summaryrefslogtreecommitdiff
path: root/mm/page_alloc.c
diff options
context:
space:
mode:
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r--mm/page_alloc.c65
1 files changed, 55 insertions, 10 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e5486d47406e..d04211f0ef0b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4708,6 +4708,30 @@ void fs_reclaim_release(gfp_t gfp_mask)
EXPORT_SYMBOL_GPL(fs_reclaim_release);
#endif
+/*
+ * Zonelists may change due to hotplug during allocation. Detect when zonelists
+ * have been rebuilt so allocation retries. Reader side does not lock and
+ * retries the allocation if zonelist changes. Writer side is protected by the
+ * embedded spin_lock.
+ */
+static DEFINE_SEQLOCK(zonelist_update_seq);
+
+static unsigned int zonelist_iter_begin(void)
+{
+ if (IS_ENABLED(CONFIG_MEMORY_HOTREMOVE))
+ return read_seqbegin(&zonelist_update_seq);
+
+ return 0;
+}
+
+static unsigned int check_retry_zonelist(unsigned int seq)
+{
+ if (IS_ENABLED(CONFIG_MEMORY_HOTREMOVE))
+ return read_seqretry(&zonelist_update_seq, seq);
+
+ return seq;
+}
+
/* Perform direct synchronous page reclaim */
static unsigned long
__perform_reclaim(gfp_t gfp_mask, unsigned int order,
@@ -5001,6 +5025,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
int compaction_retries;
int no_progress_loops;
unsigned int cpuset_mems_cookie;
+ unsigned int zonelist_iter_cookie;
int reserve_flags;
/*
@@ -5011,11 +5036,12 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
(__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)))
gfp_mask &= ~__GFP_ATOMIC;
-retry_cpuset:
+restart:
compaction_retries = 0;
no_progress_loops = 0;
compact_priority = DEF_COMPACT_PRIORITY;
cpuset_mems_cookie = read_mems_allowed_begin();
+ zonelist_iter_cookie = zonelist_iter_begin();
/*
* The fast path uses conservative alloc_flags to succeed only until
@@ -5187,9 +5213,13 @@ retry:
goto retry;
- /* Deal with possible cpuset update races before we start OOM killing */
- if (check_retry_cpuset(cpuset_mems_cookie, ac))
- goto retry_cpuset;
+ /*
+ * Deal with possible cpuset update races or zonelist updates to avoid
+ * a unnecessary OOM kill.
+ */
+ if (check_retry_cpuset(cpuset_mems_cookie, ac) ||
+ check_retry_zonelist(zonelist_iter_cookie))
+ goto restart;
/* Reclaim has failed us, start killing things */
page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress);
@@ -5209,9 +5239,13 @@ retry:
}
nopage:
- /* Deal with possible cpuset update races before we fail */
- if (check_retry_cpuset(cpuset_mems_cookie, ac))
- goto retry_cpuset;
+ /*
+ * Deal with possible cpuset update races or zonelist updates to avoid
+ * a unnecessary OOM kill.
+ */
+ if (check_retry_cpuset(cpuset_mems_cookie, ac) ||
+ check_retry_zonelist(zonelist_iter_cookie))
+ goto restart;
/*
* Make sure that __GFP_NOFAIL request doesn't leak out and make sure
@@ -5706,6 +5740,18 @@ refill:
/* reset page count bias and offset to start of new frag */
nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
offset = size - fragsz;
+ if (unlikely(offset < 0)) {
+ /*
+ * The caller is trying to allocate a fragment
+ * with fragsz > PAGE_SIZE but the cache isn't big
+ * enough to satisfy the request, this may
+ * happen in low memory conditions.
+ * We don't release the cache page because
+ * it could make memory pressure worse
+ * so we simply return NULL here.
+ */
+ return NULL;
+ }
}
nc->pagecnt_bias--;
@@ -6514,9 +6560,8 @@ static void __build_all_zonelists(void *data)
int nid;
int __maybe_unused cpu;
pg_data_t *self = data;
- static DEFINE_SPINLOCK(lock);
- spin_lock(&lock);
+ write_seqlock(&zonelist_update_seq);
#ifdef CONFIG_NUMA
memset(node_load, 0, sizeof(node_load));
@@ -6553,7 +6598,7 @@ static void __build_all_zonelists(void *data)
#endif
}
- spin_unlock(&lock);
+ write_sequnlock(&zonelist_update_seq);
}
static noinline void __init