Currently we use per-cpu stocks to do precharges of the ->memory and ->memsw
counters. Do this for the ->kmem and ->cache as well to decrease contention
on these counters as well.

https://jira.sw.ru/browse/PSBM-101300
Signed-off-by: Andrey Ryabinin <[email protected]>
---
 mm/memcontrol.c | 71 ++++++++++++++++++++++++++++++++-----------------
 1 file changed, 46 insertions(+), 25 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c2713cfd9975..34c9c4745594 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2810,6 +2810,8 @@ void mem_cgroup_update_page_stat(struct page *page,
 struct memcg_stock_pcp {
        struct mem_cgroup *cached; /* this never be root cgroup */
        unsigned int nr_pages;
+       unsigned int cache_nr_pages;
+       unsigned int kmem_nr_pages;
        struct work_struct work;
        unsigned long flags;
 #define FLUSHING_CACHED_CHARGE 0
@@ -2828,7 +2830,8 @@ static DEFINE_MUTEX(percpu_charge_mutex);
  *
  * returns true if successful, false otherwise.
  */
-static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
+static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages,
+                       bool cache, bool kmem)
 {
        struct memcg_stock_pcp *stock;
        bool ret = false;
@@ -2837,9 +2840,19 @@ static bool consume_stock(struct mem_cgroup *memcg, 
unsigned int nr_pages)
                return ret;
 
        stock = &get_cpu_var(memcg_stock);
-       if (memcg == stock->cached && stock->nr_pages >= nr_pages) {
-               stock->nr_pages -= nr_pages;
-               ret = true;
+       if (memcg == stock->cached) {
+               if (cache && stock->cache_nr_pages >= nr_pages) {
+                       stock->cache_nr_pages -= nr_pages;
+                       ret = true;
+               }
+               if (kmem && stock->kmem_nr_pages >= nr_pages) {
+                       stock->kmem_nr_pages -= nr_pages;
+                       ret = true;
+               }
+               if (!cache && !kmem && stock->nr_pages >= nr_pages) {
+                       stock->nr_pages -= nr_pages;
+                       ret = true;
+               }
        }
        put_cpu_var(memcg_stock);
        return ret;
@@ -2851,12 +2864,20 @@ static bool consume_stock(struct mem_cgroup *memcg, 
unsigned int nr_pages)
 static void drain_stock(struct memcg_stock_pcp *stock)
 {
        struct mem_cgroup *old = stock->cached;
+       unsigned long nr_pages = stock->nr_pages + stock->cache_nr_pages + 
stock->kmem_nr_pages;
+
+       if (stock->cache_nr_pages)
+               page_counter_uncharge(&old->cache, stock->cache_nr_pages);
+       if (stock->kmem_nr_pages)
+               page_counter_uncharge(&old->kmem, stock->kmem_nr_pages);
 
-       if (stock->nr_pages) {
-               page_counter_uncharge(&old->memory, stock->nr_pages);
+       if (nr_pages) {
+               page_counter_uncharge(&old->memory, nr_pages);
                if (do_swap_account)
-                       page_counter_uncharge(&old->memsw, stock->nr_pages);
+                       page_counter_uncharge(&old->memsw, nr_pages);
                stock->nr_pages = 0;
+               stock->kmem_nr_pages = 0;
+               stock->cache_nr_pages = 0;
        }
        stock->cached = NULL;
 }
@@ -2887,7 +2908,8 @@ static void __init memcg_stock_init(void)
  * Cache charges(val) to local per_cpu area.
  * This will be consumed by consume_stock() function, later.
  */
-static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
+static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages,
+                       bool cache, bool kmem)
 {
        struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
 
@@ -2895,7 +2917,13 @@ static void refill_stock(struct mem_cgroup *memcg, 
unsigned int nr_pages)
                drain_stock(stock);
                stock->cached = memcg;
        }
-       stock->nr_pages += nr_pages;
+
+       if (cache)
+               stock->cache_nr_pages += nr_pages;
+       else if (kmem)
+               stock->kmem_nr_pages += nr_pages;
+       else
+               stock->nr_pages += nr_pages;
        put_cpu_var(memcg_stock);
 }
 
@@ -2916,7 +2944,7 @@ static void drain_all_stock(struct mem_cgroup 
*root_memcg, bool sync)
                struct mem_cgroup *memcg;
 
                memcg = stock->cached;
-               if (!memcg || !stock->nr_pages)
+               if (!memcg || !(stock->nr_pages + stock->kmem_nr_pages + 
stock->cache_nr_pages))
                        continue;
                if (!mem_cgroup_same_or_subtree(root_memcg, memcg))
                        continue;
@@ -3107,21 +3135,13 @@ static int try_charge(struct mem_cgroup *memcg, gfp_t 
gfp_mask, bool kmem_charge
        bool drained = false;
 
        if (mem_cgroup_is_root(memcg))
-               goto done;
+               return 0;
 retry:
        flags = 0;
 
-       if (consume_stock(memcg, nr_pages)) {
-               if (kmem_charge && !page_counter_try_charge(
-                               &memcg->kmem, nr_pages, &counter)) {
-                       refill_stock(memcg, nr_pages);
-                       goto charge;
-               }
-
+       if (consume_stock(memcg, nr_pages, cache_charge, kmem_charge))
                goto done;
-       }
 
-charge:
        mem_over_limit = NULL;
        if (page_counter_try_charge(&memcg->memory, batch, &counter)) {
                if (do_swap_account && !page_counter_try_charge(
@@ -3134,7 +3154,7 @@ charge:
                mem_over_limit = mem_cgroup_from_counter(counter, memory);
 
        if (!mem_over_limit && kmem_charge) {
-               if (!page_counter_try_charge(&memcg->kmem, nr_pages, &counter)) 
{
+               if (!page_counter_try_charge(&memcg->kmem, batch, &counter)) {
                        flags |= MEM_CGROUP_RECLAIM_KMEM;
                        mem_over_limit = mem_cgroup_from_counter(counter, kmem);
                        page_counter_uncharge(&memcg->memory, batch);
@@ -3263,12 +3283,13 @@ done_restock:
                goto bypass;
        }
 
-       if (batch > nr_pages)
-               refill_stock(memcg, batch - nr_pages);
-done:
        if (cache_charge)
-               page_counter_charge(&memcg->cache, nr_pages);
+               page_counter_charge(&memcg->cache, batch);
+
+       if (batch > nr_pages)
+               refill_stock(memcg, batch - nr_pages, cache_charge, 
kmem_charge);
 
+done:
        /*
         * If the hierarchy is above the normal consumption range, schedule
         * reclaim on returning to userland.  We can perform reclaim here
-- 
2.26.2

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