From: Haren Myneni Subject: Re: [PATCH V3 6/6] crypto/nx: Add P9 NX support for 842 compression engine Date: Tue, 29 Aug 2017 14:54:54 -0700 Message-ID: <59A5E2AE.5060400@linux.vnet.ibm.com> References: <1500699702.23205.8.camel@hbabu-laptop> <1504041817.2358.32.camel@kernel.crashing.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Dan Streetman , Michael Ellerman , Herbert Xu , Linux Crypto Mailing List , "linuxppc-dev@lists.ozlabs.org" , mikey@neuling.org, suka@us.ibm.com, Ram Pai , npiggin@gmail.com, Haren Myneni To: Benjamin Herrenschmidt Return-path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:55416 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751492AbdH2VzP (ORCPT ); Tue, 29 Aug 2017 17:55:15 -0400 Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v7TLr1Gd062507 for ; Tue, 29 Aug 2017 17:55:15 -0400 Received: from e36.co.us.ibm.com (e36.co.us.ibm.com [32.97.110.154]) by mx0a-001b2d01.pphosted.com with ESMTP id 2cn9t4cb35-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 29 Aug 2017 17:55:14 -0400 Received: from localhost by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 29 Aug 2017 15:55:06 -0600 In-Reply-To: <1504041817.2358.32.camel@kernel.crashing.org> Sender: linux-crypto-owner@vger.kernel.org List-ID: On 08/29/2017 02:23 PM, Benjamin Herrenschmidt wrote: > On Tue, 2017-08-29 at 09:58 -0400, Dan Streetman wrote: >>> + >>> + ret = -EINVAL; >>> + if (coproc && coproc->vas.rxwin) { >>> + wmem->txwin = nx842_alloc_txwin(coproc); >> >> this is wrong. the workmem is scratch memory that's valid only for >> the duration of a single operation. Correct, workmem is used until crypto_free is called. >> >> do you actually need a txwin per crypto transform? or do you need a >> txwin per coprocessor? or txwin per processor? either per-coproc or >> per-cpu should be created at driver init and held separately >> (globally) instead of a per-transform txwin. I really don't see why >> you would need a txwin per transform, because the coproc should not >> care how many different transforms there are. > > We should only need a single window for the whole kernel really, plus > one per user process who wants direct access but that's not relevant > here. Opening send window for each crypto transform (crypto_alloc, compression/decompression, ..., crypto_free) so that does not have to wait for the previous copy/paste complete. VAS will map send and receive windows, and can cache in send windows (up to 128). So I thought using the same send window (per chip) for more requests (say 1000) may be adding overhead. I will make changes if you prefer using 1 send window per chip. > > Cheers, > Ben. >