Commit 8b913238 authored by Michal Hocko's avatar Michal Hocko Committed by Linus Torvalds
Browse files

mm: unify new_node_page and alloc_migrate_target 

Commit 394e31d2 ("mem-hotplug: alloc new page from a nearest
neighbor node when mem-offline") has duplicated a large part of
alloc_migrate_target with some hotplug specific special casing.

To be more precise it tried to enfore the allocation from a different
node than the original page.  As a result the two function diverged in
their shared logic, e.g.  the hugetlb allocation strategy.

Let's unify the two and express different NUMA requirements by the given
nodemask.  new_node_page will simply exclude the node it doesn't care
about and alloc_migrate_target will use all the available nodes.
alloc_migrate_target will then learn to migrate hugetlb pages more
sanely and use preallocated pool when possible.

Please note that alloc_migrate_target used to call alloc_page resp.
alloc_pages_current so the memory policy of the current context which is
quite strange when we consider that it is used in the context of
alloc_contig_range which just tries to migrate pages which stand in the
way.

Link: http://lkml.kernel.org/r/20170608074553.22152-4-mhocko@kernel.org


Signed-off-by: default avatarMichal Hocko <mhocko@suse.com>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: zhong jiang <zhongjiang@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4db9b2ef

include/linux/migrate.h

+16 −0
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 
#include <linux/mm.h>

#include <linux/mempolicy.h>

#include <linux/migrate_mode.h>

#include <linux/hugetlb.h>



typedef struct page *new_page_t(struct page *page, unsigned long private,

				int **reason);
@@ -30,6 +31,21 @@ enum migrate_reason { 
/* In mm/debug.c; also keep sync with include/trace/events/migrate.h */

extern char *migrate_reason_names[MR_TYPES];



static inline struct page *new_page_nodemask(struct page *page,

				int preferred_nid, nodemask_t *nodemask)

{

	gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE;



	if (PageHuge(page))

		return alloc_huge_page_nodemask(page_hstate(compound_head(page)),

				nodemask);



	if (PageHighMem(page) || (zone_idx(page_zone(page)) == ZONE_MOVABLE))

		gfp_mask |= __GFP_HIGHMEM;



	return __alloc_pages_nodemask(gfp_mask, 0, preferred_nid, nodemask);

}



#ifdef CONFIG_MIGRATION



extern void putback_movable_pages(struct list_head *l);

mm/memory_hotplug.c

+1 −10
Original line number Diff line number Diff line
@@ -1433,7 +1433,6 @@ static unsigned long scan_movable_pages(unsigned long start, unsigned long end) 
static struct page *new_node_page(struct page *page, unsigned long private,

		int **result)

{

	gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE;

	int nid = page_to_nid(page);

	nodemask_t nmask = node_states[N_MEMORY];
@@ -1446,15 +1445,7 @@ static struct page *new_node_page(struct page *page, unsigned long private, 
	if (nodes_empty(nmask))

		node_set(nid, nmask);



	if (PageHuge(page))

		return alloc_huge_page_nodemask(

				page_hstate(compound_head(page)), &nmask);



	if (PageHighMem(page)

	    || (zone_idx(page_zone(page)) == ZONE_MOVABLE))

		gfp_mask |= __GFP_HIGHMEM;



	return __alloc_pages_nodemask(gfp_mask, 0, nid, &nmask);

	return new_page_nodemask(page, nid, &nmask);

}



#define NR_OFFLINE_AT_ONCE_PAGES	(256)

mm/page_isolation.c

+2 −16
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#include <linux/memory.h>

#include <linux/hugetlb.h>

#include <linux/page_owner.h>

#include <linux/migrate.h>

#include "internal.h"



#define CREATE_TRACE_POINTS
@@ -294,20 +295,5 @@ int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn, 
struct page *alloc_migrate_target(struct page *page, unsigned long private,

				  int **resultp)

{

	gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE;



	/*

	 * TODO: allocate a destination hugepage from a nearest neighbor node,

	 * accordance with memory policy of the user process if possible. For

	 * now as a simple work-around, we use the next node for destination.

	 */

	if (PageHuge(page))

		return alloc_huge_page_node(page_hstate(compound_head(page)),

					    next_node_in(page_to_nid(page),

							 node_online_map));



	if (PageHighMem(page))

		gfp_mask |= __GFP_HIGHMEM;



	return alloc_page(gfp_mask);

	return new_page_nodemask(page, numa_node_id(), &node_states[N_MEMORY]);

}

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