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Wed, 3 Sep 2025 09:22:05 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id EFi/Hb0IuGhuZQAAD6G6ig (envelope-from ); Wed, 03 Sep 2025 09:22:05 +0000 Message-ID: <2c9d2e2f-adab-4bd6-a03e-a327a4c5d6fe@suse.cz> Date: Wed, 3 Sep 2025 11:22:05 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/2] mm/show_mem: Add trylock while printing alloc info To: Yueyang Pan , Suren Baghdasaryan , Andrew Morton , 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 References: <1491df0ac12a7626b7c9b00e26a6e10adb8c9045.1756827906.git.pyyjason@gmail.com> Content-Language: en-US From: Vlastimil Babka Autocrypt: addr=vbabka@suse.cz; keydata= xsFNBFZdmxYBEADsw/SiUSjB0dM+vSh95UkgcHjzEVBlby/Fg+g42O7LAEkCYXi/vvq31JTB KxRWDHX0R2tgpFDXHnzZcQywawu8eSq0LxzxFNYMvtB7sV1pxYwej2qx9B75qW2plBs+7+YB 87tMFA+u+L4Z5xAzIimfLD5EKC56kJ1CsXlM8S/LHcmdD9Ctkn3trYDNnat0eoAcfPIP2OZ+ 9oe9IF/R28zmh0ifLXyJQQz5ofdj4bPf8ecEW0rhcqHfTD8k4yK0xxt3xW+6Exqp9n9bydiy tcSAw/TahjW6yrA+6JhSBv1v2tIm+itQc073zjSX8OFL51qQVzRFr7H2UQG33lw2QrvHRXqD Ot7ViKam7v0Ho9wEWiQOOZlHItOOXFphWb2yq3nzrKe45oWoSgkxKb97MVsQ+q2SYjJRBBH4 8qKhphADYxkIP6yut/eaj9ImvRUZZRi0DTc8xfnvHGTjKbJzC2xpFcY0DQbZzuwsIZ8OPJCc LM4S7mT25NE5kUTG/TKQCk922vRdGVMoLA7dIQrgXnRXtyT61sg8PG4wcfOnuWf8577aXP1x 6mzw3/jh3F+oSBHb/GcLC7mvWreJifUL2gEdssGfXhGWBo6zLS3qhgtwjay0Jl+kza1lo+Cv BB2T79D4WGdDuVa4eOrQ02TxqGN7G0Biz5ZLRSFzQSQwLn8fbwARAQABzSBWbGFzdGltaWwg QmFia2EgPHZiYWJrYUBzdXNlLmN6PsLBlAQTAQoAPgIbAwULCQgHAwUVCgkICwUWAgMBAAIe AQIXgBYhBKlA1DSZLC6OmRA9UCJPp+fMgqZkBQJnyBr8BQka0IFQAAoJECJPp+fMgqZkqmMQ AIbGN95ptUMUvo6aAdhxaOCHXp1DfIBuIOK/zpx8ylY4pOwu3GRe4dQ8u4XS9gaZ96Gj4bC+ jwWcSmn+TjtKW3rH1dRKopvC07tSJIGGVyw7ieV/5cbFffA8NL0ILowzVg8w1ipnz1VTkWDr 2zcfslxJsJ6vhXw5/npcY0ldeC1E8f6UUoa4eyoskd70vO0wOAoGd02ZkJoox3F5ODM0kjHu Y97VLOa3GG66lh+ZEelVZEujHfKceCw9G3PMvEzyLFbXvSOigZQMdKzQ8D/OChwqig8wFBmV QCPS4yDdmZP3oeDHRjJ9jvMUKoYODiNKsl2F+xXwyRM2qoKRqFlhCn4usVd1+wmv9iLV8nPs 2Db1ZIa49fJet3Sk3PN4bV1rAPuWvtbuTBN39Q/6MgkLTYHb84HyFKw14Rqe5YorrBLbF3rl M51Dpf6Egu1yTJDHCTEwePWug4XI11FT8lK0LNnHNpbhTCYRjX73iWOnFraJNcURld1jL1nV r/LRD+/e2gNtSTPK0Qkon6HcOBZnxRoqtazTU6YQRmGlT0v+rukj/cn5sToYibWLn+RoV1CE Qj6tApOiHBkpEsCzHGu+iDQ1WT0Idtdynst738f/uCeCMkdRu4WMZjteQaqvARFwCy3P/jpK uvzMtves5HvZw33ZwOtMCgbpce00DaET4y/UzsBNBFsZNTUBCACfQfpSsWJZyi+SHoRdVyX5 J6rI7okc4+b571a7RXD5UhS9dlVRVVAtrU9ANSLqPTQKGVxHrqD39XSw8hxK61pw8p90pg4G /N3iuWEvyt+t0SxDDkClnGsDyRhlUyEWYFEoBrrCizbmahOUwqkJbNMfzj5Y7n7OIJOxNRkB IBOjPdF26dMP69BwePQao1M8Acrrex9sAHYjQGyVmReRjVEtv9iG4DoTsnIR3amKVk6si4Ea X/mrapJqSCcBUVYUFH8M7bsm4CSxier5ofy8jTEa/CfvkqpKThTMCQPNZKY7hke5qEq1CBk2 wxhX48ZrJEFf1v3NuV3OimgsF2odzieNABEBAAHCwXwEGAEKACYCGwwWIQSpQNQ0mSwujpkQ PVAiT6fnzIKmZAUCZ8gcVAUJFhTonwAKCRAiT6fnzIKmZLY8D/9uo3Ut9yi2YCuASWxr7QQZ lJCViArjymbxYB5NdOeC50/0gnhK4pgdHlE2MdwF6o34x7TPFGpjNFvycZqccSQPJ/gibwNA zx3q9vJT4Vw+YbiyS53iSBLXMweeVV1Jd9IjAoL+EqB0cbxoFXvnjkvP1foiiF5r73jCd4PR rD+GoX5BZ7AZmFYmuJYBm28STM2NA6LhT0X+2su16f/HtummENKcMwom0hNu3MBNPUOrujtW khQrWcJNAAsy4yMoJ2Lw51T/5X5Hc7jQ9da9fyqu+phqlVtn70qpPvgWy4HRhr25fCAEXZDp xG4RNmTm+pqorHOqhBkI7wA7P/nyPo7ZEc3L+ZkQ37u0nlOyrjbNUniPGxPxv1imVq8IyycG AN5FaFxtiELK22gvudghLJaDiRBhn8/AhXc642/Z/yIpizE2xG4KU4AXzb6C+o7LX/WmmsWP Ly6jamSg6tvrdo4/e87lUedEqCtrp2o1xpn5zongf6cQkaLZKQcBQnPmgHO5OG8+50u88D9I rywqgzTUhHFKKF6/9L/lYtrNcHU8Z6Y4Ju/MLUiNYkmtrGIMnkjKCiRqlRrZE/v5YFHbayRD dJKXobXTtCBYpLJM4ZYRpGZXne/FAtWNe4KbNJJqxMvrTOrnIatPj8NhBVI0RSJRsbilh6TE m6M14QORSWTLRg== In-Reply-To: <1491df0ac12a7626b7c9b00e26a6e10adb8c9045.1756827906.git.pyyjason@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 7264440008 X-Stat-Signature: bpaxdejm1jeapo5oug6maidcxj7onsdf X-HE-Tag: 1756891327-107002 X-HE-Meta: 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 VCeO+tmu 64MUzF7ByavwuL1CaM9Vo7hw4s+BzhZZL1x3olsLVMZq1yI6z8aeZDEjcyRLMWkK1FYf2yQEAdXqtb0yIvRBf/aSenGd2cgH1GoATqGvu5wX0qs1kInPwujdT1uF0ucxEdMu11xDmru27WoJkkfMNOlAzIuLavC12PrWB2pI+bQG5d14AkJQ2VjBK0szlRWDTko5klkA1nCmBwqkWB4xIZIBtIgJHIxnouM6/g19yYDiQJHb8nUxX/X2uCsSA0r98KCAqEERScAy4NPdsdBP+O6xnbDDvsrqpw2E8YHQQcvlL+j6u6HPy9o4mBH+CkuDwBgDUhUUS4bmlJ1mQqi4+i6l7s+6u3sH26uhEVei2r+KZglJfI4Djn0XwCLkz7wDHFebtHJqgLhd6aTA= 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: On 9/2/25 17:57, Yueyang Pan wrote: > 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: Vlastimil Babka > --- > mm/show_mem.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/mm/show_mem.c b/mm/show_mem.c > index 51892ce2efc4..4c876ea2b66f 100644 > --- a/mm/show_mem.c > +++ b/mm/show_mem.c > @@ -396,6 +396,7 @@ static void show_free_areas(unsigned int filter, nodemask_t *nodemask, int max_z > > void __show_mem(unsigned int filter, nodemask_t *nodemask, int max_zone_idx) > { > + static DEFINE_SPINLOCK(mem_alloc_profiling_spinlock); > unsigned long total = 0, reserved = 0, highmem = 0; > struct zone *zone; > > @@ -421,7 +422,7 @@ 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 (spin_trylock(&mem_alloc_profiling_spinlock)) { > struct codetag_bytes tags[10]; > size_t i, nr; > > @@ -449,6 +450,7 @@ void __show_mem(unsigned int filter, nodemask_t *nodemask, int max_zone_idx) > ct->lineno, ct->function); > } > } > + spin_unlock(&mem_alloc_profiling_spinlock); > } > #endif > }