mainlining shenanigans
43ac9b84a3
In new barrier codes, raise_barrier waits if conf->nr_pending[idx] is not zero. After all the conditions are true, the resync request can go on be handled. But it adds conf->nr_pending[idx] again. The next resync request hit the same bucket idx need to wait the resync request which is submitted before. The performance of resync/recovery is degraded. So we should use a new variable to count sync requests which are in flight. I did a simple test: 1. Without the patch, create a raid1 with two disks. The resync speed: Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await r_await w_await svctm %util sdb 0.00 0.00 166.00 0.00 10.38 0.00 128.00 0.03 0.20 0.20 0.00 0.19 3.20 sdc 0.00 0.00 0.00 166.00 0.00 10.38 128.00 0.96 5.77 0.00 5.77 5.75 95.50 2. With the patch, the result is: sdb 2214.00 0.00 766.00 0.00 185.69 0.00 496.46 2.80 3.66 3.66 0.00 1.03 79.10 sdc 0.00 2205.00 0.00 769.00 0.00 186.44 496.52 5.25 6.84 0.00 6.84 1.30 100.10 Suggested-by: Shaohua Li <shli@kernel.org> Signed-off-by: Xiao Ni <xni@redhat.com> Acked-by: Coly Li <colyli@suse.de> Signed-off-by: Shaohua Li <shli@fb.com> |
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| firmware | ||
| fs | ||
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| kernel | ||
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| README | ||
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.