mm: unify new_node_page and alloc_migrate_target

Commit 394e31d2ceb4 ("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: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 48e24844b3c5074c8bf8c26dcf2be11a32c657e0..d9675b665cc4e5b00bb4cebd54a60f02809f4f04 100644 (file)
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -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);

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 1cf3404bd065265467835c398cf6b0c63ce1f2dd..203c46306a746aa1801d4ded9323091e88e870c5 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -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)

diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 3606104893e0b8dce843d5ac8fcf3f48434ab5f9..757410d9f758a22ca6306b84d00c5929dc3fa79a 100644 (file)
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -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]);
 }