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| author | Al Viro <viro@zeniv.linux.org.uk> | 2017-06-17 15:44:06 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2017-06-17 17:22:42 -0400 |
| commit | 77e9ce327d9b607cd6e57c0f4524a654dc59c4b1 (patch) | |
| tree | cb2bc18c6c0e09e2af7f5bbc3ad007acc77c8ebf /fs | |
| parent | c0ef65d2928249e822b813beb41b6c1478c556ab (diff) | |
| download | lwn-77e9ce327d9b607cd6e57c0f4524a654dc59c4b1.tar.gz lwn-77e9ce327d9b607cd6e57c0f4524a654dc59c4b1.zip | |
ufs: fix the logics for tail relocation
* original hysteresis loop got broken by typo back in 2002; now
it never switches out of OPTTIME state. Fixed.
* critical levels for switching from OPTTIME to OPTSPACE and back
ought to be calculated once, at mount time.
* we should use mul_u64_u32_div() for those calculations, now that
->s_dsize is 64bit.
* to quote Kirk McKusick (in 1995 FreeBSD commit message):
The threshold for switching from time-space and space-time is too small
when minfree is 5%...so make it stay at space in this case.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ufs/balloc.c | 22 | ||||
| -rw-r--r-- | fs/ufs/super.c | 9 | ||||
| -rw-r--r-- | fs/ufs/ufs_fs.h | 2 |
3 files changed, 17 insertions, 16 deletions
diff --git a/fs/ufs/balloc.c b/fs/ufs/balloc.c index 0315fea1d589..f80be4c5df9d 100644 --- a/fs/ufs/balloc.c +++ b/fs/ufs/balloc.c @@ -455,24 +455,14 @@ u64 ufs_new_fragments(struct inode *inode, void *p, u64 fragment, /* * allocate new block and move data */ - switch (fs32_to_cpu(sb, usb1->fs_optim)) { - case UFS_OPTSPACE: + if (fs32_to_cpu(sb, usb1->fs_optim) == UFS_OPTSPACE) { request = newcount; - if (uspi->s_minfree < 5 || uspi->cs_total.cs_nffree - > uspi->s_dsize * uspi->s_minfree / (2 * 100)) - break; - usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME); - break; - default: - usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME); - - case UFS_OPTTIME: + if (uspi->cs_total.cs_nffree < uspi->s_space_to_time) + usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME); + } else { request = uspi->s_fpb; - if (uspi->cs_total.cs_nffree < uspi->s_dsize * - (uspi->s_minfree - 2) / 100) - break; - usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME); - break; + if (uspi->cs_total.cs_nffree > uspi->s_time_to_space) + usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTSPACE); } result = ufs_alloc_fragments (inode, cgno, goal, request, err); if (result) { diff --git a/fs/ufs/super.c b/fs/ufs/super.c index 34656c7a8e22..f211b662dd92 100644 --- a/fs/ufs/super.c +++ b/fs/ufs/super.c @@ -1211,6 +1211,15 @@ magic_found: uspi->s_root_blocks = mul_u64_u32_div(uspi->s_dsize, uspi->s_minfree, 100); + if (uspi->s_minfree <= 5) { + uspi->s_time_to_space = ~0ULL; + uspi->s_space_to_time = 0; + usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTSPACE); + } else { + uspi->s_time_to_space = (uspi->s_root_blocks / 2) + 1; + uspi->s_space_to_time = mul_u64_u32_div(uspi->s_dsize, + uspi->s_minfree - 2, 100) - 1; + } /* * Compute another frequently used values diff --git a/fs/ufs/ufs_fs.h b/fs/ufs/ufs_fs.h index 823d55a37586..150eef6f1233 100644 --- a/fs/ufs/ufs_fs.h +++ b/fs/ufs/ufs_fs.h @@ -792,6 +792,8 @@ struct ufs_sb_private_info { __s32 fs_magic; /* filesystem magic */ unsigned int s_dirblksize; __u64 s_root_blocks; + __u64 s_time_to_space; + __u64 s_space_to_time; }; /* |