linux-toradex.git/mm/zsmalloc.c, branch v4.17-rc7

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

zsmalloc: use U suffix for negative literals being shifted

2018-02-01T01:18:39+00:00

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

2018-02-01T01:18:39+00:00

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

2018-02-01T01:18:38+00:00

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

2018-01-05T00:45:09+00:00

`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

2017-11-16T02:21:03+00:00

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

mm/zsmalloc.c: change stat type parameter to int

2017-09-09T01:26:47+00:00

zs_stat_inc/dec/get() uses enum zs_stat_type for the stat type, however
some callers pass an enum fullness_group value.  Change the type to int to
reflect the actual use of the functions and get rid of 'enum-conversion'
warnings

Link: http://lkml.kernel.org/r/20170731175000.56538-1-mka@chromium.org
Signed-off-by: Matthias Kaehlcke 
Reviewed-by: Sergey Senozhatsky 
Acked-by: Minchan Kim 
Cc: Doug Anderson 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds