locking/lockdep: Rework FS_RECLAIM annotation

A while ago someone, and I cannot find the email just now, asked if we
could not implement the RECLAIM_FS inversion stuff with a 'fake' lock
like we use for other things like workqueues etc. I think this should
be possible which allows reducing the 'irq' states and will reduce the
amount of __bfs() lookups we do.

Removing the 1 IRQ state results in 4 less __bfs() walks per
dependency, improving lockdep performance. And by moving this
annotation out of the lockdep code it becomes easier for the mm people
to extend.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Nikolay Borisov <nborisov@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akpm@linux-foundation.org
Cc: boqun.feng@gmail.com
Cc: iamjoonsoo.kim@lge.com
Cc: kernel-team@lge.com
Cc: kirill@shutemov.name
Cc: npiggin@gmail.com
Cc: walken@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 1 insertions, 95 deletions

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 7d2499b..986f2fa7 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -344,14 +344,12 @@ EXPORT_SYMBOL(lockdep_on);
 #if VERBOSE
 # define HARDIRQ_VERBOSE	1
 # define SOFTIRQ_VERBOSE	1
-# define RECLAIM_VERBOSE	1
 #else
 # define HARDIRQ_VERBOSE	0
 # define SOFTIRQ_VERBOSE	0
-# define RECLAIM_VERBOSE	0
 #endif
 
-#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE
+#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE
 /*
  * Quick filtering for interesting events:
  */
@@ -2567,14 +2565,6 @@ static int SOFTIRQ_verbose(struct lock_class *class)
 	return 0;
 }
 
-static int RECLAIM_FS_verbose(struct lock_class *class)
-{
-#if RECLAIM_VERBOSE
-	return class_filter(class);
-#endif
-	return 0;
-}
-
 #define STRICT_READ_CHECKS	1
 
 static int (*state_verbose_f[])(struct lock_class *class) = {
@@ -2870,57 +2860,6 @@ void trace_softirqs_off(unsigned long ip)
 		debug_atomic_inc(redundant_softirqs_off);
 }
 
-static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags)
-{
-	struct task_struct *curr = current;
-
-	if (unlikely(!debug_locks))
-		return;
-
-	gfp_mask = current_gfp_context(gfp_mask);
-
-	/* no reclaim without waiting on it */
-	if (!(gfp_mask & __GFP_DIRECT_RECLAIM))
-		return;
-
-	/* this guy won't enter reclaim */
-	if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC))
-		return;
-
-	/* We're only interested __GFP_FS allocations for now */
-	if (!(gfp_mask & __GFP_FS) || (curr->flags & PF_MEMALLOC_NOFS))
-		return;
-
-	/*
-	 * Oi! Can't be having __GFP_FS allocations with IRQs disabled.
-	 */
-	if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)))
-		return;
-
-	/* Disable lockdep if explicitly requested */
-	if (gfp_mask & __GFP_NOLOCKDEP)
-		return;
-
-	mark_held_locks(curr, RECLAIM_FS);
-}
-
-static void check_flags(unsigned long flags);
-
-void lockdep_trace_alloc(gfp_t gfp_mask)
-{
-	unsigned long flags;
-
-	if (unlikely(current->lockdep_recursion))
-		return;
-
-	raw_local_irq_save(flags);
-	check_flags(flags);
-	current->lockdep_recursion = 1;
-	__lockdep_trace_alloc(gfp_mask, flags);
-	current->lockdep_recursion = 0;
-	raw_local_irq_restore(flags);
-}
-
 static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
 {
 	/*
@@ -2966,22 +2905,6 @@ static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
 		}
 	}
 
-	/*
-	 * We reuse the irq context infrastructure more broadly as a general
-	 * context checking code. This tests GFP_FS recursion (a lock taken
-	 * during reclaim for a GFP_FS allocation is held over a GFP_FS
-	 * allocation).
-	 */
-	if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) {
-		if (hlock->read) {
-			if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ))
-					return 0;
-		} else {
-			if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS))
-					return 0;
-		}
-	}
-
 	return 1;
 }
 
@@ -3040,10 +2963,6 @@ static inline int separate_irq_context(struct task_struct *curr,
 	return 0;
 }
 
-void lockdep_trace_alloc(gfp_t gfp_mask)
-{
-}
-
 #endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
 
 /*
@@ -3952,18 +3871,6 @@ void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
 }
 EXPORT_SYMBOL_GPL(lock_unpin_lock);
 
-void lockdep_set_current_reclaim_state(gfp_t gfp_mask)
-{
-	current->lockdep_reclaim_gfp = current_gfp_context(gfp_mask);
-}
-EXPORT_SYMBOL_GPL(lockdep_set_current_reclaim_state);
-
-void lockdep_clear_current_reclaim_state(void)
-{
-	current->lockdep_reclaim_gfp = 0;
-}
-EXPORT_SYMBOL_GPL(lockdep_clear_current_reclaim_state);
-
 #ifdef CONFIG_LOCK_STAT
 static int
 print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,
diff --git a/kernel/locking/lockdep_states.h b/kernel/locking/lockdep_states.h
index 995b0cc..35ca09f 100644
--- a/kernel/locking/lockdep_states.h
+++ b/kernel/locking/lockdep_states.h
@@ -6,4 +6,3 @@
  */
 LOCKDEP_STATE(HARDIRQ)
 LOCKDEP_STATE(SOFTIRQ)
-LOCKDEP_STATE(RECLAIM_FS)