From patchwork Fri Sep 15 18:37:07 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 13387428 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B520EED621 for ; Fri, 15 Sep 2023 18:38:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236768AbjIOSiS (ORCPT ); Fri, 15 Sep 2023 14:38:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33926 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236547AbjIOShr (ORCPT ); Fri, 15 Sep 2023 14:37:47 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 75DBA1BD4; Fri, 15 Sep 2023 11:37:42 -0700 (PDT) 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=n7u0d+abmaVaMLzO4YFLO6CA1M26m1t19aSjcVFsvyQ=; b=Ki3hIdnhdMv60FfdfEOljvltYs O2p6WhI14WeOIkOkpuGNThSphzEWgamOZ2tl4TadV+sLFcS3OGaX5vUz6YydTrxv0+xPb9J15TdfB Wkj52lf53qWnjsP77RGlXpFUIqCMw36qV8f7ZsEpS7+qGq+phMBML/R7NY85CrpdbzXbEfabQ3J0F 9hTbkW4hBz4ZwVrUc91m2AUqR+Gj771pbofj+7lhGgqrTcCND5JHMjPbpzJGYkCrsq1qgJ12msS9o ohnFu3M2vVceno8fThSIIaDRW2ceuNofx1ZW3XjdFwp9oJR6+liR9lEN879iiI+VogQUS8uSWTNBo reN4LkIA==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1qhDgk-00BMJ6-Ef; Fri, 15 Sep 2023 18:37:10 +0000 From: "Matthew Wilcox (Oracle)" To: linux-kernel@vger.kernel.org Cc: "Matthew Wilcox (Oracle)" , linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, torvalds@linux-foundation.org, Nicholas Piggin Subject: [PATCH 17/17] mm: Use folio_xor_flags_has_waiters() in folio_end_writeback() Date: Fri, 15 Sep 2023 19:37:07 +0100 Message-Id: <20230915183707.2707298-18-willy@infradead.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20230915183707.2707298-1-willy@infradead.org> References: <20230915183707.2707298-1-willy@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Match how folio_unlock() works by combining the test for PG_waiters with the clearing of PG_writeback. This should have a small performance win, and removes the last user of folio_wake(). Signed-off-by: Matthew Wilcox (Oracle) --- mm/filemap.c | 15 +++------------ mm/internal.h | 2 +- mm/page-writeback.c | 9 ++++++--- 3 files changed, 10 insertions(+), 16 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index 53c0d71aae8e..f57b62d65001 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1177,13 +1177,6 @@ static void folio_wake_bit(struct folio *folio, int bit_nr) spin_unlock_irqrestore(&q->lock, flags); } -static void folio_wake(struct folio *folio, int bit) -{ - if (!folio_test_waiters(folio)) - return; - folio_wake_bit(folio, bit); -} - /* * A choice of three behaviors for folio_wait_bit_common(): */ @@ -1620,13 +1613,11 @@ void folio_end_writeback(struct folio *folio) * Writeback does not hold a folio reference of its own, relying * on truncation to wait for the clearing of PG_writeback. * But here we must make sure that the folio is not freed and - * reused before the folio_wake(). + * reused before the folio_wake_bit(). */ folio_get(folio); - __folio_end_writeback(folio); - - smp_mb__after_atomic(); - folio_wake(folio, PG_writeback); + if (__folio_end_writeback(folio)) + folio_wake_bit(folio, PG_writeback); acct_reclaim_writeback(folio); folio_put(folio); } diff --git a/mm/internal.h b/mm/internal.h index ccb08dd9b5ec..30cf724ddbce 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -105,7 +105,7 @@ static inline void wake_throttle_isolated(pg_data_t *pgdat) vm_fault_t do_swap_page(struct vm_fault *vmf); void folio_rotate_reclaimable(struct folio *folio); -void __folio_end_writeback(struct folio *folio); +bool __folio_end_writeback(struct folio *folio); void deactivate_file_folio(struct folio *folio); void folio_activate(struct folio *folio); diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 410b53e888e3..c52514fe1d23 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -2940,10 +2940,11 @@ static void wb_inode_writeback_end(struct bdi_writeback *wb) spin_unlock_irqrestore(&wb->work_lock, flags); } -void __folio_end_writeback(struct folio *folio) +bool __folio_end_writeback(struct folio *folio) { long nr = folio_nr_pages(folio); struct address_space *mapping = folio_mapping(folio); + bool ret; folio_memcg_lock(folio); if (mapping && mapping_use_writeback_tags(mapping)) { @@ -2952,7 +2953,7 @@ void __folio_end_writeback(struct folio *folio) unsigned long flags; xa_lock_irqsave(&mapping->i_pages, flags); - folio_test_clear_writeback(folio); + ret = folio_xor_flags_has_waiters(folio, 1 << PG_writeback); __xa_clear_mark(&mapping->i_pages, folio_index(folio), PAGECACHE_TAG_WRITEBACK); if (bdi->capabilities & BDI_CAP_WRITEBACK_ACCT) { @@ -2970,13 +2971,15 @@ void __folio_end_writeback(struct folio *folio) xa_unlock_irqrestore(&mapping->i_pages, flags); } else { - folio_test_clear_writeback(folio); + ret = folio_xor_flags_has_waiters(folio, 1 << PG_writeback); } lruvec_stat_mod_folio(folio, NR_WRITEBACK, -nr); zone_stat_mod_folio(folio, NR_ZONE_WRITE_PENDING, -nr); node_stat_mod_folio(folio, NR_WRITTEN, nr); folio_memcg_unlock(folio); + + return ret; } bool __folio_start_writeback(struct folio *folio, bool keep_write)