On Sat, 18 Jan 2020 07:38:36 +0800 Wei Yang richardw.yang@linux.intel.com wrote:
If compound is true, this means it is a PMD mapped THP. Which implies the page is not linked to any defer list. So the first code chunk will not be executed.
Also with this reason, it would not be proper to add this page to a defer list. So the second code chunk is not correct.
Based on this, we should remove the defer list related code.
Fixes: 87eaceb3faa5 ("mm: thp: make deferred split shrinker memcg aware")
Signed-off-by: Wei Yang richardw.yang@linux.intel.com Suggested-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Cc: stable@vger.kernel.org [5.4+]
This patch is identical to "mm: thp: grab the lock before manipulating defer list", which is rather confusing. Please let people know when this sort of thing is done.
The earlier changelog mentioned a possible race condition. This changelog does not. In fact this changelog fails to provide any description of any userspace-visible runtime effects of the bug. Please send along such a description for inclusion, as always.