From: Hagen Paul Pfeifer Date: Mon, 20 Apr 2015 21:27:11 +0000 (+0200) Subject: x86/asm: Always inline atomics X-Git-Tag: omap-for-v4.2/fixes-rc1^2~170^2~29^2~19 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3462bd2adeadc49d9e126bca3b5536a3437a902d;p=pandora-kernel.git x86/asm: Always inline atomics During some code analysis I realized that atomic_add(), atomic_sub() and friends are not necessarily inlined AND that each function is defined multiple times: atomic_inc: 544 duplicates atomic_dec: 215 duplicates atomic_dec_and_test: 107 duplicates atomic64_inc: 38 duplicates [...] Each definition is exact equally, e.g.: ffffffff813171b8 : 55 push %rbp 48 89 e5 mov %rsp,%rbp f0 01 3e lock add %edi,(%rsi) 5d pop %rbp c3 retq In turn each definition has one or more callsites (sure): ffffffff81317c78: e8 3b f5 ff ff callq ffffffff813171b8 [...] ffffffff8131a062: e8 51 d1 ff ff callq ffffffff813171b8 [...] ffffffff8131a190: e8 23 d0 ff ff callq ffffffff813171b8 [...] The other way around would be to remove the static linkage - but I prefer an enforced inlining here. Before: text data bss dec hex filename 81467393 19874720 20168704 121510817 73e1ba1 vmlinux.orig After: text data bss dec hex filename 81461323 19874720 20168704 121504747 73e03eb vmlinux.inlined Yes, the inlining here makes the kernel even smaller! ;) Linus further observed: "I have this memory of having seen that before - the size heuristics for gcc getting confused by inlining. [...] It might be a good idea to mark things that are basically just wrappers around a single (or a couple of) asm instruction to be always_inline." Signed-off-by: Hagen Paul Pfeifer Acked-by: Linus Torvalds Cc: Borislav Petkov Cc: H. Peter Anvin Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1429565231-4609-1-git-send-email-hagen@jauu.net Signed-off-by: Ingo Molnar --- Reading git-diff-tree failed