From nobody Thu Nov 28 16:46:20 2024 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2C11A1C3317; Tue, 1 Oct 2024 10:59:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727780370; cv=none; b=ExMjlUlUxzfG1jPrv6mzfns9I656UsbsSRXSN7PgBFZsyVCV7qmuRLIn4bH7viuie3mV1obJUMrWpgwYTsmTFUiXBYQBnsBKj7k81H+2S8qydBOcekCFUiRfQpgUI1JFvTTYcBxoy9UMfjdGm2pfYHIL/fNGD6fMwevM0uCvris= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727780370; c=relaxed/simple; bh=JL2gW+C3kDxbRAGj0jMp5iB8JHuDuhS4rvTtieX78oY=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=ot923FjRpnISbqovd3kLNtvs99pFAu1P9MkIozcdVJBKleMgI4/yMrsKRAdsY6Kzgo14ZGLryZB0Bz6i1pxMI3w7hvhoCM4iq1twvupIDFUw0vhUsZLyhW2EvKwFaoazEaeTb5iunKR+8rYAB2tvFToQBCwttOL76s9pl1SriWg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=B5NsA4Y3; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="B5NsA4Y3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6ECCCC4CECE; Tue, 1 Oct 2024 10:59:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727780370; bh=JL2gW+C3kDxbRAGj0jMp5iB8JHuDuhS4rvTtieX78oY=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=B5NsA4Y3xe03GSebvPrrYvgPoGZbnw6mZTFF2+mbaE21jaWD0FJgt1XHCPTAvrT79 vPgqIbRwjLzaOimrju2AKsv/b/gSgB/4RSN0bLwKzrtHXHaDqtAnXqCJO2jpq2RqmX X6wO1EBN+PbuMQ86TBeql6QF8WTGyZ5Z00YdTsluw0mp4xGe3a07TAoeUMe6v2oxQv nVlXaK0ssXyss4VOzkZpjy37wUHfRBGsBv4J2GUWKNvzUSzUOk8cj7BRdZFIKFS+aJ vlLE50z3y5Llg/g8PlVvgDXTNVTBWwx4haJ2pHrfwkMGwuWWBl6P4sGfxxbpzF0K6U VFKXOjSzzaz3Q== From: Jeff Layton Date: Tue, 01 Oct 2024 06:59:01 -0400 Subject: [PATCH v8 07/12] timekeeping: add percpu counter for tracking floor swap events Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20241001-mgtime-v8-7-903343d91bc3@kernel.org> References: <20241001-mgtime-v8-0-903343d91bc3@kernel.org> In-Reply-To: <20241001-mgtime-v8-0-903343d91bc3@kernel.org> To: John Stultz , Thomas Gleixner , Stephen Boyd , Alexander Viro , Christian Brauner , Jan Kara , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Jonathan Corbet , Randy Dunlap , Chandan Babu R , "Darrick J. Wong" , Theodore Ts'o , Andreas Dilger , Chris Mason , Josef Bacik , David Sterba , Hugh Dickins , Andrew Morton , Chuck Lever , Vadim Fedorenko Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-mm@kvack.org, Jeff Layton X-Mailer: b4 0.14.1 X-Developer-Signature: v=1; a=openpgp-sha256; l=4015; i=jlayton@kernel.org; h=from:subject:message-id; bh=JL2gW+C3kDxbRAGj0jMp5iB8JHuDuhS4rvTtieX78oY=; b=owEBbQKS/ZANAwAIAQAOaEEZVoIVAcsmYgBm+9X6x1c8e9tak6oUEGlf0VU1qI9Vs0dKdL9Nd tgbNV9wo0aJAjMEAAEIAB0WIQRLwNeyRHGyoYTq9dMADmhBGVaCFQUCZvvV+gAKCRAADmhBGVaC Fc1QD/9eMcfRLjkeM4PSq5q9wbdZwKH0ZnxF0our+6FybuPq3dyRBmPN35tLdFGBtPY7yqdWFwS Rs/LS0WNRMUDhr1mdiuuzBDAl87afaQm6m0Ss/fKkpUFhmk/6FI30AQA1Y6CGK6rBPZYvpRMd+t xgQ8SEf51BB4aQuerAYSVbDxfIaQqxooQW4UxsVhihhRpZSz79bvs9BpfTRl7CbRAPptD7zgobF R7mUD1bo7p1UmgGdLuhyprr+Jx7N7pdA9YQpQ08sy/92KZ+vcdGFCcsOkuq10gXYaRdVyf/PRfC rRDl9JHOqi1KNQBD9zb4sWygsFJGWWPQ2CW9bYimEWy0wCKUZoEouWvbzEq4spMhwAoFngdHDsS Bz0hFemqy9Xm0kWfhA2Nfr2napvBTjUBhmHeTbT55Nfpt1HF/UZUInHDF9AdCKxXHuQ+vQSgAhY zjBXOOKmI6/5Qt1tfZh/5yUgcInlYWTFh5JfBEPO8heF5DaWba7euvt0rMdn7cjfKd4yUuyR29s oxz6la25xBwO/N9eJtho78xkfye21spBGiN+rs91RekoH21kMmErBfxm5wrhx2AsEg1f8GUUDnQ DlZ8agBEXLchtmo9h03ROpDuc/ljD3laUG05Nf9rBOcUWDcUaN4Fh4A5/crNSXCfsrkG2Taaleh he48A3qyAV/DzSQ== X-Developer-Key: i=jlayton@kernel.org; a=openpgp; fpr=4BC0D7B24471B2A184EAF5D3000E684119568215 The mgtime_floor value is a global variable for tracking the latest fine-grained timestamp handed out. Because it's a global, track the number of times that a new floor value is assigned. Add a new percpu counter to the timekeeping code to track the number of floor swap events that have occurred. Display that as a fourth integer in /sys/kernel/debug/multigrain_timestamps. Tested-by: Randy Dunlap # documentation bits Signed-off-by: Jeff Layton --- fs/inode.c | 5 +++-- include/linux/timekeeping.h | 1 + kernel/time/timekeeping.c | 1 + kernel/time/timekeeping_debug.c | 13 +++++++++++++ kernel/time/timekeeping_internal.h | 9 +++++++++ 5 files changed, 27 insertions(+), 2 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index e46f7170851b..93a9365cc22d 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -145,9 +145,10 @@ static int mgts_show(struct seq_file *s, void *p) unsigned long ctime_updates =3D get_mg_ctime_updates(); unsigned long ctime_swaps =3D get_mg_ctime_swaps(); unsigned long fine_stamps =3D get_mg_fine_stamps(); + unsigned long floor_swaps =3D timekeeping_get_mg_floor_swaps(); =20 - seq_printf(s, "%lu %lu %lu\n", - ctime_updates, ctime_swaps, fine_stamps); + seq_printf(s, "%lu %lu %lu %lu\n", + ctime_updates, ctime_swaps, fine_stamps, floor_swaps); return 0; } =20 diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h index 7aa85246c183..84a035e86ac8 100644 --- a/include/linux/timekeeping.h +++ b/include/linux/timekeeping.h @@ -48,6 +48,7 @@ extern void ktime_get_coarse_real_ts64(struct timespec64 = *ts); /* Multigrain timestamp interfaces */ extern void ktime_get_coarse_real_ts64_mg(struct timespec64 *ts); extern void ktime_get_real_ts64_mg(struct timespec64 *ts); +extern unsigned long timekeeping_get_mg_floor_swaps(void); =20 void getboottime64(struct timespec64 *ts); =20 diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 37004a4758cf..c8a934c1c8aa 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -2478,6 +2478,7 @@ void ktime_get_real_ts64_mg(struct timespec64 *ts) if (atomic64_try_cmpxchg(&mg_floor, &old, mono)) { ts->tv_nsec =3D 0; timespec64_add_ns(ts, nsecs); + timekeeping_inc_mg_floor_swaps(); } else { /* * Something has changed mg_floor since "old" was diff --git a/kernel/time/timekeeping_debug.c b/kernel/time/timekeeping_debu= g.c index b73e8850e58d..b731621ad811 100644 --- a/kernel/time/timekeeping_debug.c +++ b/kernel/time/timekeeping_debug.c @@ -17,6 +17,9 @@ =20 #define NUM_BINS 32 =20 +/* incremented every time mg_floor is updated */ +DEFINE_PER_CPU(unsigned long, timekeeping_mg_floor_swaps); + static unsigned int sleep_time_bin[NUM_BINS] =3D {0}; =20 static int tk_debug_sleep_time_show(struct seq_file *s, void *data) @@ -53,3 +56,13 @@ void tk_debug_account_sleep_time(const struct timespec64= *t) (s64)t->tv_sec, t->tv_nsec / NSEC_PER_MSEC); } =20 +unsigned long timekeeping_get_mg_floor_swaps(void) +{ + int i; + unsigned long sum =3D 0; + + for_each_possible_cpu(i) + sum +=3D per_cpu(timekeeping_mg_floor_swaps, i); + return sum < 0 ? 0 : sum; +} + diff --git a/kernel/time/timekeeping_internal.h b/kernel/time/timekeeping_i= nternal.h index 4ca2787d1642..f53e76d5ee7c 100644 --- a/kernel/time/timekeeping_internal.h +++ b/kernel/time/timekeeping_internal.h @@ -10,9 +10,18 @@ * timekeeping debug functions */ #ifdef CONFIG_DEBUG_FS +DECLARE_PER_CPU(unsigned long, timekeeping_mg_floor_swaps); +static inline void timekeeping_inc_mg_floor_swaps(void) +{ + this_cpu_inc(timekeeping_mg_floor_swaps); +} + extern void tk_debug_account_sleep_time(const struct timespec64 *t); #else #define tk_debug_account_sleep_time(x) +static inline void timekeeping_inc_mg_floor_swaps(void) +{ +} #endif =20 #ifdef CONFIG_CLOCKSOURCE_VALIDATE_LAST_CYCLE --=20 2.46.2