diff options
| author | Alex Shi | 2020-06-03 16:02:21 -0700 |
|---|---|---|
| committer | Linus Torvalds | 2020-06-03 20:09:48 -0700 |
| commit | 0a27cae1389f6342e7b09179d2b2da9011d60c96 (patch) | |
| tree | 9fd8efcb4ddfd1b526e3413ac7ba55acd4a8b73a /Documentation | |
| parent | 4c6355b25e8bb83c3cb455f532b7542089699d98 (diff) | |
mm: memcontrol: document the new swap control behavior
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-18-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/admin-guide/cgroup-v1/memory.rst | 19 |
1 files changed, 7 insertions, 12 deletions
diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst index 0ae4f564c2d6..12757e63b26c 100644 --- a/Documentation/admin-guide/cgroup-v1/memory.rst +++ b/Documentation/admin-guide/cgroup-v1/memory.rst @@ -199,11 +199,11 @@ An RSS page is unaccounted when it's fully unmapped. A PageCache page is unaccounted when it's removed from radix-tree. Even if RSS pages are fully unmapped (by kswapd), they may exist as SwapCache in the system until they are really freed. Such SwapCaches are also accounted. -A swapped-in page is not accounted until it's mapped. +A swapped-in page is accounted after adding into swapcache. Note: The kernel does swapin-readahead and reads multiple swaps at once. -This means swapped-in pages may contain pages for other tasks than a task -causing page fault. So, we avoid accounting at swap-in I/O. +Since page's memcg recorded into swap whatever memsw enabled, the page will +be accounted after swapin. At page migration, accounting information is kept. @@ -222,18 +222,13 @@ the cgroup that brought it in -- this will happen on memory pressure). But see section 8.2: when moving a task to another cgroup, its pages may be recharged to the new cgroup, if move_charge_at_immigrate has been chosen. -Exception: If CONFIG_MEMCG_SWAP is not used. -When you do swapoff and make swapped-out pages of shmem(tmpfs) to -be backed into memory in force, charges for pages are accounted against the -caller of swapoff rather than the users of shmem. - -2.4 Swap Extension (CONFIG_MEMCG_SWAP) +2.4 Swap Extension -------------------------------------- -Swap Extension allows you to record charge for swap. A swapped-in page is -charged back to original page allocator if possible. +Swap usage is always recorded for each of cgroup. Swap Extension allows you to +read and limit it. -When swap is accounted, following files are added. +When CONFIG_SWAP is enabled, following files are added. - memory.memsw.usage_in_bytes. - memory.memsw.limit_in_bytes. |