From mboxrd@z Thu Jan 1 00:00:00 1970 From: Doug Ledford Subject: Re: [PATCH] infiniband: Fix alignment of mmap cookies to support VIPT caching Date: Fri, 24 Mar 2017 16:51:26 -0400 Message-ID: <1490388686.2404.25.camel@redhat.com> References: <20170310183420.GA7410@obsidianresearch.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20170310183420.GA7410-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jason Gunthorpe , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: Moni Shoua , Dennis Dalessandro , Josh Beavers List-Id: linux-rdma@vger.kernel.org On Fri, 2017-03-10 at 11:34 -0700, Jason Gunthorpe wrote: > When vmalloc_user is used to create memory that is supposed to be > mmap'd > to user space, it is necessary for the mmap cookie (eg the offset) to > be > aligned to SHMLBA. > > This creates a situation where all virtual mappings of the same > physical > page share the same virtual cache index and guarantees VIPT > coherence. > Otherwise the cache is non-coherent and the kernel will not see > writes > by userspace when reading the shared page (or vice-versa). > > Reported-by: Josh Beavers > Signed-off-by: Jason Gunthorpe >  Thanks, applied for -rc. -- Doug Ledford     GPG KeyID: B826A3330E572FDD     Key fingerprint = AE6B 1BDA 122B 23B4 265B  1274 B826 A333 0E57 2FDD -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html