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authorRasmus Villemoes <linux@rasmusvillemoes.dk>2019-09-13 00:19:27 +0200
committerMiguel Ojeda <miguel.ojeda.sandonis@gmail.com>2019-09-15 20:14:15 +0200
commit32ee8230b2b06c50f583e14fcd174d7d2edb52f5 (patch)
treed93c7870b09acaf7f2e6570f277c6b30217305ce
parent40576e5e63ea5eeab814de7af83ad09dd64134ee (diff)
x86: bug.h: use asm_inline in _BUG_FLAGS definitions
This helps preventing a BUG* or WARN* in some static inline from preventing that (or one of its callers) being inlined, so should allow gcc to make better informed inlining decisions. For example, with gcc 9.2, tcp_fastopen_no_cookie() vanishes from net/ipv4/tcp_fastopen.o. It does not itself have any BUG or WARN, but it calls dst_metric() which has a WARN_ON_ONCE - and despite that WARN_ON_ONCE vanishing since the condition is compile-time false, dst_metric() is apparently sufficiently "large" that when it gets inlined into tcp_fastopen_no_cookie(), the latter becomes too large for inlining. Overall, if one asks size(1), .text decreases a little and .data increases by about the same amount (x86-64 defconfig) $ size vmlinux.{before,after} text data bss dec hex filename 19709726 5202600 1630280 26542606 195020e vmlinux.before 19709330 5203068 1630280 26542678 1950256 vmlinux.after while bloat-o-meter says add/remove: 10/28 grow/shrink: 103/51 up/down: 3669/-2854 (815) ... Total: Before=14783683, After=14784498, chg +0.01% Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
-rw-r--r--arch/x86/include/asm/bug.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/include/asm/bug.h b/arch/x86/include/asm/bug.h
index 6804d6642767..facba9bc30ca 100644
--- a/arch/x86/include/asm/bug.h
+++ b/arch/x86/include/asm/bug.h
@@ -32,7 +32,7 @@
#define _BUG_FLAGS(ins, flags) \
do { \
- asm volatile("1:\t" ins "\n" \
+ asm_inline volatile("1:\t" ins "\n" \
".pushsection __bug_table,\"aw\"\n" \
"2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n" \
"\t" __BUG_REL(%c0) "\t# bug_entry::file\n" \
@@ -49,7 +49,7 @@ do { \
#define _BUG_FLAGS(ins, flags) \
do { \
- asm volatile("1:\t" ins "\n" \
+ asm_inline volatile("1:\t" ins "\n" \
".pushsection __bug_table,\"aw\"\n" \
"2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n" \
"\t.word %c0" "\t# bug_entry::flags\n" \

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