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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,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 1B742C43381 for ; Wed, 6 Mar 2019 06:19:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EA0DB2064A for ; Wed, 6 Mar 2019 06:19:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727452AbfCFGTS (ORCPT ); Wed, 6 Mar 2019 01:19:18 -0500 Received: from mx2.suse.de ([195.135.220.15]:48170 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725747AbfCFGTS (ORCPT ); Wed, 6 Mar 2019 01:19:18 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 91614ADD3 for ; Wed, 6 Mar 2019 06:19:16 +0000 (UTC) From: Qu Wenruo To: linux-btrfs@vger.kernel.org Subject: [PATCH RFC 2/3] btrfs: locking: Add hooks for btrfs perf Date: Wed, 6 Mar 2019 14:19:06 +0800 Message-Id: <20190306061907.29685-3-wqu@suse.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190306061907.29685-1-wqu@suse.com> References: <20190306061907.29685-1-wqu@suse.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org For btrfs tree locking, there are only 2 functions can sleep: - btrfs_tree_read_lock() It will wait for any blocking writers - btrfs_tree_lock() It will wait for any blocking readers or writers Other functions only depends on rwlock which won't sleep. We doesn't really care about the spinning lock version. The overheads introduced are: - two ktime_get() calls - several if branches - percpu_counter_add() Which should be smaller than to ftrace function_graph. Signed-off-by: Qu Wenruo --- fs/btrfs/locking.c | 11 +++++++++++ fs/btrfs/perf.c | 20 ++++++++++++++++++++ fs/btrfs/perf.h | 8 ++++++++ 3 files changed, 39 insertions(+) diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c index 1da768e5ef75..c23c8f7450e8 100644 --- a/fs/btrfs/locking.c +++ b/fs/btrfs/locking.c @@ -11,6 +11,7 @@ #include "ctree.h" #include "extent_io.h" #include "locking.h" +#include "perf.h" static void btrfs_assert_tree_read_locked(struct extent_buffer *eb); @@ -85,10 +86,14 @@ void btrfs_clear_lock_blocking_rw(struct extent_buffer *eb, int rw) */ void btrfs_tree_read_lock(struct extent_buffer *eb) { + u64 start_ns; + + start_ns = btrfs_perf_start(); again: BUG_ON(!atomic_read(&eb->blocking_writers) && current->pid == eb->lock_owner); + read_lock(&eb->lock); if (atomic_read(&eb->blocking_writers) && current->pid == eb->lock_owner) { @@ -101,16 +106,19 @@ void btrfs_tree_read_lock(struct extent_buffer *eb) BUG_ON(eb->lock_nested); eb->lock_nested = 1; read_unlock(&eb->lock); + btrfs_perf_end(eb->fs_info, btrfs_header_owner(eb), start_ns); return; } if (atomic_read(&eb->blocking_writers)) { read_unlock(&eb->lock); + wait_event(eb->write_lock_wq, atomic_read(&eb->blocking_writers) == 0); goto again; } atomic_inc(&eb->read_locks); atomic_inc(&eb->spinning_readers); + btrfs_perf_end(eb->fs_info, btrfs_header_owner(eb), start_ns); } /* @@ -227,7 +235,9 @@ void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb) */ void btrfs_tree_lock(struct extent_buffer *eb) { + u64 start_ns; WARN_ON(eb->lock_owner == current->pid); + start_ns = btrfs_perf_start(); again: wait_event(eb->read_lock_wq, atomic_read(&eb->blocking_readers) == 0); wait_event(eb->write_lock_wq, atomic_read(&eb->blocking_writers) == 0); @@ -248,6 +258,7 @@ void btrfs_tree_lock(struct extent_buffer *eb) atomic_inc(&eb->spinning_writers); atomic_inc(&eb->write_locks); eb->lock_owner = current->pid; + btrfs_perf_end(eb->fs_info, btrfs_header_owner(eb), start_ns); } /* diff --git a/fs/btrfs/perf.c b/fs/btrfs/perf.c index 2880111f3b0c..893bfad8e6d3 100644 --- a/fs/btrfs/perf.c +++ b/fs/btrfs/perf.c @@ -50,3 +50,23 @@ void btrfs_perf_free_profiler(struct btrfs_fs_info *fs_info) kfree(profiler); } +void btrfs_perf_end(struct btrfs_fs_info *fs_info, u64 eb_owner, u64 start_ns) +{ + struct btrfs_perf_profiler *profiler = fs_info->profiler; + u64 end_ns; + int i; + + if (!profiler) + return; + + end_ns = ktime_get_ns(); + if (eb_owner == BTRFS_ROOT_TREE_OBJECTID) + i = BTRFS_PERF_TREE_LOCK_ROOT; + else if (is_fstree(eb_owner)) + i = BTRFS_PERF_TREE_LOCK_FS; + else if (eb_owner == BTRFS_EXTENT_TREE_OBJECTID) + i = BTRFS_PERF_TREE_LOCK_EXTENT; + else + i = BTRFS_PERF_TREE_LOCK_OTHER; + percpu_counter_add(&profiler->perf_counters[i], end_ns - start_ns); +} diff --git a/fs/btrfs/perf.h b/fs/btrfs/perf.h index 9dbea6458d86..7cf4b8c9a0ad 100644 --- a/fs/btrfs/perf.h +++ b/fs/btrfs/perf.h @@ -24,4 +24,12 @@ struct btrfs_perf_profiler { struct btrfs_perf_profiler *btrfs_perf_alloc_profiler(void); void btrfs_perf_free_profiler(struct btrfs_fs_info *fs_info); +void btrfs_perf_update_lock(struct btrfs_fs_info *fs_info, + u64 eb_owner, u64 ns_diff); +static inline u64 btrfs_perf_start(void) +{ + return ktime_get_ns(); +} + +void btrfs_perf_end(struct btrfs_fs_info *fs_info, u64 eb_owner, u64 start_ns); #endif -- 2.21.0