From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8C52AC04AB4 for ; Fri, 10 May 2019 17:40:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6965B217D6 for ; Fri, 10 May 2019 17:40:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727854AbfEJRkc (ORCPT ); Fri, 10 May 2019 13:40:32 -0400 Received: from smtprelay0045.hostedemail.com ([216.40.44.45]:37638 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727557AbfEJRkc (ORCPT ); Fri, 10 May 2019 13:40:32 -0400 Received: from smtprelay.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by smtpgrave03.hostedemail.com (Postfix) with ESMTP id 753E118032814; Fri, 10 May 2019 17:40:31 +0000 (UTC) Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay02.hostedemail.com (Postfix) with ESMTP id 9FE56442F; Fri, 10 May 2019 17:40:30 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: crook38_414a83b1b407 X-Filterd-Recvd-Size: 2787 Received: from XPS-9350 (unknown [172.58.19.107]) (Authenticated sender: joe@perches.com) by omf11.hostedemail.com (Postfix) with ESMTPA; Fri, 10 May 2019 17:40:27 +0000 (UTC) Message-ID: <10021f43dc5b377340fde9a7716e083f6f1261c1.camel@perches.com> Subject: Re: [PATCH 1/2] zstd: pass pointer rathen than structure to functions From: Joe Perches To: Maninder Singh , terrelln@fb.com, herbert@gondor.apana.org.au, davem@davemloft.net, keescook@chromium.org, gustavo@embeddedor.com Cc: linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, a.sahrawat@samsung.com, pankaj.m@samsung.com, Vaneet Narang Date: Fri, 10 May 2019 10:39:57 -0700 In-Reply-To: <1557468704-3014-1-git-send-email-maninder1.s@samsung.com> References: <1557468704-3014-1-git-send-email-maninder1.s@samsung.com> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.30.1-1build1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2019-05-10 at 11:41 +0530, Maninder Singh wrote: > currently params structure is passed in all functions, which increases > stack usage in all the function and lead to stack overflow on target like > ARM with kernel stack size of 8 KB so better to pass pointer. [] > diff --git a/lib/zstd/compress.c b/lib/zstd/compress.c [] > @@ -206,18 +206,18 @@ ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, u > return cPar; > } > > -static U32 ZSTD_equivalentParams(ZSTD_parameters param1, ZSTD_parameters param2) > +static U32 ZSTD_equivalentParams(const ZSTD_parameters *param1, const ZSTD_parameters *param2) > { > - return (param1.cParams.hashLog == param2.cParams.hashLog) & (param1.cParams.chainLog == param2.cParams.chainLog) & > - (param1.cParams.strategy == param2.cParams.strategy) & ((param1.cParams.searchLength == 3) == (param2.cParams.searchLength == 3)); > + return (param1->cParams.hashLog == param2->cParams.hashLog) & (param1->cParams.chainLog == param2->cParams.chainLog) & > + (param1->cParams.strategy == param2->cParams.strategy) & ((param1->cParams.searchLength == 3) == (param2->cParams.searchLength == 3)); > } trivia: Using & instead of && makes this somewhat difficult to read. It's hard to believe this is a performance optimization. It might be better as return param1->cParams.hashLog == param2->cParams.hashLog && param1->cParams.chainLog == param2->cParams.chainLog && param1->cParams.strategy == param2->cParams.strategy && param1->cParams.searchLength == 3 && param1->cParams.searchLength == param2->cParams.searchLength;