mainlining shenanigans
bd54f381a1
During renames we pin the logs of the roots a bit too early, before the calls to btrfs_insert_inode_ref(). We can pin the logs after those calls, since those will not change anything in a log tree. In a scenario where we have multiple and diverse filesystem operations running in parallel, those calls can take a significant amount of time, due to lock contention on extent buffers, and delay log commits from other tasks for longer than necessary. So just pin logs after calls to btrfs_insert_inode_ref() and right before the first operation that can update a log tree. The following script that uses dbench was used for testing: $ cat dbench-test.sh #!/bin/bash DEV=/dev/nvme0n1 MNT=/mnt/nvme0n1 MOUNT_OPTIONS="-o ssd" MKFS_OPTIONS="-m single -d single" echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor umount $DEV &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT dbench -D $MNT -t 120 16 umount $MNT The tests were run on a machine with 12 cores, 64G of RAN, a NVMe device and using a non-debug kernel config (Debian's default config). The results compare a branch without this patch and without the previous patch in the series, that has the subject: "btrfs: eliminate some false positives when checking if inode was logged" Versus the same branch with these two patches applied. dbench with 8 clients, results before: Operation Count AvgLat MaxLat ---------------------------------------- NTCreateX 4391359 0.009 249.745 Close 3225882 0.001 3.243 Rename 185953 0.065 240.643 Unlink 886669 0.049 249.906 Deltree 112 2.455 217.433 Mkdir 56 0.002 0.004 Qpathinfo 3980281 0.004 3.109 Qfileinfo 697579 0.001 0.187 Qfsinfo 729780 0.002 2.424 Sfileinfo 357764 0.004 1.415 Find 1538861 0.016 4.863 WriteX |
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| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
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| mm | ||
| net | ||
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| usr | ||
| virt | ||
| .clang-format | ||
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| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.