kernel.git/mm/zsmalloc.c, branch linux-4.18.y

mm: use octal not symbolic permissions

2018-06-14T22:55:25Z

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

2018-04-06T04:36:27Z

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()

2018-04-06T04:36:26Z

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

2018-04-06T04:36:25Z

...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

2018-02-14T12:11:13Z

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

zsmalloc: use U suffix for negative literals being shifted

2018-02-01T01:18:39Z

Fix warning about shifting unsigned literals being undefined behavior. Link: http://lkml.kernel.org/r/1515642078-4259-1-git-send-email-nick.desaulniers@gmail.com Signed-off-by: Nick Desaulniers Suggested-by: Minchan Kim Reviewed-by: Sergey Senozhatsky Cc: Andy Shevchenko Cc: Matthew Wilcox Cc: Nick Desaulniers Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

zswap: only save zswap header when necessary

2018-02-01T01:18:39Z

We waste sizeof(swp_entry_t) for zswap header when using zsmalloc as zpool driver because zsmalloc doesn't support eviction. Add zpool_evictable() to detect if zpool is potentially evictable, and use it in zswap to avoid waste memory for zswap header. [yuzhao@google.com: The zpool->" prefix is a result of copy & paste] Link: http://lkml.kernel.org/r/20180110225626.110330-1-yuzhao@google.com Link: http://lkml.kernel.org/r/20180110224741.83751-1-yuzhao@google.com Signed-off-by: Yu Zhao Acked-by: Dan Streetman Reviewed-by: Sergey Senozhatsky Cc: Seth Jennings Cc: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/zsmalloc: simplify shrinker init/destroy

2018-02-01T01:18:38Z

Structure zs_pool has special flag to indicate success of shrinker initialization. unregister_shrinker() has improved and can detect by itself whether actual deinitialization should be performed or not, so extra flag becomes redundant. [akpm@linux-foundation.org: update comment (Aliaksei), remove unneeded cast] Link: http://lkml.kernel.org/r/1513680552-9798-1-git-send-email-akaraliou.dev@gmail.com Signed-off-by: Aliaksei Karaliou Reviewed-by: Sergey Senozhatsky Acked-by: Minchan Kim Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/zsmalloc.c: include fs.h

2018-01-05T00:45:09Z

`struct file_system_type' and alloc_anon_inode() function are defined in fs.h, include it directly. Link: http://lkml.kernel.org/r/20171219104219.3017-1-sergey.senozhatsky@gmail.com Signed-off-by: Sergey Senozhatsky Cc: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

zsmalloc: calling zs_map_object() from irq is a bug

2017-11-16T02:21:03Z

Use BUG_ON(in_interrupt()) in zs_map_object(). This is not a new BUG_ON(), it's always been there, but was recently changed to VM_BUG_ON(). There are several problems there. First, we use use per-CPU mappings both in zsmalloc and in zram, and interrupt may easily corrupt those buffers. Second, and more importantly, we believe it's possible to start leaking sensitive information. Consider the following case: -> process P swap out zram per-cpu mapping CPU1 compress page A -> IRQ swap out zram per-cpu mapping CPU1 compress page B write page from per-cpu mapping CPU1 to zsmalloc pool iret -> process P write page from per-cpu mapping CPU1 to zsmalloc pool [*] return * so we store overwritten data that actually belongs to another page (task) and potentially contains sensitive data. And when process P will page fault it's going to read (swap in) that other task's data. Link: http://lkml.kernel.org/r/20170929045140.4055-1-sergey.senozhatsky@gmail.com Signed-off-by: Sergey Senozhatsky Acked-by: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds