* [PATCH v1 20/25] raid5: Use sequence counter with associated spinlock [not found] <20200519214547.352050-1-a.darwish@linutronix.de> @ 2020-05-19 21:45 ` Ahmed S. Darwish [not found] ` <20200608005729.1874024-1-a.darwish@linutronix.de> ` (2 subsequent siblings) 3 siblings, 0 replies; 5+ messages in thread From: Ahmed S. Darwish @ 2020-05-19 21:45 UTC (permalink / raw) To: Peter Zijlstra, Ingo Molnar, Will Deacon Cc: Thomas Gleixner, Paul E. McKenney, Sebastian A. Siewior, Steven Rostedt, LKML, Ahmed S. Darwish, Song Liu, linux-raid A sequence counter write side critical section must be protected by some form of locking to serialize writers. A plain seqcount_t does not contain the information of which lock must be held when entering a write side critical section. Use the new seqcount_spinlock_t data type, which allows to associate a spinlock with the sequence counter. This enables lockdep to verify that the spinlock used for writer serialization is held when the write side critical section is entered. If lockdep is disabled this lock association is compiled out and has neither storage size nor runtime overhead. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> --- drivers/md/raid5.c | 2 +- drivers/md/raid5.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index ba00e9877f02..69f31c675b58 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -6929,7 +6929,7 @@ static struct r5conf *setup_conf(struct mddev *mddev) } else goto abort; spin_lock_init(&conf->device_lock); - seqcount_init(&conf->gen_lock); + seqcount_spinlock_init(&conf->gen_lock, &conf->device_lock); mutex_init(&conf->cache_size_mutex); init_waitqueue_head(&conf->wait_for_quiescent); init_waitqueue_head(&conf->wait_for_stripe); diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h index f90e0704bed9..a2c9e9e9f5ac 100644 --- a/drivers/md/raid5.h +++ b/drivers/md/raid5.h @@ -589,7 +589,7 @@ struct r5conf { int prev_chunk_sectors; int prev_algo; short generation; /* increments with every reshape */ - seqcount_t gen_lock; /* lock against generation changes */ + seqcount_spinlock_t gen_lock; /* lock against generation changes */ unsigned long reshape_checkpoint; /* Time we last updated * metadata */ long long min_offset_diff; /* minimum difference between -- 2.20.1 ^ permalink raw reply related [flat|nested] 5+ messages in thread
[parent not found: <20200608005729.1874024-1-a.darwish@linutronix.de>]
* [PATCH v2 13/18] raid5: Use sequence counter with associated spinlock [not found] ` <20200608005729.1874024-1-a.darwish@linutronix.de> @ 2020-06-08 0:57 ` Ahmed S. Darwish 0 siblings, 0 replies; 5+ messages in thread From: Ahmed S. Darwish @ 2020-06-08 0:57 UTC (permalink / raw) To: Peter Zijlstra, Ingo Molnar, Will Deacon Cc: Thomas Gleixner, Paul E. McKenney, Sebastian A. Siewior, Steven Rostedt, LKML, Ahmed S. Darwish, Song Liu, linux-raid A sequence counter write side critical section must be protected by some form of locking to serialize writers. A plain seqcount_t does not contain the information of which lock must be held when entering a write side critical section. Use the new seqcount_spinlock_t data type, which allows to associate a spinlock with the sequence counter. This enables lockdep to verify that the spinlock used for writer serialization is held when the write side critical section is entered. If lockdep is disabled this lock association is compiled out and has neither storage size nor runtime overhead. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> --- drivers/md/raid5.c | 2 +- drivers/md/raid5.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index ba00e9877f02..69f31c675b58 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -6929,7 +6929,7 @@ static struct r5conf *setup_conf(struct mddev *mddev) } else goto abort; spin_lock_init(&conf->device_lock); - seqcount_init(&conf->gen_lock); + seqcount_spinlock_init(&conf->gen_lock, &conf->device_lock); mutex_init(&conf->cache_size_mutex); init_waitqueue_head(&conf->wait_for_quiescent); init_waitqueue_head(&conf->wait_for_stripe); diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h index f90e0704bed9..a2c9e9e9f5ac 100644 --- a/drivers/md/raid5.h +++ b/drivers/md/raid5.h @@ -589,7 +589,7 @@ struct r5conf { int prev_chunk_sectors; int prev_algo; short generation; /* increments with every reshape */ - seqcount_t gen_lock; /* lock against generation changes */ + seqcount_spinlock_t gen_lock; /* lock against generation changes */ unsigned long reshape_checkpoint; /* Time we last updated * metadata */ long long min_offset_diff; /* minimum difference between -- 2.20.1 ^ permalink raw reply related [flat|nested] 5+ messages in thread
[parent not found: <20200630054452.3675847-1-a.darwish@linutronix.de>]
* [PATCH v3 15/20] raid5: Use sequence counter with associated spinlock [not found] ` <20200630054452.3675847-1-a.darwish@linutronix.de> @ 2020-06-30 5:44 ` Ahmed S. Darwish 0 siblings, 0 replies; 5+ messages in thread From: Ahmed S. Darwish @ 2020-06-30 5:44 UTC (permalink / raw) To: Peter Zijlstra, Ingo Molnar, Will Deacon Cc: Thomas Gleixner, Paul E. McKenney, Sebastian A. Siewior, Steven Rostedt, LKML, Ahmed S. Darwish, Song Liu, linux-raid A sequence counter write side critical section must be protected by some form of locking to serialize writers. A plain seqcount_t does not contain the information of which lock must be held when entering a write side critical section. Use the new seqcount_spinlock_t data type, which allows to associate a spinlock with the sequence counter. This enables lockdep to verify that the spinlock used for writer serialization is held when the write side critical section is entered. If lockdep is disabled this lock association is compiled out and has neither storage size nor runtime overhead. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> --- drivers/md/raid5.c | 2 +- drivers/md/raid5.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index ab8067f9ce8c..892aefe88fa7 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -6935,7 +6935,7 @@ static struct r5conf *setup_conf(struct mddev *mddev) } else goto abort; spin_lock_init(&conf->device_lock); - seqcount_init(&conf->gen_lock); + seqcount_spinlock_init(&conf->gen_lock, &conf->device_lock); mutex_init(&conf->cache_size_mutex); init_waitqueue_head(&conf->wait_for_quiescent); init_waitqueue_head(&conf->wait_for_stripe); diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h index f90e0704bed9..a2c9e9e9f5ac 100644 --- a/drivers/md/raid5.h +++ b/drivers/md/raid5.h @@ -589,7 +589,7 @@ struct r5conf { int prev_chunk_sectors; int prev_algo; short generation; /* increments with every reshape */ - seqcount_t gen_lock; /* lock against generation changes */ + seqcount_spinlock_t gen_lock; /* lock against generation changes */ unsigned long reshape_checkpoint; /* Time we last updated * metadata */ long long min_offset_diff; /* minimum difference between -- 2.20.1 ^ permalink raw reply related [flat|nested] 5+ messages in thread
[parent not found: <20200720155530.1173732-1-a.darwish@linutronix.de>]
* [PATCH v4 19/24] raid5: Use sequence counter with associated spinlock [not found] ` <20200720155530.1173732-1-a.darwish@linutronix.de> @ 2020-07-20 15:55 ` Ahmed S. Darwish 2020-07-22 6:40 ` Song Liu 0 siblings, 1 reply; 5+ messages in thread From: Ahmed S. Darwish @ 2020-07-20 15:55 UTC (permalink / raw) To: Peter Zijlstra, Ingo Molnar, Will Deacon Cc: Thomas Gleixner, Paul E. McKenney, Sebastian A. Siewior, Steven Rostedt, LKML, Ahmed S. Darwish, Song Liu, linux-raid A sequence counter write side critical section must be protected by some form of locking to serialize writers. A plain seqcount_t does not contain the information of which lock must be held when entering a write side critical section. Use the new seqcount_spinlock_t data type, which allows to associate a spinlock with the sequence counter. This enables lockdep to verify that the spinlock used for writer serialization is held when the write side critical section is entered. If lockdep is disabled this lock association is compiled out and has neither storage size nor runtime overhead. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> --- drivers/md/raid5.c | 2 +- drivers/md/raid5.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index ab8067f9ce8c..892aefe88fa7 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -6935,7 +6935,7 @@ static struct r5conf *setup_conf(struct mddev *mddev) } else goto abort; spin_lock_init(&conf->device_lock); - seqcount_init(&conf->gen_lock); + seqcount_spinlock_init(&conf->gen_lock, &conf->device_lock); mutex_init(&conf->cache_size_mutex); init_waitqueue_head(&conf->wait_for_quiescent); init_waitqueue_head(&conf->wait_for_stripe); diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h index f90e0704bed9..a2c9e9e9f5ac 100644 --- a/drivers/md/raid5.h +++ b/drivers/md/raid5.h @@ -589,7 +589,7 @@ struct r5conf { int prev_chunk_sectors; int prev_algo; short generation; /* increments with every reshape */ - seqcount_t gen_lock; /* lock against generation changes */ + seqcount_spinlock_t gen_lock; /* lock against generation changes */ unsigned long reshape_checkpoint; /* Time we last updated * metadata */ long long min_offset_diff; /* minimum difference between -- 2.20.1 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v4 19/24] raid5: Use sequence counter with associated spinlock 2020-07-20 15:55 ` [PATCH v4 19/24] " Ahmed S. Darwish @ 2020-07-22 6:40 ` Song Liu 0 siblings, 0 replies; 5+ messages in thread From: Song Liu @ 2020-07-22 6:40 UTC (permalink / raw) To: Ahmed S. Darwish Cc: Peter Zijlstra, Ingo Molnar, Will Deacon, Thomas Gleixner, Paul E. McKenney, Sebastian A. Siewior, Steven Rostedt, LKML, linux-raid On Mon, Jul 20, 2020 at 8:57 AM Ahmed S. Darwish <a.darwish@linutronix.de> wrote: > > A sequence counter write side critical section must be protected by some > form of locking to serialize writers. A plain seqcount_t does not > contain the information of which lock must be held when entering a write > side critical section. > > Use the new seqcount_spinlock_t data type, which allows to associate a > spinlock with the sequence counter. This enables lockdep to verify that > the spinlock used for writer serialization is held when the write side > critical section is entered. > > If lockdep is disabled this lock association is compiled out and has > neither storage size nor runtime overhead. > > Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Acked-by: Song Liu <song@kernel.org> ^ permalink raw reply [flat|nested] 5+ messages in thread
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2020-05-19 21:45 ` [PATCH v1 20/25] raid5: Use sequence counter with associated spinlock Ahmed S. Darwish
[not found] ` <20200608005729.1874024-1-a.darwish@linutronix.de>
2020-06-08 0:57 ` [PATCH v2 13/18] " Ahmed S. Darwish
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2020-06-30 5:44 ` [PATCH v3 15/20] " Ahmed S. Darwish
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2020-07-22 6:40 ` Song Liu
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