BMC/Intel-BMC/linux.git/mm/zsmalloc.c, branch dev-5.2

mm/zsmalloc.c: fix build when CONFIG_COMPACTION=n

2019-09-06T08:23:34+00:00

commit 441e254cd40dc03beec3c650ce6ce6074bc6517f upstream. Fixes: 701d678599d0c1 ("mm/zsmalloc.c: fix race condition in zs_destroy_pool") Link: http://lkml.kernel.org/r/201908251039.5oSbEEUT%25lkp@intel.com Reported-by: kbuild test robot Cc: Sergey Senozhatsky Cc: Henry Burns Cc: Minchan Kim Cc: Shakeel Butt Cc: Jonathan Adams Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm/zsmalloc.c: fix race condition in zs_destroy_pool

2019-08-29T06:30:26+00:00

commit 701d678599d0c1623aaf4139c03eea260a75b027 upstream. In zs_destroy_pool() we call flush_work(&pool->free_work). However, we have no guarantee that migration isn't happening in the background at that time. Since migration can't directly free pages, it relies on free_work being scheduled to free the pages. But there's nothing preventing an in-progress migrate from queuing the work *after* zs_unregister_migration() has called flush_work(). Which would mean pages still pointing at the inode when we free it. Since we know at destroy time all objects should be free, no new migrations can come in (since zs_page_isolate() fails for fully-free zspages). This means it is sufficient to track a "# isolated zspages" count by class, and have the destroy logic ensure all such pages have drained before proceeding. Keeping that state under the class spinlock keeps the logic straightforward. In this case a memory leak could lead to an eventual crash if compaction hits the leaked page. This crash would only occur if people are changing their zswap backend at runtime (which eventually starts destruction). Link: http://lkml.kernel.org/r/20190809181751.219326-2-henryburns@google.com Fixes: 48b4800a1c6a ("zsmalloc: page migration support") Signed-off-by: Henry Burns Reviewed-by: Sergey Senozhatsky Cc: Henry Burns Cc: Minchan Kim Cc: Shakeel Butt Cc: Jonathan Adams Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm/zsmalloc.c: migration can leave pages in ZS_EMPTY indefinitely

2019-08-29T06:30:26+00:00

commit 1a87aa03597efa9641e92875b883c94c7f872ccb upstream. In zs_page_migrate() we call putback_zspage() after we have finished migrating all pages in this zspage. However, the return value is ignored. If a zs_free() races in between zs_page_isolate() and zs_page_migrate(), freeing the last object in the zspage, putback_zspage() will leave the page in ZS_EMPTY for potentially an unbounded amount of time. To fix this, we need to do the same thing as zs_page_putback() does: schedule free_work to occur. To avoid duplicated code, move the sequence to a new putback_zspage_deferred() function which both zs_page_migrate() and zs_page_putback() call. Link: http://lkml.kernel.org/r/20190809181751.219326-1-henryburns@google.com Fixes: 48b4800a1c6a ("zsmalloc: page migration support") Signed-off-by: Henry Burns Reviewed-by: Sergey Senozhatsky Cc: Henry Burns Cc: Minchan Kim Cc: Shakeel Butt Cc: Jonathan Adams Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm/zsmalloc.c: fix fall-through annotation

2018-10-26T23:26:35+00:00

Replace "fallthru" with a proper "fall through" annotation. This fix is part of the ongoing efforts to enabling -Wimplicit-fallthrough Link: http://lkml.kernel.org/r/20181003105114.GA24423@embeddedor.com Signed-off-by: Gustavo A. R. Silva Reviewed-by: Sergey Senozhatsky Cc: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/zsmalloc.c: make several functions and a struct static

2018-08-17T23:20:30+00:00

The functions zs_page_isolate, zs_page_migrate, zs_page_putback, lock_zspage, trylock_zspage and structure zsmalloc_aops are local to source and do not need to be in global scope, so make them static. Cleans up sparse warnings: symbol 'zs_page_isolate' was not declared. Should it be static? symbol 'zs_page_migrate' was not declared. Should it be static? symbol 'zs_page_putback' was not declared. Should it be static? symbol 'zsmalloc_aops' was not declared. Should it be static? symbol 'lock_zspage' was not declared. Should it be static? symbol 'trylock_zspage' was not declared. Should it be static? [arnd@arndb.de: hide unused lock_zspage] Link: http://lkml.kernel.org/r/20180706130924.3891230-1-arnd@arndb.de Link: http://lkml.kernel.org/r/20180624213322.13776-1-colin.king@canonical.com Signed-off-by: Colin Ian King Reviewed-by: Sergey Senozhatsky Reviewed-by: Andrew Morton Cc: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: use octal not symbolic permissions

2018-06-14T22:55:25+00:00

mm/*.c files use symbolic and octal styles for permissions. Using octal and not symbolic permissions is preferred by many as more readable. https://lkml.org/lkml/2016/8/2/1945 Prefer the direct use of octal for permissions. Done using $ scripts/checkpatch.pl -f --types=SYMBOLIC_PERMS --fix-inplace mm/*.c and some typing. Before: $ git grep -P -w "0[0-7]{3,3}" mm | wc -l 44 After: $ git grep -P -w "0[0-7]{3,3}" mm | wc -l 86 Miscellanea: o Whitespace neatening around these conversions. Link: http://lkml.kernel.org/r/2e032ef111eebcd4c5952bae86763b541d373469.1522102887.git.joe@perches.com Signed-off-by: Joe Perches Acked-by: David Rientjes Acked-by: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: kernel-doc: add missing parameter descriptions

2018-04-06T04:36:27+00:00

Link: http://lkml.kernel.org/r/1519585191-10180-4-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport Reviewed-by: Andrew Morton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

zsmalloc: introduce zs_huge_class_size()

2018-04-06T04:36:26+00:00

Patch series "zsmalloc/zram: drop zram's max_zpage_size", v3. ZRAM's max_zpage_size is a bad thing. It forces zsmalloc to store normal objects as huge ones, which results in bigger zsmalloc memory usage. Drop it and use actual zsmalloc huge-class value when decide if the object is huge or not. This patch (of 2): Not every object can be share its zspage with other objects, e.g. when the object is as big as zspage or nearly as big a zspage. For such objects zsmalloc has a so called huge class - every object which belongs to huge class consumes the entire zspage (which consists of a physical page). On x86_64, PAGE_SHIFT 12 box, the first non-huge class size is 3264, so starting down from size 3264, objects can share page(-s) and thus minimize memory wastage. ZRAM, however, has its own statically defined watermark for huge objects, namely "3 * PAGE_SIZE / 4 = 3072", and forcibly stores every object larger than this watermark (3072) as a PAGE_SIZE object, in other words, to a huge class, while zsmalloc can keep some of those objects in non-huge classes. This results in increased memory consumption. zsmalloc knows better if the object is huge or not. Introduce zs_huge_class_size() function which tells if the given object can be stored in one of non-huge classes or not. This will let us to drop ZRAM's huge object watermark and fully rely on zsmalloc when we decide if the object is huge. [sergey.senozhatsky.work@gmail.com: add pool param to zs_huge_class_size()] Link: http://lkml.kernel.org/r/20180314081833.1096-2-sergey.senozhatsky@gmail.com Link: http://lkml.kernel.org/r/20180306070639.7389-2-sergey.senozhatsky@gmail.com Signed-off-by: Sergey Senozhatsky Acked-by: Minchan Kim Cc: Mike Rapoport Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: reuse DEFINE_SHOW_ATTRIBUTE() macro

2018-04-06T04:36:25+00:00

...instead of open coding file operations followed by custom ->open() callbacks per each attribute. [andriy.shevchenko@linux.intel.com: add tags, fix compilation issue] Link: http://lkml.kernel.org/r/20180217144253.58604-1-andriy.shevchenko@linux.intel.com Link: http://lkml.kernel.org/r/20180214154644.54505-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Reviewed-by: Matthew Wilcox Reviewed-by: Andrew Morton Reviewed-by: Sergey Senozhatsky Acked-by: Christoph Lameter Cc: Tejun Heo Cc: Dennis Zhou Cc: Minchan Kim Cc: Nitin Gupta Cc: Sergey Senozhatsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/zsmalloc: Prepare to variable MAX_PHYSMEM_BITS

2018-02-14T12:11:13+00:00

With boot-time switching between paging mode we will have variable MAX_PHYSMEM_BITS. Let's use the maximum variable possible for CONFIG_X86_5LEVEL=y configuration to define zsmalloc data structures. The patch introduces MAX_POSSIBLE_PHYSMEM_BITS to cover such case. It also suits well to handle PAE special case. Signed-off-by: Kirill A. Shutemov Reviewed-by: Nitin Gupta Acked-by: Minchan Kim Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Sergey Senozhatsky Cc: Thomas Gleixner Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180214111656.88514-3-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar