在 2020/4/21 下午10:39, Johannes Weiner 写道: > Hi Alex, > > thanks for your quick review so far, I'll add the tags to the patches. > > On Tue, Apr 21, 2020 at 05:27:30PM +0800, Alex Shi wrote: >> >> >> 在 2020/4/21 上午6:11, Johannes Weiner 写道: >>> The swapaccount=0 boot option will continue to exist, and it will >>> eliminate the page_counter overhead and hide the swap control files, >>> but it won't disable swap slot ownership tracking. >> >> May we add extra explanation for this change to user? and the default >> memsw limitations? > > Can you elaborate what you think is missing and where you would like > to see it documented? > Maybe the following doc change is better after whole patchset? Guess users would would happy to know details of this change. Also as to the RSS account name change, I don't know if it's good to polish them in docs. Thanks Alex diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst index 0ae4f564c2d6..1fd0878089fe 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. @@ -230,10 +230,10 @@ caller of swapoff rather than the users of shmem. 2.4 Swap Extension (CONFIG_MEMCG_SWAP) -------------------------------------- -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 swap is limited, following files are added. - memory.memsw.usage_in_bytes. - memory.memsw.limit_in_bytes. > From a semantics POV, nothing changes with this patch. The memsw limit > defaults to "max", so it doesn't exert any control per default. The > only difference is whether we maintain swap records or not. >
