The patch titled Subject: memcg: gix memory accounting scalability in shrink_page_list has been removed from the -mm tree. Its filename was cgroup-fix-memory-accounting-scalability-in-shrink_page_list.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx> Subject: memcg: gix memory accounting scalability in shrink_page_list I noticed in a multi-process parallel files reading benchmark I ran on a 8 socket machine, throughput slowed down by a factor of 8 when I ran the benchmark within a cgroup container. I traced the problem to the following code path (see below) when we are trying to reclaim memory from file cache. The res_counter_uncharge function is called on every page that's reclaimed and created heavy lock contention. The patch below allows the reclaimed pages to be uncharged from the resource counter in batch and recovered the regression. Tim 40.67% usemem [kernel.kallsyms] [k] _raw_spin_lock | --- _raw_spin_lock | |--92.61%-- res_counter_uncharge | | | |--100.00%-- __mem_cgroup_uncharge_common | | | | | |--100.00%-- mem_cgroup_uncharge_cache_page | | | __remove_mapping | | | shrink_page_list | | | shrink_inactive_list | | | shrink_mem_cgroup_zone | | | shrink_zone | | | do_try_to_free_pages | | | try_to_free_pages | | | __alloc_pages_nodemask | | | alloc_pages_current Signed-off-by: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/vmscan.c | 2 ++ 1 file changed, 2 insertions(+) diff -puN mm/vmscan.c~cgroup-fix-memory-accounting-scalability-in-shrink_page_list mm/vmscan.c --- a/mm/vmscan.c~cgroup-fix-memory-accounting-scalability-in-shrink_page_list +++ a/mm/vmscan.c @@ -687,6 +687,7 @@ static unsigned long shrink_page_list(st cond_resched(); + mem_cgroup_uncharge_start(); while (!list_empty(page_list)) { enum page_references references; struct address_space *mapping; @@ -953,6 +954,7 @@ keep: list_splice(&ret_pages, page_list); count_vm_events(PGACTIVATE, pgactivate); + mem_cgroup_uncharge_end(); *ret_nr_dirty += nr_dirty; *ret_nr_writeback += nr_writeback; return nr_reclaimed; _ Patches currently in -mm which might be from tim.c.chen@xxxxxxxxxxxxxxx are origin.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html