cpuset,mm: fix no node to alloc memory when changing cpuset's mems
Before applying this patch, cpuset updates task->mems_allowed and
mempolicy by setting all new bits in the nodemask first, and clearing all
old unallowed bits later. But in the way, the allocator may find that
there is no node to alloc memory.
The reason is that cpuset rebinds the task's mempolicy, it cleans the
nodes which the allocater can alloc pages on, for example:
(mpol: mempolicy)
task1 task1's mpol task2
alloc page 1
alloc on node0? NO 1
1 change mems from 1 to 0
1 rebind task1's mpol
0-1 set new bits
0 clear disallowed bits
alloc on node1? NO 0
...
can't alloc page
goto oom
This patch fixes this problem by expanding the nodes range first(set newly
allowed bits) and shrink it lazily(clear newly disallowed bits). So we
use a variable to tell the write-side task that read-side task is reading
nodemask, and the write-side task clears newly disallowed nodes after
read-side task ends the current memory allocation.
[akpm@linux-foundation.org: fix spello]
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Paul Menage <menage@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/filemap.c b/mm/filemap.c
index d6f4f07..88d7196 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -461,9 +461,15 @@
#ifdef CONFIG_NUMA
struct page *__page_cache_alloc(gfp_t gfp)
{
+ int n;
+ struct page *page;
+
if (cpuset_do_page_mem_spread()) {
- int n = cpuset_mem_spread_node();
- return alloc_pages_exact_node(n, gfp, 0);
+ get_mems_allowed();
+ n = cpuset_mem_spread_node();
+ page = alloc_pages_exact_node(n, gfp, 0);
+ put_mems_allowed();
+ return page;
}
return alloc_pages(gfp, 0);
}
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 4c9e6bb..54d42b0 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -465,11 +465,13 @@
struct page *page = NULL;
struct mempolicy *mpol;
nodemask_t *nodemask;
- struct zonelist *zonelist = huge_zonelist(vma, address,
- htlb_alloc_mask, &mpol, &nodemask);
+ struct zonelist *zonelist;
struct zone *zone;
struct zoneref *z;
+ get_mems_allowed();
+ zonelist = huge_zonelist(vma, address,
+ htlb_alloc_mask, &mpol, &nodemask);
/*
* A child process with MAP_PRIVATE mappings created by their parent
* have no page reserves. This check ensures that reservations are
@@ -477,11 +479,11 @@
*/
if (!vma_has_reserves(vma) &&
h->free_huge_pages - h->resv_huge_pages == 0)
- return NULL;
+ goto err;
/* If reserves cannot be used, ensure enough pages are in the pool */
if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
- return NULL;
+ goto err;;
for_each_zone_zonelist_nodemask(zone, z, zonelist,
MAX_NR_ZONES - 1, nodemask) {
@@ -500,7 +502,9 @@
break;
}
}
+err:
mpol_cond_put(mpol);
+ put_mems_allowed();
return page;
}
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 8a993db..721b2b3 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1639,6 +1639,8 @@
* to the struct mempolicy for conditional unref after allocation.
* If the effective policy is 'BIND, returns a pointer to the mempolicy's
* @nodemask for filtering the zonelist.
+ *
+ * Must be protected by get_mems_allowed()
*/
struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr,
gfp_t gfp_flags, struct mempolicy **mpol,
@@ -1684,6 +1686,7 @@
if (!(mask && current->mempolicy))
return false;
+ task_lock(current);
mempolicy = current->mempolicy;
switch (mempolicy->mode) {
case MPOL_PREFERRED:
@@ -1703,6 +1706,7 @@
default:
BUG();
}
+ task_unlock(current);
return true;
}
@@ -1750,13 +1754,17 @@
{
struct mempolicy *pol = get_vma_policy(current, vma, addr);
struct zonelist *zl;
+ struct page *page;
+ get_mems_allowed();
if (unlikely(pol->mode == MPOL_INTERLEAVE)) {
unsigned nid;
nid = interleave_nid(pol, vma, addr, PAGE_SHIFT);
mpol_cond_put(pol);
- return alloc_page_interleave(gfp, 0, nid);
+ page = alloc_page_interleave(gfp, 0, nid);
+ put_mems_allowed();
+ return page;
}
zl = policy_zonelist(gfp, pol);
if (unlikely(mpol_needs_cond_ref(pol))) {
@@ -1766,12 +1774,15 @@
struct page *page = __alloc_pages_nodemask(gfp, 0,
zl, policy_nodemask(gfp, pol));
__mpol_put(pol);
+ put_mems_allowed();
return page;
}
/*
* fast path: default or task policy
*/
- return __alloc_pages_nodemask(gfp, 0, zl, policy_nodemask(gfp, pol));
+ page = __alloc_pages_nodemask(gfp, 0, zl, policy_nodemask(gfp, pol));
+ put_mems_allowed();
+ return page;
}
/**
@@ -1796,18 +1807,23 @@
struct page *alloc_pages_current(gfp_t gfp, unsigned order)
{
struct mempolicy *pol = current->mempolicy;
+ struct page *page;
if (!pol || in_interrupt() || (gfp & __GFP_THISNODE))
pol = &default_policy;
+ get_mems_allowed();
/*
* No reference counting needed for current->mempolicy
* nor system default_policy
*/
if (pol->mode == MPOL_INTERLEAVE)
- return alloc_page_interleave(gfp, order, interleave_nodes(pol));
- return __alloc_pages_nodemask(gfp, order,
+ page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
+ else
+ page = __alloc_pages_nodemask(gfp, order,
policy_zonelist(gfp, pol), policy_nodemask(gfp, pol));
+ put_mems_allowed();
+ return page;
}
EXPORT_SYMBOL(alloc_pages_current);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 596180f..f7da2a2 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1990,10 +1990,13 @@
if (unlikely(!zonelist->_zonerefs->zone))
return NULL;
+ get_mems_allowed();
/* The preferred zone is used for statistics later */
first_zones_zonelist(zonelist, high_zoneidx, nodemask, &preferred_zone);
- if (!preferred_zone)
+ if (!preferred_zone) {
+ put_mems_allowed();
return NULL;
+ }
/* First allocation attempt */
page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order,
@@ -2003,6 +2006,7 @@
page = __alloc_pages_slowpath(gfp_mask, order,
zonelist, high_zoneidx, nodemask,
preferred_zone, migratetype);
+ put_mems_allowed();
trace_mm_page_alloc(page, order, gfp_mask, migratetype);
return page;
diff --git a/mm/slab.c b/mm/slab.c
index 50a73fc..02786e1 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3217,10 +3217,12 @@
if (in_interrupt() || (flags & __GFP_THISNODE))
return NULL;
nid_alloc = nid_here = numa_node_id();
+ get_mems_allowed();
if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD))
nid_alloc = cpuset_mem_spread_node();
else if (current->mempolicy)
nid_alloc = slab_node(current->mempolicy);
+ put_mems_allowed();
if (nid_alloc != nid_here)
return ____cache_alloc_node(cachep, flags, nid_alloc);
return NULL;
@@ -3247,6 +3249,7 @@
if (flags & __GFP_THISNODE)
return NULL;
+ get_mems_allowed();
zonelist = node_zonelist(slab_node(current->mempolicy), flags);
local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
@@ -3302,6 +3305,7 @@
}
}
}
+ put_mems_allowed();
return obj;
}
diff --git a/mm/slub.c b/mm/slub.c
index e46e312..26f0cb9 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1360,6 +1360,7 @@
get_cycles() % 1024 > s->remote_node_defrag_ratio)
return NULL;
+ get_mems_allowed();
zonelist = node_zonelist(slab_node(current->mempolicy), flags);
for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
struct kmem_cache_node *n;
@@ -1369,10 +1370,13 @@
if (n && cpuset_zone_allowed_hardwall(zone, flags) &&
n->nr_partial > s->min_partial) {
page = get_partial_node(n);
- if (page)
+ if (page) {
+ put_mems_allowed();
return page;
+ }
}
}
+ put_mems_allowed();
#endif
return NULL;
}
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 3ff3311..f2c367c 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1774,6 +1774,7 @@
enum zone_type high_zoneidx = gfp_zone(sc->gfp_mask);
unsigned long writeback_threshold;
+ get_mems_allowed();
delayacct_freepages_start();
if (scanning_global_lru(sc))
@@ -1857,6 +1858,7 @@
mem_cgroup_record_reclaim_priority(sc->mem_cgroup, priority);
delayacct_freepages_end();
+ put_mems_allowed();
return ret;
}