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 24BF3C369B2 for ; Tue, 15 Apr 2025 00:12:34 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 048C4280108; Mon, 14 Apr 2025 20:12:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F10EE2800B3; Mon, 14 Apr 2025 20:12:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DB111280108; Mon, 14 Apr 2025 20:12:32 -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 B8F9F2800B3 for ; Mon, 14 Apr 2025 20:12:32 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id CB6B85B6FA for ; Tue, 15 Apr 2025 00:12:33 +0000 (UTC) X-FDA: 83334351786.13.B498307 Received: from nyc.source.kernel.org (nyc.source.kernel.org [147.75.193.91]) by imf01.hostedemail.com (Postfix) with ESMTP id 2C37540007 for ; Tue, 15 Apr 2025 00:12:31 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=PFfNHWLZ; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf01.hostedemail.com: domain of sj@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=sj@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1744675952; 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-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=7P8ADh88VgijcQSzIr+kn3r5vzjPVAwm9V7tQO2j3Uo=; b=gSsD2cm09sowG5ZmZU4YXdlV9hFUk4o8FffHDnEg5sky7UDTuw5eIQrRKF/jdG1ZqpQEER Wp+J1HrDACpxht8O8TsF2xBFIulQ5KFNa1S+1LKftGNRCBB4BL9oLofL5Eg5gPrr8D5jlV /qnS6DMleZu6d8lSGCYukOM/GSsHZvE= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1744675952; a=rsa-sha256; cv=none; b=8awS+mdkSNTt3FOp6rm+fXQXMLX9yylL+Omh45iBfU3HGsfpFRd0tbCA1r2m6jr6Dz7em1 QSvjfW/OI3X/ZuLnVtmxnTDt91nswOAAtpwy0jYXcMiQDJBmaodmiEg60MWISRNcArVWhv evvm1oBcKQh/kxsn4lHo+Vl+Gb34tmw= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=PFfNHWLZ; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf01.hostedemail.com: domain of sj@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=sj@kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id E6582A4056C; Tue, 15 Apr 2025 00:07:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D191DC4CEE2; Tue, 15 Apr 2025 00:12:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744675951; bh=lLHJknmMDrd657zbVsXqHKzj3VV+nPBAXxPnLx4i2J8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PFfNHWLZvF6uiK+MSsrWlqgynhi0GMWdB3/lXZVJMEiBYKj5EFuDz8fqu42Tzr3iz jAcqK66bEK4W4RKpgD5NwElzEtvtOsd66B/GsE0UCRwa1QFMXaJgY4EoX7HMg8gPIE UQZOcUlHUk1AfcU7AMD/umrJQqM1mUXtLOVHFePAF3kHrrHO0U/lKrBLLihGyQOoNY L/IWtgNYrbHDOfQatDmNPYkY0027RSNicvK9ff9URXmS6XX1YRYEp6sX2MohgFUygI HUWsfnWShqc/7LzvewBXO+pF4NxSIsDUef//Ui48WvYx/CFFt8VY3/y8VyQFH5K3yM qK5Rf+kaawlwA== From: SeongJae Park To: Gregory Price Cc: SeongJae Park , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, akpm@linux-foundation.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, hannes@cmpxchg.org, mhocko@kernel.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev, donettom@linux.ibm.com Subject: Re: [RFC PATCH v4 1/6] migrate: Allow migrate_misplaced_folio_prepare() to accept a NULL VMA. Date: Mon, 14 Apr 2025 17:12:28 -0700 Message-Id: <20250415001228.120684-1-sj@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250411221111.493193-2-gourry@gourry.net> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 2C37540007 X-Stat-Signature: iasadginjjtkpptgd8zcejt6tnbze5uw X-Rspam-User: X-HE-Tag: 1744675951-993121 X-HE-Meta: U2FsdGVkX18RQE2s8DfEreANPXfLSvxUEcE0BPMQJ6f7GQmiDyVd6i1+f5ATQ88LhU8kzH2cL4fantzPaeF1NHZTfDxq4bqn8ICpuM1YC+5csKH2W/X+0+xgjcK7c0UyJX8uh4VqgI4SPSnZznyUTjKXP1SY5oaSPi8Vq91Qz16jmzaCoDOkxbWk2nswfepl1hcA8GIeu/t7C6lfcfnJX8U8Dq3FqOULUdFAyWNYdmzg5X7YTXYNP47B9u1IOy36v6vo6RxJspzdCha4PaYYEfOMp0UPquo7zaE4yFR4jKOzT0e+MbOcnlRG9YH3UwZHdeLhqn4P60q1i98QLgV4yZ8IqRknabMV1lZSnXsd3JOYee9mTDwY8A14ljoN1DO5O1DmEq8hneaMo9WJC6ce0ZFKVrzb+x2pvSiRrS87+PFMuIh/YAYpIYR9kwU/rcrxRwHoMXUR3Bcm3D+keoau+pPmcuNme+eFiXFkC7EyhUSgHSjR8QnqFk9Z2NTonH6NB3xPcC/YGhg/TApExK6/JVqQYOn5qR4saBtHfYEpTBDjJd4tq7ZQE7FXowl5VKrDa2YWR+3U0jshbkMsyEgZ9Lwl7xFSv+hMt2J4iK5JI8eCJWXPxfVo/k0MRROkWmthKThJr6U0460/F4QXkofSYsqRkUWOTB4XyXmtIek/qoQ92QH8yveYEjwPtuKcKz+uW8VwcRpfEcvIhRyXoIxT37SfEfpOtfIE84LMqIL2Vg/2KFPhSdnt2wjRTDNv1oMAjZn6uq9oppZ2h0ZhIEBdjF1Umw26ClHKyIh870Q/WWdalDHFUbX2Zdjsc6dwPdx8r3n2awXoKd5CpRuBIW/s15TkaKMo1stSz2nq4pbrdP3tBCnpRpsYBVbrb2T5HVLO6TJYg9Z5zPHzWPc/iwaMDX3nIJv6nhZovBtV7k8ufSIkPtIuvbToUyuxfUCR5+8hGWyi7TKFnpa0Z0Mlz3g Hq3SFt1T rlM3JpNKrT9tQrOvPkx8Z4vwDoyo4iTk0tG4SvPi+n5p735r2xv5KI2FwUPCa2VtDC3ALGaR9NkMpUY+tnJ3ixp8TR5ui/sCLvHVeqPQ6Nx2+UKk+uVMogWeGDXpRJZVD6Cr+WJINudvwZYP+yeOdRbiosURitHTseGU+/dITQWD42wcAfHaI45VU0IJJReDDs0i3Qe1Kg/fOdt1x9sagAf6WULq2paXLG7Gqh5BKG/i/RE0uyMKjfIxvtZpIob2RjTAiz+8opnesCRUQInIs0HOlho2SS7h6v7uaIsbztj98+dF6C8ZzS8UAjcaMAyRwQLrT 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 Fri, 11 Apr 2025 18:11:06 -0400 Gregory Price wrote: > migrate_misplaced_folio_prepare() may be called on a folio without > a VMA, and so it must be made to accept a NULL VMA. The comment of the function says "Must be called with the PTL still held". I understand it is not needed for NULL VMA case because it is for unmapped folios? If I'm understanding correctly, could you please also clarify such details including when NULL VMA case happens and if locking requirement is changed, on the comment? Thanks, SJ [...]