From 69809354636787a34eccee9b1b66749c69f9d00d Mon Sep 17 00:00:00 2001 From: Zygo Blaxell Date: Mon, 9 Jan 2017 00:02:23 -0500 Subject: [PATCH] README: "btrfs: improve delayed refs iterations" has been merged into v4.10-rc1 Signed-off-by: Zygo Blaxell --- README.md | 23 ++++++++++------------- 1 file changed, 10 insertions(+), 13 deletions(-) diff --git a/README.md b/README.md index 2de000d..cd7ff94 100644 --- a/README.md +++ b/README.md @@ -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. * 4.7: *slow backref* bug no longer triggers a softlockup panic. It still too long to resolve a block address to a root/inode/offset triple. - -Fixed bugs not yet integrated in mainline Linux: - -* 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%). +* 4.10-rc1: reduced CPU time cost of the LOGICAL_INO ioctl and dedup + backref processing in general. Unfixed kernel bugs (as of 4.5.7) with workarounds in Bees: -* *slow backref*: If the number of references to a single shared extent - within a single file grows above a few thousand, the kernel consumes CPU - for up to 40 uninterruptible minutes while holding various locks that - block access to the filesystem. Bees avoids this bug by measuring the - time the kernel spends performing certain operations and permanently - blacklisting any extent or hash where the kernel starts to get slow. - Inside Bees, such blocks are marked as 'toxic' hash/block addresses. +* *slow backrefs* (aka toxic extents): If the number of references to a + single shared extent within a single file grows above a few thousand, + the kernel consumes CPU for minutes at a time while holding various + locks that block access to the filesystem. Bees avoids this bug by + measuring the time the kernel spends performing certain operations + and permanently blacklisting any extent or hash where the kernel + starts to get slow. Inside Bees, such blocks are marked as 'toxic' + hash/block addresses. * `LOGICAL_INO` output is arbitrarily limited to 2730 references even if more buffer space is provided for results. Once this number