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-rw-r--r--mm/memcontrol.c67
1 files changed, 52 insertions, 15 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 3878cfe399d..da53a252b25 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -612,8 +612,10 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
/* pagein of a big page is an event. So, ignore page size */
if (nr_pages > 0)
__this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGIN_COUNT]);
- else
+ else {
__this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGOUT_COUNT]);
+ nr_pages = -nr_pages; /* for event */
+ }
__this_cpu_add(mem->stat->count[MEM_CGROUP_EVENTS], nr_pages);
@@ -1111,6 +1113,23 @@ static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem)
return false;
}
+/**
+ * mem_cgroup_check_margin - check if the memory cgroup allows charging
+ * @mem: memory cgroup to check
+ * @bytes: the number of bytes the caller intends to charge
+ *
+ * Returns a boolean value on whether @mem can be charged @bytes or
+ * whether this would exceed the limit.
+ */
+static bool mem_cgroup_check_margin(struct mem_cgroup *mem, unsigned long bytes)
+{
+ if (!res_counter_check_margin(&mem->res, bytes))
+ return false;
+ if (do_swap_account && !res_counter_check_margin(&mem->memsw, bytes))
+ return false;
+ return true;
+}
+
static unsigned int get_swappiness(struct mem_cgroup *memcg)
{
struct cgroup *cgrp = memcg->css.cgroup;
@@ -1837,23 +1856,34 @@ static int __mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask,
flags |= MEM_CGROUP_RECLAIM_NOSWAP;
} else
mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
-
- if (csize > PAGE_SIZE) /* change csize and retry */
+ /*
+ * csize can be either a huge page (HPAGE_SIZE), a batch of
+ * regular pages (CHARGE_SIZE), or a single regular page
+ * (PAGE_SIZE).
+ *
+ * Never reclaim on behalf of optional batching, retry with a
+ * single page instead.
+ */
+ if (csize == CHARGE_SIZE)
return CHARGE_RETRY;
if (!(gfp_mask & __GFP_WAIT))
return CHARGE_WOULDBLOCK;
ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
- gfp_mask, flags);
+ gfp_mask, flags);
+ if (mem_cgroup_check_margin(mem_over_limit, csize))
+ return CHARGE_RETRY;
/*
- * try_to_free_mem_cgroup_pages() might not give us a full
- * picture of reclaim. Some pages are reclaimed and might be
- * moved to swap cache or just unmapped from the cgroup.
- * Check the limit again to see if the reclaim reduced the
- * current usage of the cgroup before giving up
+ * Even though the limit is exceeded at this point, reclaim
+ * may have been able to free some pages. Retry the charge
+ * before killing the task.
+ *
+ * Only for regular pages, though: huge pages are rather
+ * unlikely to succeed so close to the limit, and we fall back
+ * to regular pages anyway in case of failure.
*/
- if (ret || mem_cgroup_check_under_limit(mem_over_limit))
+ if (csize == PAGE_SIZE && ret)
return CHARGE_RETRY;
/*
@@ -2323,13 +2353,19 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask, enum charge_type ctype)
{
struct mem_cgroup *mem = NULL;
+ int page_size = PAGE_SIZE;
struct page_cgroup *pc;
+ bool oom = true;
int ret;
- int page_size = PAGE_SIZE;
if (PageTransHuge(page)) {
page_size <<= compound_order(page);
VM_BUG_ON(!PageTransHuge(page));
+ /*
+ * Never OOM-kill a process for a huge page. The
+ * fault handler will fall back to regular pages.
+ */
+ oom = false;
}
pc = lookup_page_cgroup(page);
@@ -2338,7 +2374,7 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
return 0;
prefetchw(pc);
- ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true, page_size);
+ ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, oom, page_size);
if (ret || !mem)
return ret;
@@ -5024,9 +5060,9 @@ struct cgroup_subsys mem_cgroup_subsys = {
static int __init enable_swap_account(char *s)
{
/* consider enabled if no parameter or 1 is given */
- if (!s || !strcmp(s, "1"))
+ if (!(*s) || !strcmp(s, "=1"))
really_do_swap_account = 1;
- else if (!strcmp(s, "0"))
+ else if (!strcmp(s, "=0"))
really_do_swap_account = 0;
return 1;
}
@@ -5034,7 +5070,8 @@ __setup("swapaccount", enable_swap_account);
static int __init disable_swap_account(char *s)
{
- enable_swap_account("0");
+ printk_once("noswapaccount is deprecated and will be removed in 2.6.40. Use swapaccount=0 instead\n");
+ enable_swap_account("=0");
return 1;
}
__setup("noswapaccount", disable_swap_account);