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Wed, 27 Aug 2025 11:34:27 -0700 (PDT) Received: from localhost ([2a03:2880:31ff::]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3cce1724939sm3580972f8f.26.2025.08.27.11.34.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 27 Aug 2025 11:34:27 -0700 (PDT) From: Yueyang Pan To: Suren Baghdasaryan , Andrew Morton , Vlastimil Babka , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Usama Arif Cc: linux-mm@kvack.org, kernel-team@meta.com, linux-kernel@vger.kernel.org Subject: [PATCH v1 2/2] mm/show_mem: Add trylock while printing alloc info Date: Wed, 27 Aug 2025 11:34:23 -0700 Message-ID: <7e2bc96faab1a338829e549246189ad96e6c866b.1756318426.git.pyyjason@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 0562D180003 X-Stat-Signature: zcaha4p3m6eesj153y4gyhzhsqzae49m X-HE-Tag: 1756319668-780957 X-HE-Meta: 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 4bdFKTUT 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: In production, show_mem() can be called concurrently from two different entities, for example one from oom_kill_process() another from __alloc_pages_slowpath from another kthread. This patch adds a mutex and invokes trylock before printing out the kernel alloc info in show_mem(). This way two alloc info won't interleave with each other, which then makes parsing easier. Signed-off-by: Yueyang Pan --- mm/show_mem.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/show_mem.c b/mm/show_mem.c index b71e222fde86..8814b5f8a7dc 100644 --- a/mm/show_mem.c +++ b/mm/show_mem.c @@ -23,6 +23,8 @@ EXPORT_SYMBOL(_totalram_pages); unsigned long totalreserve_pages __read_mostly; unsigned long totalcma_pages __read_mostly; +static DEFINE_MUTEX(mem_alloc_profiling_mutex); + static inline void show_node(struct zone *zone) { if (IS_ENABLED(CONFIG_NUMA)) @@ -419,7 +421,7 @@ void __show_mem(unsigned int filter, nodemask_t *nodemask, int max_zone_idx) printk("%lu pages hwpoisoned\n", atomic_long_read(&num_poisoned_pages)); #endif #ifdef CONFIG_MEM_ALLOC_PROFILING - if (mem_alloc_profiling_enabled()) { + if (mem_alloc_profiling_enabled() && mutex_trylock(&mem_alloc_profiling_mutex)) { struct codetag_bytes tags[10]; size_t i, nr; @@ -445,6 +447,7 @@ void __show_mem(unsigned int filter, nodemask_t *nodemask, int max_zone_idx) ct->lineno, ct->function); } } + mutex_unlock(&mem_alloc_profiling_mutex); } #endif } -- 2.47.3