On Mon, Sep 02, 2013 at 08:33:42PM +0800, Wanpeng Li wrote:
> PageTransHuge() can't guarantee the page is transparent huge page since it
> return true for both transparent huge and hugetlbfs pages. This patch fix
> it by check the page is also !hugetlbfs page.
>
> Before patch:
>
> [ 121.571128] Injecting memory failure at pfn 23a200
> [ 121.571141] MCE 0x23a200: huge page recovery: Delayed
> [ 140.355100] MCE: Memory failure is now running on 0x23a200
>
> After patch:
>
> [ 94.290793] Injecting memory failure at pfn 23a000
> [ 94.290800] MCE 0x23a000: huge page recovery: Delayed
> [ 105.722303] MCE: Software-unpoisoned page 0x23a000
>
> Signed-off-by: Wanpeng Li <[email protected]>
PageTransHuge doesn't care about hugetlbfs at all, assuming that it
shouldn't be called hugetlbfs context as commented.
/*
* PageHuge() only returns true for hugetlbfs pages, but not for
* normal or transparent huge pages.
*
* PageTransHuge() returns true for both transparent huge and
* hugetlbfs pages, but not normal pages. PageTransHuge() can only be
* called only in the core VM paths where hugetlbfs pages can't exist.
*/
static inline int PageTransHuge(struct page *page)
I think it's for the ultra optimization of thp, so we can't change that.
So we need to follow the pattern whenever possible.
if (PageHuge) {
hugetlb specific code
} else if (PageTransHuge) {
thp specific code
}
normal page code / common code
> ---
> mm/memory-failure.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index e28ee77..b114570 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1349,7 +1349,7 @@ int unpoison_memory(unsigned long pfn)
> * worked by memory_failure() and the page lock is not held yet.
> * In such case, we yield to memory_failure() and make unpoison fail.
> */
> - if (PageTransHuge(page)) {
> + if (PageTransHuge(page) && !PageHuge(page)) {
> pr_info("MCE: Memory failure is now running on %#lx\n", pfn);
> return 0;
> }
I think that we can effectively follow the above pattern by reversing
these two checks.
Thanks,
Naoya Horiguchi
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