From patchwork Wed Oct 4 16:53:02 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 13409059 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 49126E7C4E7 for ; Wed, 4 Oct 2023 16:54:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243508AbjJDQyM (ORCPT ); Wed, 4 Oct 2023 12:54:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60878 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243562AbjJDQxl (ORCPT ); Wed, 4 Oct 2023 12:53:41 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5C5EFF9; Wed, 4 Oct 2023 09:53:37 -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=D/8R0cQXGxymytv8qeJZP60gdDV9xdbcF13gSUAJ8s0=; b=P9PqackIT0b7fZvk2PUiwq2eEL ogL4pXi4p90LlQsy6dqVmscrou91ZCSdQPbrsXf44oAxDyO/BxwBm5Z2vIwKUlQlUDpjFbnFPG9fM BrJ63AckCUHqeJPCN9sjwAn+cG1XEsPXgyCNIWA2qvjPyp6VYgJA83cYUMVSJesCNkv4zWzv7yoTQ gP2Z1xQ6jEcNIyFm3dsMavIcKirjm580itF3FOEGmJRHUDqy4pF9sGf2LiGyEorzm8grd31hr/VVK KTTbbG5C8guCMxuwevbECmyH8mc5IYYAvCK+Lb8Nkenf0880jROkyzHaXctQk/+6ULTCzBapwqBs3 erU9zo2g==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1qo57f-004SEv-92; Wed, 04 Oct 2023 16:53:19 +0000 From: "Matthew Wilcox (Oracle)" To: Andrew Morton Cc: "Matthew Wilcox (Oracle)" , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, torvalds@linux-foundation.org, npiggin@gmail.com Subject: [PATCH v2 02/17] iomap: Protect read_bytes_pending with the state_lock Date: Wed, 4 Oct 2023 17:53:02 +0100 Message-Id: <20231004165317.1061855-3-willy@infradead.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20231004165317.1061855-1-willy@infradead.org> References: <20231004165317.1061855-1-willy@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Perform one atomic operation (acquiring the spinlock) instead of two (spinlock & atomic_sub) per read completion. Signed-off-by: Matthew Wilcox (Oracle) --- fs/iomap/buffered-io.c | 37 +++++++++++++++++++++++++------------ 1 file changed, 25 insertions(+), 12 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 6e780ca64ce3..4a996c5327ef 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -29,9 +29,9 @@ typedef int (*iomap_punch_t)(struct inode *inode, loff_t offset, loff_t length); * and I/O completions. */ struct iomap_folio_state { - atomic_t read_bytes_pending; - atomic_t write_bytes_pending; spinlock_t state_lock; + unsigned int read_bytes_pending; + atomic_t write_bytes_pending; /* * Each block has two bits in this bitmap: @@ -183,7 +183,7 @@ static void ifs_free(struct folio *folio) if (!ifs) return; - WARN_ON_ONCE(atomic_read(&ifs->read_bytes_pending)); + WARN_ON_ONCE(ifs->read_bytes_pending != 0); WARN_ON_ONCE(atomic_read(&ifs->write_bytes_pending)); WARN_ON_ONCE(ifs_is_fully_uptodate(folio, ifs) != folio_test_uptodate(folio)); @@ -250,19 +250,29 @@ static void iomap_adjust_read_range(struct inode *inode, struct folio *folio, *lenp = plen; } -static void iomap_finish_folio_read(struct folio *folio, size_t offset, +static void iomap_finish_folio_read(struct folio *folio, size_t off, size_t len, int error) { struct iomap_folio_state *ifs = folio->private; + bool uptodate = !error; + bool finished = true; - if (unlikely(error)) { - folio_clear_uptodate(folio); - folio_set_error(folio); - } else { - iomap_set_range_uptodate(folio, offset, len); + if (ifs) { + unsigned long flags; + + spin_lock_irqsave(&ifs->state_lock, flags); + if (!error) + uptodate = ifs_set_range_uptodate(folio, ifs, off, len); + ifs->read_bytes_pending -= len; + finished = !ifs->read_bytes_pending; + spin_unlock_irqrestore(&ifs->state_lock, flags); } - if (!ifs || atomic_sub_and_test(len, &ifs->read_bytes_pending)) + if (error) + folio_set_error(folio); + if (uptodate) + folio_mark_uptodate(folio); + if (finished) folio_unlock(folio); } @@ -360,8 +370,11 @@ static loff_t iomap_readpage_iter(const struct iomap_iter *iter, } ctx->cur_folio_in_bio = true; - if (ifs) - atomic_add(plen, &ifs->read_bytes_pending); + if (ifs) { + spin_lock_irq(&ifs->state_lock); + ifs->read_bytes_pending += plen; + spin_unlock_irq(&ifs->state_lock); + } sector = iomap_sector(iomap, pos); if (!ctx->bio ||