From mboxrd@z Thu Jan 1 00:00:00 1970 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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 4594AC3A5A2 for ; Tue, 3 Sep 2019 16:24:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1D38623717 for ; Tue, 3 Sep 2019 16:24:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567527868; bh=PRw3RDuhrCa64X2CNf+loXfXKXVaqK0V7MFX6ZrbaBY=; h=From:To:Cc:Subject:Date:List-ID:From; b=12+Z2yMFRbOVjzpFI7nWhNsvxaST2e0U/0AeiirqeU8Q9b3REGh/u/ahJNM0c/IEG w8KWNQr1yzZOH26gcB7OBmuKM+LOSmdjbqs5es0JNBZM0z4uXLh8Grtib45F3HdHz4 Ipcxw1GwcgiT8HUgsVhpQZt57ZHlTB9R1GP0Vvmk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730084AbfICQY1 (ORCPT ); Tue, 3 Sep 2019 12:24:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:44112 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729692AbfICQY1 (ORCPT ); Tue, 3 Sep 2019 12:24:27 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A7C6A23431; Tue, 3 Sep 2019 16:24:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567527866; bh=PRw3RDuhrCa64X2CNf+loXfXKXVaqK0V7MFX6ZrbaBY=; h=From:To:Cc:Subject:Date:From; b=rP2Ry4O3QsjL3OUMIhsW2E2NT/d3uio4qLoLPUy3mbcRiGkU0vyFBbu/5cTEsOqM2 V+yI6fc1lCwXrGkgmToYE46BLT6+OmX09vI1U4eCn7QRdJZ6z9NIaVsGARvK22rcqD XXKQXwagNJPEONxgi811zQ96a+i5d4U0WrStXtug= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Coly Li , Jens Axboe , linux-bcache@vger.kernel.org Subject: [PATCH AUTOSEL 5.2 01/23] bcache: only clear BTREE_NODE_dirty bit when it is set Date: Tue, 3 Sep 2019 12:24:02 -0400 Message-Id: <20190903162424.6877-1-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Coly Li In bch_btree_cache_free() and btree_node_free(), BTREE_NODE_dirty is always set no matter btree node is dirty or not. The code looks like this, if (btree_node_dirty(b)) btree_complete_write(b, btree_current_write(b)); clear_bit(BTREE_NODE_dirty, &b->flags); Indeed if btree_node_dirty(b) returns false, it means BTREE_NODE_dirty bit is cleared, then it is unnecessary to clear the bit again. This patch only clears BTREE_NODE_dirty when btree_node_dirty(b) is true (the bit is set), to save a few CPU cycles. Signed-off-by: Coly Li Signed-off-by: Jens Axboe --- drivers/md/bcache/btree.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c index 773f5fdad25fb..3fbadf2058a65 100644 --- a/drivers/md/bcache/btree.c +++ b/drivers/md/bcache/btree.c @@ -778,10 +778,10 @@ void bch_btree_cache_free(struct cache_set *c) while (!list_empty(&c->btree_cache)) { b = list_first_entry(&c->btree_cache, struct btree, list); - if (btree_node_dirty(b)) + if (btree_node_dirty(b)) { btree_complete_write(b, btree_current_write(b)); - clear_bit(BTREE_NODE_dirty, &b->flags); - + clear_bit(BTREE_NODE_dirty, &b->flags); + } mca_data_free(b); } @@ -1069,9 +1069,10 @@ static void btree_node_free(struct btree *b) mutex_lock(&b->write_lock); - if (btree_node_dirty(b)) + if (btree_node_dirty(b)) { btree_complete_write(b, btree_current_write(b)); - clear_bit(BTREE_NODE_dirty, &b->flags); + clear_bit(BTREE_NODE_dirty, &b->flags); + } mutex_unlock(&b->write_lock); -- 2.20.1