From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qc0-f170.google.com (mail-qc0-f170.google.com [209.85.216.170]) by kanga.kvack.org (Postfix) with ESMTP id 2CF8D6B0032 for ; Sat, 10 Jan 2015 01:48:48 -0500 (EST) Received: by mail-qc0-f170.google.com with SMTP id x3so12292865qcv.1 for ; Fri, 09 Jan 2015 22:48:48 -0800 (PST) Received: from mail-qc0-x229.google.com (mail-qc0-x229.google.com. [2607:f8b0:400d:c01::229]) by mx.google.com with ESMTPS id h10si15166027qcm.42.2015.01.09.22.48.47 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 09 Jan 2015 22:48:47 -0800 (PST) Received: by mail-qc0-f169.google.com with SMTP id w7so12193819qcr.0 for ; Fri, 09 Jan 2015 22:48:46 -0800 (PST) Date: Sat, 10 Jan 2015 01:48:32 -0500 From: Jerome Glisse Subject: Re: [PATCH 5/6] HMM: add per mirror page table. Message-ID: <20150110064831.GA19689@gmail.com> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <54AE6485.60402@mellanox.com> Sender: owner-linux-mm@kvack.org List-ID: To: Haggai Eran 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 , =?iso-8859-1?B?Suly9G1l?= Glisse , Jatin Kumar 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. Cheers, Jerome > > > +static void hmm_device_fence_wait(struct hmm_device *device, > > + struct hmm_fence *fence) > > +{ > > + struct hmm_mirror *mirror; > > + int r; > > + > > + if (fence == NULL) > > + return; > > + > > + list_del_init(&fence->list); > > + do { > > + r = device->ops->fence_wait(fence); > > + if (r == -EAGAIN) > > + io_schedule(); > > + } while (r == -EAGAIN); > > + > > + mirror = fence->mirror; > > + device->ops->fence_unref(fence); > > + if (r) > > + hmm_mirror_release(mirror); > > +} > > + > > Regards, > 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