From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart Van Assche Subject: Re: [PATCH for kernel v4.6] IB/srpt: Revert "Convert to percpu_ida tag allocation" Date: Thu, 31 Mar 2016 20:12:57 -0700 Message-ID: <56FDE739.9090801@sandisk.com> References: <56FDBA63.7010804@sandisk.com> <20160401030322.GH2670@leon.nu> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160401030322.GH2670-2ukJVAZIZ/Y@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "leon-2ukJVAZIZ/Y@public.gmane.org" Cc: Doug Ledford , "Nicholas A. Bellinger" , Christoph Hellwig , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-rdma@vger.kernel.org On 03/31/16 20:05, Leon Romanovsky wrote: > On Thu, Mar 31, 2016 at 05:01:39PM -0700, Bart Van Assche wrote: >> That patch is wrong because it makes the ib_srpt driver use I/O >> contexts allocated by transport_alloc_session_tags() but it does >> not initialize these I/O contexts properly. > > Did you have a chance to see which initializations are missing in this > case? What is needed to do if we decide to fix original patch? > > Except these questions, the revert is fine :) > Reviewed-by: Leon Romanovsky Hello Leon, Thanks for the review. The initializations that are missing from that patch are the 'buf' pointer in the srpt_ioctx structure and mapping that buffer for DMA. Another bug introduced by that patch is that it doubles the amount of memory that is allocated for I/O contexts. New I/O context allocations were added by that patch but the existing I/O context allocation code was not removed. Regarding reconsidering the original patch: before we do that it has to be shown with numbers that the percpu_ida conversion does not decrease performance. This is something I had already asked two months ago. See also http://thread.gmane.org/gmane.linux.scsi.target.devel/11253/focus=110559. Bart. -- 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