101-7/+0
| | | | | | | | | Signed-off-by: Vasily Kulikov <segoon@openwall.com> Cc: Solar Designer <solar@openwall.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* include/linux/poison.h: fix LIST_POISON{1,2} offsetVasily Kulikov2015-09-101-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | Poison pointer values should be small enough to find a room in non-mmap'able/hardly-mmap'able space. E.g. on x86 "poison pointer space" is located starting from 0x0. Given unprivileged users cannot mmap anything below mmap_min_addr, it should be safe to use poison pointers lower than mmap_min_addr. The current poison pointer values of LIST_POISON{1,2} might be too big for mmap_min_addr values equal or less than 1 MB (common case, e.g. Ubuntu uses only 0x10000). There is little point to use such a big value given the "poison pointer space" below 1 MB is not yet exhausted. Changing it to a smaller value solves the problem for small mmap_min_addr setups. The values are suggested by Solar Designer: http://www.openwall.com/lists/oss-security/2015/05/02/6 Signed-off-by: Vasily Kulikov <segoon@openwall.com> Cc: Solar Designer <solar@openwall.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: change proc_subdir_lock to a rwlockWaiman Long2015-09-101-22/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The proc_subdir_lock spinlock is used to allow only one task to make change to the proc directory structure as well as looking up information in it. However, the information lookup part can actually be entered by more than one task as the pde_get() and pde_put() reference count update calls in the critical sections are atomic increment and decrement respectively and so are safe with concurrent updates. The x86 architecture has already used qrwlock which is fair and other architectures like ARM are in the process of switching to qrwlock. So unfairness shouldn't be a concern in that conversion. This patch changed the proc_subdir_lock to a rwlock in order to enable concurrent lookup. The following functions were modified to take a write lock: - proc_register() - remove_proc_entry() - remove_proc_subtree() The following functions were modified to take a read lock: - xlate_proc_name() - proc_lookup_de() - proc_readdir_de() A parallel /proc filesystem search with the "find" command (1000 threads) was run on a 4-socket Haswell-EX box (144 threads). Before the patch, the parallel search took about 39s. After the patch, the parallel find took only 25s, a saving of about 14s. The micro-benchmark that I used was artificial, but it was used to reproduce an exit hanging problem that I saw in real application. In fact, only allow one task to do a lookup seems too limiting to me. Signed-off-by: Waiman Long <Waiman.Long@hp.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Scott J Norton <scott.norton@hp.com> Cc: Douglas Hatch <doug.hatch@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* procfs: always expose /proc/<pid>/map_files/ and make it readableCalvin Owens2015-09-101-19/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, /proc/<pid>/map_files/ is restricted to CAP_SYS_ADMIN, and is only exposed if CONFIG_CHECKPOINT_RESTORE is set. Each mapped file region gets a symlink in /proc/<pid>/map_files/ corresponding to the virtual address range at which it is mapped. The symlinks work like the symlinks in /proc/<pid>/fd/, so you can follow them to the backing file even if that backing file has been unlinked. Currently, files which are mapped, unlinked, and closed are impossible to stat() from userspace. Exposing /proc/<pid>/map_files/ closes this functionality "hole". Not being able to stat() such files makes noticing and explicitly accounting for the space they use on the filesystem impossible. You can work around this by summing up the space used by every file in the filesystem and subtracting that total from what statfs() tells you, but that obviously isn't great, and it becomes unworkable once your filesystem becomes large enough. This patch moves map_files/ out from behind CONFIG_CHECKPOINT_RESTORE, and adjusts the permissions enforced on it as follows: * proc_map_files_lookup() * proc_map_files_readdir() * map_files_d_revalidate() Remove the CAP_SYS_ADMIN restriction, leaving only the current restriction requiring PTRACE_MODE_READ. The information made available to userspace by these three functions is already available in /proc/PID/maps with MODE_READ, so I don't see any reason to limit them any further (see below for more detail). * proc_map_files_follow_link() This stub has been added, and requires that the user have CAP_SYS_ADMIN in order to follow the links in map_files/, since there was concern on LKML both about the potential for bypassing permissions on ancestor directories in the path to files pointed to, and about what happens with more exotic memory mappings created by some drivers (ie dma-buf). In older versions of this patch, I changed every permission check in the four functions above to enforce MODE_ATTACH instead of MODE_READ. This was an oversight on my part, and after revisiting the discussion it seems that nobody was concerned about anything outside of what is made possible by ->follow_link(). So in this version, I've left the checks for PTRACE_MODE_READ as-is. [akpm@linux-foundation.org: catch up with concurrent proc_pid_follow_link() changes] Signed-off-by: Calvin Owens <calvinowens@fb.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Joe Perches <joe@perches.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: add cond_resched to /proc/kpage* read/write loopVladimir Davydov2015-09-101-0/+6
| | | | | | | | | | | | | | | | | | | | | Reading/writing a /proc/kpage* file may take long on machines with a lot of RAM installed. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Suggested-by: Andres Lagar-Cavilla <andreslc@google.com> Reviewed-by: Andres Lagar-Cavilla <andreslc@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: export idle flag via kpageflagsVladimir Davydov2015-09-103-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | As noted by Minchan, a benefit of reading idle flag from /proc/kpageflags is that one can easily filter dirty and/or unevictable pages while estimating the size of unused memory. Note that idle flag read from /proc/kpageflags may be stale in case the page was accessed via a PTE, because it would be too costly to iterate over all page mappings on each /proc/kpageflags read to provide an up-to-date value. To make sure the flag is up-to-date one has to read /sys/kernel/mm/page_idle/bitmap first. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Reviewed-by: Andres Lagar-Cavilla <andreslc@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: introduce idle page trackingVladimir Davydov2015-09-1017-3/+512
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Knowing the portion of memory that is not used by a certain application or memory cgroup (idle memory) can be useful for partitioning the system efficiently, e.g. by setting memory cgroup limits appropriately. Currently, the only means to estimate the amount of idle memory provided by the kernel is /proc/PID/{clear_refs,smaps}: the user can clear the access bit for all pages mapped to a particular process by writing 1 to clear_refs, wait for some time, and then count smaps:Referenced. However, this method has two serious shortcomings: - it does not count unmapped file pages - it affects the reclaimer logic To overcome these drawbacks, this patch introduces two new page flags, Idle and Young, and a new sysfs file, /sys/kernel/mm/page_idle/bitmap. A page's Idle flag can only be set from userspace by setting bit in /sys/kernel/mm/page_idle/bitmap at the offset corresponding to the page, and it is cleared whenever the page is accessed either through page tables (it is cleared in page_referenced() in this case) or using the read(2) system call (mark_page_accessed()). Thus by setting the Idle flag for pages of a particular workload, which can be found e.g. by reading /proc/PID/pagemap, waiting for some time to let the workload access its working set, and then reading the bitmap file, one can estimate the amount of pages that are not used by the workload. The Young page flag is used to avoid interference with the memory reclaimer. A page's Young flag is set whenever the Access bit of a page table entry pointing to the page is cleared by writing to the bitmap file. If page_referenced() is called on a Young page, it will add 1 to its return value, therefore concealing the fact that the Access bit was cleared. Note, since there is no room for extra page flags on 32 bit, this feature uses extended page flags when compiled on 32 bit. [akpm@linux-foundation.org: fix build] [akpm@linux-foundation.org: kpageidle requires an MMU] [akpm@linux-foundation.org: decouple from page-flags rework] Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Reviewed-by: Andres Lagar-Cavilla <andreslc@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mmu-notifier: add clear_young callbackVladimir Davydov2015-09-103-0/+92
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the scope of the idle memory tracking feature, which is introduced by the following patch, we need to clear the referenced/accessed bit not only in primary, but also in secondary ptes. The latter is required in order to estimate wss of KVM VMs. At the same time we want to avoid flushing tlb, because it is quite expensive and it won't really affect the final result. Currently, there is no function for clearing pte young bit that would meet our requirements, so this patch introduces one. To achieve that we have to add a new mmu-notifier callback, clear_young, since there is no method for testing-and-clearing a secondary pte w/o flushing tlb. The new method is not mandatory and currently only implemented by KVM. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Reviewed-by: Andres Lagar-Cavilla <andreslc@google.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: add kpagecgroup fileVladimir Davydov2015-09-102-1/+58
| | | | | | | | | | | | | | | | | | | | | | | /proc/kpagecgroup contains a 64-bit inode number of the memory cgroup each page is charged to, indexed by PFN. Having this information is useful for estimating a cgroup working set size. The file is present if CONFIG_PROC_PAGE_MONITOR && CONFIG_MEMCG. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Reviewed-by: Andres Lagar-Cavilla <andreslc@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: zap try_get_mem_cgroup_from_pageVladimir Davydov2015-09-102-44/+13
| | | | | | | | | | | | | | | | | | | It is only used in mem_cgroup_try_charge, so fold it in and zap it. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Reviewed-by: Andres Lagar-Cavilla <andreslc@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hwpoison: use page_cgroup_ino for filtering by memcgVladimir Davydov2015-09-102-18/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | Hwpoison allows to filter pages by memory cgroup ino. Currently, it calls try_get_mem_cgroup_from_page to obtain the cgroup from a page and then its ino using cgroup_ino, but now we have a helper method for that, page_cgroup_ino, so use it instead. This patch also loosens the hwpoison memcg filter dependency rules - it makes it depend on CONFIG_MEMCG instead of CONFIG_MEMCG_SWAP, because hwpoison memcg filter does not require anything (nor it used to) from CONFIG_MEMCG_SWAP side. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Reviewed-by: Andres Lagar-Cavilla <andreslc@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: add page_cgroup_ino helperVladimir Davydov2015-09-102-0/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patchset introduces a new user API for tracking user memory pages that have not been used for a given period of time. The purpose of this is to provide the userspace with the means of tracking a workload's working set, i.e. the set of pages that are actively used by the workload. Knowing the working set size can be useful for partitioning the system more efficiently, e.g. by tuning memory cgroup limits appropriately, or for job placement within a compute cluster. ==== USE CASES ==== The unified cgroup hierarchy has memory.low and memory.high knobs, which are defined as the low and high boundaries for the workload working set size. However, the working set size of a workload may be unknown or change in time. With this patch set, one can periodically estimate the amount of memory unused by each cgroup and tune their memory.low and memory.high parameters accordingly, therefore optimizing the overall memory utilization. Another use case is balancing workloads within a compute cluster. Knowing how much memory is not really used by a workload unit may help take a more optimal decision when considering migrating the unit to another node within the cluster. Also, as noted by Minchan, this would be useful for per-process reclaim (https://lwn.net/Articles/545668/). With idle tracking, we could reclaim idle pages only by smart user memory manager. ==== USER API ==== The user API consists of two new files: * /sys/kernel/mm/page_idle/bitmap. This file implements a bitmap where each bit corresponds to a page, indexed by PFN. When the bit is set, the corresponding page is idle. A page is considered idle if it has not been accessed since it was marked idle. To mark a page idle one should set the bit corresponding to the page by writing to the file. A value written to the file is OR-ed with the current bitmap value. Only user memory pages can be marked idle, for other page types input is silently ignored. Writing to this file beyond max PFN results in the ENXIO error. Only available when CONFIG_IDLE_PAGE_TRACKING is set. This file can be used to estimate the amount of pages that are not used by a particular workload as follows: 1. mark all pages of interest idle by setting corresponding bits in the /sys/kernel/mm/page_idle/bitmap 2. wait until the workload accesses its working set 3. read /sys/kernel/mm/page_idle/bitmap and count the number of bits set * /proc/kpagecgroup. This file contains a 64-bit inode number of the memory cgroup each page is charged to, indexed by PFN. Only available when CONFIG_MEMCG is set. This file can be used to find all pages (including unmapped file pages) accounted to a particular cgroup. Using /sys/kernel/mm/page_idle/bitmap, one can then estimate the cgroup working set size. For an example of using these files for estimating the amount of unused memory pages per each memory cgroup, please see the script attached below. ==== REASONING ==== The reason to introduce the new user API instead of using /proc/PID/{clear_refs,smaps} is that the latter has two serious drawbacks: - it does not count unmapped file pages - it affects the reclaimer logic The new API attempts to overcome them both. For more details on how it is achieved, please see the comment to patch 6. ==== PATCHSET STRUCTURE ==== The patch set is organized as follows: - patch 1 adds page_cgroup_ino() helper for the sake of /proc/kpagecgroup and patches 2-3 do related cleanup - patch 4 adds /proc/kpagecgroup, which reports cgroup ino each page is charged to - patch 5 introduces a new mmu notifier callback, clear_young, which is a lightweight version of clear_flush_young; it is used in patch 6 - patch 6 implements the idle page tracking feature, including the userspace API, /sys/kernel/mm/page_idle/bitmap - patch 7 exports idle flag via /proc/kpageflags ==== SIMILAR WORKS ==== Originally, the patch for tracking idle memory was proposed back in 2011 by Michel Lespinasse (see http://lwn.net/Articles/459269/). The main difference between Michel's patch and this one is that Michel implemented a kernel space daemon for estimating idle memory size per cgroup while this patch only provides the userspace with the minimal API for doing the job, leaving the rest up to the userspace. However, they both share the same idea of Idle/Young page flags to avoid affecting the reclaimer logic. ==== PERFORMANCE EVALUATION ==== SPECjvm2008 (https://www.spec.org/jvm2008/) was used to evaluate the performance impact introduced by this patch set. Three runs were carried out: - base: kernel without the patch - patched: patched kernel, the feature is not used - patched-active: patched kernel, 1 minute-period daemon is used for tracking idle memory For tracking idle memory, idlememstat utility was used: https://github.com/locker/idlememstat testcase base patched patched-active compiler 537.40 ( 0.00)% 532.26 (-0.96)% 538.31 ( 0.17)% compress 305.47 ( 0.00)% 301.08 (-1.44)% 300.71 (-1.56)% crypto 284.32 ( 0.00)% 282.21 (-0.74)% 284.87 ( 0.19)% derby 411.05 ( 0.00)% 413.44 ( 0.58)% 412.07 ( 0.25)% mpegaudio 189.96 ( 0.00)% 190.87 ( 0.48)% 189.42 (-0.28)% scimark.large 46.85 ( 0.00)% 46.41 (-0.94)% 47.83 ( 2.09)% scimark.small 412.91 ( 0.00)% 415.41 ( 0.61)% 421.17 ( 2.00)% serial 204.23 ( 0.00)% 213.46 ( 4.52)% 203.17 (-0.52)% startup 36.76 ( 0.00)% 35.49 (-3.45)% 35.64 (-3.05)% sunflow 115.34 ( 0.00)% 115.08 (-0.23)% 117.37 ( 1.76)% xml 620.55 ( 0.00)% 619.95 (-0.10)% 620.39 (-0.03)% composite 211.50 ( 0.00)% 211.15 (-0.17)% 211.67 ( 0.08)% time idlememstat: 17.20user 65.16system 2:15:23elapsed 1%CPU (0avgtext+0avgdata 8476maxresident)k 448inputs+40outputs (1major+36052minor)pagefaults 0swaps ==== SCRIPT FOR COUNTING IDLE PAGES PER CGROUP ==== #! /usr/bin/python # import os import stat import errno import struct CGROUP_MOUNT = "/sys/fs/cgroup/memory" BUFSIZE = 8 * 1024 # must be multiple of 8 def get_hugepage_size(): with open("/proc/meminfo", "r") as f: for s in f: k, v = s.split(":") if k == "Hugepagesize": return int(v.split()[0]) * 1024 PAGE_SIZE = os.sysconf("SC_PAGE_SIZE") HUGEPAGE_SIZE = get_hugepage_size() def set_idle(): f = open("/sys/kernel/mm/page_idle/bitmap", "wb", BUFSIZE) while True: try: f.write(struct.pack("Q", pow(2, 64) - 1)) except IOError as err: if err.errno == errno.ENXIO: break raise f.close() def count_idle(): f_flags = open("/proc/kpageflags", "rb", BUFSIZE) f_cgroup = open("/proc/kpagecgroup", "rb", BUFSIZE) with open("/sys/kernel/mm/page_idle/bitmap", "rb", BUFSIZE) as f: while f.read(BUFSIZE): pass # update idle flag idlememsz = {} while True: s1, s2 = f_flags.read(8), f_cgroup.read(8) if not s1 or not s2: break flags, = struct.unpack('Q', s1) cgino, = struct.unpack('Q', s2) unevictable = (flags >> 18) & 1 huge = (flags >> 22) & 1 idle = (flags >> 25) & 1 if idle and not unevictable: idlememsz[cgino] = idlememsz.get(cgino, 0) + \ (HUGEPAGE_SIZE if huge else PAGE_SIZE) f_flags.close() f_cgroup.close() return idlememsz if __name__ == "__main__": print "Setting the idle flag for each page..." set_idle() raw_input("Wait until the workload accesses its working set, " "then press Enter") print "Counting idle pages..." idlememsz = count_idle() for dir, subdirs, files in os.walk(CGROUP_MOUNT): ino = os.stat(dir)[stat.ST_INO] print dir + ": " + str(idlememsz.get(ino, 0) / 1024) + " kB" ==== END SCRIPT ==== This patch (of 8): Add page_cgroup_ino() helper to memcg. This function returns the inode number of the closest online ancestor of the memory cgroup a page is charged to. It is required for exporting information about which page is charged to which cgroup to userspace, which will be introduced by a following patch. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Reviewed-by: Andres Lagar-Cavilla <andreslc@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zswap: update docs for runtime-changeable attributesDan Streetman2015-09-101-8/+28
| | | | | | | | | | | | Change the Documentation/vm/zswap.txt doc to indicate that the "zpool" and "compressor" params are now changeable at runtime. Signed-off-by: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zswap: change zpool/compressor at runtimeDan Streetman2015-09-101-13/+129
| | | | | | | | | | | | | | Update the zpool and compressor parameters to be changeable at runtime. When changed, a new pool is created with the requested zpool/compressor, and added as the current pool at the front of the pool list. Previous pools remain in the list only to remove existing compressed pages from. The old pool(s) are removed once they become empty. Signed-off-by: Dan Streetman <ddstreet@ieee.org> Acked-by: Seth Jennings <sjennings@variantweb.net> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zswap: dynamic pool creationDan Streetman2015-09-101-143/+405
| | | | | | | | | | | | | | | | Add dynamic creation of pools. Move the static crypto compression per-cpu transforms into each pool. Add a pointer to zswap_entry to the pool it's in. This is required by the following patch which enables changing the zswap zpool and compressor params at runtime. [akpm@linux-foundation.org: fix merge snafus] Signed-off-by: Dan Streetman <ddstreet@ieee.org> Acked-by: Seth Jennings <sjennings@variantweb.net> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zpool: add zpool_has_pool()Dan Streetman2015-09-102-0/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This series makes creation of the zpool and compressor dynamic, so that they can be changed at runtime. This makes using/configuring zswap easier, as before this zswap had to be configured at boot time, using boot params. This uses a single list to track both the zpool and compressor together, although Seth had mentioned an alternative which is to track the zpools and compressors using separate lists. In the most common case, only a single zpool and single compressor, using one list is slightly simpler than using two lists, and for the uncommon case of multiple zpools and/or compressors, using one list is slightly less simple (and uses slightly more memory, probably) than using two lists. This patch (of 4): Add zpool_has_pool() function, indicating if the specified type of zpool is available (i.e. zsmalloc or zbud). This allows checking if a pool is available, without actually trying to allocate it, similar to crypto_has_alg(). This is used by a following patch to zswap that enables the dynamic runtime creation of zswap zpools. Signed-off-by: Dan Streetman <ddstreet@ieee.org> Acked-by: Seth Jennings <sjennings@variantweb.net> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'for-linus' of ↵Linus Torvalds2015-09-09231-2731/+64431
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma Pull inifiniband/rdma updates from Doug Ledford: "This is a fairly sizeable set of changes. I've put them through a decent amount of testing prior to sending the pull request due to that. There are still a few fixups that I know are coming, but I wanted to go ahead and get the big, sizable chunk into your hands sooner rather than waiting for those last few fixups. Of note is the fact that this creates what is intended to be a temporary area in the drivers/staging tree specifically for some cleanups and additions that are coming for the RDMA stack. We deprecated two drivers (ipath and amso1100) and are waiting to hear back if we can deprecate another one (ehca). We also put Intel's new hfi1 driver into this area because it needs to be refactored and a transfer library created out of the factored out code, and then it and the qib driver and the soft-roce driver should all be modified to use that library. I expect drivers/staging/rdma to be around for three or four kernel releases and then to go away as all of the work is completed and final deletions of deprecated drivers are done. Summary of changes for 4.3: - Create drivers/staging/rdma - Move amso1100 driver to staging/rdma and schedule for deletion - Move ipath driver to staging/rdma and schedule for deletion - Add hfi1 driver to staging/rdma and set TODO for move to regular tree - Initial support for namespaces to be used on RDMA devices - Add RoCE GID table handling to the RDMA core caching code - Infrastructure to support handling of devices with differing read and write scatter gather capabilities - Various iSER updates - Kill off unsafe usage of global mr registrations - Update SRP driver - Misc mlx4 driver updates - Support for the mr_alloc verb - Support for a netlink interface between kernel and user space cache daemon to speed path record queries and route resolution - Ininitial support for safe hot removal of verbs devices" * tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma: (136 commits) IB/ipoib: Suppress warning for send only join failures IB/ipoib: Clean up send-only multicast joins IB/srp: Fix possible protection fault IB/core: Move SM class defines from ib_mad.h to ib_smi.h IB/core: Remove unnecessary defines from ib_mad.h IB/hfi1: Add PSM2 user space header to header_install IB/hfi1: Add CSRs for CONFIG_SDMA_VERBOSITY mlx5: Fix incorrect wc pkey_index assignment for GSI messages IB/mlx5: avoid destroying a NULL mr in reg_user_mr error flow IB/uverbs: reject invalid or unknown opcodes IB/cxgb4: Fix if statement in pick_local_ip6adddrs IB/sa: Fix rdma netlink message flags IB/ucma: HW Device hot-removal support IB/mlx4_ib: Disassociate support IB/uverbs: Enable device removal when there are active user space applications IB/uverbs: Explicitly pass ib_dev to uverbs commands IB/uverbs: Fix race between ib_uverbs_open and remove_one IB/uverbs: Fix reference counting usage of event files IB/core: Make ib_dealloc_pd return void IB/srp: Create an insecure all physical rkey only if needed ...
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