Re: [PATCH v4 3/7] mm,hwpoison: Try to narrow window race for free pages

From: Aristeu Rozanski
Date: Fri Sep 18 2020 - 15:33:10 EST

On Thu, Sep 17, 2020 at 10:10:45AM +0200, Oscar Salvador wrote:
> Aristeu Rozanski reported that a customer test case started
> to report -EBUSY after the hwpoison report patchset.
> There is a race window between spotting a free page and taking it off
> its buddy freelist, so it might be that by the time we try to take it off,
> the page has been already allocated.
> This patch tries to handle such race window by trying to handle the new
> type of page again if the page was allocated under us.
> After this patch, Aristeu said the test cases work properly.
> Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
> Reported-by: Aristeu Rozanski <aris@xxxxxxxxx>

Tested-by: Aristeu Rozanski <aris@xxxxxxxxx>