From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f41.google.com (mail-wg0-f41.google.com [74.125.82.41]) by kanga.kvack.org (Postfix) with ESMTP id 8F1D46B0071 for ; Sun, 11 Jan 2015 00:46:29 -0500 (EST) Received: by mail-wg0-f41.google.com with SMTP id l18so14304134wgh.0 for ; Sat, 10 Jan 2015 21:46:29 -0800 (PST) Received: from emea01-db3-obe.outbound.protection.outlook.com (mail-db3on0064.outbound.protection.outlook.com. [157.55.234.64]) by mx.google.com with ESMTPS id k11si6824918wiv.63.2015.01.10.21.46.28 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sat, 10 Jan 2015 21:46:28 -0800 (PST) Message-ID: <54B20DEA.5050803@mellanox.com> Date: Sun, 11 Jan 2015 07:45:14 +0200 From: Haggai Eran MIME-Version: 1.0 Subject: Re: [PATCH 5/6] HMM: add per mirror page table. References: <1420497889-10088-1-git-send-email-j.glisse@gmail.com> <1420497889-10088-6-git-send-email-j.glisse@gmail.com> <54AE6485.60402@mellanox.com> <20150110064831.GA19689@gmail.com> In-Reply-To: <20150110064831.GA19689@gmail.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Jerome Glisse Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Linus Torvalds , joro@8bytes.org, Mel Gorman , "H. Peter Anvin" , Peter Zijlstra , Andrea Arcangeli , Johannes Weiner , Larry Woodman , Rik van Riel , Dave Airlie , Brendan Conoboy , Joe Donohue , Duncan Poole , Sherry Cheung , Subhash Gutti , John Hubbard , Mark Hairgrove , Lucien Dunning , Cameron Buschardt , Arvind Gopalakrishnan , Shachar Raindel , Liran Liss , Roland Dreier , Ben Sander , Greg Stoner , John Bridgman , Michael Mantor , Paul Blinzer , Laurent Morichetti , Alexander Deucher , Oded Gabbay , =?windows-1252?Q?J=E9r=F4me_Glisse?= , Jatin Kumar On 10/01/2015 08:48, Jerome Glisse wrote: > On Thu, Jan 08, 2015 at 01:05:41PM +0200, Haggai Eran wrote: >> On 06/01/2015 00:44, j.glisse@gmail.com wrote: >>> + /* fence_wait() - to wait on device driver fence. >>> + * >>> + * @fence: The device driver fence struct. >>> + * Returns: 0 on success,-EIO on error, -EAGAIN to wait again. >>> + * >>> + * Called when hmm want to wait for all operations associated with a >>> + * fence to complete (including device cache flush if the event mandate >>> + * it). >>> + * >>> + * Device driver must free fence and associated resources if it returns >>> + * something else thant -EAGAIN. On -EAGAIN the fence must not be free >>> + * as hmm will call back again. >>> + * >>> + * Return error if scheduled operation failed or if need to wait again. >>> + * -EIO Some input/output error with the device. >>> + * -EAGAIN The fence not yet signaled, hmm reschedule waiting thread. >>> + * >>> + * All other return value trigger warning and are transformed to -EIO. >>> + */ >>> + int (*fence_wait)(struct hmm_fence *fence); >> >> According to the comment, the device frees the fence struct when the >> fence_wait callback returns zero or -EIO, but the code below calls >> fence_unref after fence_wait on the same fence. > > Yes comment is out of date, i wanted to simplify fence before readding > it once needed (by device memory migration). > >> >>> + >>> + /* fence_ref() - take a reference fence structure. >>> + * >>> + * @fence: Fence structure hmm is referencing. >>> + */ >>> + void (*fence_ref)(struct hmm_fence *fence); >> >> I don't see fence_ref being called anywhere in the patchset. Is it >> actually needed? > > Not right now but the page migration to device memory use it. But i > can remove it now. > > I can respin to make comment match code but i would like to know where > i stand on everythings else. > Well, I've read patches 1 through 4, and they seemed fine, although I still want to have a deeper look into patch 4, because the page table code seems a little tricky. I haven't completed reading patch 5 and 6 yet. Haggai -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org