From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 99F7822E402; Wed, 12 Mar 2025 15:17:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741792636; cv=none; b=qFcLbNOt2tY+Ag8CdczO8HSD0cvZmPoWQA+T3byG6tHcRtVmPjJlMs9UrFToDpy17+oY+ExHVcagXpSqHWciLeToz6gqIl2OS81fCzYAAhcFqVRzBgcVIiVjRyC+KoZZXOpn81W3toFMFR0wCypQq3tQcvfIlmn0sYRYVeT1vCU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741792636; c=relaxed/simple; bh=tSkMFGu47t+CvWuXVdH/hsK0ULncBiLZuf0VSvKKQXM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Y3KVoo/lJiBgsu6YXnpMzX/i45B4SgedlTfpPTY5cQa3ffDfS+b5cqT9SuSc0LjfgpW351iUPjYqk0/0Lnm8hKpxIVmoVO6GVrEmyyO5xOblXy/pzNRSYqG/bIxaW+XGtd+QgMSAFD7zNuQW1vGw06kNtWlTHjtcVKl5UTZkzg8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=ZLeRwH6o; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ZLeRwH6o" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=cc1IRF4EhJKY8LXoN7q2qpy3BjmvcLDyzu1HWXRb5PQ=; b=ZLeRwH6oaWpY7zx8CJowpM1xLa bWukiSc5jXW/4wAXeX5MqQuwIq8csAasq8cuYqDfJ/VfugB5z9rqd7L7g9II+Eg1PJUoPsK8spSwb lECxCEMsj7Hav08+Q8E4zFOGsUt5TeZCy4RYGGTYeYwkRNz+SACX8TK4N/LjYb6LrC6MrvtrpVVan FYB5Xsrd7DE5GXbhegcuTDsAOQTeOfB3Wd1BH+YD0k3PZXkF9dTF05EtMr82gEAYFr+E9o8AMKpXg qW8FK3uKsgk1cN8PoyyyNLQOkwzkXdHtduVto6BRK1ARMtF/fOyrF5H3jwLI+AjuNHIk3PX+7Ln0+ r0W7EC6Q==; Received: from hch by bombadil.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1tsNpY-00000008oxP-05M4; Wed, 12 Mar 2025 15:17:12 +0000 Date: Wed, 12 Mar 2025 08:17:11 -0700 From: Christoph Hellwig To: Suren Baghdasaryan Cc: Sooyong Suk , Jaewon Kim , Christoph Hellwig , viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org, spssyr@gmail.com, axboe@kernel.dk, linux-block@vger.kernel.org, dhavale@google.com Subject: Re: [RFC PATCH] block, fs: use FOLL_LONGTERM as gup_flags for direct IO Message-ID: References: <20250306074056.246582-1-s.suk@samsung.com> <848301db8f05$a1d79430$e586bc90$@samsung.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Thu, Mar 06, 2025 at 06:28:40PM -0800, Suren Baghdasaryan wrote: > I think this will help you only when the pages are faulted in but if > __get_user_pages() finds an already mapped page which happens to be > allocated from CMA, it will not migrate it. So, you might still end up > with unmovable pages inside CMA. Direct I/O pages are not unmovable. They are temporarily pinned for the duration of the direct I/O. I really don't understand what problem you're trying to fix here.