3 Commits

Author	SHA1	Message	Date
Denys Vlasenko	bc27fb68aa	include/uapi/linux/byteorder, swab: force inlining of some byteswap operations ... 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 With this .config: http://busybox.net/~vda/kernel_config_OPTIMIZE_INLINING_and_Os, the following functions get deinlined many times. Examples of disassembly: <get_unaligned_be16> (12 copies, 51 calls): 66 8b 07 mov (%rdi),%ax 55 push %rbp 48 89 e5 mov %rsp,%rbp 86 e0 xchg %ah,%al 5d pop %rbp c3 retq <get_unaligned_be32> (12 copies, 135 calls): 8b 07 mov (%rdi),%eax 55 push %rbp 48 89 e5 mov %rsp,%rbp 0f c8 bswap %eax 5d pop %rbp c3 retq <get_unaligned_be64> (2 copies, 20 calls): 48 8b 07 mov (%rdi),%rax 55 push %rbp 48 89 e5 mov %rsp,%rbp 48 0f c8 bswap %rax 5d pop %rbp c3 retq <__swab16p> (16 copies, 146 calls): 55 push %rbp 89 f8 mov %edi,%eax 86 e0 xchg %ah,%al 48 89 e5 mov %rsp,%rbp 5d pop %rbp c3 retq <__swab32p> (43 copies, ~560 calls): 55 push %rbp 89 f8 mov %edi,%eax 0f c8 bswap %eax 48 89 e5 mov %rsp,%rbp 5d pop %rbp c3 retq <__swab64p> (21 copies, 119 calls): 55 push %rbp 48 89 f8 mov %rdi,%rax 48 0f c8 bswap %rax 48 89 e5 mov %rsp,%rbp 5d pop %rbp c3 retq <__swab32s> (6 copies, 47 calls): 8b 07 mov (%rdi),%eax 55 push %rbp 48 89 e5 mov %rsp,%rbp 0f c8 bswap %eax 89 07 mov %eax,(%rdi) 5d pop %rbp c3 retq This patch fixes this via s/inline/__always_inline/. Code size decrease after the patch is ~4.5k: text data bss dec hex filename 92202377 20826112 36417536 149446025 8e85d89 vmlinux 92197848 20826112 36417536 149441496 8e84bd8 vmlinux5_swap_after Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Thomas Graf <tgraf@suug.ch> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David Rientjes <rientjes@google.com> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>	2016-03-17 15:09:34 -07:00
David Woodhouse	cf66bb93e0	byteorder: allow arch to opt to use GCC intrinsics for byteswapping ... Since GCC 4.4, there have been __builtin_bswap32() and __builtin_bswap16() intrinsics. A __builtin_bswap16() came a little later (4.6 for PowerPC, 48 for other platforms). By using these instead of the inline assembler that most architectures have in their __arch_swabXX() macros, we let the compiler see what's actually happening. The resulting code should be at least as good, and much *better* in the cases where it can be combined with a nearby load or store, using a load-and-byteswap or store-and-byteswap instruction (e.g. lwbrx/stwbrx on PowerPC, movbe on Atom). When GCC is sufficiently recent *and* the architecture opts in to using the intrinsics by setting CONFIG_ARCH_USE_BUILTIN_BSWAP, they will be used in preference to the __arch_swabXX() macros. An architecture which does not set ARCH_USE_BUILTIN_BSWAP will continue to use its own hand-crafted macros. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Acked-by: H. Peter Anvin <hpa@linux.intel.com>	2012-12-06 01:22:31 +00:00
David Howells	607ca46e97	UAPI: (Scripted) Disintegrate include/linux ... Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Dave Jones <davej@redhat.com>	2012-10-13 10:46:48 +01:00