search for: rw_semaphore

...empted(task_cpu(owner)))) { ret = false; break; } diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c index 2ad8d8d..7a884a6 100644 --- a/kernel/locking/rwsem-xadd.c +++ b/kernel/locking/rwsem-xadd.c @@ -351,6 +351,7 @@ static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem) static noinline bool rwsem_spin_on_owner(struct rw_semaphore *sem) { struct task_struct *owner = READ_ONCE(sem->owner); + int loop = 0; if (!rwsem_owner_is_writer(owner)) goto out; @@ -367,10 +368,11 @@ static noinline bool rwsem_spin_on_owner(struct rw_semaphore *sem) /*...

...+++------------------------- 5 files changed, 55 insertions(+), 36 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index f6ad2d5..ec7884c 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -859,8 +859,9 @@ struct btrfs_fs_info { struct mutex ordered_operations_mutex; struct rw_semaphore extent_commit_sem; - struct rw_semaphore subvol_sem; + struct rw_semaphore cleanup_work_sem; + struct rw_semaphore subvol_sem; struct srcu_struct subvol_srcu; struct list_head trans_list; @@ -1034,12 +1035,12 @@ struct btrfs_root { int ref_cows; int track_dirty; int in_radix; + int...

i_alloc_sem has always been a bit of an odd "lock". It''s the only remaining rw_semaphore that can be released by a different thread than the one that locked it, and it''s use case in the core direct I/O code is more like a counter given that the writers already have external serialization. This series removes it in favour of a simpler counter scheme, thus getting rid of the rw...

...linux/rwsem.h | 1 + lib/rwsem.c | 17 +++++++++++++++++ 2 files changed, 18 insertions(+), 0 deletions(-) diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index 0616ffe..61a8802 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -35,6 +35,7 @@ extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem); extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem); extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *); extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem); +extern int rwsem_is_conten...

It was found when running fio sequential write test with a XFS ramdisk on a 2-socket x86-64 system, the %CPU times as reported by perf were as follows: 71.27% 0.28% fio [k] down_write 70.99% 0.01% fio [k] call_rwsem_down_write_failed 69.43% 1.18% fio [k] rwsem_down_write_failed 65.51% 54.57% fio [k] osq_lock 9.72% 7.99% fio [k] __raw_callee_save___kvm_vcpu_is_preempted 4.16%

It was found when running fio sequential write test with a XFS ramdisk on a 2-socket x86-64 system, the %CPU times as reported by perf were as follows: 71.27% 0.28% fio [k] down_write 70.99% 0.01% fio [k] call_rwsem_down_write_failed 69.43% 1.18% fio [k] rwsem_down_write_failed 65.51% 54.57% fio [k] osq_lock 9.72% 7.99% fio [k] __raw_callee_save___kvm_vcpu_is_preempted 4.16%

...gt;owner is not set, the mutex owner may have just acquired diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c index 09e30c6..99eb8fd 100644 --- a/kernel/locking/rwsem-xadd.c +++ b/kernel/locking/rwsem-xadd.c @@ -319,7 +319,11 @@ static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem) goto done; } - ret = owner->on_cpu; + /* + * As lock holder preemption issue, we both skip spinning if task is not + * on cpu or its cpu is preempted + */ + ret = owner->on_cpu && !vcpu_is_preempted(task_cpu(owner)); done: rcu_read_unlock(); return ret; @@ -340,8...

...(); } unlock: arch_spin_unlock(&lock->wait_lock); diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c index 2337b4b..2fa2e2e6 100644 --- a/kernel/locking/rwsem-xadd.c +++ b/kernel/locking/rwsem-xadd.c @@ -368,7 +368,7 @@ static noinline bool rwsem_spin_on_owner(struct rw_semaphore *sem) return false; } - cpu_relax_lowlatency(); + cpu_relax(); } rcu_read_unlock(); out: @@ -423,7 +423,7 @@ static bool rwsem_optimistic_spin(struct rw_semaphore *sem) * memory barriers as we'll eventually observe the right * values at the cost of a few extra spins....

...ctls_need_rwsem; + const struct file_operations *fops; union { struct pci_driver *pci; @@ -1070,6 +1072,8 @@ struct drm_device { /*@{ */ spinlock_t count_lock; /**< For inuse, drm_device::open_count, drm_device::buf_use */ struct mutex struct_mutex; /**< For others */ + + struct rw_semaphore ioctls_rwsem; /*@} */ /** \name Usage Counters */ -- 1.7.8.5

change from v2: no code change, fix typos, update some comments change from v1: a simplier definition of default vcpu_is_preempted skip mahcine type check on ppc, and add config. remove dedicated macro. add one patch to drop overload of rwsem_spin_on_owner and mutex_spin_on_owner. add more comments thanks boqun and Peter's suggestion. This patch set aims to fix lock holder preemption

change from v2: no code change, fix typos, update some comments change from v1: a simplier definition of default vcpu_is_preempted skip mahcine type check on ppc, and add config. remove dedicated macro. add one patch to drop overload of rwsem_spin_on_owner and mutex_spin_on_owner. add more comments thanks boqun and Peter's suggestion. This patch set aims to fix lock holder preemption

...le_operations 462 file_system_type 462 iattr 462 inode 462 inode_operations 462 kiocb 462 lock_manager_operations 462 mem_dqinfo 462 mm_struct 462 page 462 path 462 quotactl_ops 462 quota_format_ops 462 quota_format_type 462 quota_info 462 rw_semaphore 462 super_block 462 super_operations 462 task_struct 462 vm_area_struct 471 bus_type 471 class 471 device 471 device_driver 471 device_type 471 dev_pm_domain 471 dev_pm_info 471 dev_pm_ops On why the struct types are duplicated *that* often: I skimme...

...dex 7d922950caaf..7fc8153671e0 100644 > --- a/drivers/vfio/mdev/mdev_private.h > +++ b/drivers/vfio/mdev/mdev_private.h > @@ -22,6 +22,7 @@ struct mdev_parent { > struct list_head type_list; > /* Synchronize device creation/removal with parent unregistration > */ > struct rw_semaphore unreg_sem; > + u8 device_id; > }; > > struct mdev_device { > diff --git a/drivers/vfio/mdev/vfio_mdev.c > b/drivers/vfio/mdev/vfio_mdev.c > index 30964a4e0a28..887c57f10880 100644 > --- a/drivers/vfio/mdev/vfio_mdev.c > +++ b/drivers/vfio/mdev/vfio_mdev.c > @@ -120,...

change fomr v1: a simplier definition of default vcpu_is_preempted skip mahcine type check on ppc, and add config. remove dedicated macro. add one patch to drop overload of rwsem_spin_on_owner and mutex_spin_on_owner. add more comments thanks boqun and Peter's suggestion. This patch set aims to fix lock holder preemption issues. test-case: perf record -a perf bench sched messaging -g

change fomr v1: a simplier definition of default vcpu_is_preempted skip mahcine type check on ppc, and add config. remove dedicated macro. add one patch to drop overload of rwsem_spin_on_owner and mutex_spin_on_owner. add more comments thanks boqun and Peter's suggestion. This patch set aims to fix lock holder preemption issues. test-case: perf record -a perf bench sched messaging -g

...drivers/vfio/mdev/mdev_private.h index 7d922950caaf..7fc8153671e0 100644 --- a/drivers/vfio/mdev/mdev_private.h +++ b/drivers/vfio/mdev/mdev_private.h @@ -22,6 +22,7 @@ struct mdev_parent { struct list_head type_list; /* Synchronize device creation/removal with parent unregistration */ struct rw_semaphore unreg_sem; + u8 device_id; }; struct mdev_device { diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c index 30964a4e0a28..887c57f10880 100644 --- a/drivers/vfio/mdev/vfio_mdev.c +++ b/drivers/vfio/mdev/vfio_mdev.c @@ -120,10 +120,16 @@ static void vfio_mdev_remove(struct...

...drivers/vfio/mdev/mdev_private.h index 7d922950caaf..e58b07c866b1 100644 --- a/drivers/vfio/mdev/mdev_private.h +++ b/drivers/vfio/mdev/mdev_private.h @@ -22,6 +22,7 @@ struct mdev_parent { struct list_head type_list; /* Synchronize device creation/removal with parent unregistration */ struct rw_semaphore unreg_sem; + u8 class_id; }; struct mdev_device { diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c index 30964a4e0a28..fd2a4d9a3f26 100644 --- a/drivers/vfio/mdev/vfio_mdev.c +++ b/drivers/vfio/mdev/vfio_mdev.c @@ -120,10 +120,16 @@ static void vfio_mdev_remove(struct...

...t;jbacik@redhat.com> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 8559f39..fad58b9 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -508,6 +508,7 @@ struct btrfs_space_info { /* for block groups in our same type */ struct list_head block_groups; spinlock_t lock; + struct rw_semaphore groups_sem; }; struct btrfs_free_space { diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 280ac1a..ad648a3 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -317,59 +317,6 @@ struct btrfs_block_group_cache *btrfs_lookup_block_group(struct return cache; }...

...58b07c866b1 100644 >> --- a/drivers/vfio/mdev/mdev_private.h >> +++ b/drivers/vfio/mdev/mdev_private.h >> @@ -22,6 +22,7 @@ struct mdev_parent { >> struct list_head type_list; >> /* Synchronize device creation/removal with parent unregistration */ >> struct rw_semaphore unreg_sem; >> + u8 class_id; >> }; >> >> struct mdev_device { >> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c >> index 30964a4e0a28..fd2a4d9a3f26 100644 >> --- a/drivers/vfio/mdev/vfio_mdev.c >> +++ b/drivers/vfio/mdev/...

...ialisation */ > - struct amdgpu_device *adev; > - enum amdgpu_mn_type type; > - > - /* only used on destruction */ > - struct work_struct work; > - > - /* protected by adev->mn_lock */ > - struct hlist_node node; > - > - /* objects protected by lock */ > - struct rw_semaphore lock; > - > -#ifdef CONFIG_HMM_MIRROR > - /* HMM mirror */ > - struct hmm_mirror mirror; > -#endif > -}; > - > #if defined(CONFIG_HMM_MIRROR) > -void amdgpu_mn_lock(struct amdgpu_mn *mn); > -void amdgpu_mn_unlock(struct amdgpu_mn *mn); > -struct amdgpu_mn *amdgpu_...