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author | Chris Mason <chris.mason@oracle.com> | 2011-07-25 10:50:50 (GMT) |
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committer | Chris Mason <chris.mason@oracle.com> | 2011-07-27 16:46:47 (GMT) |
commit | 19b6caf4acbf065dc96b47741d99f1b87243c468 (patch) | |
tree | 4bce889648c2459e1dbd9fd835a196db26c06f9b /fs/btrfs/extent_io.c | |
parent | 31533fb263928c93a34cda41b66a6e83ade5c766 (diff) | |
download | linux-fsl-qoriq-19b6caf4acbf065dc96b47741d99f1b87243c468.tar.xz |
Btrfs: reduce extent_state lock contention for metadata
For metadata buffers that don't straddle pages (all of them), btrfs
can safely use the page uptodate bits and extent_buffer uptodate bit
instead of needing to use the extent_state tree.
This greatly reduces contention on the state tree lock.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/extent_io.c')
-rw-r--r-- | fs/btrfs/extent_io.c | 55 |
1 files changed, 41 insertions, 14 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 5392c3b..7b60f62 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3268,6 +3268,22 @@ int set_extent_buffer_dirty(struct extent_io_tree *tree, return was_dirty; } +static int __eb_straddles_pages(u64 start, u64 len) +{ + if (len < PAGE_CACHE_SIZE) + return 1; + if (start & (PAGE_CACHE_SIZE - 1)) + return 1; + if ((start + len) & (PAGE_CACHE_SIZE - 1)) + return 1; + return 0; +} + +static int eb_straddles_pages(struct extent_buffer *eb) +{ + return __eb_straddles_pages(eb->start, eb->len); +} + int clear_extent_buffer_uptodate(struct extent_io_tree *tree, struct extent_buffer *eb, struct extent_state **cached_state) @@ -3279,8 +3295,10 @@ int clear_extent_buffer_uptodate(struct extent_io_tree *tree, num_pages = num_extent_pages(eb->start, eb->len); clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags); - clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1, - cached_state, GFP_NOFS); + if (eb_straddles_pages(eb)) { + clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1, + cached_state, GFP_NOFS); + } for (i = 0; i < num_pages; i++) { page = extent_buffer_page(eb, i); if (page) @@ -3298,8 +3316,10 @@ int set_extent_buffer_uptodate(struct extent_io_tree *tree, num_pages = num_extent_pages(eb->start, eb->len); - set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1, - NULL, GFP_NOFS); + if (eb_straddles_pages(eb)) { + set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1, + NULL, GFP_NOFS); + } for (i = 0; i < num_pages; i++) { page = extent_buffer_page(eb, i); if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) || @@ -3322,9 +3342,12 @@ int extent_range_uptodate(struct extent_io_tree *tree, int uptodate; unsigned long index; - ret = test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL); - if (ret) - return 1; + if (__eb_straddles_pages(start, end - start + 1)) { + ret = test_range_bit(tree, start, end, + EXTENT_UPTODATE, 1, NULL); + if (ret) + return 1; + } while (start <= end) { index = start >> PAGE_CACHE_SHIFT; page = find_get_page(tree->mapping, index); @@ -3352,10 +3375,12 @@ int extent_buffer_uptodate(struct extent_io_tree *tree, if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags)) return 1; - ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1, - EXTENT_UPTODATE, 1, cached_state); - if (ret) - return ret; + if (eb_straddles_pages(eb)) { + ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1, + EXTENT_UPTODATE, 1, cached_state); + if (ret) + return ret; + } num_pages = num_extent_pages(eb->start, eb->len); for (i = 0; i < num_pages; i++) { @@ -3388,9 +3413,11 @@ int read_extent_buffer_pages(struct extent_io_tree *tree, if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags)) return 0; - if (test_range_bit(tree, eb->start, eb->start + eb->len - 1, - EXTENT_UPTODATE, 1, NULL)) { - return 0; + if (eb_straddles_pages(eb)) { + if (test_range_bit(tree, eb->start, eb->start + eb->len - 1, + EXTENT_UPTODATE, 1, NULL)) { + return 0; + } } if (start) { |