On 03/10/2012 12:39 AM, Suleiman Souhlal wrote:
Signed-off-by: Suleiman Souhlal<suleiman@xxxxxxxxxx>
---
mm/memcontrol.c | 18 +++++++++---------
1 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6fbb438..f605100 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1965,19 +1965,19 @@ static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
static DEFINE_MUTEX(percpu_charge_mutex);
/*
- * Try to consume stocked charge on this cpu. If success, one page is consumed
- * from local stock and true is returned. If the stock is 0 or charges from a
- * cgroup which is not current target, returns false. This stock will be
- * refilled.
+ * Try to consume stocked charge on this cpu. If success, nr_pages pages are
+ * consumed from local stock and true is returned. If the stock is 0 or
+ * charges from a cgroup which is not current target, returns false.
+ * This stock will be refilled.
*/
-static bool consume_stock(struct mem_cgroup *memcg)
+static bool consume_stock(struct mem_cgroup *memcg, int nr_pages)
{
struct memcg_stock_pcp *stock;
bool ret = true;
stock =&get_cpu_var(memcg_stock);
- if (memcg == stock->cached&& stock->nr_pages)
- stock->nr_pages--;
+ if (memcg == stock->cached&& stock->nr_pages>= nr_pages)
+ stock->nr_pages -= nr_pages;
else /* need to call res_counter_charge */
ret = false;
put_cpu_var(memcg_stock);
@@ -2290,7 +2290,7 @@ again:
VM_BUG_ON(css_is_removed(&memcg->css));
if (mem_cgroup_is_root(memcg))
goto done;
- if (nr_pages == 1&& consume_stock(memcg))
+ if (consume_stock(memcg, nr_pages))
goto done;
css_get(&memcg->css);
} else {
@@ -2315,7 +2315,7 @@ again:
rcu_read_unlock();
goto done;
}
- if (nr_pages == 1&& consume_stock(memcg)) {
+ if (consume_stock(memcg, nr_pages)) {
/*
* It seems dagerous to access memcg without css_get().
* But considering how consume_stok works, it's not
This patch itself is fine in what it wants to achieve.
But it made me think:
We'll jump into the stock code which makes user allocation faster.
but we're not getting the benefit of it when we're accounting kmem.
since we're allocating to both res_counters, we're actually defeating it
altogether, since we now have to go to the global poll *everytime* (for
memcg->kmem).
It would make a whole lot more sense to have the stock code moved to the
res_counter. We're now starting to have more users of that anyway, so
a common implementation makes sense.
--
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