UPSTREAM: locking/percpu-rwsem: Remove preempt_disable variants
Effective revert commit:
87709e28dc
("fs/locks: Use percpu_down_read_preempt_disable()")
This is causing major pain for PREEMPT_RT.
Sebastian did a lot of lockperf runs on 2 and 4 node machines with all
preemption modes (PREEMPT=n should be an obvious NOP for this patch
and thus serves as a good control) and no results showed significance
over 2-sigma (the PREEMPT=n results were almost empty at 1-sigma).
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Change-Id: Ic81171045eba8a615163e97d27bc282bb0e998a2
Signed-off-by: UtsavBalar1231 <utsavbalar1231@gmail.com>
This commit is contained in:
parent
7d41c747f3
commit
e3a6fa2b16
32
fs/locks.c
32
fs/locks.c
@ -936,7 +936,7 @@ static int flock_lock_inode(struct inode *inode, struct file_lock *request)
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return -ENOMEM;
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return -ENOMEM;
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}
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}
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percpu_down_read_preempt_disable(&file_rwsem);
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percpu_down_read(&file_rwsem);
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spin_lock(&ctx->flc_lock);
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spin_lock(&ctx->flc_lock);
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if (request->fl_flags & FL_ACCESS)
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if (request->fl_flags & FL_ACCESS)
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goto find_conflict;
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goto find_conflict;
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@ -977,7 +977,7 @@ find_conflict:
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out:
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out:
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spin_unlock(&ctx->flc_lock);
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spin_unlock(&ctx->flc_lock);
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percpu_up_read_preempt_enable(&file_rwsem);
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percpu_up_read(&file_rwsem);
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if (new_fl)
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if (new_fl)
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locks_free_lock(new_fl);
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locks_free_lock(new_fl);
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locks_dispose_list(&dispose);
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locks_dispose_list(&dispose);
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@ -1015,7 +1015,7 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request,
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new_fl2 = locks_alloc_lock();
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new_fl2 = locks_alloc_lock();
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}
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}
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percpu_down_read_preempt_disable(&file_rwsem);
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percpu_down_read(&file_rwsem);
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spin_lock(&ctx->flc_lock);
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spin_lock(&ctx->flc_lock);
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/*
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/*
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* New lock request. Walk all POSIX locks and look for conflicts. If
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* New lock request. Walk all POSIX locks and look for conflicts. If
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@ -1187,7 +1187,7 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request,
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}
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}
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out:
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out:
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spin_unlock(&ctx->flc_lock);
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spin_unlock(&ctx->flc_lock);
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percpu_up_read_preempt_enable(&file_rwsem);
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percpu_up_read(&file_rwsem);
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/*
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/*
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* Free any unused locks.
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* Free any unused locks.
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*/
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*/
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@ -1462,7 +1462,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
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return error;
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return error;
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}
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}
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percpu_down_read_preempt_disable(&file_rwsem);
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percpu_down_read(&file_rwsem);
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spin_lock(&ctx->flc_lock);
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spin_lock(&ctx->flc_lock);
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time_out_leases(inode, &dispose);
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time_out_leases(inode, &dispose);
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@ -1514,13 +1514,13 @@ restart:
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locks_insert_block(fl, new_fl);
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locks_insert_block(fl, new_fl);
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trace_break_lease_block(inode, new_fl);
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trace_break_lease_block(inode, new_fl);
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spin_unlock(&ctx->flc_lock);
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spin_unlock(&ctx->flc_lock);
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percpu_up_read_preempt_enable(&file_rwsem);
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percpu_up_read(&file_rwsem);
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locks_dispose_list(&dispose);
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locks_dispose_list(&dispose);
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error = wait_event_interruptible_timeout(new_fl->fl_wait,
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error = wait_event_interruptible_timeout(new_fl->fl_wait,
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!new_fl->fl_next, break_time);
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!new_fl->fl_next, break_time);
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percpu_down_read_preempt_disable(&file_rwsem);
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percpu_down_read(&file_rwsem);
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spin_lock(&ctx->flc_lock);
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spin_lock(&ctx->flc_lock);
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trace_break_lease_unblock(inode, new_fl);
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trace_break_lease_unblock(inode, new_fl);
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locks_delete_block(new_fl);
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locks_delete_block(new_fl);
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@ -1537,7 +1537,7 @@ restart:
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}
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}
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out:
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out:
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spin_unlock(&ctx->flc_lock);
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spin_unlock(&ctx->flc_lock);
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percpu_up_read_preempt_enable(&file_rwsem);
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percpu_up_read(&file_rwsem);
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locks_dispose_list(&dispose);
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locks_dispose_list(&dispose);
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locks_free_lock(new_fl);
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locks_free_lock(new_fl);
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return error;
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return error;
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@ -1609,7 +1609,7 @@ int fcntl_getlease(struct file *filp)
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ctx = smp_load_acquire(&inode->i_flctx);
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ctx = smp_load_acquire(&inode->i_flctx);
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if (ctx && !list_empty_careful(&ctx->flc_lease)) {
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if (ctx && !list_empty_careful(&ctx->flc_lease)) {
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percpu_down_read_preempt_disable(&file_rwsem);
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percpu_down_read(&file_rwsem);
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spin_lock(&ctx->flc_lock);
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spin_lock(&ctx->flc_lock);
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time_out_leases(inode, &dispose);
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time_out_leases(inode, &dispose);
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list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
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list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
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@ -1619,7 +1619,7 @@ int fcntl_getlease(struct file *filp)
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break;
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break;
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}
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}
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spin_unlock(&ctx->flc_lock);
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spin_unlock(&ctx->flc_lock);
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percpu_up_read_preempt_enable(&file_rwsem);
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percpu_up_read(&file_rwsem);
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locks_dispose_list(&dispose);
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locks_dispose_list(&dispose);
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}
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}
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@ -1693,7 +1693,7 @@ generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **pr
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return -EINVAL;
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return -EINVAL;
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}
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}
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percpu_down_read_preempt_disable(&file_rwsem);
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percpu_down_read(&file_rwsem);
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spin_lock(&ctx->flc_lock);
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spin_lock(&ctx->flc_lock);
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time_out_leases(inode, &dispose);
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time_out_leases(inode, &dispose);
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error = check_conflicting_open(dentry, arg, lease->fl_flags);
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error = check_conflicting_open(dentry, arg, lease->fl_flags);
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@ -1764,7 +1764,7 @@ out_setup:
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lease->fl_lmops->lm_setup(lease, priv);
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lease->fl_lmops->lm_setup(lease, priv);
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out:
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out:
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spin_unlock(&ctx->flc_lock);
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spin_unlock(&ctx->flc_lock);
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percpu_up_read_preempt_enable(&file_rwsem);
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percpu_up_read(&file_rwsem);
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locks_dispose_list(&dispose);
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locks_dispose_list(&dispose);
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if (is_deleg)
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if (is_deleg)
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inode_unlock(inode);
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inode_unlock(inode);
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@ -1787,7 +1787,7 @@ static int generic_delete_lease(struct file *filp, void *owner)
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return error;
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return error;
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}
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}
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percpu_down_read_preempt_disable(&file_rwsem);
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percpu_down_read(&file_rwsem);
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spin_lock(&ctx->flc_lock);
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spin_lock(&ctx->flc_lock);
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list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
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list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
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if (fl->fl_file == filp &&
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if (fl->fl_file == filp &&
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@ -1800,7 +1800,7 @@ static int generic_delete_lease(struct file *filp, void *owner)
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if (victim)
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if (victim)
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error = fl->fl_lmops->lm_change(victim, F_UNLCK, &dispose);
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error = fl->fl_lmops->lm_change(victim, F_UNLCK, &dispose);
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spin_unlock(&ctx->flc_lock);
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spin_unlock(&ctx->flc_lock);
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percpu_up_read_preempt_enable(&file_rwsem);
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percpu_up_read(&file_rwsem);
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locks_dispose_list(&dispose);
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locks_dispose_list(&dispose);
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return error;
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return error;
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}
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}
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@ -2531,13 +2531,13 @@ locks_remove_lease(struct file *filp, struct file_lock_context *ctx)
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if (list_empty(&ctx->flc_lease))
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if (list_empty(&ctx->flc_lease))
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return;
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return;
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percpu_down_read_preempt_disable(&file_rwsem);
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percpu_down_read(&file_rwsem);
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spin_lock(&ctx->flc_lock);
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spin_lock(&ctx->flc_lock);
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list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list)
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list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list)
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if (filp == fl->fl_file)
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if (filp == fl->fl_file)
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lease_modify(fl, F_UNLCK, &dispose);
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lease_modify(fl, F_UNLCK, &dispose);
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spin_unlock(&ctx->flc_lock);
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spin_unlock(&ctx->flc_lock);
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percpu_up_read_preempt_enable(&file_rwsem);
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percpu_up_read(&file_rwsem);
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locks_dispose_list(&dispose);
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locks_dispose_list(&dispose);
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}
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}
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@ -29,7 +29,7 @@ static struct percpu_rw_semaphore name = { \
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extern int __percpu_down_read(struct percpu_rw_semaphore *, int);
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extern int __percpu_down_read(struct percpu_rw_semaphore *, int);
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extern void __percpu_up_read(struct percpu_rw_semaphore *);
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extern void __percpu_up_read(struct percpu_rw_semaphore *);
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static inline void percpu_down_read_preempt_disable(struct percpu_rw_semaphore *sem)
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static inline void percpu_down_read(struct percpu_rw_semaphore *sem)
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{
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{
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might_sleep();
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might_sleep();
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@ -47,16 +47,10 @@ static inline void percpu_down_read_preempt_disable(struct percpu_rw_semaphore *
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__this_cpu_inc(*sem->read_count);
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__this_cpu_inc(*sem->read_count);
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if (unlikely(!rcu_sync_is_idle(&sem->rss)))
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if (unlikely(!rcu_sync_is_idle(&sem->rss)))
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__percpu_down_read(sem, false); /* Unconditional memory barrier */
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__percpu_down_read(sem, false); /* Unconditional memory barrier */
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barrier();
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/*
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/*
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* The barrier() prevents the compiler from
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* The preempt_enable() prevents the compiler from
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* bleeding the critical section out.
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* bleeding the critical section out.
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*/
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*/
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}
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static inline void percpu_down_read(struct percpu_rw_semaphore *sem)
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{
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percpu_down_read_preempt_disable(sem);
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preempt_enable();
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preempt_enable();
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}
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}
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@ -83,13 +77,9 @@ static inline int percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
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return ret;
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return ret;
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}
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}
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static inline void percpu_up_read_preempt_enable(struct percpu_rw_semaphore *sem)
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static inline void percpu_up_read(struct percpu_rw_semaphore *sem)
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{
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{
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/*
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preempt_disable();
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* The barrier() prevents the compiler from
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* bleeding the critical section out.
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*/
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barrier();
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/*
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/*
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* Same as in percpu_down_read().
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* Same as in percpu_down_read().
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*/
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*/
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@ -102,12 +92,6 @@ static inline void percpu_up_read_preempt_enable(struct percpu_rw_semaphore *sem
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rwsem_release(&sem->rw_sem.dep_map, 1, _RET_IP_);
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rwsem_release(&sem->rw_sem.dep_map, 1, _RET_IP_);
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}
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}
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static inline void percpu_up_read(struct percpu_rw_semaphore *sem)
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{
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preempt_disable();
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percpu_up_read_preempt_enable(sem);
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}
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extern void percpu_down_write(struct percpu_rw_semaphore *);
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extern void percpu_down_write(struct percpu_rw_semaphore *);
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extern void percpu_up_write(struct percpu_rw_semaphore *);
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extern void percpu_up_write(struct percpu_rw_semaphore *);
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