diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2018-10-26 19:33:41 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-10-26 19:33:41 -0700 |
commit | 345671ea0f9258f410eb057b9ced9cefbbe5dc78 (patch) | |
tree | fe97ba3d27679789e6aa34e39b002ee64ce25412 /mm/page-writeback.c | |
parent | 4904008165c8a1c48602b8316139691b8c735e6e (diff) | |
parent | 22146c3ce98962436e401f7b7016a6f664c9ffb5 (diff) |
Merge branch 'akpm' (patches from Andrew)
Merge updates from Andrew Morton:
- a few misc things
- ocfs2 updates
- most of MM
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (132 commits)
hugetlbfs: dirty pages as they are added to pagecache
mm: export add_swap_extent()
mm: split SWP_FILE into SWP_ACTIVATED and SWP_FS
tools/testing/selftests/vm/map_fixed_noreplace.c: add test for MAP_FIXED_NOREPLACE
mm: thp: relocate flush_cache_range() in migrate_misplaced_transhuge_page()
mm: thp: fix mmu_notifier in migrate_misplaced_transhuge_page()
mm: thp: fix MADV_DONTNEED vs migrate_misplaced_transhuge_page race condition
mm/kasan/quarantine.c: make quarantine_lock a raw_spinlock_t
mm/gup: cache dev_pagemap while pinning pages
Revert "x86/e820: put !E820_TYPE_RAM regions into memblock.reserved"
mm: return zero_resv_unavail optimization
mm: zero remaining unavailable struct pages
tools/testing/selftests/vm/gup_benchmark.c: add MAP_HUGETLB option
tools/testing/selftests/vm/gup_benchmark.c: add MAP_SHARED option
tools/testing/selftests/vm/gup_benchmark.c: allow user specified file
tools/testing/selftests/vm/gup_benchmark.c: fix 'write' flag usage
mm/gup_benchmark.c: add additional pinning methods
mm/gup_benchmark.c: time put_page()
mm: don't raise MEMCG_OOM event due to failed high-order allocation
mm/page-writeback.c: fix range_cyclic writeback vs writepages deadlock
...
Diffstat (limited to 'mm/page-writeback.c')
-rw-r--r-- | mm/page-writeback.c | 33 |
1 files changed, 15 insertions, 18 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 84ae9bf5858a..439a304a6c92 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -2149,6 +2149,13 @@ EXPORT_SYMBOL(tag_pages_for_writeback); * not miss some pages (e.g., because some other process has cleared TOWRITE * tag we set). The rule we follow is that TOWRITE tag can be cleared only * by the process clearing the DIRTY tag (and submitting the page for IO). + * + * To avoid deadlocks between range_cyclic writeback and callers that hold + * pages in PageWriteback to aggregate IO until write_cache_pages() returns, + * we do not loop back to the start of the file. Doing so causes a page + * lock/page writeback access order inversion - we should only ever lock + * multiple pages in ascending page->index order, and looping back to the start + * of the file violates that rule and causes deadlocks. */ int write_cache_pages(struct address_space *mapping, struct writeback_control *wbc, writepage_t writepage, @@ -2162,7 +2169,6 @@ int write_cache_pages(struct address_space *mapping, pgoff_t index; pgoff_t end; /* Inclusive */ pgoff_t done_index; - int cycled; int range_whole = 0; int tag; @@ -2170,23 +2176,17 @@ int write_cache_pages(struct address_space *mapping, if (wbc->range_cyclic) { writeback_index = mapping->writeback_index; /* prev offset */ index = writeback_index; - if (index == 0) - cycled = 1; - else - cycled = 0; end = -1; } else { index = wbc->range_start >> PAGE_SHIFT; end = wbc->range_end >> PAGE_SHIFT; if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) range_whole = 1; - cycled = 1; /* ignore range_cyclic tests */ } if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages) tag = PAGECACHE_TAG_TOWRITE; else tag = PAGECACHE_TAG_DIRTY; -retry: if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages) tag_pages_for_writeback(mapping, index, end); done_index = index; @@ -2272,17 +2272,14 @@ continue_unlock: pagevec_release(&pvec); cond_resched(); } - if (!cycled && !done) { - /* - * range_cyclic: - * We hit the last page and there is more work to be done: wrap - * back to the start of the file - */ - cycled = 1; - index = 0; - end = writeback_index - 1; - goto retry; - } + + /* + * If we hit the last page and there is more work to be done: wrap + * back the index back to the start of the file for the next + * time we are called. + */ + if (wbc->range_cyclic && !done) + done_index = 0; if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) mapping->writeback_index = done_index; |