From facc8a2247340a9735fe8cc123c5da2102f5ef1b Mon Sep 17 00:00:00 2001 From: Miao Xie Date: Thu, 25 Jul 2013 19:22:34 +0800 Subject: Btrfs: don't cache the csum value into the extent state tree Before applying this patch, we cached the csum value into the extent state tree when reading some data from the disk, this operation increased the lock contention of the state tree. Now, we just store the csum value into the bio structure or other unshared structure, so we can reduce the lock contention. Signed-off-by: Miao Xie Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/file-item.c | 81 ++++++++++++++++++++++++++++++++++------------------ 1 file changed, 54 insertions(+), 27 deletions(-) (limited to 'fs/btrfs/file-item.c') diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c index a7bfc9541803..f87d09a0dfaa 100644 --- a/fs/btrfs/file-item.c +++ b/fs/btrfs/file-item.c @@ -23,6 +23,7 @@ #include "ctree.h" #include "disk-io.h" #include "transaction.h" +#include "volumes.h" #include "print-tree.h" #define __MAX_CSUM_ITEMS(r, size) ((unsigned long)(((BTRFS_LEAF_DATA_SIZE(r) - \ @@ -152,28 +153,54 @@ int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans, return ret; } +static void btrfs_io_bio_endio_readpage(struct btrfs_io_bio *bio, int err) +{ + kfree(bio->csum_allocated); +} + static int __btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode, struct bio *bio, u64 logical_offset, u32 *dst, int dio) { - u32 sum[16]; - int len; struct bio_vec *bvec = bio->bi_io_vec; - int bio_index = 0; + struct btrfs_io_bio *btrfs_bio = btrfs_io_bio(bio); + struct btrfs_csum_item *item = NULL; + struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; + struct btrfs_path *path; + u8 *csum; u64 offset = 0; u64 item_start_offset = 0; u64 item_last_offset = 0; u64 disk_bytenr; u32 diff; - u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy); + int nblocks; + int bio_index = 0; int count; - struct btrfs_path *path; - struct btrfs_csum_item *item = NULL; - struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; + u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy); path = btrfs_alloc_path(); if (!path) return -ENOMEM; + + nblocks = bio->bi_size >> inode->i_sb->s_blocksize_bits; + if (!dst) { + if (nblocks * csum_size > BTRFS_BIO_INLINE_CSUM_SIZE) { + btrfs_bio->csum_allocated = kmalloc(nblocks * csum_size, + GFP_NOFS); + if (!btrfs_bio->csum_allocated) { + btrfs_free_path(path); + return -ENOMEM; + } + btrfs_bio->csum = btrfs_bio->csum_allocated; + btrfs_bio->end_io = btrfs_io_bio_endio_readpage; + } else { + btrfs_bio->csum = btrfs_bio->csum_inline; + } + csum = btrfs_bio->csum; + } else { + csum = (u8 *)dst; + } + if (bio->bi_size > PAGE_CACHE_SIZE * 8) path->reada = 2; @@ -194,11 +221,10 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root, if (dio) offset = logical_offset; while (bio_index < bio->bi_vcnt) { - len = min_t(int, ARRAY_SIZE(sum), bio->bi_vcnt - bio_index); if (!dio) offset = page_offset(bvec->bv_page) + bvec->bv_offset; - count = btrfs_find_ordered_sum(inode, offset, disk_bytenr, sum, - len); + count = btrfs_find_ordered_sum(inode, offset, disk_bytenr, + (u32 *)csum, nblocks); if (count) goto found; @@ -213,7 +239,7 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root, path, disk_bytenr, 0); if (IS_ERR(item)) { count = 1; - sum[0] = 0; + memset(csum, 0, csum_size); if (BTRFS_I(inode)->root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID) { set_extent_bits(io_tree, offset, @@ -249,23 +275,14 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root, diff = disk_bytenr - item_start_offset; diff = diff / root->sectorsize; diff = diff * csum_size; - count = min_t(int, len, (item_last_offset - disk_bytenr) >> - inode->i_sb->s_blocksize_bits); - read_extent_buffer(path->nodes[0], sum, + count = min_t(int, nblocks, (item_last_offset - disk_bytenr) >> + inode->i_sb->s_blocksize_bits); + read_extent_buffer(path->nodes[0], csum, ((unsigned long)item) + diff, csum_size * count); found: - if (dst) { - memcpy(dst, sum, count * csum_size); - dst += count; - } else { - if (dio) - extent_cache_csums_dio(io_tree, offset, sum, - count); - else - extent_cache_csums(io_tree, bio, bio_index, sum, - count); - } + csum += count * csum_size; + nblocks -= count; while (count--) { disk_bytenr += bvec->bv_len; offset += bvec->bv_len; @@ -284,9 +301,19 @@ int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode, } int btrfs_lookup_bio_sums_dio(struct btrfs_root *root, struct inode *inode, - struct bio *bio, u64 offset) + struct btrfs_dio_private *dip, struct bio *bio, + u64 offset) { - return __btrfs_lookup_bio_sums(root, inode, bio, offset, NULL, 1); + int len = (bio->bi_sector << 9) - dip->disk_bytenr; + u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy); + int ret; + + len >>= inode->i_sb->s_blocksize_bits; + len *= csum_size; + + ret = __btrfs_lookup_bio_sums(root, inode, bio, offset, + (u32 *)(dip->csum + len), 1); + return ret; } int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end, -- cgit v1.2.3