Re: memcg memory accounting in vmalloc is broken
flat view
From: Vlastimil Babka <hidden>
Date: 2021-10-07 14:00:27
Also in:
linux-mm, lkml
On 10/7/21 10:50, Vasily Averin wrote:
quoted hunk ↗ jump to hunk
On 10/7/21 11:16 AM, Michal Hocko wrote:quoted
Cc Mel and Uladzislau On Thu 07-10-21 10:13:23, Michal Hocko wrote:quoted
On Thu 07-10-21 11:04:40, Vasily Averin wrote:quoted
vmalloc was switched to __alloc_pages_bulk but it does not account the memory to memcg. Is it known issue perhaps?No, I think this was just overlooked. Definitely doesn't look intentional to me.I use following patch as a quick fix, it helps though it is far from ideal and can be optimized.diff --git a/mm/page_alloc.c b/mm/page_alloc.c index b37435c274cf..e6abe2cac159 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c@@ -5290,6 +5290,12 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid, page = __rmqueue_pcplist(zone, 0, ac.migratetype, alloc_flags, pcp, pcp_list); + + if (memcg_kmem_enabled() && (gfp & __GFP_ACCOUNT) && page && + unlikely(__memcg_kmem_charge_page(page, gfp, 0) != 0)) { + __free_pages(page, 0);
It's too early for this here, we didn't go through prep_new_page() yet, minimally the post_alloc_hook() -> set_page_refcounted() part, required for put_page_testzero() in __free_pages() to work properly, and probably other stuff. Either do the full prep+free or a minimal reversion of __rmqueue_pcplist - something to just put the page back to pcplist. Probably the former so we don't introduce subtle errors.
quoted hunk ↗ jump to hunk
+ page = NULL; + } if (unlikely(!page)) { /* Try and get at least one page */ if (!nr_populated)