[PATCH] memcg: page_alloc: skip bulk allocator for __GFP_ACCOUNT

From: Shakeel Butt <shakeelb@google.com>
To: Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@kernel.org>,
	Mel Gorman <mgorman@techsingularity.net>
Cc: Uladzislau Rezki <urezki@gmail.com>,
	Vasily Averin <vvs@virtuozzo.com>, Roman Gushchin <guro@fb.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	cgroups@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, Shakeel Butt <shakeelb@google.com>
Subject: [PATCH] memcg: page_alloc: skip bulk allocator for __GFP_ACCOUNT
Date: Wed, 13 Oct 2021 12:43:38 -0700	[thread overview]
Message-ID: <20211013194338.1804247-1-shakeelb@google.com> (raw)

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
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 <shakeelb@google.com>
---
 mm/page_alloc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 668edb16446a..b3acad4615d3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5215,6 +5215,10 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid,
 	unsigned int alloc_flags = ALLOC_WMARK_LOW;
 	int nr_populated = 0, nr_account = 0;
 
+	/* Bulk allocator does not support memcg accounting. */
+	if (unlikely(gfp & __GFP_ACCOUNT))
+		goto out;
+
 	/*
 	 * Skip populated array elements to determine if any pages need
 	 * to be allocated before disabling IRQs.
-- 
2.33.0.882.g93a45727a2-goog

