diff options
Diffstat (limited to 'fs/xfs/xfs_buf_item.c')
| -rw-r--r-- | fs/xfs/xfs_buf_item.c | 141 |
1 files changed, 111 insertions, 30 deletions
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c index dc0be2a639cc..fb69879e4b2b 100644 --- a/fs/xfs/xfs_buf_item.c +++ b/fs/xfs/xfs_buf_item.c @@ -55,6 +55,24 @@ xfs_buf_log_format_size( (blfp->blf_map_size * sizeof(blfp->blf_data_map[0])); } +static inline bool +xfs_buf_item_straddle( + struct xfs_buf *bp, + uint offset, + int first_bit, + int nbits) +{ + void *first, *last; + + first = xfs_buf_offset(bp, offset + (first_bit << XFS_BLF_SHIFT)); + last = xfs_buf_offset(bp, + offset + ((first_bit + nbits) << XFS_BLF_SHIFT)); + + if (last - first != nbits * XFS_BLF_CHUNK) + return true; + return false; +} + /* * This returns the number of log iovecs needed to log the * given buf log item. @@ -69,24 +87,56 @@ STATIC void xfs_buf_item_size_segment( struct xfs_buf_log_item *bip, struct xfs_buf_log_format *blfp, + uint offset, int *nvecs, int *nbytes) { struct xfs_buf *bp = bip->bli_buf; + int first_bit; + int nbits; int next_bit; int last_bit; - last_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size, 0); - if (last_bit == -1) + first_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size, 0); + if (first_bit == -1) return; - /* - * initial count for a dirty buffer is 2 vectors - the format structure - * and the first dirty region. - */ - *nvecs += 2; - *nbytes += xfs_buf_log_format_size(blfp) + XFS_BLF_CHUNK; + (*nvecs)++; + *nbytes += xfs_buf_log_format_size(blfp); + + do { + nbits = xfs_contig_bits(blfp->blf_data_map, + blfp->blf_map_size, first_bit); + ASSERT(nbits > 0); + /* + * Straddling a page is rare because we don't log contiguous + * chunks of unmapped buffers anywhere. + */ + if (nbits > 1 && + xfs_buf_item_straddle(bp, offset, first_bit, nbits)) + goto slow_scan; + + (*nvecs)++; + *nbytes += nbits * XFS_BLF_CHUNK; + + /* + * This takes the bit number to start looking from and + * returns the next set bit from there. It returns -1 + * if there are no more bits set or the start bit is + * beyond the end of the bitmap. + */ + first_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size, + (uint)first_bit + nbits + 1); + } while (first_bit != -1); + + return; + +slow_scan: + /* Count the first bit we jumped out of the above loop from */ + (*nvecs)++; + *nbytes += XFS_BLF_CHUNK; + last_bit = first_bit; while (last_bit != -1) { /* * This takes the bit number to start looking from and @@ -103,16 +153,15 @@ xfs_buf_item_size_segment( */ if (next_bit == -1) { break; - } else if (next_bit != last_bit + 1) { - last_bit = next_bit; - (*nvecs)++; - } else if (xfs_buf_offset(bp, next_bit * XFS_BLF_CHUNK) != - (xfs_buf_offset(bp, last_bit * XFS_BLF_CHUNK) + - XFS_BLF_CHUNK)) { + } else if (next_bit != last_bit + 1 || + xfs_buf_item_straddle(bp, offset, first_bit, nbits)) { last_bit = next_bit; + first_bit = next_bit; (*nvecs)++; + nbits = 1; } else { last_bit++; + nbits++; } *nbytes += XFS_BLF_CHUNK; } @@ -142,7 +191,10 @@ xfs_buf_item_size( int *nbytes) { struct xfs_buf_log_item *bip = BUF_ITEM(lip); + struct xfs_buf *bp = bip->bli_buf; int i; + int bytes; + uint offset = 0; ASSERT(atomic_read(&bip->bli_refcount) > 0); if (bip->bli_flags & XFS_BLI_STALE) { @@ -174,7 +226,7 @@ xfs_buf_item_size( } /* - * the vector count is based on the number of buffer vectors we have + * The vector count is based on the number of buffer vectors we have * dirty bits in. This will only be greater than one when we have a * compound buffer with more than one segment dirty. Hence for compound * buffers we need to track which segment the dirty bits correspond to, @@ -182,10 +234,19 @@ xfs_buf_item_size( * count for the extra buf log format structure that will need to be * written. */ + bytes = 0; for (i = 0; i < bip->bli_format_count; i++) { - xfs_buf_item_size_segment(bip, &bip->bli_formats[i], - nvecs, nbytes); + xfs_buf_item_size_segment(bip, &bip->bli_formats[i], offset, + nvecs, &bytes); + offset += BBTOB(bp->b_maps[i].bm_len); } + + /* + * Round up the buffer size required to minimise the number of memory + * allocations that need to be done as this item grows when relogged by + * repeated modifications. + */ + *nbytes = round_up(bytes, 512); trace_xfs_buf_item_size(bip); } @@ -204,18 +265,6 @@ xfs_buf_item_copy_iovec( nbits * XFS_BLF_CHUNK); } -static inline bool -xfs_buf_item_straddle( - struct xfs_buf *bp, - uint offset, - int next_bit, - int last_bit) -{ - return xfs_buf_offset(bp, offset + (next_bit << XFS_BLF_SHIFT)) != - (xfs_buf_offset(bp, offset + (last_bit << XFS_BLF_SHIFT)) + - XFS_BLF_CHUNK); -} - static void xfs_buf_item_format_segment( struct xfs_buf_log_item *bip, @@ -268,6 +317,38 @@ xfs_buf_item_format_segment( /* * Fill in an iovec for each set of contiguous chunks. */ + do { + ASSERT(first_bit >= 0); + nbits = xfs_contig_bits(blfp->blf_data_map, + blfp->blf_map_size, first_bit); + ASSERT(nbits > 0); + + /* + * Straddling a page is rare because we don't log contiguous + * chunks of unmapped buffers anywhere. + */ + if (nbits > 1 && + xfs_buf_item_straddle(bp, offset, first_bit, nbits)) + goto slow_scan; + + xfs_buf_item_copy_iovec(lv, vecp, bp, offset, + first_bit, nbits); + blfp->blf_size++; + + /* + * This takes the bit number to start looking from and + * returns the next set bit from there. It returns -1 + * if there are no more bits set or the start bit is + * beyond the end of the bitmap. + */ + first_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size, + (uint)first_bit + nbits + 1); + } while (first_bit != -1); + + return; + +slow_scan: + ASSERT(bp->b_addr == NULL); last_bit = first_bit; nbits = 1; for (;;) { @@ -292,7 +373,7 @@ xfs_buf_item_format_segment( blfp->blf_size++; break; } else if (next_bit != last_bit + 1 || - xfs_buf_item_straddle(bp, offset, next_bit, last_bit)) { + xfs_buf_item_straddle(bp, offset, first_bit, nbits)) { xfs_buf_item_copy_iovec(lv, vecp, bp, offset, first_bit, nbits); blfp->blf_size++; |