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Wed, 03 Sep 2025 04:16:16 -0700 (PDT) From: Yueyang Pan To: Suren Baghdasaryan , Andrew Morton , Vlastimil Babka , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Vishal Moola , Shakeel Butt , Usama Arif Cc: linux-mm@kvack.org, kernel-team@meta.com, linux-kernel@vger.kernel.org Subject: [PATCH v3 1/2] mm/show_mem: Dump the status of the mem alloc profiling before printing Date: Wed, 3 Sep 2025 04:16:13 -0700 Message-ID: X-Mailer: git-send-email 2.47.3 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This patch prints the status of the memory allocation profiling before __show_mem actually prints the detailed allocation info. This way will let us know the `0B` we saw in allocation info is because the profiling is disabled or the allocation is actually 0B. Signed-off-by: Yueyang Pan Acked-by: Shakeel Butt Acked-by: Suren Baghdasaryan Acked-by: Usama Arif Acked-by: Vlastimil Babka Acked-by: Zi Yan Reviewed-by: Vishal Moola (Oracle) --- mm/show_mem.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/show_mem.c b/mm/show_mem.c index ecf20a93ea54..fd85a028a926 100644 --- a/mm/show_mem.c +++ b/mm/show_mem.c @@ -427,7 +427,8 @@ void __show_mem(unsigned int filter, nodemask_t *nodema= sk, int max_zone_idx) =20 nr =3D alloc_tag_top_users(tags, ARRAY_SIZE(tags), false); if (nr) { - pr_notice("Memory allocations:\n"); + pr_notice("Memory allocations (profiling is currently turned %s):\n", + mem_alloc_profiling_enabled() ? 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Wed, 03 Sep 2025 04:16:18 -0700 (PDT) From: Yueyang Pan To: Suren Baghdasaryan , Andrew Morton , Vlastimil Babka , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Vishal Moola , Shakeel Butt , Usama Arif Cc: linux-mm@kvack.org, kernel-team@meta.com, linux-kernel@vger.kernel.org Subject: [PATCH v3 2/2] mm/show_mem: Add trylock while printing alloc info Date: Wed, 3 Sep 2025 04:16:14 -0700 Message-ID: <4ed91296e0c595d945a38458f7a8d9611b0c1e52.1756897825.git.pyyjason@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 spinlock 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 Acked-by: Shakeel Butt Acked-by: Suren Baghdasaryan Acked-by: Usama Arif Acked-by: Vlastimil Babka Acked-by: Zi Yan --- 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 fd85a028a926..e9701d07549b 100644 --- a/mm/show_mem.c +++ b/mm/show_mem.c @@ -421,7 +421,9 @@ void __show_mem(unsigned int filter, nodemask_t *nodema= sk, int max_zone_idx) printk("%lu pages hwpoisoned\n", atomic_long_read(&num_poisoned_pages)); #endif #ifdef CONFIG_MEM_ALLOC_PROFILING - { + static DEFINE_SPINLOCK(mem_alloc_profiling_spinlock); + + if (spin_trylock(&mem_alloc_profiling_spinlock)) { struct codetag_bytes tags[10]; size_t i, nr; =20 @@ -448,6 +450,7 @@ void __show_mem(unsigned int filter, nodemask_t *nodema= sk, int max_zone_idx) ct->lineno, ct->function); } } + spin_unlock(&mem_alloc_profiling_spinlock); } #endif } --=20 2.47.3