lkml.org 
[lkml]   [2017]   [May]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH V2] mm/madvise: Enable (soft|hard) offline of HugeTLB pages at PGD level
From
Date
On 05/13/2017 03:05 AM, Andrew Morton wrote:
> On Wed, 26 Apr 2017 09:27:31 +0530 Anshuman Khandual <khandual@linux.vnet.ibm.com> wrote:
>
>> Though migrating gigantic HugeTLB pages does not sound much like real
>> world use case, they can be affected by memory errors. Hence migration
>> at the PGD level HugeTLB pages should be supported just to enable soft
>> and hard offline use cases.
>>
>> While allocating the new gigantic HugeTLB page, it should not matter
>> whether new page comes from the same node or not. There would be very
>> few gigantic pages on the system afterall, we should not be bothered
>> about node locality when trying to save a big page from crashing.
>>
>> This introduces a new HugeTLB allocator called alloc_huge_page_nonid()
>> which will scan over all online nodes on the system and allocate a
>> single HugeTLB page.
>>
>> ...
>>
>> --- a/mm/hugetlb.c
>> +++ b/mm/hugetlb.c
>> @@ -1669,6 +1669,23 @@ struct page *__alloc_buddy_huge_page_with_mpol(struct hstate *h,
>> return __alloc_buddy_huge_page(h, vma, addr, NUMA_NO_NODE);
>> }
>>
>> +struct page *alloc_huge_page_nonid(struct hstate *h)
>> +{
>> + struct page *page = NULL;
>> + int nid = 0;
>> +
>> + spin_lock(&hugetlb_lock);
>> + if (h->free_huge_pages - h->resv_huge_pages > 0) {
>> + for_each_online_node(nid) {
>> + page = dequeue_huge_page_node(h, nid);
>> + if (page)
>> + break;
>> + }
>> + }
>> + spin_unlock(&hugetlb_lock);
>> + return page;
>> +}
>> +
>> /*
>> * This allocation function is useful in the context where vma is irrelevant.
>> * E.g. soft-offlining uses this function because it only cares physical
>> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
>> index fe64d7729a8e..d4f5710cf3f7 100644
>> --- a/mm/memory-failure.c
>> +++ b/mm/memory-failure.c
>> @@ -1481,11 +1481,15 @@ EXPORT_SYMBOL(unpoison_memory);
>> static struct page *new_page(struct page *p, unsigned long private, int **x)
>> {
>> int nid = page_to_nid(p);
>> - if (PageHuge(p))
>> + if (PageHuge(p)) {
>> + if (hstate_is_gigantic(page_hstate(compound_head(p))))
>> + return alloc_huge_page_nonid(page_hstate(compound_head(p)));
>> +
>> return alloc_huge_page_node(page_hstate(compound_head(p)),
>> nid);
>> - else
>> + } else {
>> return __alloc_pages_node(nid, GFP_HIGHUSER_MOVABLE, 0);
>> + }
>> }
>
> Rather than adding alloc_huge_page_nonid(), would it be neater to teach
> alloc_huge_page_node() (actually dequeue_huge_page_node()) to understand
> nid==NUMA_NO_NODE?

Sure, will change dequeue_huge_page_node() to accommodate NUMA_NO_NODE and
let soft offline call with NUMA_NO_NODE in case of gigantic huge pages.

\
 
 \ /
  Last update: 2017-05-14 06:13    [W:0.741 / U:0.052 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site