From patchwork Mon Jun 14 20:14:09 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 12319795 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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 076CEC48BE8 for ; Mon, 14 Jun 2021 20:21:05 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A3EBA61246 for ; Mon, 14 Jun 2021 20:21:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A3EBA61246 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6CE156B006E; Mon, 14 Jun 2021 16:21:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5B6D16B0072; Mon, 14 Jun 2021 16:21:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 36E046B0070; Mon, 14 Jun 2021 16:21:03 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0185.hostedemail.com [216.40.44.185]) by kanga.kvack.org (Postfix) with ESMTP id 018796B006E for ; Mon, 14 Jun 2021 16:21:02 -0400 (EDT) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 94D6B824999B for ; Mon, 14 Jun 2021 20:21:02 +0000 (UTC) X-FDA: 78253448364.18.758DE52 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf06.hostedemail.com (Postfix) with ESMTP id C25FCC00CBD7 for ; Mon, 14 Jun 2021 20:20:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=QVDOe6OiXrrGJ5fzyfIPNMJOAVIqo7jy8parNKdUXig=; b=EC7MweMdhQ1M7XpYA+wo4FwPMs pLUvFjlTvBNCn3yBAsZ4/i/fleYrr/7IGeGHJdvMQ6cw7ZTd3R6kv5pRunisruP4wyeAjskO+1KFm vFMqxFhZQUtinVT6KFLTmnMT8wjFDhK/d2lfeztoOnm6Z1pmZcEbYRELL+hTqdW02BL9wTy7psFzN 04W1lepa27I9XV2TW8pLip+cIHhOqqNBlKCrHSuEK9Z8ZtmKhw8rd5EeYuo4SJqpmK9VQ7RS7+H3G lJzB0cocamqm0Jq6REfJ7bamcYaKmJY5VZlhQZoQTxyezhscnjKBdioUHoijvkLjAxE0hQXlEc+YP Rjno33FQ==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lst3B-005n9D-26; Mon, 14 Jun 2021 20:19:26 +0000 From: "Matthew Wilcox (Oracle)" To: akpm@linux-foundation.org Cc: "Matthew Wilcox (Oracle)" , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Zi Yan , Christoph Hellwig , Jeff Layton , "Kirill A . Shutemov" , Vlastimil Babka , William Kucharski Subject: [PATCH v11 07/33] mm: Add folio_put() Date: Mon, 14 Jun 2021 21:14:09 +0100 Message-Id: <20210614201435.1379188-8-willy@infradead.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210614201435.1379188-1-willy@infradead.org> References: <20210614201435.1379188-1-willy@infradead.org> MIME-Version: 1.0 X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: C25FCC00CBD7 Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=EC7MweMd; spf=none (imf06.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none X-Stat-Signature: cdkx5zcwc3waturm8wh5m1hy4t8guk64 X-HE-Tag: 1623702053-35955 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: If we know we have a folio, we can call folio_put() instead of put_page() and save the overhead of calling compound_head(). Also skips the devmap checks. This commit looks like it should be a no-op, but actually saves 684 bytes of text with the distro-derived config that I'm testing. Some functions grow a little while others shrink. I presume the compiler is making different inlining decisions. Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Zi Yan Reviewed-by: Christoph Hellwig Acked-by: Jeff Layton Acked-by: Kirill A. Shutemov Acked-by: Vlastimil Babka Reviewed-by: William Kucharski Reviewed-by: David Howells --- include/linux/mm.h | 33 ++++++++++++++++++++++++++++----- 1 file changed, 28 insertions(+), 5 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 0432f811f1b5..b68a55cc8d93 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -751,6 +751,11 @@ static inline int put_page_testzero(struct page *page) return page_ref_dec_and_test(page); } +static inline int folio_put_testzero(struct folio *folio) +{ + return put_page_testzero(&folio->page); +} + /* * Try to grab a ref unless the page has a refcount of zero, return false if * that is the case. @@ -1247,9 +1252,28 @@ static inline __must_check bool try_get_page(struct page *page) return true; } +/** + * folio_put - Decrement the reference count on a folio. + * @folio: The folio. + * + * If the folio's reference count reaches zero, the memory will be + * released back to the page allocator and may be used by another + * allocation immediately. Do not access the memory or the struct folio + * after calling folio_put() unless you can be sure that it wasn't the + * last reference. + * + * Context: May be called in process or interrupt context, but not in NMI + * context. May be called while holding a spinlock. + */ +static inline void folio_put(struct folio *folio) +{ + if (folio_put_testzero(folio)) + __put_page(&folio->page); +} + static inline void put_page(struct page *page) { - page = compound_head(page); + struct folio *folio = page_folio(page); /* * For devmap managed pages we need to catch refcount transition from @@ -1257,13 +1281,12 @@ static inline void put_page(struct page *page) * need to inform the device driver through callback. See * include/linux/memremap.h and HMM for details. */ - if (page_is_devmap_managed(page)) { - put_devmap_managed_page(page); + if (page_is_devmap_managed(&folio->page)) { + put_devmap_managed_page(&folio->page); return; } - if (put_page_testzero(page)) - __put_page(page); + folio_put(folio); } /*