From patchwork Wed Oct 2 18:49:35 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 13820310 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 58DCA21BAFB; Wed, 2 Oct 2024 18:50:11 +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=1727895012; cv=none; b=QnJd/pwU4Nipy7lvdPgikx9A6K9hI8vHIe41XzgiIq9KACq37YHQ5cQWahKkGKaI+JSth9+N7rALw+RYZB/9Z/4Zs0dUVd6fA0GAXJOInDUxOvj631npXtZy5DR0odiLEBAE8KWRelddkE4PFpTUkPw+sOlpAWzuYcQWiGCr+ek= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727895012; c=relaxed/simple; bh=FAEtrer/wxauwCEIrxfqdGNO00oW6MLUKCATzsbfXLI=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=D4Pj5W9hv5/Y72fcNPnXKuHwpHh/w/tJQf0s+ep4mnuEO1LFj3DzGwVEnv7SmKCWgQcR/i+QiZTmeMI9Q+EsvEjf8kPfEN9ojpJil6jMvZcv8ODC60AdBjdUGSENO67h0ScUS1l9/xtdgrp72p7F5eYVcP1Opm0M34Kp4RgacHg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fpAwcvtX; 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="fpAwcvtX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5535EC4CECE; Wed, 2 Oct 2024 18:50:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727895011; bh=FAEtrer/wxauwCEIrxfqdGNO00oW6MLUKCATzsbfXLI=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=fpAwcvtXD8gfXd+PRfOJ+eqsAUC72UscmwOYTBkuWJzbNNB4lEzo1BS9ykVMuQnzL I1anPto2AGBaLRz0Q+v3kDGQ8gWnGoPQTXUPSI9cfLGMpD3YnDpElJIrvmztyv6fMA QkHfGNeYclB/Qh3WRx1AfgQR0AKMYASoueR/HIBIZI1s2l9Xk2eqtyQkwL7IEI9Ego z8V83SwLi6tetczfYZ8miK3HwZNhMdeRP5cZe9WWmUP8dRbxXA09wyqwaNZdzCUj54 bJ/UxGRxJ085xIavpXrM3j0Z8mU/0QaSxe60rs/RYwR4Ab5Gul1xTwAFM43qml1b0d ry3eRS2sLlcWQ== From: Jeff Layton Date: Wed, 02 Oct 2024 14:49:35 -0400 Subject: [PATCH v9 07/12] timekeeping: add percpu counter for tracking floor swap events Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20241002-mgtime-v9-7-77e2baad57ac@kernel.org> References: <20241002-mgtime-v9-0-77e2baad57ac@kernel.org> In-Reply-To: <20241002-mgtime-v9-0-77e2baad57ac@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=4023; i=jlayton@kernel.org; h=from:subject:message-id; bh=FAEtrer/wxauwCEIrxfqdGNO00oW6MLUKCATzsbfXLI=; b=owEBbQKS/ZANAwAIAQAOaEEZVoIVAcsmYgBm/ZXMjLTfOiELFgyyDhd7gxbf4QE/JplmWCrQl HH5l56MD7SJAjMEAAEIAB0WIQRLwNeyRHGyoYTq9dMADmhBGVaCFQUCZv2VzAAKCRAADmhBGVaC FTH4D/kBv/Pckw5cqhCOB6dqYpa9qps2pXUNeKu2ETbMkfkS9X4q8TDcK80iM/edS2D9zjeuEAx dlLzn6rHLiWHxyauX5kFVWDTjMISqrraFxbEX9RA1FI8Kr1OIJoYof20HadOT2uApXtnswJL680 NjBU3qCtIic1QfxkOs3kfme3JJ7lS917DSFkrEuwGKGCMfV2ug44Ka+EmlyRaTHgaMMT/yjqTKT Z3ECTJCfmKPRbpbrjvphcx5vMRKpngzgPq6tlDx8qvm0hGao4wNR+cl2g4sqGFvATw4x7C/BT6v mSAESlBpjD7XWrhL2IvmIP6NjtPjknSe84QJjoJTDWpAeo6YZ1DzWja546B7NfCfS63N7KJ4l2+ SRs9p4DneuGAgiH9xMkjR6Z7CpghFFebG2X7XeOOL7Qp9GR7VMiOvH859wZlSSMT/VHQStfhySU xgzaRuUDYuuFeDmShYt4BQ4n3eprchbdIWH9FlQ6LcH16YHY2jhkCHS8EkdEIfFk/idMVsGaIuw OhTptpcKtQ7BUB7DwnZ8OTq3UykDihR1UKba07UMvN3l5JRyO883UWIqauXfGygHnzK0ZBENuFO DkEoXCUxw3nxHTNqxHzaRdKWd4xbqcNWWrf/YtQj+A1TP7lia9MoZdQJwqzhmLEUnCClCNEoQTy 57Aq63B6eJV6wUQ== 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 0223f8ec3cfb..1edac9ab1ecc 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 = get_mg_ctime_updates(); unsigned long ctime_swaps = get_mg_ctime_swaps(); unsigned long fine_stamps = get_mg_fine_stamps(); + unsigned long floor_swaps = timekeeping_get_mg_floor_swaps(); - 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; } 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); void getboottime64(struct timespec64 *ts); diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index ebfe846ebde3..e8b713e8ce55 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -2488,6 +2488,7 @@ void ktime_get_real_ts64_mg(struct timespec64 *ts) if (atomic64_try_cmpxchg(&mg_floor, &old, mono)) { ts->tv_nsec = 0; timespec64_add_ns(ts, nsecs); + timekeeping_inc_mg_floor_swaps(); } else { /* * Another task changed mg_floor since "old" was fetched. diff --git a/kernel/time/timekeeping_debug.c b/kernel/time/timekeeping_debug.c index b73e8850e58d..b731621ad811 100644 --- a/kernel/time/timekeeping_debug.c +++ b/kernel/time/timekeeping_debug.c @@ -17,6 +17,9 @@ #define NUM_BINS 32 +/* incremented every time mg_floor is updated */ +DEFINE_PER_CPU(unsigned long, timekeeping_mg_floor_swaps); + static unsigned int sleep_time_bin[NUM_BINS] = {0}; 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); } +unsigned long timekeeping_get_mg_floor_swaps(void) +{ + int i; + unsigned long sum = 0; + + for_each_possible_cpu(i) + sum += per_cpu(timekeeping_mg_floor_swaps, i); + return sum < 0 ? 0 : sum; +} + diff --git a/kernel/time/timekeeping_internal.h b/kernel/time/timekeeping_internal.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 #ifdef CONFIG_CLOCKSOURCE_VALIDATE_LAST_CYCLE