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From: Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Jason Gunthorpe
	<jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>,
	linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: Moni Shoua <monis-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>,
	Dennis Dalessandro
	<dennis.dalessandro-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	Josh Beavers
	<josh.beavers-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: [PATCH] infiniband: Fix alignment of mmap cookies to support VIPT caching
Date: Fri, 24 Mar 2017 16:51:26 -0400	[thread overview]
Message-ID: <1490388686.2404.25.camel@redhat.com> (raw)
In-Reply-To: <20170310183420.GA7410-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.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 <josh.beavers-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Signed-off-by: Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
> 

Thanks, applied for -rc.

-- 
Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
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      parent reply	other threads:[~2017-03-24 20:51 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-10 18:34 [PATCH] infiniband: Fix alignment of mmap cookies to support VIPT caching Jason Gunthorpe
     [not found] ` <20170310183420.GA7410-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-24 20:51   ` Doug Ledford [this message]

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