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(unknown []) by gzsmtp3 (Coremail) with SMTP id PigvCgA39QGdcN9pD65+AA--.81S2; Wed, 15 Apr 2026 19:04:01 +0800 (CST) From: ranxiaokai627@163.com To: mkoutny@suse.com Cc: akpm@linux-foundation.org, cgroups@vger.kernel.org, hannes@cmpxchg.org, hughd@google.com, kuba@kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, mhocko@kernel.org, muchun.song@linux.dev, ran.xiaokai@zte.com.cn, ranxiaokai627@163.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, shuah@kernel.org, tj@kernel.org Subject: Re: [PATCH 1/2] kselftests: cgroup: update kmem test tolerance for multi-memcg stock Date: Wed, 15 Apr 2026 11:03:56 +0000 Message-ID: <20260415110356.3546-1-ranxiaokai627@163.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:PigvCgA39QGdcN9pD65+AA--.81S2 X-Coremail-Antispam: 1Uf129KBjvdXoWrurWUurWDJF4fJr43GrWUCFg_yoWkuFX_uF Wjyr1DKw4UKFyxuFZ0yFs3XF12vrWUArn7Xa95tF4xta4Dta1kJrZ5Wryjkw4rGay3GryS 9ws0q34Yq3ZIgjkaLaAFLSUrUUUUjb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUvcSsGvfC2KfnxnUUI43ZEXa7sRM8n5JUUUUU== X-Originating-IP: [117.176.243.250] X-CM-SenderInfo: xudq5x5drntxqwsxqiywtou0bp/xtbCxQGW4mnfcKGkwgAA3x X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 49B35120012 X-Stat-Signature: 9x8g86ab8grtonqkapmu8wp5jbcezndd X-Rspam-User: X-HE-Tag: 1776251074-111002 X-HE-Meta: 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 /kQy+Yza ibRiU9k7LFkcnlTI0y+fUrwM+mVNpb0BPoMl1AGe4aLfQ9/kzbn0XLTAgH9YshUY2aWvuo78AJNzksM3FPyvJal4eDv4x+ccVnlA7fodStq0Ti3e364EpU6V5zhKmkXuOm10wyOipOWGd2DaIEH8l/104avJrsp+aERy8eag7RRfyVCyG+J9gDbMM7aPXv74iAIdAmPXK7nnscD3bM81bnKPXD3VJbjOVCsUlpi8i4oqb4637unzv2ecBN3JpyiDSYT/PL1GK8bZEeppFOMxUqwECx3icAdUrQ/lSIRSKJEc8Dj7Ffm3kPaQzWW3RJJ8PpWKXYGAo3FUdfEWZS6UxQjESzMgqbR+aa3NVt67kwErNeDI= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: >Hello Xiaokai. > >On Tue, Apr 14, 2026 at 11:05:23AM +0000, ranxiaokai627@163.com wrote: >> Fixes: f735eebe55f8 ("memcg: multi-memcg percpu charge cache") > >An interesting catch. > >> -#define MAX_VMSTAT_ERROR (4096 * 64 * get_nprocs()) >> +#define NR_MEMCG_STOCK 7 >> +#define MAX_VMSTAT_ERROR (4096 * 64 * NR_MEMCG_STOCK * get_nprocs()) > >When you touch this, I think this could be factored into it too: > >+#define MAX_VMSTAT_ERROR (sysconf(_SC_PAGESIZE) * 64 * NR_MEMCG_STOCK * get_nprocs()) Thanks for the review, yes, this will improve the test' portability across architectures with different page sizes. >And given how much the selftest depends in this implementation >detail(?), I see that there are other selftests that include directly >from the tree, I'd suggest also >#include "../../../../include/linux/memcontrol.h" > >and use the constant from there (i.e. move NR_MEMCG_STOCK to there too). > >That should make the selftest more flexible, resilient to future changes >and it'd document ramification of these constants too. Agreed. Including memcontrol.h ensures the test stays in sync with kernel changes. >Thanks, >Michal