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README: "btrfs: improve delayed refs iterations" has been merged into v4.10-rc1

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Signed-off-by: Zygo Blaxell <bees@furryterror.org>
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Zygo Blaxell 2017-01-09 00:02:23 -05:00
parent cf04fb17de
commit 6980935463
1 changed files with 10 additions and 13 deletions
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README.md
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@ -234,22 +234,19 @@ Bug fixes (sometimes included in older LTS kernels):
* 4.5: use-after-free in the `FILE_EXTENT_SAME` ioctl used by Bees. * 4.5: use-after-free in the `FILE_EXTENT_SAME` ioctl used by Bees.
* 4.7: *slow backref* bug no longer triggers a softlockup panic. It still * 4.7: *slow backref* bug no longer triggers a softlockup panic. It still
too long to resolve a block address to a root/inode/offset triple. too long to resolve a block address to a root/inode/offset triple.
* 4.10-rc1: reduced CPU time cost of the LOGICAL_INO ioctl and dedup
Fixed bugs not yet integrated in mainline Linux: backref processing in general.
* 7f8e406 ("btrfs: improve delayed refs iterations"): significantly
reduces the CPU time cost of the LOGICAL_INO ioctl (from 30-70% of
bees running time to under 5%).
Unfixed kernel bugs (as of 4.5.7) with workarounds in Bees: Unfixed kernel bugs (as of 4.5.7) with workarounds in Bees:
* *slow backref*: If the number of references to a single shared extent * *slow backrefs* (aka toxic extents): If the number of references to a
within a single file grows above a few thousand, the kernel consumes CPU single shared extent within a single file grows above a few thousand,
for up to 40 uninterruptible minutes while holding various locks that the kernel consumes CPU for minutes at a time while holding various
block access to the filesystem. Bees avoids this bug by measuring the locks that block access to the filesystem. Bees avoids this bug by
time the kernel spends performing certain operations and permanently measuring the time the kernel spends performing certain operations
blacklisting any extent or hash where the kernel starts to get slow. and permanently blacklisting any extent or hash where the kernel
Inside Bees, such blocks are marked as 'toxic' hash/block addresses. starts to get slow. Inside Bees, such blocks are marked as 'toxic'
hash/block addresses.
* `LOGICAL_INO` output is arbitrarily limited to 2730 references * `LOGICAL_INO` output is arbitrarily limited to 2730 references
even if more buffer space is provided for results. Once this number even if more buffer space is provided for results. Once this number