Re: [PATCH 00/16] IB/hfi1: Add a page pinning cache for PSM sdma
From: Dennis Dalessandro <hidden>
Date: 2016-03-09 19:21:10
On Wed, Mar 09, 2016 at 07:07:31AM +0200, Leon Romanovsky wrote:
On Tue, Mar 08, 2016 at 07:21:58PM -0500, Dennis Dalessandro wrote:quoted
On Tue, Mar 08, 2016 at 10:56:48PM +0200, Or Gerlitz wrote:quoted
On Tue, Mar 8, 2016 at 9:14 PM, Dennis Dalessandro [off-list ref] wrote:quoted
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?
We should not be putting something which is specific to PSM in the IB core. We feel the driver is the most appropriate place for this. -Denny -- 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