From 3490565b633c705d2fb1f6ede51228952664663d Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Mon, 13 Jul 2015 20:31:03 +0200 Subject: [PATCH] locking/spinlocks: Force inlining of spinlock ops With both gcc 4.7.2 and 4.9.2, sometimes GCC mysteriously doesn't inline very small functions we expect to be inlined. See: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66122 In particular, with this config: http://busybox.net/~vda/kernel_config there are more than a thousand copies of tiny spinlock-related functions: $ nm --size-sort vmlinux | grep -iF ' t ' | uniq -c | grep -v '^ *1 ' | sort -rn | grep ' spin' 473 000000000000000b t spin_unlock_irqrestore 292 000000000000000b t spin_unlock 215 000000000000000b t spin_lock 134 000000000000000b t spin_unlock_irq 130 000000000000000b t spin_unlock_bh 120 000000000000000b t spin_lock_irq 106 000000000000000b t spin_lock_bh Disassembly: ffffffff81004720 : ffffffff81004720: 55 push %rbp ffffffff81004721: 48 89 e5 mov %rsp,%rbp ffffffff81004724: e8 f8 4e e2 02 callq <_raw_spin_lock> ffffffff81004729: 5d pop %rbp ffffffff8100472a: c3 retq This patch fixes this via s/inline/__always_inline/ in spinlock.h. This decreases vmlinux by about 40k: text data bss dec hex filename 82375570 22255544 20627456 125258570 7774b4a vmlinux.before 82335059 22255416 20627456 125217931 776ac8b vmlinux Signed-off-by: Denys Vlasenko Cc: Andrew Morton Cc: Andy Lutomirski Cc: Bart Van Assche Cc: Borislav Petkov Cc: Brian Gerst Cc: David Rientjes Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Thomas Graf Link: http://lkml.kernel.org/r/1436812263-15243-1-git-send-email-dvlasenk@redhat.com Signed-off-by: Ingo Molnar --- include/linux/spinlock.h | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h index 0063b24b4f36..ffcd053ca89a 100644 --- a/include/linux/spinlock.h +++ b/include/linux/spinlock.h @@ -296,7 +296,7 @@ static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock) * Map the spin_lock functions to the raw variants for PREEMPT_RT=n */ -static inline raw_spinlock_t *spinlock_check(spinlock_t *lock) +static __always_inline raw_spinlock_t *spinlock_check(spinlock_t *lock) { return &lock->rlock; } @@ -307,17 +307,17 @@ do { \ raw_spin_lock_init(&(_lock)->rlock); \ } while (0) -static inline void spin_lock(spinlock_t *lock) +static __always_inline void spin_lock(spinlock_t *lock) { raw_spin_lock(&lock->rlock); } -static inline void spin_lock_bh(spinlock_t *lock) +static __always_inline void spin_lock_bh(spinlock_t *lock) { raw_spin_lock_bh(&lock->rlock); } -static inline int spin_trylock(spinlock_t *lock) +static __always_inline int spin_trylock(spinlock_t *lock) { return raw_spin_trylock(&lock->rlock); } @@ -337,7 +337,7 @@ do { \ raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock); \ } while (0) -static inline void spin_lock_irq(spinlock_t *lock) +static __always_inline void spin_lock_irq(spinlock_t *lock) { raw_spin_lock_irq(&lock->rlock); } @@ -352,32 +352,32 @@ do { \ raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \ } while (0) -static inline void spin_unlock(spinlock_t *lock) +static __always_inline void spin_unlock(spinlock_t *lock) { raw_spin_unlock(&lock->rlock); } -static inline void spin_unlock_bh(spinlock_t *lock) +static __always_inline void spin_unlock_bh(spinlock_t *lock) { raw_spin_unlock_bh(&lock->rlock); } -static inline void spin_unlock_irq(spinlock_t *lock) +static __always_inline void spin_unlock_irq(spinlock_t *lock) { raw_spin_unlock_irq(&lock->rlock); } -static inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags) +static __always_inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags) { raw_spin_unlock_irqrestore(&lock->rlock, flags); } -static inline int spin_trylock_bh(spinlock_t *lock) +static __always_inline int spin_trylock_bh(spinlock_t *lock) { return raw_spin_trylock_bh(&lock->rlock); } -static inline int spin_trylock_irq(spinlock_t *lock) +static __always_inline int spin_trylock_irq(spinlock_t *lock) { return raw_spin_trylock_irq(&lock->rlock); } @@ -387,22 +387,22 @@ static inline int spin_trylock_irq(spinlock_t *lock) raw_spin_trylock_irqsave(spinlock_check(lock), flags); \ }) -static inline void spin_unlock_wait(spinlock_t *lock) +static __always_inline void spin_unlock_wait(spinlock_t *lock) { raw_spin_unlock_wait(&lock->rlock); } -static inline int spin_is_locked(spinlock_t *lock) +static __always_inline int spin_is_locked(spinlock_t *lock) { return raw_spin_is_locked(&lock->rlock); } -static inline int spin_is_contended(spinlock_t *lock) +static __always_inline int spin_is_contended(spinlock_t *lock) { return raw_spin_is_contended(&lock->rlock); } -static inline int spin_can_lock(spinlock_t *lock) +static __always_inline int spin_can_lock(spinlock_t *lock) { return raw_spin_can_lock(&lock->rlock); } -- 2.30.2