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| author | Hugh Dickins <hughd@google.com> | 2016-12-12 16:44:44 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-12-12 18:55:08 -0800 |
| commit | dc644a073769dd8949a75691eb4a5bdeb70a7d51 (patch) | |
| tree | da576c3a8a1e38cbef5f00ce3974f45295832a63 /mm/swapfile.c | |
| parent | a6de734bc002fe2027ccc074fbbd87d72957b7a4 (diff) | |
| download | lwn-dc644a073769dd8949a75691eb4a5bdeb70a7d51.tar.gz lwn-dc644a073769dd8949a75691eb4a5bdeb70a7d51.zip | |
mm: add three more cond_resched() in swapoff
Add a cond_resched() in the unuse_pmd_range() loop (so as to call it
even when pmd none or trans_huge, like zap_pmd_range() does); and in the
unuse_mm() loop (since that might skip over many vmas). shmem_unuse()
and radix_tree_locate_item() look good enough already.
Those were the obvious places, but in fact the stalls came from
find_next_to_unuse(), which sometimes scans through many unused entries.
Apply scan_swap_map()'s LATENCY_LIMIT of 256 there too; and only go off
to test frontswap_map when a used entry is found.
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1612052155140.13021@eggly.anvils
Signed-off-by: Hugh Dickins <hughd@google.com>
Reported-by: Eric Dumazet <edumazet@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/swapfile.c')
| -rw-r--r-- | mm/swapfile.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c index f30438970cd1..1c6e0321205d 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1234,6 +1234,7 @@ static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud, pmd = pmd_offset(pud, addr); do { + cond_resched(); next = pmd_addr_end(addr, end); if (pmd_none_or_trans_huge_or_clear_bad(pmd)) continue; @@ -1313,6 +1314,7 @@ static int unuse_mm(struct mm_struct *mm, for (vma = mm->mmap; vma; vma = vma->vm_next) { if (vma->anon_vma && (ret = unuse_vma(vma, entry, page))) break; + cond_resched(); } up_read(&mm->mmap_sem); return (ret < 0)? ret: 0; @@ -1350,15 +1352,12 @@ static unsigned int find_next_to_unuse(struct swap_info_struct *si, prev = 0; i = 1; } - if (frontswap) { - if (frontswap_test(si, i)) - break; - else - continue; - } count = READ_ONCE(si->swap_map[i]); if (count && swap_count(count) != SWAP_MAP_BAD) - break; + if (!frontswap || frontswap_test(si, i)) + break; + if ((i % LATENCY_LIMIT) == 0) + cond_resched(); } return i; } |