Commit de1cbee which removed b_file_offset in favor of b_bn introduced a bug causing xfs_buf_allocate_memory() to overestimate the number of necessary pages. The problem is that xfs_buf_alloc() sets b_bn to -1 and thus effectively every buffer is straddling a page boundary which causes xfs_buf_allocate_memory() to allocate two pages and use vmalloc() for access which is unnecessary. Dave says xfs_buf_alloc() doesn't need to set b_bn to -1 anymore since the buffer is inserted into the cache only after being fully initialized now. So just make xfs_buf_alloc() fill in proper block number from the beginning. CC: David Chinner <dchinner@xxxxxxxxxx> Signed-off-by: Jan Kara <jack@xxxxxxx> --- fs/xfs/xfs_buf.c | 16 ++-------------- 1 files changed, 2 insertions(+), 14 deletions(-) diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index 172d3cc..a4beb42 100644 --- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c @@ -201,14 +201,7 @@ xfs_buf_alloc( bp->b_length = numblks; bp->b_io_length = numblks; bp->b_flags = flags; - - /* - * We do not set the block number here in the buffer because we have not - * finished initialising the buffer. We insert the buffer into the cache - * in this state, so this ensures that we are unable to do IO on a - * buffer that hasn't been fully initialised. - */ - bp->b_bn = XFS_BUF_DADDR_NULL; + bp->b_bn = blkno; atomic_set(&bp->b_pin_count, 0); init_waitqueue_head(&bp->b_waiters); @@ -567,11 +560,6 @@ xfs_buf_get( if (bp != new_bp) xfs_buf_free(new_bp); - /* - * Now we have a workable buffer, fill in the block number so - * that we can do IO on it. - */ - bp->b_bn = blkno; bp->b_io_length = bp->b_length; found: @@ -772,7 +760,7 @@ xfs_buf_get_uncached( int error, i; xfs_buf_t *bp; - bp = xfs_buf_alloc(target, 0, numblks, 0); + bp = xfs_buf_alloc(target, XFS_BUF_DADDR_NULL, numblks, 0); if (unlikely(bp == NULL)) goto fail; -- 1.7.1 _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
