On Wed, Jan 25, 2012 at 02:41:00PM +0900, KAMEZAWA Hiroyuki wrote:

Subject: [PATCH v5] memcg: remove PCG_CACHE

We record 'the page is cache' by PCG_CACHE bit to page_cgroup.
Here, "CACHE" means anonymous user pages (and SwapCache). This
doesn't include shmem.

Consdering callers, at charge/uncharge, the caller should know
what  the page is and we don't need to record it by using 1bit
per page.

This patch removes PCG_CACHE bit and make callers of
mem_cgroup_charge_statistics() to specify what the page is.

About page migration:
Mapping of the used page is not touched during migration (see
page_remove_rmap) so we can rely on it and push the correct charge type
down to __mem_cgroup_uncharge_common from end_migration for unused page.
The force flag was misleading was abused for skipping the needless
page_mapped() / PageCgroupMigration() check, as we know the unused page
is no longer mapped and cleared the migration flag just a few lines
up.  But doing the checks is no biggie and it's not worth adding another
flag just to skip them.

Changelog since v4
 - fixed a bug at page migration by Michal Hokko.

Changelog since v3
 - renamed a variable 'rss' to 'anon'

Changelog since v2
 - removed 'not_rss', added 'anon'
 - changed a meaning of arguments to mem_cgroup_charge_statisitcs()
 - removed a patch to mem_cgroup_uncharge_cache
 - simplified comment.

Changelog since RFC.
 - rebased onto memcg-devel
 - rename 'file' to 'not_rss'
 - some cleanup and added comment.

Signed-off-by: KAMEZAWA Hiroyuki <redacted>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>