From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leon Romanovsky Subject: Re: [PATCH 00/16] IB/hfi1: Add a page pinning cache for PSM sdma Date: Wed, 9 Mar 2016 07:07:31 +0200 Message-ID: <20160309050731.GM13396@leon.nu> References: <20160308191210.30542.91885.stgit@scvm10.sc.intel.com> <20160309002157.GA20105@phlsvsds.ph.intel.com> Reply-To: leon-2ukJVAZIZ/Y@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20160309002157.GA20105-W4f6Xiosr+yv7QzWx2u06xL4W9x8LtSr@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Dennis Dalessandro Cc: Or Gerlitz , Doug Ledford , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-rdma@vger.kernel.org On Tue, Mar 08, 2016 at 07:21:58PM -0500, Dennis Dalessandro wrote: > On Tue, Mar 08, 2016 at 10:56:48PM +0200, Or Gerlitz wrote: > >On Tue, Mar 8, 2016 at 9:14 PM, Dennis Dalessandro > > wrote: > > > >>This patch series adds a performance improvement to user SDMA transfers from > >>PSM applications by caching user buffer pages after pinning them. Subsequent > >>uses of the same user buffer will not incur the cost of pinning the same pages > >>again. Additionally, the cost of unpinning the same pages is avoided. Buffer > >>pages are unpinned when the context is torn down or when the driver determines > >>that the buffer should be evicted from the cache. Cache evictions happen when > >>there is a request for a new, uncached buffer and the current size of the cache > >>has reached a pre-defined limit. > > > >If indeed there's a need for such a pin down cache, it should have > >been implemented in the IB core, b/c both the problem and the solution > >are generic and have nothing to do with certain device driver. > > Since this is for psm it has nothing to do with the IB core. I fail to see > what that would achieve. I tend to agree with Or, your proposal goes far beyond the driver code. Do you expect that all drivers which will be needed to support PSM will implement (copy/paste) the same generic logic? -- 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