| Message ID | 20190719084808.5877-1-nborisov@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RFC] btrfs: Hook btrfs' DRW lock to locktorture infrastructure | expand |
On Fri, Jul 19, 2019 at 11:48:08AM +0300, Nikolay Borisov wrote: > Signed-off-by: Nikolay Borisov <nborisov@suse.com> > --- > > Hello Paul, > > Here is the code I used to test the DRW lock via the lock torture infrastructure. > It's rather ugly but got the job done for me. It's definitely not in a mergeable > form. At the very least I think including btrfs headers constitutes a violation > of separation of different subsystems. Would it be acceptable to guard them > behind something like "#if BTRFS && BTRFS_DEBUG" ? > > I'm really posting this just for posterity/provenance purposes. I'm fine with > dropping the patch. > > > fs/btrfs/locking.h | 1 + > kernel/locking/locktorture.c | 77 +++++++++++++++++++++++++++++++++++- > 2 files changed, 77 insertions(+), 1 deletion(-) > > diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h > index 44378c65f843..27627d4fd3a9 100644 > --- a/fs/btrfs/locking.h > +++ b/fs/btrfs/locking.h > @@ -9,6 +9,7 @@ > #include <linux/atomic.h> > #include <linux/wait.h> > #include <linux/percpu_counter.h> > +#include "extent_io.h" > > #define BTRFS_WRITE_LOCK 1 > #define BTRFS_READ_LOCK 2 > diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c > index 80a463d31a8d..774e10a25876 100644 > --- a/kernel/locking/locktorture.c > +++ b/kernel/locking/locktorture.c > @@ -30,6 +30,8 @@ > #include <linux/slab.h> > #include <linux/percpu-rwsem.h> > #include <linux/torture.h> > +#include "../../fs/btrfs/ctree.h" > +#include "../../fs/btrfs/locking.h" > > MODULE_LICENSE("GPL"); > MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>"); > @@ -85,6 +87,7 @@ struct lock_torture_ops { > > unsigned long flags; /* for irq spinlocks */ > const char *name; > + bool multiple; > }; > > struct lock_torture_cxt { > @@ -600,6 +603,7 @@ static void torture_percpu_rwsem_up_read(void) __releases(pcpu_rwsem) > percpu_up_read(&pcpu_rwsem); > } > > + > static struct lock_torture_ops percpu_rwsem_lock_ops = { > .init = torture_percpu_rwsem_init, > .writelock = torture_percpu_rwsem_down_write, > @@ -612,6 +616,76 @@ static struct lock_torture_ops percpu_rwsem_lock_ops = { > .name = "percpu_rwsem_lock" > }; > > +static struct btrfs_drw_lock torture_drw_lock; > + > +void torture_drw_init(void) > +{ > + BUG_ON(btrfs_drw_lock_init(&torture_drw_lock)); > +} > + > +static int torture_drw_write_lock(void) __acquires(torture_drw_lock) > +{ > + btrfs_drw_write_lock(&torture_drw_lock); > + return 0; > +} > + > +static void torture_drw_write_unlock(void) __releases(torture_drw_lock) > +{ > + btrfs_drw_write_unlock(&torture_drw_lock); > +} > + > +static int torture_drw_read_lock(void) __acquires(torture_drw_lock) > +{ > + btrfs_drw_read_lock(&torture_drw_lock); > + return 0; > +} > + > +static void torture_drw_read_unlock(void) __releases(torture_drw_lock) > +{ > + btrfs_drw_read_unlock(&torture_drw_lock); > +} > + > +static void torture_drw_write_delay(struct torture_random_state *trsp) > +{ > + const unsigned long longdelay_ms = 100; > + > + /* We want a long delay occasionally to force massive contention. */ > + if (!(torture_random(trsp) % > + (cxt.nrealwriters_stress * 2000 * longdelay_ms))) > + mdelay(longdelay_ms * 10); > + else > + mdelay(longdelay_ms / 10); > + if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000))) > + torture_preempt_schedule(); /* Allow test to be preempted. */ > +} > + > +static void torture_drw_read_delay(struct torture_random_state *trsp) > +{ > + const unsigned long longdelay_ms = 100; > + > + /* We want a long delay occasionally to force massive contention. */ > + if (!(torture_random(trsp) % > + (cxt.nrealreaders_stress * 2000 * longdelay_ms))) > + mdelay(longdelay_ms * 2); > + else > + mdelay(longdelay_ms / 2); > + if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000))) > + torture_preempt_schedule(); /* Allow test to be preempted. */ > +} > + > +static struct lock_torture_ops btrfs_drw_lock_ops = { > + .init = torture_drw_init, > + .writelock = torture_drw_write_lock, > + .write_delay = torture_drw_write_delay, > + .task_boost = torture_boost_dummy, > + .writeunlock = torture_drw_write_unlock, > + .readlock = torture_drw_read_lock, > + .read_delay = torture_drw_read_delay, /* figure what to do with this */ > + .readunlock = torture_drw_read_unlock, > + .multiple = true, > + .name = "btrfs_drw_lock" > +}; > + > /* > * Lock torture writer kthread. Repeatedly acquires and releases > * the lock, checking for duplicate acquisitions. > @@ -630,7 +704,7 @@ static int lock_torture_writer(void *arg) > > cxt.cur_ops->task_boost(&rand); > cxt.cur_ops->writelock(); > - if (WARN_ON_ONCE(lock_is_write_held)) > + if (!cxt.cur_ops->multiple && WARN_ON_ONCE(lock_is_write_held)) > lwsp->n_lock_fail++; > lock_is_write_held = 1; > if (WARN_ON_ONCE(lock_is_read_held)) > @@ -852,6 +926,7 @@ static int __init lock_torture_init(void) > #endif > &rwsem_lock_ops, > &percpu_rwsem_lock_ops, > + &btrfs_drw_lock_ops > }; > > if (!torture_init_begin(torture_type, verbose)) > -- > 2.17.1 > Looks like this is in next-20190805 and causes a link time error when CONFIG_BTRFS_FS is unset: LD vmlinux.o MODPOST vmlinux.o MODINFO modules.builtin.modinfo ld.lld: error: undefined symbol: btrfs_drw_lock_init >>> referenced by locktorture.c >>> locking/locktorture.o:(torture_drw_init) in archive kernel/built-in.a ld.lld: error: undefined symbol: btrfs_drw_write_lock >>> referenced by locktorture.c >>> locking/locktorture.o:(torture_drw_write_lock) in archive kernel/built-in.a ld.lld: error: undefined symbol: btrfs_drw_write_unlock >>> referenced by locktorture.c >>> locking/locktorture.o:(torture_drw_write_unlock) in archive kernel/built-in.a ld.lld: error: undefined symbol: btrfs_drw_read_lock >>> referenced by locktorture.c >>> locking/locktorture.o:(torture_drw_read_lock) in archive kernel/built-in.a ld.lld: error: undefined symbol: btrfs_drw_read_unlock >>> referenced by locktorture.c >>> locking/locktorture.o:(torture_drw_read_unlock) in archive kernel/built-in.a If this commit is to remain around, there should probably be static inline stubs in fs/btrfs/locking.h. Apologies if this has already been reported, I still see the commit in the btrfs for-next branch. Cheers, Nathan
On Mon, Aug 05, 2019 at 09:36:21AM -0700, Nathan Chancellor wrote: > Looks like this is in next-20190805 and causes a link time error when > CONFIG_BTRFS_FS is unset: > > LD vmlinux.o > MODPOST vmlinux.o > MODINFO modules.builtin.modinfo > ld.lld: error: undefined symbol: btrfs_drw_lock_init > >>> referenced by locktorture.c > >>> locking/locktorture.o:(torture_drw_init) in archive kernel/built-in.a > > ld.lld: error: undefined symbol: btrfs_drw_write_lock > >>> referenced by locktorture.c > >>> locking/locktorture.o:(torture_drw_write_lock) in archive kernel/built-in.a > > ld.lld: error: undefined symbol: btrfs_drw_write_unlock > >>> referenced by locktorture.c > >>> locking/locktorture.o:(torture_drw_write_unlock) in archive kernel/built-in.a > > ld.lld: error: undefined symbol: btrfs_drw_read_lock > >>> referenced by locktorture.c > >>> locking/locktorture.o:(torture_drw_read_lock) in archive kernel/built-in.a > > ld.lld: error: undefined symbol: btrfs_drw_read_unlock > >>> referenced by locktorture.c > >>> locking/locktorture.o:(torture_drw_read_unlock) in archive kernel/built-in.a > > If this commit is to remain around, there should probably be static > inline stubs in fs/btrfs/locking.h. Apologies if this has already been > reported, I still see the commit in the btrfs for-next branch. Sorry for the build breakage, the patch is not essential for the patchset so I'll remove it from the upcoming for-next branch.
diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h index 44378c65f843..27627d4fd3a9 100644 --- a/fs/btrfs/locking.h +++ b/fs/btrfs/locking.h @@ -9,6 +9,7 @@ #include <linux/atomic.h> #include <linux/wait.h> #include <linux/percpu_counter.h> +#include "extent_io.h" #define BTRFS_WRITE_LOCK 1 #define BTRFS_READ_LOCK 2 diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c index 80a463d31a8d..774e10a25876 100644 --- a/kernel/locking/locktorture.c +++ b/kernel/locking/locktorture.c @@ -30,6 +30,8 @@ #include <linux/slab.h> #include <linux/percpu-rwsem.h> #include <linux/torture.h> +#include "../../fs/btrfs/ctree.h" +#include "../../fs/btrfs/locking.h" MODULE_LICENSE("GPL"); MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>"); @@ -85,6 +87,7 @@ struct lock_torture_ops { unsigned long flags; /* for irq spinlocks */ const char *name; + bool multiple; }; struct lock_torture_cxt { @@ -600,6 +603,7 @@ static void torture_percpu_rwsem_up_read(void) __releases(pcpu_rwsem) percpu_up_read(&pcpu_rwsem); } + static struct lock_torture_ops percpu_rwsem_lock_ops = { .init = torture_percpu_rwsem_init, .writelock = torture_percpu_rwsem_down_write, @@ -612,6 +616,76 @@ static struct lock_torture_ops percpu_rwsem_lock_ops = { .name = "percpu_rwsem_lock" }; +static struct btrfs_drw_lock torture_drw_lock; + +void torture_drw_init(void) +{ + BUG_ON(btrfs_drw_lock_init(&torture_drw_lock)); +} + +static int torture_drw_write_lock(void) __acquires(torture_drw_lock) +{ + btrfs_drw_write_lock(&torture_drw_lock); + return 0; +} + +static void torture_drw_write_unlock(void) __releases(torture_drw_lock) +{ + btrfs_drw_write_unlock(&torture_drw_lock); +} + +static int torture_drw_read_lock(void) __acquires(torture_drw_lock) +{ + btrfs_drw_read_lock(&torture_drw_lock); + return 0; +} + +static void torture_drw_read_unlock(void) __releases(torture_drw_lock) +{ + btrfs_drw_read_unlock(&torture_drw_lock); +} + +static void torture_drw_write_delay(struct torture_random_state *trsp) +{ + const unsigned long longdelay_ms = 100; + + /* We want a long delay occasionally to force massive contention. */ + if (!(torture_random(trsp) % + (cxt.nrealwriters_stress * 2000 * longdelay_ms))) + mdelay(longdelay_ms * 10); + else + mdelay(longdelay_ms / 10); + if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000))) + torture_preempt_schedule(); /* Allow test to be preempted. */ +} + +static void torture_drw_read_delay(struct torture_random_state *trsp) +{ + const unsigned long longdelay_ms = 100; + + /* We want a long delay occasionally to force massive contention. */ + if (!(torture_random(trsp) % + (cxt.nrealreaders_stress * 2000 * longdelay_ms))) + mdelay(longdelay_ms * 2); + else + mdelay(longdelay_ms / 2); + if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000))) + torture_preempt_schedule(); /* Allow test to be preempted. */ +} + +static struct lock_torture_ops btrfs_drw_lock_ops = { + .init = torture_drw_init, + .writelock = torture_drw_write_lock, + .write_delay = torture_drw_write_delay, + .task_boost = torture_boost_dummy, + .writeunlock = torture_drw_write_unlock, + .readlock = torture_drw_read_lock, + .read_delay = torture_drw_read_delay, /* figure what to do with this */ + .readunlock = torture_drw_read_unlock, + .multiple = true, + .name = "btrfs_drw_lock" +}; + /* * Lock torture writer kthread. Repeatedly acquires and releases * the lock, checking for duplicate acquisitions. @@ -630,7 +704,7 @@ static int lock_torture_writer(void *arg) cxt.cur_ops->task_boost(&rand); cxt.cur_ops->writelock(); - if (WARN_ON_ONCE(lock_is_write_held)) + if (!cxt.cur_ops->multiple && WARN_ON_ONCE(lock_is_write_held)) lwsp->n_lock_fail++; lock_is_write_held = 1; if (WARN_ON_ONCE(lock_is_read_held)) @@ -852,6 +926,7 @@ static int __init lock_torture_init(void) #endif &rwsem_lock_ops, &percpu_rwsem_lock_ops, + &btrfs_drw_lock_ops }; if (!torture_init_begin(torture_type, verbose))
Signed-off-by: Nikolay Borisov <nborisov@suse.com> --- Hello Paul, Here is the code I used to test the DRW lock via the lock torture infrastructure. It's rather ugly but got the job done for me. It's definitely not in a mergeable form. At the very least I think including btrfs headers constitutes a violation of separation of different subsystems. Would it be acceptable to guard them behind something like "#if BTRFS && BTRFS_DEBUG" ? I'm really posting this just for posterity/provenance purposes. I'm fine with dropping the patch. fs/btrfs/locking.h | 1 + kernel/locking/locktorture.c | 77 +++++++++++++++++++++++++++++++++++- 2 files changed, 77 insertions(+), 1 deletion(-)