From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5A941C8303F for ; Thu, 28 Aug 2025 08:41:29 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A6D9C8E0013; Thu, 28 Aug 2025 04:41:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A456C8E000B; Thu, 28 Aug 2025 04:41:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 90D2D8E0013; Thu, 28 Aug 2025 04:41:28 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 7FA678E000B for ; Thu, 28 Aug 2025 04:41:28 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 02C71853AB for ; Thu, 28 Aug 2025 08:41:27 +0000 (UTC) X-FDA: 83825522256.19.2381203 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.223.131]) by imf20.hostedemail.com (Postfix) with ESMTP id B98E21C0007 for ; Thu, 28 Aug 2025 08:41:25 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=0zugYSPR; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=livtRXkE; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=0zugYSPR; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=livtRXkE; dmarc=none; spf=pass (imf20.hostedemail.com: domain of vbabka@suse.cz designates 195.135.223.131 as permitted sender) smtp.mailfrom=vbabka@suse.cz ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1756370486; a=rsa-sha256; cv=none; b=tlyTsqNCXyCj43kMvRUapo4PUl5i46xzUDebf763jf0Y4rUHG5Z3sS6Aah/CQdZRIibuib 7BeLsXujCmKf4FtkzO5iW6zyaVD3lfH50iEUwYj4pjNUl6GvCFfVTc4Q9PsR9vZDuPwP4C IvarNm05cscyZDf2n0v/iXjRjx5a9YA= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=0zugYSPR; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=livtRXkE; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=0zugYSPR; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=livtRXkE; dmarc=none; spf=pass (imf20.hostedemail.com: domain of vbabka@suse.cz designates 195.135.223.131 as permitted sender) smtp.mailfrom=vbabka@suse.cz ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1756370486; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=xoT3WpLXuS5g1YdpdWEcQMKSsUF2k8LBxp9VlBICog8=; b=QhjcsnQ98Ej8p6O866DUE4mMfyZHQNh9x/7zuHPBNp+rwf70VOBvlZxaLE+CNm6fI5cZjC cjfmRtvkJK2FsQays8XqespitSsWX25rsCEF29RhopiO+w2RedS/YGU7em5v4IczZDoo9P Id+yxdywR5GbgEPwvEqVTNZ4GkNvzXI= Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 03F5820ADA; Thu, 28 Aug 2025 08:41:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1756370484; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=xoT3WpLXuS5g1YdpdWEcQMKSsUF2k8LBxp9VlBICog8=; b=0zugYSPRaDN/zgfsqne/WIBUJnnRNvcwknLZS9R7BTqnI3lNm1eyv8hPg5oU6tlC2sU2ih 2Cst6vYKW5xiYW5NHJAYTGNqz7iUqkD8nJoxmrdoHu7+Kw65QC7ayD4K6qeNNhgaLtPJ0q FZMWM+6Ik0UvU6662B0RiL814UCYZg0= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1756370484; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=xoT3WpLXuS5g1YdpdWEcQMKSsUF2k8LBxp9VlBICog8=; b=livtRXkEUtDMGHtTSzI/ZxyJIz71e67buIPw5OyZfpU7Gq2DJ3hT/GWZTM/Y/Y4uIFV+dP Z83H3Dpnp36H1cCg== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1756370484; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=xoT3WpLXuS5g1YdpdWEcQMKSsUF2k8LBxp9VlBICog8=; b=0zugYSPRaDN/zgfsqne/WIBUJnnRNvcwknLZS9R7BTqnI3lNm1eyv8hPg5oU6tlC2sU2ih 2Cst6vYKW5xiYW5NHJAYTGNqz7iUqkD8nJoxmrdoHu7+Kw65QC7ayD4K6qeNNhgaLtPJ0q FZMWM+6Ik0UvU6662B0RiL814UCYZg0= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1756370484; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=xoT3WpLXuS5g1YdpdWEcQMKSsUF2k8LBxp9VlBICog8=; b=livtRXkEUtDMGHtTSzI/ZxyJIz71e67buIPw5OyZfpU7Gq2DJ3hT/GWZTM/Y/Y4uIFV+dP Z83H3Dpnp36H1cCg== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id D30BB1368B; Thu, 28 Aug 2025 08:41:23 +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 vqqAMjMWsGikLwAAD6G6ig (envelope-from ); Thu, 28 Aug 2025 08:41:23 +0000 Message-ID: Date: Thu, 28 Aug 2025 10:41:23 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 2/2] mm/show_mem: Add trylock while printing alloc info To: Yueyang Pan , Andrew Morton Cc: Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Usama Arif , linux-mm@kvack.org, kernel-team@meta.com, linux-kernel@vger.kernel.org References: <7e2bc96faab1a338829e549246189ad96e6c866b.1756318426.git.pyyjason@gmail.com> <20250827150619.4e468e68988f224f9f9bea6f@linux-foundation.org> 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: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Action: no action X-Rspamd-Queue-Id: B98E21C0007 X-Stat-Signature: jieqataj4jcbfy5a1bqgd7onu87r6rpw X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1756370485-550914 X-HE-Meta: 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 BaPV6XfO fLCe6+rxxeEA6NfY= 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 8/28/25 10:34, Yueyang Pan wrote: > On Wed, Aug 27, 2025 at 03:06:19PM -0700, Andrew Morton wrote: >> On Wed, 27 Aug 2025 11:34:23 -0700 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 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. What about the rest of the information printed by show_mem() being interleaved? >> > >> >> Fair enough, I guess. >> >> > --- 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); >> >> It would be a bit neater to make this local to __show_mem() - it didn't >> need file scope. > > Thanks for your feedback, Andrew. I will move it the next version. > >> >> Also, mutex_unlock() isn't to be used from interrupt context, so >> problem. >> >> Something like atomic cmpxchg or test_and_set_bit could be used and >> wouldn't involve mutex_unlock()'s wakeup logic, which isn't needed >> here. > > I was not aware of interrupt context before. I will change to test-and-set > lock in the next version. Perhaps simply spinlock_t with spin_trylock()?