Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> writes:
> On Fri, Oct 18, 2019 at 01:48:32PM +0200, Michal Hocko wrote:
>> On Thu 17-10-19 16:21:08, Oscar Salvador wrote:
>> > From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
>> >
>> > Drop the PageHuge check since memory_failure forks into memory_failure_hugetlb()
>> > for hugetlb pages.
>> >
>> > Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
>> > Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
>>
>> s-o-b chain is reversed.
>>
>> The code is a bit confusing. Doesn't this check aim for THP?
>
> No, PageHuge() is false for thp, so this if branch is just dead code.
memory_failure()
{
if (PageTransHuge(hpage)) {
lock_page(p);
if (!PageAnon(p) || unlikely(split_huge_page(p))) {
unlock_page(p);
if (!PageAnon(p))
pr_err("Memory failure: %#lx: non anonymous thp\n",
pfn);
else
pr_err("Memory failure: %#lx: thp split failed\n",
pfn);
if (TestClearPageHWPoison(p))
num_poisoned_pages_dec();
put_hwpoison_page(p);
return -EBUSY;
}
unlock_page(p);
VM_BUG_ON_PAGE(!page_count(p), p);
hpage = compound_head(p);
}
}
Do we need that hpage = compund_head(p) conversion there? We should just
be able to say hpage = p, or even better after this change use p
directly instead of hpage in the code following?
-aneesh
