From: Mel Gorman <mgorman@techsingularity.net> To: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Weiner <hannes@cmpxchg.org>, Minchan Kim <minchan@kernel.org>, Michal Hocko <mhocko@suse.cz>, Vlastimil Babka <vbabka@suse.cz>, Linux-MM <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>, Mel Gorman <mgorman@techsingularity.net> Subject: [PATCH 5/5] mm, vmscan: Account for skipped pages as a partial scan Date: Thu, 21 Jul 2016 15:11:01 +0100 [thread overview] Message-ID: <1469110261-7365-6-git-send-email-mgorman@techsingularity.net> (raw) In-Reply-To: <1469110261-7365-1-git-send-email-mgorman@techsingularity.net> Page reclaim determines whether a pgdat is unreclaimable by examining how many pages have been scanned since a page was freed and comparing that to the LRU sizes. Skipped pages are not reclaim candidates but contribute to scanned. This can prematurely mark a pgdat as unreclaimable and trigger an OOM kill. This patch accounts for skipped pages as a partial scan so that an unreclaimable pgdat will still be marked as such but by scaling the cost of a skip, it'll avoid the pgdat being marked prematurely. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> --- mm/vmscan.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 6810d81f60c7..e5af357dd4ac 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1424,7 +1424,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, LIST_HEAD(pages_skipped); for (scan = 0; scan < nr_to_scan && nr_taken < nr_to_scan && - !list_empty(src); scan++) { + !list_empty(src);) { struct page *page; page = lru_to_page(src); @@ -1438,6 +1438,12 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, continue; } + /* + * Account for scanned and skipped separetly to avoid the pgdat + * being prematurely marked unreclaimable by pgdat_reclaimable. + */ + scan++; + switch (__isolate_lru_page(page, mode)) { case 0: nr_pages = hpage_nr_pages(page); @@ -1465,14 +1471,24 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, */ if (!list_empty(&pages_skipped)) { int zid; + unsigned long total_skipped = 0; - list_splice(&pages_skipped, src); for (zid = 0; zid < MAX_NR_ZONES; zid++) { if (!nr_skipped[zid]) continue; __count_zid_vm_events(PGSCAN_SKIP, zid, nr_skipped[zid]); + total_skipped += nr_skipped[zid]; } + + /* + * Account skipped pages as a partial scan as the pgdat may be + * close to unreclaimable. If the LRU list is empty, account + * skipped pages as a full scan. + */ + scan += list_empty(src) ? total_skipped : total_skipped >> 2; + + list_splice(&pages_skipped, src); } *nr_scanned = scan; trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan, scan, -- 2.6.4
WARNING: multiple messages have this Message-ID (diff)
From: Mel Gorman <mgorman@techsingularity.net> To: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Weiner <hannes@cmpxchg.org>, Minchan Kim <minchan@kernel.org>, Michal Hocko <mhocko@suse.cz>, Vlastimil Babka <vbabka@suse.cz>, Linux-MM <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>, Mel Gorman <mgorman@techsingularity.net> Subject: [PATCH 5/5] mm, vmscan: Account for skipped pages as a partial scan Date: Thu, 21 Jul 2016 15:11:01 +0100 [thread overview] Message-ID: <1469110261-7365-6-git-send-email-mgorman@techsingularity.net> (raw) In-Reply-To: <1469110261-7365-1-git-send-email-mgorman@techsingularity.net> Page reclaim determines whether a pgdat is unreclaimable by examining how many pages have been scanned since a page was freed and comparing that to the LRU sizes. Skipped pages are not reclaim candidates but contribute to scanned. This can prematurely mark a pgdat as unreclaimable and trigger an OOM kill. This patch accounts for skipped pages as a partial scan so that an unreclaimable pgdat will still be marked as such but by scaling the cost of a skip, it'll avoid the pgdat being marked prematurely. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> --- mm/vmscan.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 6810d81f60c7..e5af357dd4ac 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1424,7 +1424,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, LIST_HEAD(pages_skipped); for (scan = 0; scan < nr_to_scan && nr_taken < nr_to_scan && - !list_empty(src); scan++) { + !list_empty(src);) { struct page *page; page = lru_to_page(src); @@ -1438,6 +1438,12 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, continue; } + /* + * Account for scanned and skipped separetly to avoid the pgdat + * being prematurely marked unreclaimable by pgdat_reclaimable. + */ + scan++; + switch (__isolate_lru_page(page, mode)) { case 0: nr_pages = hpage_nr_pages(page); @@ -1465,14 +1471,24 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, */ if (!list_empty(&pages_skipped)) { int zid; + unsigned long total_skipped = 0; - list_splice(&pages_skipped, src); for (zid = 0; zid < MAX_NR_ZONES; zid++) { if (!nr_skipped[zid]) continue; __count_zid_vm_events(PGSCAN_SKIP, zid, nr_skipped[zid]); + total_skipped += nr_skipped[zid]; } + + /* + * Account skipped pages as a partial scan as the pgdat may be + * close to unreclaimable. If the LRU list is empty, account + * skipped pages as a full scan. + */ + scan += list_empty(src) ? total_skipped : total_skipped >> 2; + + list_splice(&pages_skipped, src); } *nr_scanned = scan; trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan, scan, -- 2.6.4 -- 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/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2016-07-21 14:11 UTC|newest] Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-07-21 14:10 [PATCH 0/5] Candidate fixes for premature OOM kills with node-lru v2 Mel Gorman 2016-07-21 14:10 ` Mel Gorman 2016-07-21 14:10 ` [PATCH 1/5] mm: add per-zone lru list stat Mel Gorman 2016-07-21 14:10 ` Mel Gorman 2016-07-22 15:51 ` Johannes Weiner 2016-07-22 15:51 ` Johannes Weiner 2016-07-21 14:10 ` [PATCH 2/5] mm, vmscan: Remove highmem_file_pages Mel Gorman 2016-07-21 14:10 ` Mel Gorman 2016-07-22 15:53 ` Johannes Weiner 2016-07-22 15:53 ` Johannes Weiner 2016-07-25 8:09 ` Minchan Kim 2016-07-25 8:09 ` Minchan Kim 2016-07-25 9:23 ` [PATCH] mm, vmscan: remove highmem_file_pages -fix Mel Gorman 2016-07-25 9:23 ` Mel Gorman 2016-07-21 14:10 ` [PATCH 3/5] mm: Remove reclaim and compaction retry approximations Mel Gorman 2016-07-21 14:10 ` Mel Gorman 2016-07-22 15:57 ` Johannes Weiner 2016-07-22 15:57 ` Johannes Weiner 2016-07-25 8:18 ` Minchan Kim 2016-07-25 8:18 ` Minchan Kim 2016-07-21 14:11 ` [PATCH 4/5] mm: consider per-zone inactive ratio to deactivate Mel Gorman 2016-07-21 14:11 ` Mel Gorman 2016-07-21 15:52 ` Johannes Weiner 2016-07-21 15:52 ` Johannes Weiner 2016-07-21 14:11 ` Mel Gorman [this message] 2016-07-21 14:11 ` [PATCH 5/5] mm, vmscan: Account for skipped pages as a partial scan Mel Gorman 2016-07-22 16:02 ` Johannes Weiner 2016-07-22 16:02 ` Johannes Weiner 2016-07-25 8:39 ` Minchan Kim 2016-07-25 8:39 ` Minchan Kim 2016-07-25 9:52 ` Mel Gorman 2016-07-25 9:52 ` Mel Gorman 2016-07-26 8:16 ` Joonsoo Kim 2016-07-26 8:16 ` Joonsoo Kim 2016-07-26 8:26 ` Joonsoo Kim 2016-07-26 8:26 ` Joonsoo Kim 2016-07-26 8:11 ` [PATCH 0/5] Candidate fixes for premature OOM kills with node-lru v2 Joonsoo Kim 2016-07-26 8:11 ` Joonsoo Kim 2016-07-26 12:50 ` Mel Gorman 2016-07-26 12:50 ` Mel Gorman 2016-07-28 6:44 ` Joonsoo Kim 2016-07-28 6:44 ` Joonsoo Kim 2016-07-28 10:27 ` Mel Gorman 2016-07-28 10:27 ` Mel Gorman
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=1469110261-7365-6-git-send-email-mgorman@techsingularity.net \ --to=mgorman@techsingularity.net \ --cc=akpm@linux-foundation.org \ --cc=hannes@cmpxchg.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-mm@kvack.org \ --cc=mhocko@suse.cz \ --cc=minchan@kernel.org \ --cc=vbabka@suse.cz \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.