Messages in this thread | | | From | Miklos Szeredi <> | Date | Mon, 13 Sep 2021 16:59:51 +0200 | Subject | Re: [LTP] [mm/page] ab19939a6a: ltp.msync04.fail |
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On Mon, Sep 13, 2021 at 10:19 AM Cyril Hrubis <chrubis@suse.cz> wrote: > > 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.
Weird. Does this reproduce 100% of the time? If not, then I guess it's a race and we can ignore this report (or improve the test to make it less likely to trigger).
Thanks, Miklos
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