In f2fs_precache_extents(), For large files, It requires reading many node blocks. Instead of reading each node block with synchronous I/O, this patch applies readahead so that node blocks can be fetched in advance.
It reduces the overhead of repeated sync reads and improves efficiency when precaching extents of large files. I created a file with the same largest extent and executed the test. For this experiment, I set the file's largest extent with an offset of 0 and a size of 1GB. I configured the remaining area with 100MB extents. 5GB test file: dd if=/dev/urandom of=test1 bs=1m count=5120 cp test1 test2 fsync test1 dd if=test1 of=test2 bs=1m skip=1024 seek=1024 count=100 conv=notrunc dd if=test1 of=test2 bs=1m skip=1224 seek=1224 count=100 conv=notrunc ... dd if=test1 of=test2 bs=1m skip=5024 seek=5024 count=100 conv=notrunc reboot I also created 10GB and 20GB files with large extents using the same method. ioctl(F2FS_IOC_PRECACHE_EXTENTS) test results are as follows: +-----------+---------+---------+-----------+ | File size | Before | After | Reduction | +-----------+---------+---------+-----------+ | 5GB | 101.8ms | 37.0ms | 72.1% | | 10GB | 222.9ms | 56.0ms | 74.9% | | 20GB | 446.2ms | 116.4ms | 73.9% | +-----------+---------+---------+-----------+ Tested on a 256GB mobile device with an SM8750 chipset. Reviewed-by: Sungjong Seo <[email protected]> Reviewed-by: Sunmin Jeong <[email protected]> Signed-off-by: Yunji Kang <[email protected]> --- v2: - Modify the readahead condition check routine for better code readability. - Update the title from 'node block' to 'node blocks'. v3: - Bug fix to allow more node pages to be readahead. - Updated with test results. fs/f2fs/data.c | 3 +++ fs/f2fs/f2fs.h | 1 + fs/f2fs/node.c | 4 +++- 3 files changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 7961e0ddfca3..ab3117e3b24a 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -1572,6 +1572,9 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map, int flag) pgofs = (pgoff_t)map->m_lblk; end = pgofs + maxblocks; + if (flag == F2FS_GET_BLOCK_PRECACHE) + mode = LOOKUP_NODE_PRECACHE; + next_dnode: if (map->m_may_create) { if (f2fs_lfs_mode(sbi)) diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 9d3bc9633c1d..3ce41528d48e 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -651,6 +651,7 @@ enum { * look up a node with readahead called * by get_data_block. */ + LOOKUP_NODE_PRECACHE, /* look up a node for F2FS_GET_BLOCK_PRECACHE */ }; #define DEFAULT_RETRY_IO_COUNT 8 /* maximum retry read IO or flush count */ diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index 4254db453b2d..63e9ee7ab911 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -860,7 +860,9 @@ int f2fs_get_dnode_of_data(struct dnode_of_data *dn, pgoff_t index, int mode) set_nid(parent, offset[i - 1], nids[i], i == 1); f2fs_alloc_nid_done(sbi, nids[i]); done = true; - } else if (mode == LOOKUP_NODE_RA && i == level && level > 1) { + } else if ((mode == LOOKUP_NODE_RA || + (mode == LOOKUP_NODE_PRECACHE)) + && i == level && level > 1) { nfolio[i] = f2fs_get_node_folio_ra(parent, offset[i - 1]); if (IS_ERR(nfolio[i])) { err = PTR_ERR(nfolio[i]); -- 2.34.1 _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
