Commits
Denys Vlasenko committed 3490565b633
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 <spin_lock>:
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 <dvlasenk@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
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: Thomas Graf <tgraf@suug.ch>
Link: http://lkml.kernel.org/r/1436812263-15243-1-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>