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 02CB3C27C4F for ; Fri, 21 Jun 2024 19:22:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 851B48D0183; Fri, 21 Jun 2024 15:22:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 802478D0196; Fri, 21 Jun 2024 15:22:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 654758D0183; Fri, 21 Jun 2024 15:22:59 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 7BBBC6B00D9 for ; Fri, 21 Jun 2024 15:22:58 -0400 (EDT) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id E1D39A3DF0 for ; Fri, 21 Jun 2024 19:22:57 +0000 (UTC) X-FDA: 82255868394.28.0E92B98 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by imf22.hostedemail.com (Postfix) with ESMTP id 28349C0006 for ; Fri, 21 Jun 2024 19:22:55 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=linutronix.de header.s=2020 header.b=Wy2iKkI7; dkim=pass header.d=linutronix.de header.s=2020e header.b=lJttQ362; spf=pass (imf22.hostedemail.com: domain of bigeasy@linutronix.de designates 193.142.43.55 as permitted sender) smtp.mailfrom=bigeasy@linutronix.de; dmarc=pass (policy=none) header.from=linutronix.de ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1718997766; 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=JUlWsAMB1jxwwOj6uw3ptcHahhiIDFuD+/+iPluqHa4=; b=buPMHy/OjgTwCqhTBMey4N7WB7381F7YlQcUg/lCevA6mUPXF2vN+8J7Ga/51Zp/EEoPrr tCP5vWyLpqM5q8MDwPPd0o78H6RxYdAPegM01t6Vwo7lIVjSgdLx0th6ywMliA9A+bmVyP VoNHOg74wbO3bvtPnQSoCb+gfdMaXlg= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1718997766; a=rsa-sha256; cv=none; b=jTN/dTcTy0C2qVH+P/Erm8ChsyLPMTEuMTHjZ1Iaa8a2ouruBkvQvRk6+q1HsbqaPa0ijP cPKDYi1mkrzW48vEftpiHCj+7ivN3HItN7Dgx2lWkU7qfDkXA+d+UZHD6pgkv6R67Opmxl jAB2N3qAuD8mmkcQ8lusbmmrPfFeHiU= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=pass header.d=linutronix.de header.s=2020 header.b=Wy2iKkI7; dkim=pass header.d=linutronix.de header.s=2020e header.b=lJttQ362; spf=pass (imf22.hostedemail.com: domain of bigeasy@linutronix.de designates 193.142.43.55 as permitted sender) smtp.mailfrom=bigeasy@linutronix.de; dmarc=pass (policy=none) header.from=linutronix.de Date: Fri, 21 Jun 2024 21:22:52 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1718997774; h=from:from: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; bh=JUlWsAMB1jxwwOj6uw3ptcHahhiIDFuD+/+iPluqHa4=; b=Wy2iKkI7qtDir4I9fRhkk+LpCwEmTjeiV5LvpkL/Pu6Ohj2Nh5dSv2yM5ASFfpdbDdHY8s V51Ta7lCv6AH/46y749qgn0zjiE8SC+mla87zG5cN4TJYocafQYhvFmfHZWUQZjv9/fidw 6kTketWxqfS4o6bKqRmZMi7/4T7kidvZrVM38amLz1uoXfeViFi1EYVKHhsmlklJbtUJfb jdFVfPZTHtABPbExKko6rvcxBgdfUrxmY40q3FLV/mcnmWWwn0E7rwTgQoHkaWXLOwcBjT eFFVgm8QYRJJsQQD8IbN/gf3UmHtLqmlCKwiVMb9uOtFfqF/d4/NM8BMnWd2uw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1718997774; h=from:from: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; bh=JUlWsAMB1jxwwOj6uw3ptcHahhiIDFuD+/+iPluqHa4=; b=lJttQ362DLbgh6tndVMGK4rBqRcfiskbLbTD39L18iJ0AIVIJgQcSAns9DV8VvMcFf5peF 77KYbr+tPzShgFAA== From: Sebastian Andrzej Siewior To: Kent Overstreet Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Ben Segall , Daniel Bristot de Oliveira , Dietmar Eggemann , Ingo Molnar , Juri Lelli , Klara Modin , Mel Gorman , Peter Zijlstra , Steven Rostedt , Suren Baghdasaryan , Thomas Gleixner , Valentin Schneider , Vincent Guittot Subject: Re: [PATCH] sched/task_struct: Move alloc_tag to the end of the struct. Message-ID: <20240621192252.-whn_Ae8@linutronix.de> References: <20240621102750.oH9p1FQq@linutronix.de> <7zretxxixkpfxt6lr7x64n67ql2v2qpb7abbbjklclwlu4u2kx@22o5sdlnpkea> <20240621182915.S-ULWn0O@linutronix.de> <20240621190719.TeLTxI9M@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 28349C0006 X-Stat-Signature: qj9brk3jcux5byy8fnxbjmog487yrcz3 X-HE-Tag: 1718997775-812275 X-HE-Meta: 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 3ESZccTu nKO1gUa2sCw64/WGs1mTcdHFmZGo1hiF6GC/cUqVck0WeHhYD96Lz8lfZgmOW33PsyQmHCbKcgKxhJfEQWJ+p5V2xFUpgikrvNs3kF0Op36UcziU2zKAjbcFZuBQa6KWXctehRftji4P8a9QUUldY3Uf6CQZW9lwb31PYP2eYTqA7+3dCbjOHaPkCOA== 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 2024-06-21 15:13:19 [-0400], Kent Overstreet wrote: > > > > random code=E2=80=A6 Puh. So if the end is too cold, what about aro= und the mm > > > > pointer? > > >=20 > > > Not there, that's not actually that hot. It needs to be by > > > task_struct->flags; that's used in the same paths. > >=20 > > But there is no space without the additional 52 bytes. Was this by any > > chance on purpose? >=20 > No, that wasn't, and it doesn't have to be the exact same cacheline, but > we do want it near current->flags; we store PF_MEMALLOC flags there that > are converted to gfp flags and used exactly where we're using > current->alloc_tag. Hmm. `stack' and `usage' are the only two member that you would have to move (away) in order the stash the conditional variable there. The `ptrace' one uses the same flags as `flags' so it wouldn't make sense to move that one. Sebastian