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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,T_DKIMWL_WL_HIGH 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 95E4AC46470 for ; Tue, 4 Jun 2019 12:30:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7013823F50 for ; Tue, 4 Jun 2019 12:30:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b="fHogesG7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727750AbfFDMaO (ORCPT ); Tue, 4 Jun 2019 08:30:14 -0400 Received: from mailout3.samsung.com ([203.254.224.33]:34879 "EHLO mailout3.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727394AbfFDMaO (ORCPT ); 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Tue, 4 Jun 2019 12:30:08 +0000 (GMT) X-AuditID: b6c32a49-5b7ff70000000fe7-f9-5cf66450b68f Received: from epcas5p2.samsung.com ( [182.195.41.40]) by epsmges5p1new.samsung.com (Symantec Messaging Gateway) with SMTP id 90.8C.04071.05466FC5; Tue, 4 Jun 2019 21:30:08 +0900 (KST) Mime-Version: 1.0 Subject: RE:(2) [PATCH 0/4] zstd: reduce stack usage Reply-To: v.narang@samsung.com From: Vaneet Narang To: Andrew Morton , Maninder Singh CC: "herbert@gondor.apana.org.au" , "davem@davemloft.net" , "keescook@chromium.org" , "gustavo@embeddedor.com" , "joe@perches.com" , "linux-crypto@vger.kernel.org" , "linux-kernel@vger.kernel.org" , AMIT SAHRAWAT , PANKAJ MISHRA , Vaneet Narang X-Priority: 3 X-Content-Kind-Code: NORMAL In-Reply-To: <20190603144912.34e1414376e07c7b1af53205@linux-foundation.org> X-Drm-Type: N,general X-Msg-Generator: Mail X-Msg-Type: PERSONAL X-Reply-Demand: N Message-ID: <20190604120623epcms5p3fc13e98047e7b44d6da144425213b4fe@epcms5p3> Date: Tue, 04 Jun 2019 17:36:23 +0530 X-CMS-MailID: 20190604120623epcms5p3fc13e98047e7b44d6da144425213b4fe Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" X-Sendblock-Type: REQ_APPROVE CMS-TYPE: 105P X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFtrJJsWRmVeSWpSXmKPExsWy7bCmhm5AyrcYg2NrpSwu7k61mLN+DZvF nPMtLBZb96hadL+SsZh9/zGLxZnuXIv7934yWVzeNYfN4vD8NhaLe2+2MlkcOjmX0YHHY3bD RRaPLStvMnmsO6jqse2AqseJGb9ZPL6susbs0bdlFaPH501yARxROTYZqYkpqUUKqXnJ+SmZ eem2St7B8c7xpmYGhrqGlhbmSgp5ibmptkouPgG6bpk5QIcqKZQl5pQChQISi4uV9O1sivJL S1IVMvKLS2yVUgtScgoMjQr0ihNzi0vz0vWS83OtDA0MjEyBKhNyMnYd3MtWsIWtYu6yj4wN jFNZuxg5OCQETCTeP7fsYuTiEBLYzSjRfuIWG0icV0BQ4u8O4S5GTg5hoJIVm88ygdhCAnIS x2/sZoSI60icmLeGEaScTUBL4mNLOIgpIhApcWuVOshEZoHPzBLtZz6BlUsI8ErMaH/KAmFL S2xfvhUszingLbFu62uouKjEzdVv2WHs98fmQ/WKSLTeO8sMYQtKPPi5mxHiehmJXW/FQXZJ CHQzSkw4t5wVwpnBKHGq9w1Ug7nE+ZPzwWxeAV+Je49ngC1jEVCV+HPwMCtEjYvE5Y+vwRYz C2hLLFv4mhlkAbOApsT6XfoQJbISU0+tY4Io4ZPo/f2ECeavHfNgbCWJcwd3skHYEhJPOmdC neAh8WTrSkZIMJ9nlFh06Aj7BEaFWYiQnoVk8yyEzQsYmVcxSqYWFOempxabFhjmpZYjR+8m RnCy1fLcwTjrnM8hRgEORiUe3hnx32KEWBPLiitzDzFKcDArifAm3v4SI8SbklhZlVqUH19U mpNafIjRFBgGE5mlRJPzgZkgryTe0NTIzMzA0sDU2MLMUEmcdxLr1RghgfTEktTs1NSC1CKY PiYOTqkGRomzCvYV6s/DTxoneDdOK+Y8VsWfr7WjqWH33MBdc0Qs4ryP781/H8iXPs9LVWzO qZLLS2ed0sn8m/HZy//xRO7ykKTyp07xBroqN9kF3nSunN7/JOzJu6MfzCq4lr+Yue6k29kJ avfMom+pzpxbvf2VlIGO4v/CHVNnfi+euE/24p/7P5o7nyixFGckGmoxFxUnAgA5QNF2zAMA AA== DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20190603090227epcas5p348327061a3facbb9dfcf662bf2bc196e References: <20190603144912.34e1414376e07c7b1af53205@linux-foundation.org> <1559552526-4317-1-git-send-email-maninder1.s@samsung.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andrew, >> This patch set reduces stack usage for zstd code, because target like AR= M has >> limited 8KB kernel stack, which is getting overflowed due to hight stack= usage >> of zstd code with call flow like: =20 >That's rather bad behaviour. I assume the patchset actually fixes this? Yes, patchset tries to reduce around 300 bytes of stack usage of zstd compr= ession path.=20 We faced high stack usage issue on switching compression algo from LZO/LZ4 = to zstd algo. zstd compression uses around 1200 bytes of stack which is huge as compared= =20 to LZO/LZ4 which uses negligible stack (< 200 bytes). =20 >I think I'll schedule the patchset for 5.2-rcX so that zstd is actually >usable on arm in 5.2. Does that sound OK?=C2=A0=0D=0AOK=0D=0A=0D=0ARegard= s,=0D=0AVaneet=20Narang=0D=0A