From patchwork Thu Jul 1 01:52:52 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 12353269 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED 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 47C1DC11F68 for ; Thu, 1 Jul 2021 01:52:55 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F35406105A for ; Thu, 1 Jul 2021 01:52:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F35406105A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 74F308D023D; Wed, 30 Jun 2021 21:52:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 726AA8D0236; Wed, 30 Jun 2021 21:52:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5C82A8D023D; Wed, 30 Jun 2021 21:52:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0194.hostedemail.com [216.40.44.194]) by kanga.kvack.org (Postfix) with ESMTP id 3638D8D0236 for ; Wed, 30 Jun 2021 21:52:54 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 0F0A9250B8 for ; Thu, 1 Jul 2021 01:52:54 +0000 (UTC) X-FDA: 78312345468.20.2ECC355 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf14.hostedemail.com (Postfix) with ESMTP id C64236001A82 for ; Thu, 1 Jul 2021 01:52:53 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id C89736147D; Thu, 1 Jul 2021 01:52:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1625104373; bh=AuzkxrQVo8R8WrkG+pnqM9i67wekf2KlHU1uS/jlPIQ=; h=Date:From:To:Subject:In-Reply-To:From; b=ILKSKGVsyj+9F1ktVGspZpsLsZByqik1j2gsFNLJ7U36WhN6so7MioOUsb8Rl9fhF 4jDcx2oCqcaLn6Pii3r+2283ioLqTWbHbSOYHyyKvuugtZLSObWv24fkue9bXD2HtS hYZuMTN0FK1JbCaMnBovKWmM/7jIyP6uJe8065cA= Date: Wed, 30 Jun 2021 18:52:52 -0700 From: Andrew Morton To: akpm@linux-foundation.org, bigeasy@linutronix.de, colin.king@canonical.com, ddstreet@ieee.org, linmiaohe@huawei.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, nathan@kernel.org, sjenning@redhat.com, tiantao6@hisilicon.com, torvalds@linux-foundation.org, vitaly.wool@konsulko.com Subject: [patch 106/192] mm/zswap.c: avoid unnecessary copy-in at map time Message-ID: <20210701015252.gEmynGXv0%akpm@linux-foundation.org> In-Reply-To: <20210630184624.9ca1937310b0dd5ce66b30e7@linux-foundation.org> User-Agent: s-nail v14.8.16 Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=ILKSKGVs; spf=pass (imf14.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none X-Stat-Signature: 4mc6dft4q7im96bzd9nko8bbbfkyc4if X-Rspamd-Queue-Id: C64236001A82 X-Rspamd-Server: rspam06 X-HE-Tag: 1625104373-309930 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Miaohe Lin Subject: mm/zswap.c: avoid unnecessary copy-in at map time The buf mapped via zpool_map_handle() is only used to store compressed page buffer and there is no information to extract from it. So we could use ZPOOL_MM_WO instead to avoid unnecessary copy-in at map time. Link: https://lkml.kernel.org/r/20210522092242.3233191-3-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Cc: Colin Ian King Cc: Dan Streetman Cc: Nathan Chancellor Cc: Sebastian Andrzej Siewior Cc: Seth Jennings Cc: Tian Tao Cc: Vitaly Wool Signed-off-by: Andrew Morton --- mm/zswap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/zswap.c~mm-zswapc-avoid-unnecessary-copy-in-at-map-time +++ a/mm/zswap.c @@ -1203,7 +1203,7 @@ static int zswap_frontswap_store(unsigne zswap_reject_alloc_fail++; goto put_dstmem; } - buf = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW); + buf = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_WO); memcpy(buf, &zhdr, hlen); memcpy(buf + hlen, dst, dlen); zpool_unmap_handle(entry->pool->zpool, handle);