From patchwork Mon Jun 14 20:14:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 12319861 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 323B8C2B9F4 for ; Mon, 14 Jun 2021 20:27:25 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D1C116124B for ; Mon, 14 Jun 2021 20:27:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D1C116124B 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 5D92F6B006E; Mon, 14 Jun 2021 16:27:24 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5896B6B0071; Mon, 14 Jun 2021 16:27:24 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 451EA6B0072; Mon, 14 Jun 2021 16:27:24 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0129.hostedemail.com [216.40.44.129]) by kanga.kvack.org (Postfix) with ESMTP id 1318C6B006E for ; Mon, 14 Jun 2021 16:27:24 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id A3A00A8D1 for ; Mon, 14 Jun 2021 20:27:23 +0000 (UTC) X-FDA: 78253464366.17.ECB412C Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf09.hostedemail.com (Postfix) with ESMTP id 6C8FF6000148 for ; Mon, 14 Jun 2021 20:27:18 +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=pwQ6DarmYD8ZadbTVnlcGA6/mVanbX639dA7W+omAjk=; b=abTiplHMScG2j7E4FGpC1zVkjA 0u0vD7DIcKC93MvBKChkNBaKSSODMTbR6LMF78xkU8fUgTMxw5OT+1NwTfKP7wI1lSbKozX6DiLm9 DsNE5dCPUAlJ29B/5lTG0NrjIGMHOaJ1Db16VJJGNbY+b9ITarJ8gR6ifCYJhEPhWnhOFb+jXqCtX ogJRnVRlgqZ5gQaXjl0ww+I27dOpcw3HQ5Jy2TyNparWzWcVy2XqU9mqHe1xtavSqZgN2EmaWV31x VA806YSRhy/2p6W21aPM1TZ5yrGXLSHcJCaMdMNL7QSWXSqZW/uo7KOwmrnn1BZqpiAGF5yY+hhF8 Xgh9hHjQ==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lstA9-005nol-2U; Mon, 14 Jun 2021 20:26:31 +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, Christoph Hellwig , Jeff Layton , "Kirill A . Shutemov" , William Kucharski Subject: [PATCH v11 18/33] mm/filemap: Add folio_unlock() Date: Mon, 14 Jun 2021 21:14:20 +0100 Message-Id: <20210614201435.1379188-19-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 Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=abTiplHM; dmarc=none; spf=none (imf09.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org X-Rspamd-Server: rspam02 X-Stat-Signature: ekx8opqe41ea9yupy4cwspnwe9s4hx4r X-Rspamd-Queue-Id: 6C8FF6000148 X-HE-Tag: 1623702438-759825 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: Convert unlock_page() to call folio_unlock(). By using a folio we avoid a call to compound_head(). This shortens the function from 39 bytes to 25 and removes 4 instructions on x86-64. Because we still have unlock_page(), it's a net increase of 16 bytes of text for the kernel as a whole, but any path that uses folio_unlock() will execute 4 fewer instructions. Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig Acked-by: Jeff Layton Acked-by: Kirill A. Shutemov Reviewed-by: William Kucharski Reviewed-by: David Howells --- include/linux/pagemap.h | 3 ++- mm/filemap.c | 29 ++++++++++++----------------- mm/folio-compat.c | 6 ++++++ 3 files changed, 20 insertions(+), 18 deletions(-) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 98becc81f069..9faf19f4c9f9 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -646,7 +646,8 @@ extern int __lock_page_killable(struct page *page); extern int __lock_page_async(struct page *page, struct wait_page_queue *wait); extern int __lock_page_or_retry(struct page *page, struct mm_struct *mm, unsigned int flags); -extern void unlock_page(struct page *page); +void unlock_page(struct page *page); +void folio_unlock(struct folio *folio); /* * Return true if the page was successfully locked diff --git a/mm/filemap.c b/mm/filemap.c index 817a47059bd0..4cbed91d456a 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1435,29 +1435,24 @@ static inline bool clear_bit_unlock_is_negative_byte(long nr, volatile void *mem #endif /** - * unlock_page - unlock a locked page - * @page: the page + * folio_unlock - Unlock a locked folio. + * @folio: The folio. * - * Unlocks the page and wakes up sleepers in wait_on_page_locked(). - * Also wakes sleepers in wait_on_page_writeback() because the wakeup - * mechanism between PageLocked pages and PageWriteback pages is shared. - * But that's OK - sleepers in wait_on_page_writeback() just go back to sleep. + * Unlocks the folio and wakes up any thread sleeping on the page lock. * - * Note that this depends on PG_waiters being the sign bit in the byte - * that contains PG_locked - thus the BUILD_BUG_ON(). That allows us to - * clear the PG_locked bit and test PG_waiters at the same time fairly - * portably (architectures that do LL/SC can test any bit, while x86 can - * test the sign bit). + * Context: May be called from interrupt or process context. May not be + * called from NMI context. */ -void unlock_page(struct page *page) +void folio_unlock(struct folio *folio) { + /* Bit 7 allows x86 to check the byte's sign bit */ BUILD_BUG_ON(PG_waiters != 7); - page = compound_head(page); - VM_BUG_ON_PAGE(!PageLocked(page), page); - if (clear_bit_unlock_is_negative_byte(PG_locked, &page->flags)) - wake_up_page_bit(page, PG_locked); + BUILD_BUG_ON(PG_locked > 7); + VM_BUG_ON_FOLIO(!folio_locked(folio), folio); + if (clear_bit_unlock_is_negative_byte(PG_locked, folio_flags(folio, 0))) + wake_up_page_bit(&folio->page, PG_locked); } -EXPORT_SYMBOL(unlock_page); +EXPORT_SYMBOL(folio_unlock); /** * end_page_private_2 - Clear PG_private_2 and release any waiters diff --git a/mm/folio-compat.c b/mm/folio-compat.c index 5e107aa30a62..91b3d00a92f7 100644 --- a/mm/folio-compat.c +++ b/mm/folio-compat.c @@ -11,3 +11,9 @@ struct address_space *page_mapping(struct page *page) return folio_mapping(page_folio(page)); } EXPORT_SYMBOL(page_mapping); + +void unlock_page(struct page *page) +{ + return folio_unlock(page_folio(page)); +} +EXPORT_SYMBOL(unlock_page);