linux-kernel - [PATCH] dma-buf: system_heap: account for system heap allocation in memcg

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Message-ID: <20251211193106.755485-2-echanude@redhat.com>
Date: Thu, 11 Dec 2025 14:31:07 -0500
From: Eric Chanudet <echanude@...hat.com>
To: Sumit Semwal <sumit.semwal@...aro.org>,
	Benjamin Gaignard <benjamin.gaignard@...labora.com>,
	Brian Starkey <Brian.Starkey@....com>,
	John Stultz <jstultz@...gle.com>,
	"T.J. Mercier" <tjmercier@...gle.com>,
	Christian Koenig <christian.koenig@....com>,
	Maxime Ripard <mripard@...hat.com>
Cc: linux-media@...r.kernel.org,
	dri-devel@...ts.freedesktop.org,
	linaro-mm-sig@...ts.linaro.org,
	linux-kernel@...r.kernel.org,
	Eric Chanudet <echanude@...hat.com>
Subject: [PATCH] dma-buf: system_heap: account for system heap allocation in memcg

The system dma-buf heap lets userspace allocate buffers from the page
allocator. However, these allocations are not accounted for in memcg,
allowing processes to escape limits that may be configured.

Pass the __GFP_ACCOUNT for our allocations to account them into memcg.

Userspace components using the system heap can be constrained with, e.g:
  systemd-run --user --scope -p MemoryMax=10M ...

Signed-off-by: Eric Chanudet <echanude@...hat.com>
---
 drivers/dma-buf/heaps/system_heap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c
index 4c782fe33fd4..c91fcdff4b77 100644
--- a/drivers/dma-buf/heaps/system_heap.c
+++ b/drivers/dma-buf/heaps/system_heap.c
@@ -38,10 +38,10 @@ struct dma_heap_attachment {
 	bool mapped;
 };
 
-#define LOW_ORDER_GFP (GFP_HIGHUSER | __GFP_ZERO)
+#define LOW_ORDER_GFP (GFP_HIGHUSER | __GFP_ZERO | __GFP_ACCOUNT)
 #define HIGH_ORDER_GFP  (((GFP_HIGHUSER | __GFP_ZERO | __GFP_NOWARN \
 				| __GFP_NORETRY) & ~__GFP_RECLAIM) \
-				| __GFP_COMP)
+				| __GFP_COMP | __GFP_ACCOUNT)
 static gfp_t order_flags[] = {HIGH_ORDER_GFP, HIGH_ORDER_GFP, LOW_ORDER_GFP};
 /*
  * The selection of the orders used for allocation (1MB, 64K, 4K) is designed
-- 
2.52.0