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]) by smtp.lore.kernel.org (Postfix) with ESMTP id B7CB5C48260 for ; Tue, 13 Feb 2024 15:32:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4F6DD8D000F; Tue, 13 Feb 2024 10:32:27 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4A7468D0001; Tue, 13 Feb 2024 10:32:27 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 347A58D000F; Tue, 13 Feb 2024 10:32:27 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 21F018D0001 for ; Tue, 13 Feb 2024 10:32:27 -0500 (EST) Received: from smtpin15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id EEE4D160C6C for ; Tue, 13 Feb 2024 15:32:26 +0000 (UTC) X-FDA: 81787172292.15.8599367 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.223.131]) by imf30.hostedemail.com (Postfix) with ESMTP id 8028C80034 for ; Tue, 13 Feb 2024 15:32:23 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=es4UNiST; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=+mHTXTqZ; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=es4UNiST; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=+mHTXTqZ; dmarc=pass (policy=none) header.from=suse.de; spf=pass (imf30.hostedemail.com: domain of osalvador@suse.de designates 195.135.223.131 as permitted sender) smtp.mailfrom=osalvador@suse.de ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1707838343; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Lwad023+VpCp8Em+c31I+OWYiRbkKktBQYYUbNSO2Bg=; b=TIqrzY5+EURujHvh+lP57AMKZM4yf+ZZOGeUv82SPSvA4JUP9LMKYOO8NNoguFnv2iTJe2 X7zfBVH3UCRodRkPvDO/un0KTCI2xoSuWcwwNIt9/hNV7PtNaVnIuh+Ufg2LCgW55EoJuJ eLKlLoOJDuRx+ykoaUxKXDQ4Tb0xGg8= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=es4UNiST; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=+mHTXTqZ; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=es4UNiST; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=+mHTXTqZ; dmarc=pass (policy=none) header.from=suse.de; spf=pass (imf30.hostedemail.com: domain of osalvador@suse.de designates 195.135.223.131 as permitted sender) smtp.mailfrom=osalvador@suse.de ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1707838343; a=rsa-sha256; cv=none; b=ODctHcZTmygpleL4EXxhsmhCEZuubfTJ/11kFx1eDlxgDqn/fN27Zcg7uIDpAV4obhqwXW 6HzkAOz2yOie1+ouoHbz/Iln7rgG0qv7XjpbQ1z2hXCzVXLwac/zarzLhIwdH8f0Ao41Fz S6kDCZIFXj/Fscz0yGh/tlnuAO1XwCw= Received: from imap2.dmz-prg2.suse.org (imap2.dmz-prg2.suse.org [10.150.64.98]) (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 E424C1FCE2; Tue, 13 Feb 2024 15:32:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1707838341; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Lwad023+VpCp8Em+c31I+OWYiRbkKktBQYYUbNSO2Bg=; b=es4UNiSTfoBYDBzKtt5jQvZx0jSaafqS3+MdTQ9QMIP69JC8IMTGc8cf4E31MEQodQbx9E 9i2seiwxuXdntZep8C6D4x2KTFYjAQKBe8OzDC4in0JQbXaaP1bh2pMAWZzxU6Oc6/SD3r ZJembWCzqMx94E4v7Q5J7LU7ZgZPKlc= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1707838341; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Lwad023+VpCp8Em+c31I+OWYiRbkKktBQYYUbNSO2Bg=; b=+mHTXTqZ1+F6RWZObuc1tTqn3dwoELDnmrt3xxLyML731VQ5NkPkZtL/Tn8rXmyVlITN2x 1J9hS91wKUwmt/CQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1707838341; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Lwad023+VpCp8Em+c31I+OWYiRbkKktBQYYUbNSO2Bg=; b=es4UNiSTfoBYDBzKtt5jQvZx0jSaafqS3+MdTQ9QMIP69JC8IMTGc8cf4E31MEQodQbx9E 9i2seiwxuXdntZep8C6D4x2KTFYjAQKBe8OzDC4in0JQbXaaP1bh2pMAWZzxU6Oc6/SD3r ZJembWCzqMx94E4v7Q5J7LU7ZgZPKlc= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1707838341; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Lwad023+VpCp8Em+c31I+OWYiRbkKktBQYYUbNSO2Bg=; b=+mHTXTqZ1+F6RWZObuc1tTqn3dwoELDnmrt3xxLyML731VQ5NkPkZtL/Tn8rXmyVlITN2x 1J9hS91wKUwmt/CQ== Received: from imap2.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 imap2.dmz-prg2.suse.org (Postfix) with ESMTPS id 65EAA13A0E; Tue, 13 Feb 2024 15:32:21 +0000 (UTC) Received: from dovecot-director2.suse.de ([10.150.64.162]) by imap2.dmz-prg2.suse.org with ESMTPSA id NYe6FYWLy2UPfQAAn2gu4w (envelope-from ); Tue, 13 Feb 2024 15:32:21 +0000 Date: Tue, 13 Feb 2024 16:33:30 +0100 From: Oscar Salvador To: Vlastimil Babka Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michal Hocko , Marco Elver , Andrey Konovalov , Alexander Potapenko Subject: Re: [PATCH v8 3/5] mm,page_owner: Display all stacks and their count Message-ID: References: <20240212223029.30769-1-osalvador@suse.de> <20240212223029.30769-4-osalvador@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 8028C80034 X-Stat-Signature: mjwodxhzby5kppji4bywckmdez64ygim X-HE-Tag: 1707838343-122891 X-HE-Meta: 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 +4pwO/Nw QUfhl6R3Oc+tpRiRanlb+ntL6c4vvo2RQ3JXkRnVl01OoTya6ZHjFk6Gx0wBW4hIB3utLYonHqsh71zzQVyF4d/Vo/nOt+WWwcujp2B4E2RJ9MRDqOQcXPgZQ4822W8frld9rHIGBsyvDgGvNMoEuUHfkFJaMFbw30qXJ/PysLtAyY3FcwhevhXoUXDFxzgDFEpHZKhz89J9wzm6bu88IBGN3zGYCvImdgGMR 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 Tue, Feb 13, 2024 at 03:25:26PM +0100, Vlastimil Babka wrote: > On 2/12/24 23:30, Oscar Salvador wrote: > > +static int stack_print(struct seq_file *m, void *v) > > +{ > > + char *buf; > > + int ret = 0; > > + struct stack *stack = v; > > + struct stack_record *stack_record = stack->stack_record; > > + > > + if (!stack_record->size || stack_record->size < 0 || > > + refcount_read(&stack_record->count) < 2) > > + return 0; > > + > > + buf = kzalloc(PAGE_SIZE, GFP_KERNEL); > > + > > + ret += stack_trace_snprint(buf, PAGE_SIZE, stack_record->entries, > > + stack_record->size, 0); > > + if (!ret) > > + goto out; > > + > > + scnprintf(buf + ret, PAGE_SIZE - ret, "stack_count: %d\n\n", > > + refcount_read(&stack_record->count)); > > + > > + seq_printf(m, buf); > > + seq_puts(m, "\n\n"); > > +out: > > + kfree(buf); > > Seems rather wasteful to do kzalloc/kfree so you can print into that buffer > first and then print/copy it again using seq_printf. If you give up on using > stack_trace_snprintf() it's not much harder to print the stack directly with > a loop of seq_printf. See e.g. slab_debugfs_show(). Well, I thought about not reinventing the wheel there, but fair enough than performing a kmalloc/free op on every print might be suboptimal. I will try to do ir with seq_printf alone. Thanks -- Oscar Salvador SUSE Labs