From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
To: x86@kernel.org, linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>, Nadav Amit <namit@vmware.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
ndesaulniers@google.com,
Rasmus Villemoes <linux@rasmusvillemoes.dk>
Subject: [RFC PATCH 5/5] x86: bug.h: use asm_inline in _BUG_FLAGS definitions
Date: Thu, 29 Aug 2019 10:32:33 +0200 [thread overview]
Message-ID: <20190829083233.24162-6-linux@rasmusvillemoes.dk> (raw)
In-Reply-To: <20190829083233.24162-1-linux@rasmusvillemoes.dk>
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%
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
arch/x86/include/asm/bug.h | 4 ++--
1 file 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" \
--
2.20.1
next prev parent reply other threads:[~2019-08-29 8:33 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-29 8:32 [RFC PATCH 0/5] make use of gcc 9's "asm inline()" Rasmus Villemoes
2019-08-29 8:32 ` [RFC PATCH 1/5] treewide: replace __inline__ by inline Rasmus Villemoes
2019-08-29 16:29 ` Joe Perches
2019-08-29 8:32 ` [RFC PATCH 2/5] compiler_types.h: don't #define __inline__ Rasmus Villemoes
2019-08-29 8:32 ` [RFC PATCH 3/5] compiler-gcc.h: add asm_inline definition Rasmus Villemoes
2019-08-29 8:32 ` [RFC PATCH 4/5] x86: alternative.h: use asm_inline for all alternative variants Rasmus Villemoes
2019-08-29 8:32 ` Rasmus Villemoes [this message]
2019-08-29 16:05 ` [RFC PATCH 0/5] make use of gcc 9's "asm inline()" Linus Torvalds
2019-08-30 7:45 ` Rasmus Villemoes
2019-08-29 17:36 ` Nick Desaulniers
2019-08-29 18:15 ` Linus Torvalds
2019-08-29 18:26 ` Nadav Amit
2019-08-29 18:42 ` Borislav Petkov
2019-08-29 19:41 ` Masahiro Yamada
2019-08-30 23:15 ` [PATCH v2 0/6] " Rasmus Villemoes
2019-08-30 23:15 ` [PATCH v2 1/6] staging: rtl8723bs: replace __inline by inline Rasmus Villemoes
2019-09-04 23:54 ` Nick Desaulniers
2019-08-30 23:15 ` [PATCH v2 2/6] lib/zstd/mem.h: " Rasmus Villemoes
2019-09-04 23:59 ` Nick Desaulniers
2019-09-05 0:07 ` Miguel Ojeda
2019-09-05 9:28 ` Rasmus Villemoes
2019-08-30 23:15 ` [PATCH v2 3/6] compiler_types.h: don't #define __inline Rasmus Villemoes
2019-09-05 0:13 ` Nick Desaulniers
2019-09-05 9:45 ` Rasmus Villemoes
2019-08-30 23:15 ` [PATCH v2 4/6] compiler-gcc.h: add asm_inline definition Rasmus Villemoes
2019-09-05 0:18 ` Nick Desaulniers
2019-09-05 5:43 ` Nadav Amit
2019-09-05 11:07 ` Rasmus Villemoes
2019-09-05 13:45 ` Segher Boessenkool
2019-09-05 14:23 ` Rasmus Villemoes
2019-09-05 14:47 ` Segher Boessenkool
2019-09-05 15:52 ` Miguel Ojeda
2019-09-05 16:13 ` Miguel Ojeda
2019-09-06 12:23 ` Segher Boessenkool
2019-09-06 15:13 ` Miguel Ojeda
2019-09-06 16:30 ` Segher Boessenkool
2019-09-06 16:39 ` Jakub Jelinek
2019-09-06 18:14 ` Nick Desaulniers
2019-09-06 22:03 ` Segher Boessenkool
2019-09-06 22:35 ` Nick Desaulniers
2019-09-06 22:56 ` Segher Boessenkool
2019-09-06 23:42 ` Nick Desaulniers
2019-09-07 0:14 ` Segher Boessenkool
2019-09-07 1:04 ` Nick Desaulniers
2019-09-07 13:11 ` Segher Boessenkool
2019-09-08 13:55 ` Miguel Ojeda
2019-09-12 21:54 ` Nick Desaulniers
2019-09-12 22:12 ` Rasmus Villemoes
2019-09-20 0:50 ` Segher Boessenkool
2019-09-06 16:47 ` Miguel Ojeda
2019-08-30 23:15 ` [PATCH v2 5/6] x86: alternative.h: use asm_inline for all alternative variants Rasmus Villemoes
2019-08-30 23:15 ` [PATCH v2 6/6] x86: bug.h: use asm_inline in _BUG_FLAGS definitions Rasmus Villemoes
2019-09-12 22:19 ` [PATCH v3 0/6] make use of gcc 9's "asm inline()" Rasmus Villemoes
2019-09-12 22:19 ` [PATCH v3 1/6] staging: rtl8723bs: replace __inline by inline Rasmus Villemoes
2019-09-29 10:40 ` Greg Kroah-Hartman
2019-09-12 22:19 ` [PATCH v3 2/6] lib/zstd/mem.h: " Rasmus Villemoes
2019-09-12 22:19 ` [PATCH v3 3/6] compiler_types.h: don't #define __inline Rasmus Villemoes
2019-09-12 22:19 ` [PATCH v3 4/6] compiler-types.h: add asm_inline definition Rasmus Villemoes
2019-09-12 22:19 ` [PATCH v3 5/6] x86: alternative.h: use asm_inline for all alternative variants Rasmus Villemoes
2019-09-13 5:41 ` Ingo Molnar
2019-09-12 22:19 ` [PATCH v3 6/6] x86: bug.h: use asm_inline in _BUG_FLAGS definitions Rasmus Villemoes
2019-09-13 5:42 ` Ingo Molnar
2019-09-12 22:30 ` [PATCH v3 0/6] make use of gcc 9's "asm inline()" Miguel Ojeda
2019-09-13 6:11 ` Rasmus Villemoes
2019-09-13 15:21 ` Greg Kroah-Hartman
2019-09-15 18:20 ` Miguel Ojeda
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190829083233.24162-6-linux@rasmusvillemoes.dk \
--to=linux@rasmusvillemoes.dk \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=miguel.ojeda.sandonis@gmail.com \
--cc=mingo@redhat.com \
--cc=namit@vmware.com \
--cc=ndesaulniers@google.com \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).