Messages in this thread | | | Date | Mon, 13 Sep 2021 10:11:22 +0200 | From | Cyril Hrubis <> | Subject | Re: [LTP] [mm/page] ab19939a6a: ltp.msync04.fail |
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Hi! > FYI, we noticed the following commit (built with gcc-9): > > commit: ab19939a6a5010cba4e9cb04dd8bee03c72edcbd ("mm/page-writeback: Fix performance when BDI's share of ratio is 0.") > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master > > > in testcase: ltp > version: ltp-x86_64-14c1f76-1_20210907 > with following parameters: > > disk: 1HDD > fs: xfs > test: syscalls-03 > ucode: 0xe2 > > test-description: The LTP testsuite contains a collection of tools for testing the Linux kernel and related features. > test-url: http://linux-test-project.github.io/
The msync04 test formats a device with a diffrent filesystems, for each filesystem it maps a file, writes to the mapped page and the checks a dirty bit in /proc/kpageflags before and after msync() on that page.
This seems to be broken after this patch for ntfs over FUSE and it looks like the page does not have a dirty bit set right after it has been written to.
Also I guess that we should increase the number of the pages we dirty or attempt to retry since a single page may be flushed to the storage if we are unlucky and the process is preempted between the write and the initial check for the dirty bit.
-- Cyril Hrubis chrubis@suse.cz
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