From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Hocko Subject: Re: [PATCH v2] memcg: page_alloc: skip bulk allocator for __GFP_ACCOUNT Date: Thu, 14 Oct 2021 17:32:50 +0200 Message-ID: References: <20211014151607.2171970-1-shakeelb@google.com> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1634225571; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=8NI5g+v3yznxinmmoFT7TMX1/0izl9PQ4EZKztZniWc=; b=jeXGfJreavv0Vk459TOje+YdBW0yWUXEzJlCcgd1R6KNcwJmHB97kYcO92BPxFHaXR0Ufw dDD6vxtsXrtGNcnsbb9Za0hOJ7x0rXnSZ012V27ZkFjbj90RB+myCkmR0Jy6SxZiM+cU/5 LMQcrqnZw8fG8HOpl4dayFORdLAHKLo= Content-Disposition: inline In-Reply-To: <20211014151607.2171970-1-shakeelb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Shakeel Butt Cc: Johannes Weiner , Mel Gorman , Uladzislau Rezki , Vasily Averin , Roman Gushchin , Matthew Wilcox , Andrew Morton , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On Thu 14-10-21 08:16:07, Shakeel Butt wrote: > The commit 5c1f4e690eec ("mm/vmalloc: switch to bulk allocator in > __vmalloc_area_node()") switched to bulk page allocator for order 0 > allocation backing vmalloc. However bulk page allocator does not support > __GFP_ACCOUNT allocations and there are several users of > kvmalloc(__GFP_ACCOUNT). > > For now make __GFP_ACCOUNT allocations bypass bulk page allocator. In I would go with For now make __GFP_ACCOUNT allocations bypass the fast path of the bulk allocator and make it fallback to the regular page allocator as if the former failed. > future if there is workload that can be significantly improved with the > bulk page allocator with __GFP_ACCCOUNT support, we can revisit the > decision. > > Fixes: 5c1f4e690eec ("mm/vmalloc: switch to bulk allocator in __vmalloc_area_node()") > Signed-off-by: Shakeel Butt Acked-by: Michal Hocko Thanks! > --- > Changes since v1: > - do fallback allocation instead of failure, suggested by Michal Hocko. > - Added memcg_kmem_enabled() check, corrected by Vasily Averin > > mm/page_alloc.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 668edb16446a..9ca871dc8602 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -5230,6 +5230,10 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid, > if (unlikely(page_array && nr_pages - nr_populated == 0)) > goto out; > > + /* Bulk allocator does not support memcg accounting. */ > + if (memcg_kmem_enabled() && (gfp & __GFP_ACCOUNT)) > + goto failed; > + > /* Use the single page allocator for one page. */ > if (nr_pages - nr_populated == 1) > goto failed; > -- > 2.33.0.882.g93a45727a2-goog -- Michal Hocko SUSE Labs