From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 47B671361; Tue, 15 Apr 2025 00:12:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744675951; cv=none; b=P30LkkXywBFORI2HuhYh+xT3fQZlGebIuTvJSrA1nSbNGm5kc8dFFE1cUouC5wenvl6ZfGDK3gHcunm8gJ2wJeVWa5nAw4vS44BG4OAxRXY9IoF1ycZ9d6fo/Hy0o9S/FOz1bMKImrDzeb936r5x+Ttjc5SYVCdOV02WO5IdomE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744675951; c=relaxed/simple; bh=lLHJknmMDrd657zbVsXqHKzj3VV+nPBAXxPnLx4i2J8=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=mHc/oE7NWtwbjY46LZsT0MAiS4TBSe/BMcSZI6bW+zud29LMdtA0VvVA/NB92jSCDx5Xukvzy/EY4raJrttp1zxC3Ys5kRcAABQ9XbFCBSefdLNOad7tYkwFnrw0l1gWj/wsDdRPu3poM22XQMHWGEeplDHUPpr/x6RUT7ZW8Os= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PFfNHWLZ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="PFfNHWLZ" 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: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 [...]