On Thu, 6 Jun 2024 20:36:19 +0000 "Pankaj Raghav (Samsung)" <kernel@xxxxxxxxxxxxxxxx> wrote:
> From: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
>
> create_pagecache_thp_and_fd() in split_huge_page_test.c used the
> variable dummy to perform mmap read.
>
> However, this test was skipped even on XFS which has large folio
> support. The issue was compiler (gcc 13.2.0) was optimizing out the
> dummy variable, therefore, not creating huge page in the page cache.
>
> Use asm volatile() trick to force the compiler not to optimize out
> the loop where we read from the mmaped addr. This is similar to what is
> being done in other tests (cow.c, etc)
>
> As the variable is now used in the asm statement, remove the unused
> attribute.
>
What are the runtime effects of this change? An inappropriate test
failure? If so, shouldn't we fix 6.9.x kernels also? And is
fc4d182316bd ("mm: huge_memory: enable debugfs to split huge pages to
any order") an appropriate Fixes: target?
