Re: [PATCH mm v3] memcg: enable memory accounting in __alloc_pages_bulk

Michal Hocko
2021-10-12T15:36:17Z

On Tue 12-10-21 17:58:21, Vasily Averin wrote:
> Enable memory accounting for bulk page allocator.

ENOCHANGELOG

And I have to say I am not very happy about the solution. It adds a very
tricky code where it splits different charging steps apart.

Would it be just too inefficient to charge page-by-page once all pages
are already taken away from the pcp lists? This bulk should be small so
this shouldn't really cause massive problems. I mean something like

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b37435c274cf..8bcd69195ef5 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5308,6 +5308,10 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid,

local_unlock_irqrestore(&pagesets.lock, flags);

+ if (memcg_kmem_enabled() && (gfp & __GFP_ACCOUNT)) {
+ /* charge pages here */
+ }
+
__count_zid_vm_events(PGALLOC, zone_idx(zone), nr_account);
zone_statistics(ac.preferred_zoneref->zone, zone, nr_account);
--
Michal Hocko
SUSE Labs