| Message ID | 20231003225208.1936359-1-jaegeuk@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 4ed33e69e136e7b295ff69449853beac605e8502 |
| Headers | show |
| Series | [f2fs-dev] f2fs: stop iterating f2fs_map_block if hole exists | expand |
On 2023/10/4 6:52, Jaegeuk Kim wrote: > Let's avoid unnecessary f2fs_map_block calls to load extents. > > # f2fs_io fadvise willneed 0 4096 /data/local/tmp/test > > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 386, start blkaddr = 0x34ac00, len = 0x1400, flags = 2, > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 5506, start blkaddr = 0x34c200, len = 0x1000, flags = 2, > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 9602, start blkaddr = 0x34d600, len = 0x1200, flags = 2, > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 14210, start blkaddr = 0x34ec00, len = 0x400, flags = 2, > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 15235, start blkaddr = 0x34f401, len = 0xbff, flags = 2, > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 18306, start blkaddr = 0x350200, len = 0x1200, flags = 2 > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 22915, start blkaddr = 0x351601, len = 0xa7d, flags = 2 > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25600, start blkaddr = 0x351601, len = 0x0, flags = 0 > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25601, start blkaddr = 0x351601, len = 0x0, flags = 0 > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25602, start blkaddr = 0x351601, len = 0x0, flags = 0 > ... > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1037188, start blkaddr = 0x351601, len = 0x0, flags = 0 > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1038206, start blkaddr = 0x351601, len = 0x0, flags = 0 > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1039224, start blkaddr = 0x351601, len = 0x0, flags = 0 > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 2075548, start blkaddr = 0x351601, len = 0x0, flags = 0 Jaegeuk, Not sure, but it looks it's due to f2fs_precache_extents() will traverse file w/ range [0, max_file_blocks), since data which exceeds EOF will always be zero, so it's not necessary to precache its mapping info, so we'd better adjust upper boundary to i_size rather than max_file_blocks(). > > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> > --- > fs/f2fs/file.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > index 161826c6e200..2403fd1de5a0 100644 > --- a/fs/f2fs/file.c > +++ b/fs/f2fs/file.c > @@ -3270,7 +3270,7 @@ int f2fs_precache_extents(struct inode *inode) > f2fs_down_write(&fi->i_gc_rwsem[WRITE]); > err = f2fs_map_blocks(inode, &map, F2FS_GET_BLOCK_PRECACHE); > f2fs_up_write(&fi->i_gc_rwsem[WRITE]); > - if (err) > + if (err || !map.m_len) Well, if there is a hole in the head of file, it may break here rather than precaching following valid map info. What about passing parameter offset|len from f2fs_file_fadvise() to f2fs_precache_extents(), and then precaching mapping info on demand. Thanks, > return err; > > map.m_lblk = m_next_extent;
On 10/07, Chao Yu wrote: > On 2023/10/4 6:52, Jaegeuk Kim wrote: > > Let's avoid unnecessary f2fs_map_block calls to load extents. > > > > # f2fs_io fadvise willneed 0 4096 /data/local/tmp/test > > > > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 386, start blkaddr = 0x34ac00, len = 0x1400, flags = 2, > > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 5506, start blkaddr = 0x34c200, len = 0x1000, flags = 2, > > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 9602, start blkaddr = 0x34d600, len = 0x1200, flags = 2, > > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 14210, start blkaddr = 0x34ec00, len = 0x400, flags = 2, > > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 15235, start blkaddr = 0x34f401, len = 0xbff, flags = 2, > > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 18306, start blkaddr = 0x350200, len = 0x1200, flags = 2 > > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 22915, start blkaddr = 0x351601, len = 0xa7d, flags = 2 > > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25600, start blkaddr = 0x351601, len = 0x0, flags = 0 > > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25601, start blkaddr = 0x351601, len = 0x0, flags = 0 > > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25602, start blkaddr = 0x351601, len = 0x0, flags = 0 > > ... > > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1037188, start blkaddr = 0x351601, len = 0x0, flags = 0 > > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1038206, start blkaddr = 0x351601, len = 0x0, flags = 0 > > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1039224, start blkaddr = 0x351601, len = 0x0, flags = 0 > > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 2075548, start blkaddr = 0x351601, len = 0x0, flags = 0 > > Jaegeuk, > > Not sure, but it looks it's due to f2fs_precache_extents() will traverse file > w/ range [0, max_file_blocks), since data which exceeds EOF will always be zero, > so it's not necessary to precache its mapping info, so we'd better adjust upper > boundary to i_size rather than max_file_blocks(). > > > > > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> > > --- > > fs/f2fs/file.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > > index 161826c6e200..2403fd1de5a0 100644 > > --- a/fs/f2fs/file.c > > +++ b/fs/f2fs/file.c > > @@ -3270,7 +3270,7 @@ int f2fs_precache_extents(struct inode *inode) > > f2fs_down_write(&fi->i_gc_rwsem[WRITE]); > > err = f2fs_map_blocks(inode, &map, F2FS_GET_BLOCK_PRECACHE); > > f2fs_up_write(&fi->i_gc_rwsem[WRITE]); > > - if (err) > > + if (err || !map.m_len) > Well, if there is a hole in the head of file, it may break here rather > than precaching following valid map info. > > What about passing parameter offset|len from f2fs_file_fadvise() to > f2fs_precache_extents(), and then precaching mapping info on demand. I'd rather stop reading metadata if it meets a hole within i_size, since this gives benefits when reading the entire non-hole case, FWIW. Rather than that, I think generic readahead flow can hide the metadata loading. > > Thanks, > > > return err; > > map.m_lblk = m_next_extent;
Hello: This patch was applied to jaegeuk/f2fs.git (dev) by Jaegeuk Kim <jaegeuk@kernel.org>: On Tue, 3 Oct 2023 15:52:08 -0700 you wrote: > Let's avoid unnecessary f2fs_map_block calls to load extents. > > # f2fs_io fadvise willneed 0 4096 /data/local/tmp/test > > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 386, start blkaddr = 0x34ac00, len = 0x1400, flags = 2, > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 5506, start blkaddr = 0x34c200, len = 0x1000, flags = 2, > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 9602, start blkaddr = 0x34d600, len = 0x1200, flags = 2, > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 14210, start blkaddr = 0x34ec00, len = 0x400, flags = 2, > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 15235, start blkaddr = 0x34f401, len = 0xbff, flags = 2, > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 18306, start blkaddr = 0x350200, len = 0x1200, flags = 2 > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 22915, start blkaddr = 0x351601, len = 0xa7d, flags = 2 > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25600, start blkaddr = 0x351601, len = 0x0, flags = 0 > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25601, start blkaddr = 0x351601, len = 0x0, flags = 0 > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25602, start blkaddr = 0x351601, len = 0x0, flags = 0 > ... > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1037188, start blkaddr = 0x351601, len = 0x0, flags = 0 > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1038206, start blkaddr = 0x351601, len = 0x0, flags = 0 > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1039224, start blkaddr = 0x351601, len = 0x0, flags = 0 > f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 2075548, start blkaddr = 0x351601, len = 0x0, flags = 0 > > [...] Here is the summary with links: - [f2fs-dev] f2fs: stop iterating f2fs_map_block if hole exists https://git.kernel.org/jaegeuk/f2fs/c/4ed33e69e136 You are awesome, thank you!
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 161826c6e200..2403fd1de5a0 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -3270,7 +3270,7 @@ int f2fs_precache_extents(struct inode *inode) f2fs_down_write(&fi->i_gc_rwsem[WRITE]); err = f2fs_map_blocks(inode, &map, F2FS_GET_BLOCK_PRECACHE); f2fs_up_write(&fi->i_gc_rwsem[WRITE]); - if (err) + if (err || !map.m_len) return err; map.m_lblk = m_next_extent;
Let's avoid unnecessary f2fs_map_block calls to load extents. # f2fs_io fadvise willneed 0 4096 /data/local/tmp/test f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 386, start blkaddr = 0x34ac00, len = 0x1400, flags = 2, f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 5506, start blkaddr = 0x34c200, len = 0x1000, flags = 2, f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 9602, start blkaddr = 0x34d600, len = 0x1200, flags = 2, f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 14210, start blkaddr = 0x34ec00, len = 0x400, flags = 2, f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 15235, start blkaddr = 0x34f401, len = 0xbff, flags = 2, f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 18306, start blkaddr = 0x350200, len = 0x1200, flags = 2 f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 22915, start blkaddr = 0x351601, len = 0xa7d, flags = 2 f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25600, start blkaddr = 0x351601, len = 0x0, flags = 0 f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25601, start blkaddr = 0x351601, len = 0x0, flags = 0 f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25602, start blkaddr = 0x351601, len = 0x0, flags = 0 ... f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1037188, start blkaddr = 0x351601, len = 0x0, flags = 0 f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1038206, start blkaddr = 0x351601, len = 0x0, flags = 0 f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1039224, start blkaddr = 0x351601, len = 0x0, flags = 0 f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 2075548, start blkaddr = 0x351601, len = 0x0, flags = 0 Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> --- fs/f2fs/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)