Commit 94310cbc authored by Anshuman Khandual's avatar Anshuman Khandual Committed by Linus Torvalds
Browse files

mm/madvise: enable (soft|hard) offline of HugeTLB pages at PGD level 

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 change renames dequeu_huge_page_node() function as dequeue_huge
_page_node_exact() preserving it's original functionality.  Now the new
dequeue_huge_page_node() function scans through all available online nodes
to allocate a huge page for the NUMA_NO_NODE case and just falls back
calling dequeu_huge_page_node_exact() for all other cases.

[arnd@arndb.de: make hstate_is_gigantic() inline]
  Link: http://lkml.kernel.org/r/20170522124748.3911296-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20170516100509.20122-1-khandual@linux.vnet.ibm.com


Signed-off-by: default avatarAnshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f93ae364

include/linux/hugetlb.h

+10 −1
Original line number Diff line number Diff line
@@ -466,7 +466,11 @@ extern int dissolve_free_huge_pages(unsigned long start_pfn, 
static inline bool hugepage_migration_supported(struct hstate *h)

{

#ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION

	return huge_page_shift(h) == PMD_SHIFT;

	if ((huge_page_shift(h) == PMD_SHIFT) ||

		(huge_page_shift(h) == PGDIR_SHIFT))

		return true;

	else

		return false;

#else

	return false;

#endif
@@ -518,6 +522,11 @@ struct hstate {}; 
#define vma_mmu_pagesize(v) PAGE_SIZE

#define huge_page_order(h) 0

#define huge_page_shift(h) PAGE_SHIFT

static inline bool hstate_is_gigantic(struct hstate *h)

{

	return false;

}



static inline unsigned int pages_per_huge_page(struct hstate *h)

{

	return 1;

mm/hugetlb.c

+17 −1
Original line number Diff line number Diff line
@@ -867,7 +867,7 @@ static void enqueue_huge_page(struct hstate *h, struct page *page) 
	h->free_huge_pages_node[nid]++;

}



static struct page *dequeue_huge_page_node(struct hstate *h, int nid)

static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)

{

	struct page *page;
@@ -887,6 +887,22 @@ static struct page *dequeue_huge_page_node(struct hstate *h, int nid) 
	return page;

}



static struct page *dequeue_huge_page_node(struct hstate *h, int nid)

{

	struct page *page;

	int node;



	if (nid != NUMA_NO_NODE)

		return dequeue_huge_page_node_exact(h, nid);



	for_each_online_node(node) {

		page = dequeue_huge_page_node_exact(h, node);

		if (page)

			return page;

	}

	return NULL;

}



/* Movability of hugepages depends on migration support. */

static inline gfp_t htlb_alloc_mask(struct hstate *h)

{

mm/memory-failure.c

+9 −4
Original line number Diff line number Diff line
@@ -1492,12 +1492,17 @@ 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))

		return alloc_huge_page_node(page_hstate(compound_head(p)),

						   nid);

	else

	if (PageHuge(p)) {

		struct hstate *hstate = page_hstate(compound_head(p));



		if (hstate_is_gigantic(hstate))

			return alloc_huge_page_node(hstate, NUMA_NO_NODE);



		return alloc_huge_page_node(hstate, nid);

	} else {

		return __alloc_pages_node(nid, GFP_HIGHUSER_MOVABLE, 0);

	}

}



/*

 * Safely get reference count of an arbitrary page.

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