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From: "Ahmed S. Darwish" <a.darwish@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	"Sebastian A. Siewior" <bigeasy@linutronix.de>,
	Steven Rostedt <rostedt@goodmis.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"Ahmed S. Darwish" <a.darwish@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
	linux-mm@kvack.org
Subject: [PATCH v1 02/25] mm/swap: Don't abuse the seqcount latching API
Date: Tue, 19 May 2020 23:45:24 +0200	[thread overview]
Message-ID: <20200519214547.352050-3-a.darwish@linutronix.de> (raw)
In-Reply-To: <20200519214547.352050-1-a.darwish@linutronix.de>

Commit eef1a429f234 ("mm/swap.c: piggyback lru_add_drain_all() calls")
implemented an optimization mechanism to exit the to-be-started LRU
drain operation (name it A) if another drain operation *started and
finished* while (A) was blocked on the LRU draining mutex.

This was done through a seqcount latch, which is an abuse of its
semantics:

  1. Seqcount latching should be used for the purpose of switching
     between two storage places with sequence protection to allow
     interruptible, preemptible writer sections. The optimization
     mechanism has absolutely nothing to do with that.

  2. The used raw_write_seqcount_latch() has two smp write memory
     barriers to always insure one consistent storage place out of the
     two storage places available. This extra smp_wmb() is redundant for
     the optimization use case.

Beside the API abuse, the semantics of a latch sequence counter was
force fitted into the optimization. What was actually meant is to track
generations of LRU draining operations, where "current lru draining
generation = x" implies that all generations 0 < n <= x are already
*scheduled* for draining.

Remove the conceptually-inappropriate seqcount latch usage and manually
implement the optimization using a counter and SMP memory barriers.

Link: https://lkml.kernel.org/r/CALYGNiPSr-cxV9MX9czaVh6Wz_gzSv3H_8KPvgjBTGbJywUJpA@mail.gmail.com
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
---
 mm/swap.c | 57 +++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 47 insertions(+), 10 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index bf9a79fed62d..d6910eeed43d 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -713,10 +713,20 @@ static void lru_add_drain_per_cpu(struct work_struct *dummy)
  */
 void lru_add_drain_all(void)
 {
-	static seqcount_t seqcount = SEQCNT_ZERO(seqcount);
-	static DEFINE_MUTEX(lock);
+	/*
+	 * lru_drain_gen - Current generation of pages that could be in vectors
+	 *
+	 * (A) Definition: lru_drain_gen = x implies that all generations
+	 *     0 < n <= x are already scheduled for draining.
+	 *
+	 * This is an optimization for the highly-contended use case where a
+	 * user space workload keeps constantly generating a flow of pages
+	 * for each CPU.
+	 */
+	static unsigned int lru_drain_gen;
 	static struct cpumask has_work;
-	int cpu, seq;
+	static DEFINE_MUTEX(lock);
+	int cpu, this_gen;
 
 	/*
 	 * Make sure nobody triggers this path before mm_percpu_wq is fully
@@ -725,21 +735,48 @@ void lru_add_drain_all(void)
 	if (WARN_ON(!mm_percpu_wq))
 		return;
 
-	seq = raw_read_seqcount_latch(&seqcount);
+	/*
+	 * (B) Cache the LRU draining generation number
+	 *
+	 * smp_rmb() ensures that the counter is loaded before the mutex is
+	 * taken. It pairs with the smp_wmb() inside the mutex critical section
+	 * at (D).
+	 */
+	this_gen = READ_ONCE(lru_drain_gen);
+	smp_rmb();
 
 	mutex_lock(&lock);
 
 	/*
-	 * Piggyback on drain started and finished while we waited for lock:
-	 * all pages pended at the time of our enter were drained from vectors.
+	 * (C) Exit the draining operation if a newer generation, from another
+	 * lru_add_drain_all(), was already scheduled for draining. Check (A).
 	 */
-	if (__read_seqcount_retry(&seqcount, seq))
+	if (unlikely(this_gen != lru_drain_gen))
 		goto done;
 
-	raw_write_seqcount_latch(&seqcount);
+	/*
+	 * (D) Increment generation number
+	 *
+	 * Pairs with READ_ONCE() and smp_rmb() at (B), outside of the critical
+	 * section.
+	 *
+	 * This pairing must be done here, before the for_each_online_cpu loop
+	 * below which drains the page vectors.
+	 *
+	 * Let x, y, and z represent some system CPU numbers, where x < y < z.
+	 * Assume CPU #z is is in the middle of the for_each_online_cpu loop
+	 * below and has already reached CPU #y's per-cpu data. CPU #x comes
+	 * along, adds some pages to its per-cpu vectors, then calls
+	 * lru_add_drain_all().
+	 *
+	 * If the paired smp_wmb() below is done at any later step, e.g. after
+	 * the loop, CPU #x will just exit at (C) and miss flushing out all of
+	 * its added pages.
+	 */
+	WRITE_ONCE(lru_drain_gen, lru_drain_gen + 1);
+	smp_wmb();
 
 	cpumask_clear(&has_work);
-
 	for_each_online_cpu(cpu) {
 		struct work_struct *work = &per_cpu(lru_add_drain_work, cpu);
 
@@ -766,7 +803,7 @@ void lru_add_drain_all(void)
 {
 	lru_add_drain();
 }
-#endif
+#endif /* CONFIG_SMP */
 
 /**
  * release_pages - batched put_page()
-- 
2.20.1


  parent reply	other threads:[~2020-05-19 21:46 UTC|newest]

Thread overview: 258+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-19 21:45 [PATCH v1 00/25] seqlock: Extend seqcount API with associated locks Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 01/25] net: core: device_rename: Use rwsem instead of a seqcount Ahmed S. Darwish
2020-05-19 22:01   ` Stephen Hemminger
2020-05-19 22:23     ` Thomas Gleixner
2020-05-19 23:11       ` Stephen Hemminger
2020-05-19 23:42         ` Thomas Gleixner
2020-05-20  0:06           ` Stephen Hemminger
2020-05-20  1:55             ` Thomas Gleixner
2020-05-20  2:57           ` David Miller
2020-05-20  3:18             ` Eric Dumazet
2020-05-20  4:36               ` Stephen Hemminger
2020-05-20 19:37             ` Thomas Gleixner
2020-05-20 21:36               ` Stephen Hemminger
2020-05-20  2:01   ` Eric Dumazet
2020-05-20  6:42     ` Ahmed S. Darwish
2020-05-20 12:51       ` Eric Dumazet
2020-06-03 14:33         ` Ahmed S. Darwish
2020-05-20 14:37   ` Dan Carpenter
2020-05-25 16:22     ` Ahmed S. Darwish
2020-05-19 21:45 ` Ahmed S. Darwish [this message]
2020-05-20 12:22   ` [PATCH v1 02/25] mm/swap: Don't abuse the seqcount latching API Konstantin Khlebnikov
2020-05-20 13:05     ` Peter Zijlstra
2020-05-22 14:57   ` Peter Zijlstra
2020-05-22 15:17     ` Sebastian A. Siewior
2020-05-22 16:23       ` Peter Zijlstra
2020-05-25 15:24     ` Ahmed S. Darwish
2020-05-25 15:45       ` Peter Zijlstra
2020-05-25 16:10     ` John Ogness
2020-09-10 15:08       ` [tip: locking/core] mm/swap: Do not abuse the seqcount_t " tip-bot2 for Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 03/25] net: phy: fixed_phy: Remove unused seqcount Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 04/25] block: nr_sects_write(): Disable preemption on seqcount write Ahmed S. Darwish
2020-05-22 16:39   ` Peter Zijlstra
2020-05-25  9:56     ` Ahmed S. Darwish
     [not found]   ` <20200522001237.A00E8206BE@mail.kernel.org>
2020-05-25 10:12     ` Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 05/25] u64_stats: Document writer non-preemptibility requirement Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 06/25] dma-buf: Remove custom seqcount lockdep class key Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 07/25] lockdep: Add preemption disabled assertion API Ahmed S. Darwish
2020-05-22 17:55   ` Peter Zijlstra
2020-05-23 14:59     ` Sebastian A. Siewior
2020-05-23 22:41       ` Peter Zijlstra
2020-05-24 10:50         ` Sebastian A. Siewior
2020-05-25 10:22         ` Peter Zijlstra
2020-05-26  0:52           ` Ahmed S. Darwish
2020-05-26  8:13             ` Peter Zijlstra
2020-05-26  9:45               ` Ahmed S. Darwish
2020-06-03 15:30               ` Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 08/25] seqlock: lockdep assert non-preemptibility on seqcount_t write Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 09/25] Documentation: locking: Describe seqlock design and usage Ahmed S. Darwish
2020-05-22 18:01   ` Peter Zijlstra
2020-05-22 22:24     ` Steven Rostedt
2020-05-25 10:50       ` Ahmed S. Darwish
2020-05-25 11:02         ` Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 10/25] seqlock: Add RST directives to kernel-doc code samples and notes Ahmed S. Darwish
2020-05-22 18:02   ` Peter Zijlstra
2020-05-22 18:03     ` Peter Zijlstra
2020-05-22 18:26       ` Thomas Gleixner
2020-05-22 18:32         ` Peter Zijlstra
2020-05-25  9:36           ` Ahmed S. Darwish
2020-05-25 13:44             ` Peter Zijlstra
2020-05-25 14:07               ` Peter Zijlstra
2020-05-19 21:45 ` [PATCH v1 11/25] seqlock: Add missing kernel-doc annotations Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 12/25] seqlock: Extend seqcount API with associated locks Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 13/25] dma-buf: Use sequence counter with associated wound/wait mutex Ahmed S. Darwish
2020-05-20 10:48   ` Christian König
2020-05-21  0:09     ` Ahmed S. Darwish
2020-05-21 13:20       ` Christian König
2020-05-19 21:45 ` [PATCH v1 14/25] sched: tasks: Use sequence counter with associated spinlock Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 15/25] netfilter: conntrack: " Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 16/25] netfilter: nft_set_rbtree: Use sequence counter with associated rwlock Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 17/25] xfrm: policy: Use sequence counters with associated lock Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 18/25] timekeeping: Use sequence counter with associated raw spinlock Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 19/25] vfs: Use sequence counter with associated spinlock Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 20/25] raid5: " Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 21/25] iocost: " Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 22/25] NFSv4: " Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 23/25] userfaultfd: " Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 24/25] kvm/eventfd: " Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 25/25] hrtimer: Use sequence counter with associated raw spinlock Ahmed S. Darwish
2020-06-08  0:57 ` [PATCH v2 00/18] seqlock: Extend seqcount API with associated locks Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 01/18] Documentation: locking: Describe seqlock design and usage Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 02/18] seqlock: Properly format kernel-doc code samples Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 03/18] seqlock: Add missing kernel-doc annotations Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 04/18] seqlock: Extend seqcount API with associated locks Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 05/18] dma-buf: Remove custom seqcount lockdep class key Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 06/18] dma-buf: Use sequence counter with associated wound/wait mutex Ahmed S. Darwish
2020-06-08 14:32     ` Daniel Vetter
2020-06-08  0:57   ` [PATCH v2 07/18] sched: tasks: Use sequence counter with associated spinlock Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 08/18] netfilter: conntrack: " Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 09/18] netfilter: nft_set_rbtree: Use sequence counter with associated rwlock Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 10/18] xfrm: policy: Use sequence counters with associated lock Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 11/18] timekeeping: Use sequence counter with associated raw spinlock Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 12/18] vfs: Use sequence counter with associated spinlock Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 13/18] raid5: " Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 14/18] iocost: " Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 15/18] NFSv4: " Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 16/18] userfaultfd: " Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 17/18] kvm/eventfd: " Ahmed S. Darwish
2020-06-08 12:57     ` Paolo Bonzini
2020-06-08  0:57   ` [PATCH v2 18/18] hrtimer: Use sequence counter with associated raw spinlock Ahmed S. Darwish
2020-06-30  5:44 ` [PATCH v3 00/20] seqlock: Extend seqcount API with associated locks Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 01/20] Documentation: locking: Describe seqlock design and usage Ahmed S. Darwish
2020-07-06 21:04     ` Peter Zijlstra
2020-07-06 21:12       ` Jonathan Corbet
2020-07-06 21:16       ` Peter Zijlstra
2020-07-07 10:12       ` Ahmed S. Darwish
2020-07-07 12:47         ` Peter Zijlstra
2020-06-30  5:44   ` [PATCH v3 02/20] seqlock: Properly format kernel-doc code samples Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 03/20] seqlock: Add missing kernel-doc annotations Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 04/20] lockdep: Add preemption enabled/disabled assertion APIs Ahmed S. Darwish
2020-07-06 20:50     ` Peter Zijlstra
2020-07-07  7:34       ` Sebastian A. Siewior
2020-06-30  5:44   ` [PATCH v3 05/20] seqlock: lockdep assert non-preemptibility on seqcount_t write Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 06/20] seqlock: Extend seqcount API with associated locks Ahmed S. Darwish
2020-07-06 21:21     ` Peter Zijlstra
2020-07-07  8:40       ` Ahmed S. Darwish
2020-07-07 13:04         ` Peter Zijlstra
2020-07-07 14:37           ` Peter Zijlstra
2020-07-08  9:12             ` Peter Zijlstra
2020-07-08 10:43               ` Ahmed S. Darwish
2020-07-08 10:33             ` Ahmed S. Darwish
2020-07-08 12:29               ` Peter Zijlstra
2020-07-08 14:13                 ` Peter Zijlstra
2020-07-08 14:25                   ` Peter Zijlstra
2020-07-08 15:09                 ` Ahmed S. Darwish
2020-07-08 15:35                   ` Peter Zijlstra
2020-07-08 15:58                     ` Ahmed S. Darwish
2020-07-08 16:16                       ` Peter Zijlstra
2020-07-08 16:18                       ` Peter Zijlstra
2020-07-08 16:01                     ` Peter Zijlstra
2020-06-30  5:44   ` [PATCH v3 07/20] dma-buf: Remove custom seqcount lockdep class key Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 08/20] dma-buf: Use sequence counter with associated wound/wait mutex Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 09/20] sched: tasks: Use sequence counter with associated spinlock Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 10/20] netfilter: conntrack: " Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 11/20] netfilter: nft_set_rbtree: Use sequence counter with associated rwlock Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 12/20] xfrm: policy: Use sequence counters with associated lock Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 13/20] timekeeping: Use sequence counter with associated raw spinlock Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 14/20] vfs: Use sequence counter with associated spinlock Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 15/20] raid5: " Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 16/20] iocost: " Ahmed S. Darwish
2020-06-30  7:11     ` Daniel Wagner
2020-06-30  5:44   ` [PATCH v3 17/20] NFSv4: " Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 18/20] userfaultfd: " Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 19/20] kvm/eventfd: " Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 20/20] hrtimer: Use sequence counter with associated raw spinlock Ahmed S. Darwish
2020-07-20 15:55 ` [PATCH v4 00/24] seqlock: Extend seqcount API with associated locks Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 01/24] Documentation: locking: Describe seqlock design and usage Ahmed S. Darwish
2020-07-21  1:35     ` Steven Rostedt
2020-07-21  1:37       ` Steven Rostedt
2020-07-21  5:34       ` Ahmed S. Darwish
2020-07-21  1:44     ` Steven Rostedt
2020-07-21  1:51       ` Steven Rostedt
2020-07-21  7:15         ` Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 02/24] seqlock: Properly format kernel-doc code samples Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 03/24] seqlock: seqcount_t latch: End read sections with read_seqcount_retry() Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 04/24] seqlock: Reorder seqcount_t and seqlock_t API definitions Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 05/24] seqlock: Add kernel-doc for seqcount_t and seqlock_t APIs Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 06/24] seqlock: Implement raw_seqcount_begin() in terms of raw_read_seqcount() Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 07/24] lockdep: Add preemption enabled/disabled assertion APIs Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 08/24] seqlock: lockdep assert non-preemptibility on seqcount_t write Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-08-08 23:21     ` [PATCH v4 08/24] " Guenter Roeck
2020-08-08 23:23       ` Guenter Roeck
2020-08-09 18:42       ` Ahmed S. Darwish
2020-08-10  8:59         ` Greg KH
2020-08-10  9:48           ` peterz
2020-08-10 10:03             ` Greg KH
2020-08-10  9:54           ` [PATCH] Revert "seqlock: lockdep assert non-preemptibility on seqcount_t write" Ahmed S. Darwish
2020-08-10 10:05             ` Greg KH
2020-08-10 10:35               ` Ahmed S. Darwish
2020-08-10 14:10               ` Guenter Roeck
2020-08-18 22:51                 ` Valdis Klētnieks
2020-08-19  0:56                   ` Guenter Roeck
2020-08-19  7:00                     ` Sebastian Andrzej Siewior
2020-08-19  7:34                       ` Valdis Klētnieks
2020-08-19 16:15                         ` Guenter Roeck
2020-08-10 19:55           ` [PATCH v4 08/24] seqlock: lockdep assert non-preemptibility on seqcount_t write Thomas Gleixner
2020-08-11 10:06             ` Greg KH
2020-07-20 15:55   ` [PATCH v4 09/24] seqlock: Extend seqcount API with associated locks Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 10/24] seqlock: Align multi-line macros newline escapes at 72 columns Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 11/24] dma-buf: Remove custom seqcount lockdep class key Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 12/24] dma-buf: Use sequence counter with associated wound/wait mutex Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 13/24] sched: tasks: Use sequence counter with associated spinlock Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 14/24] netfilter: conntrack: " Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 15/24] netfilter: nft_set_rbtree: Use sequence counter with associated rwlock Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 16/24] xfrm: policy: Use sequence counters with associated lock Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 17/24] timekeeping: Use sequence counter with associated raw spinlock Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 18/24] vfs: Use sequence counter with associated spinlock Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 19/24] raid5: " Ahmed S. Darwish
2020-07-22  6:40     ` Song Liu
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 20/24] iocost: " Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 21/24] NFSv4: " Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 22/24] userfaultfd: " Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 23/24] kvm/eventfd: " Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 24/24] hrtimer: Use sequence counter with associated raw spinlock Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 16:49   ` [PATCH v4 00/24] seqlock: Extend seqcount API with associated locks Eric Biggers
2020-07-20 17:33     ` Ahmed S. Darwish
2020-08-27 11:40 ` [PATCH v1 0/8] seqlock: Introduce seqcount_latch_t Ahmed S. Darwish
2020-08-27 11:40   ` [PATCH v1 1/8] time/sched_clock: Use raw_read_seqcount_latch() during suspend Ahmed S. Darwish
2020-08-27 11:40   ` [PATCH v1 2/8] mm/swap: Do not abuse the seqcount_t latching API Ahmed S. Darwish
2020-08-27 11:40   ` [PATCH v1 3/8] seqlock: Introduce seqcount_latch_t Ahmed S. Darwish
2020-09-10 15:08     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-08-27 11:40   ` [PATCH v1 4/8] time/sched_clock: Use seqcount_latch_t Ahmed S. Darwish
2020-09-10 15:08     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-08-27 11:40   ` [PATCH v1 5/8] timekeeping: " Ahmed S. Darwish
2020-09-10 15:08     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-08-27 11:40   ` [PATCH v1 6/8] x86/tsc: " Ahmed S. Darwish
2020-09-04  7:41     ` peterz
2020-09-04  8:03       ` peterz
2020-09-07 16:29         ` Ahmed S. Darwish
2020-09-07 17:30           ` peterz
2020-09-08  6:23             ` Ahmed S. Darwish
2020-09-10 15:08     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-08-27 11:40   ` [PATCH v1 7/8] rbtree_latch: " Ahmed S. Darwish
2020-09-10 15:08     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-08-27 11:40   ` [PATCH v1 8/8] seqlock: seqcount latch APIs: Only allow seqcount_latch_t Ahmed S. Darwish
2020-09-10 15:08     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-08-28  1:07 ` [PATCH v1 0/5] seqlock: Introduce PREEMPT_RT support Ahmed S. Darwish
2020-08-28  1:07   ` [PATCH v1 1/5] seqlock: seqcount_LOCKTYPE_t: Standardize naming convention Ahmed S. Darwish
2020-08-28  8:18     ` peterz
2020-08-28  8:24       ` Ahmed S. Darwish
2020-08-28  1:07   ` [PATCH v1 2/5] seqlock: Use unique prefix for seqcount_t property accessors Ahmed S. Darwish
2020-08-28  8:27     ` peterz
2020-08-28  8:59       ` Ahmed S. Darwish
2020-08-28  1:07   ` [PATCH v1 3/5] seqlock: seqcount_t: Implement all read APIs as statement expressions Ahmed S. Darwish
2020-08-28  8:30     ` peterz
2020-08-28  8:37       ` Ahmed S. Darwish
2020-08-28  1:07   ` [PATCH v1 4/5] seqlock: seqcount_LOCKTYPE_t: Introduce PREEMPT_RT support Ahmed S. Darwish
2020-08-28  8:57     ` peterz
2020-08-28  8:59     ` peterz
2020-08-28  9:31       ` Ahmed S. Darwish
2020-08-28 14:36         ` Ahmed S. Darwish
2020-08-28  1:07   ` [PATCH v1 5/5] seqlock: PREEMPT_RT: Do not starve seqlock_t writers Ahmed S. Darwish
2020-09-04  6:52   ` [PATCH v1 0/5] seqlock: Introduce PREEMPT_RT support peterz
2020-09-04  7:30     ` Ahmed S. Darwish
2020-09-10 15:08 ` [tip: locking/core] seqlock: seqcount_LOCKNAME_t: " tip-bot2 for Ahmed S. Darwish

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