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Thu, 15 Feb 2024 09:22:57 +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 gyDbMfHXzWUfGQAAD6G6ig (envelope-from ); Thu, 15 Feb 2024 09:22:57 +0000 Date: Thu, 15 Feb 2024 10:22:57 +0100 From: Michal Hocko To: Suren Baghdasaryan Cc: akpm@linux-foundation.org, kent.overstreet@linux.dev, vbabka@suse.cz, hannes@cmpxchg.org, roman.gushchin@linux.dev, mgorman@suse.de, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, corbet@lwn.net, void@manifault.com, peterz@infradead.org, juri.lelli@redhat.com, catalin.marinas@arm.com, will@kernel.org, arnd@arndb.de, tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com, x86@kernel.org, peterx@redhat.com, david@redhat.com, axboe@kernel.dk, mcgrof@kernel.org, masahiroy@kernel.org, nathan@kernel.org, dennis@kernel.org, tj@kernel.org, muchun.song@linux.dev, rppt@kernel.org, paulmck@kernel.org, pasha.tatashin@soleen.com, yosryahmed@google.com, yuzhao@google.com, dhowells@redhat.com, hughd@google.com, andreyknvl@gmail.com, keescook@chromium.org, ndesaulniers@google.com, vvvvvv@google.com, gregkh@linuxfoundation.org, ebiggers@google.com, ytcoode@gmail.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, bristot@redhat.com, vschneid@redhat.com, cl@linux.com, penberg@kernel.org, iamjoonsoo.kim@lge.com, 42.hyeyoo@gmail.com, glider@google.com, elver@google.com, dvyukov@google.com, shakeelb@google.com, songmuchun@bytedance.com, jbaron@akamai.com, rientjes@google.com, minchan@google.com, kaleshsingh@google.com, kernel-team@android.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, iommu@lists.linux.dev, linux-arch@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-modules@vger.kernel.org, kasan-dev@googlegroups.com, cgroups@vger.kernel.org Subject: Re: [PATCH v3 31/35] lib: add memory allocations report in show_mem() Message-ID: References: <20240212213922.783301-1-surenb@google.com> <20240212213922.783301-32-surenb@google.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240212213922.783301-32-surenb@google.com> Authentication-Results: smtp-out2.suse.de; dkim=pass header.d=suse.com header.s=susede1 header.b=sfOAoS4D X-Spamd-Result: default: False [1.65 / 50.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; R_DKIM_ALLOW(-0.20)[suse.com:s=susede1]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; BAYES_HAM(-0.04)[58.58%]; TAGGED_RCPT(0.00)[]; MIME_GOOD(-0.10)[text/plain]; RCVD_COUNT_THREE(0.00)[3]; TO_MATCH_ENVRCPT_SOME(0.00)[]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; DKIM_TRACE(0.00)[suse.com:+]; MX_GOOD(-0.01)[]; RCPT_COUNT_GT_50(0.00)[73]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:dkim]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; MID_RHS_NOT_FQDN(0.50)[]; FREEMAIL_CC(0.00)[linux-foundation.org,linux.dev,suse.cz,cmpxchg.org,suse.de,stgolabs.net,infradead.org,oracle.com,lwn.net,manifault.com,redhat.com,arm.com,kernel.org,arndb.de,linutronix.de,linux.intel.com,kernel.dk,soleen.com,google.com,gmail.com,chromium.org,linuxfoundation.org,linaro.org,goodmis.org,linux.com,lge.com,bytedance.com,akamai.com,android.com,vger.kernel.org,lists.linux.dev,kvack.org,googlegroups.com]; RCVD_TLS_ALL(0.00)[]; SUSPICIOUS_RECIPS(1.50)[] X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Spam-Score: 1.65 X-Rspamd-Queue-Id: 0F1001F871 X-Spam-Level: * X-Spam-Flag: NO X-Spamd-Bar: + On Mon 12-02-24 13:39:17, Suren Baghdasaryan wrote: [...] > @@ -423,4 +424,18 @@ void __show_mem(unsigned int filter, nodemask_t *nodemask, int max_zone_idx) > #ifdef CONFIG_MEMORY_FAILURE > printk("%lu pages hwpoisoned\n", atomic_long_read(&num_poisoned_pages)); > #endif > +#ifdef CONFIG_MEM_ALLOC_PROFILING > + { > + struct seq_buf s; > + char *buf = kmalloc(4096, GFP_ATOMIC); > + > + if (buf) { > + printk("Memory allocations:\n"); > + seq_buf_init(&s, buf, 4096); > + alloc_tags_show_mem_report(&s); > + printk("%s", buf); > + kfree(buf); > + } > + } > +#endif I am pretty sure I have already objected to this. Memory allocations in the oom path are simply no go unless there is absolutely no other way around that. In this case the buffer could be preallocated. -- Michal Hocko SUSE Labs