Commit fe490cc0 authored Sep 06, 2017 by Huang Ying Committed by Linus Torvalds Sep 06, 2017

mm, THP, swap: add THP swapping out fallback counting

When swapping out THP (Transparent Huge Page), instead of swapping out
the THP as a whole, sometimes we have to fallback to split the THP into
normal pages before swapping, because no free swap clusters are
available, or cgroup limit is exceeded, etc.  To count the number of the
fallback, a new VM event THP_SWPOUT_FALLBACK is added, and counted when
we fallback to split the THP.

Link: http://lkml.kernel.org/r/20170724051840.2309-13-ying.huang@intel.com


Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Ross Zwisler <ross.zwisler@intel.com> [for brd.c, zram_drv.c, pmem.c]
Cc: Vishal L Verma <vishal.l.verma@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent bd4c82c2

include/linux/vm_event_item.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -86,6 +86,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
		THP_ZERO_PAGE_ALLOC,
		THP_ZERO_PAGE_ALLOC_FAILED,
		THP_SWPOUT,
		THP_SWPOUT_FALLBACK,
		#endif
		#ifdef CONFIG_MEMORY_BALLOON
		BALLOON_INFLATE,

mm/vmscan.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -1154,6 +1154,9 @@ static unsigned long shrink_page_list(struct list_head *page_list,
		if (split_huge_page_to_list(page,
		page_list))
		goto activate_locked;
		#ifdef CONFIG_TRANSPARENT_HUGEPAGE
		count_vm_event(THP_SWPOUT_FALLBACK);
		#endif
		if (!add_to_swap(page))
		goto activate_locked;
		}

mm/vmstat.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -1072,6 +1072,7 @@ const char * const vmstat_text[] = {
		"thp_zero_page_alloc",
		"thp_zero_page_alloc_failed",
		"thp_swpout",
		"thp_swpout_fallback",
		#endif
		#ifdef CONFIG_MEMORY_BALLOON
		"balloon_inflate",

Admin message