From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yong Wu Subject: Re: [PATCH v2] iommu/dma: Map scatterlists more parsimoniously Date: Tue, 16 Feb 2016 07:00:53 +0800 Message-ID: <1455577253.15899.4.camel@mhfsdcap03> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Robin Murphy Cc: Daniel Kurtz , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, srv_heupstream-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org List-Id: iommu@lists.linux-foundation.org On Fri, 2015-11-20 at 10:57 +0000, Robin Murphy wrote: > Whilst blindly assuming the worst case for segment boundaries and > aligning every segment individually is safe from the point of view > of respecting the device's parameters, it is also undeniably a waste > of IOVA space. Futhermore, the knock-on effects of more pages than > necessary being exposed to device access, additional overhead in page > table updates and TLB invalidations, etc., are even more undesirable. > > Improve matters by taking the actual boundary mask into account to > actively detect the cases in which we really do need to adjust a > segment, and avoid wasting space in the remainder. > > Tested-by: Yong Wu > Signed-off-by: Robin Murphy > --- Hi Robin, Joerg, Is there any plan for this patch? It seems to be lost. Could we pick this up as a fix for v4.5? Thanks.