diff options
| -rw-r--r-- | fs/xfs/xfs_buf.c | 48 |
1 files changed, 28 insertions, 20 deletions
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index e3af85095dd..6785b7bd952 100644 --- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c @@ -477,8 +477,6 @@ _xfs_buf_find( /* No match found */ if (new_bp) { - _xfs_buf_initialize(new_bp, btp, range_base, - range_length, flags); rb_link_node(&new_bp->b_rbnode, parent, rbp); rb_insert_color(&new_bp->b_rbnode, &pag->pag_buf_tree); /* the buffer keeps the perag reference until it is freed */ @@ -521,35 +519,53 @@ found: } /* - * Assembles a buffer covering the specified range. - * Storage in memory for all portions of the buffer will be allocated, - * although backing storage may not be. + * Assembles a buffer covering the specified range. The code is optimised for + * cache hits, as metadata intensive workloads will see 3 orders of magnitude + * more hits than misses. */ -xfs_buf_t * +struct xfs_buf * xfs_buf_get( xfs_buftarg_t *target,/* target for buffer */ xfs_off_t ioff, /* starting offset of range */ size_t isize, /* length of range */ xfs_buf_flags_t flags) { - xfs_buf_t *bp, *new_bp; + struct xfs_buf *bp; + struct xfs_buf *new_bp; int error = 0; + bp = _xfs_buf_find(target, ioff, isize, flags, NULL); + if (likely(bp)) + goto found; + new_bp = xfs_buf_allocate(flags); if (unlikely(!new_bp)) return NULL; + _xfs_buf_initialize(new_bp, target, + ioff << BBSHIFT, isize << BBSHIFT, flags); + bp = _xfs_buf_find(target, ioff, isize, flags, new_bp); + if (!bp) { + xfs_buf_deallocate(new_bp); + return NULL; + } + if (bp == new_bp) { error = xfs_buf_allocate_memory(bp, flags); if (error) goto no_buffer; - } else { + } else xfs_buf_deallocate(new_bp); - if (unlikely(bp == NULL)) - return NULL; - } + /* + * Now we have a workable buffer, fill in the block number so + * that we can do IO on it. + */ + bp->b_bn = ioff; + bp->b_count_desired = bp->b_buffer_length; + +found: if (!(bp->b_flags & XBF_MAPPED)) { error = _xfs_buf_map_pages(bp, flags); if (unlikely(error)) { @@ -560,18 +576,10 @@ xfs_buf_get( } XFS_STATS_INC(xb_get); - - /* - * Always fill in the block number now, the mapped cases can do - * their own overlay of this later. - */ - bp->b_bn = ioff; - bp->b_count_desired = bp->b_buffer_length; - trace_xfs_buf_get(bp, flags, _RET_IP_); return bp; - no_buffer: +no_buffer: if (flags & (XBF_LOCK | XBF_TRYLOCK)) xfs_buf_unlock(bp); xfs_buf_rele(bp); |