diff options
| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2016-02-03 03:57:15 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-02-03 19:28:43 +0300 |
| commit | e3ae19535c665771e2c03cdd63df9bc4d6b37941 (patch) | |
| tree | d25d4a9c455874aac68e34e37d46fcb8d50b05ae /mm/huge_memory.c | |
| parent | cb8d68ec16a511f8be7e1028fd8f869ef7c6a1a8 (diff) | |
| download | linux-e3ae19535c665771e2c03cdd63df9bc4d6b37941.tar.xz | |
thp: limit number of object to scan on deferred_split_scan()
If we have a lot of pages in queue to be split, deferred_split_scan()
can spend unreasonable amount of time under spinlock with disabled
interrupts.
Let's cap number of pages to split on scan by sc->nr_to_scan.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/huge_memory.c')
| -rw-r--r-- | mm/huge_memory.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 7aae72114583..c1411961167e 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3478,17 +3478,19 @@ static unsigned long deferred_split_scan(struct shrinker *shrink, int split = 0; spin_lock_irqsave(&pgdata->split_queue_lock, flags); - list_splice_init(&pgdata->split_queue, &list); - /* Take pin on all head pages to avoid freeing them under us */ list_for_each_safe(pos, next, &list) { page = list_entry((void *)pos, struct page, mapping); page = compound_head(page); - /* race with put_compound_page() */ - if (!get_page_unless_zero(page)) { + if (get_page_unless_zero(page)) { + list_move(page_deferred_list(page), &list); + } else { + /* We lost race with put_compound_page() */ list_del_init(page_deferred_list(page)); pgdata->split_queue_len--; } + if (!--sc->nr_to_scan) + break; } spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |