• Jeff Mahoney's avatar
    [PATCH] reiserfs: eliminate minimum window size for bitmap searching · 9ea0f949
    Jeff Mahoney authored
    When a file system becomes fragmented (using MythTV, for example), the
    bigalloc window searching ends up causing huge performance problems.  In a
    file system presented by a user experiencing this bug, the file system was
    90% free, but no 32-block free windows existed on the entire file system.
    This causes the allocator to scan the entire file system for each 128k
    write before backing down to searching for individual blocks.
    
    In the end, finding a contiguous window for all the blocks in a write is an
    advantageous special case, but one that can be found naturally when such a
    window exists anyway.
    
    This patch removes the bigalloc window searching, and has been proven to
    fix the test case described above.
    Signed-off-by: default avatarJeff Mahoney <jeffm@suse.com>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    9ea0f949
bitmap.c 38.4 KB