summaryrefslogtreecommitdiffstats
path: root/include/linux/hw_breakpoint.h
diff options
context:
space:
mode:
authorMarco Elver <elver@google.com>2022-08-29 14:47:12 +0200
committerPeter Zijlstra <peterz@infradead.org>2022-08-30 10:56:22 +0200
commit9caf87be118f4639537404eeb67dd444a3716e9a (patch)
tree59e4d4f8eb569b097d9e61ca9fa3bfbc53c06ce8 /include/linux/hw_breakpoint.h
parentbe3f152568cc7f5f573d21d5f86a2c4f3cc047ab (diff)
downloadlinux-stable-9caf87be118f4639537404eeb67dd444a3716e9a.tar.gz
linux-stable-9caf87be118f4639537404eeb67dd444a3716e9a.tar.bz2
linux-stable-9caf87be118f4639537404eeb67dd444a3716e9a.zip
perf/hw_breakpoint: Make hw_breakpoint_weight() inlinable
Due to being a __weak function, hw_breakpoint_weight() will cause the compiler to always emit a call to it. This generates unnecessarily bad code (register spills etc.) for no good reason; in fact it appears in profiles of `perf bench -r 100 breakpoint thread -b 4 -p 128 -t 512`: ... 0.70% [kernel] [k] hw_breakpoint_weight ... While a small percentage, no architecture defines its own hw_breakpoint_weight() nor are there users outside hw_breakpoint.c, which makes the fact it is currently __weak a poor choice. Change hw_breakpoint_weight()'s definition to follow a similar protocol to hw_breakpoint_slots(), such that if <asm/hw_breakpoint.h> defines hw_breakpoint_weight(), we'll use it instead. The result is that it is inlined and no longer shows up in profiles. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Ian Rogers <irogers@google.com> Link: https://lore.kernel.org/r/20220829124719.675715-8-elver@google.com
Diffstat (limited to 'include/linux/hw_breakpoint.h')
-rw-r--r--include/linux/hw_breakpoint.h1
1 files changed, 0 insertions, 1 deletions
diff --git a/include/linux/hw_breakpoint.h b/include/linux/hw_breakpoint.h
index a3fb846705eb..f319bd26b030 100644
--- a/include/linux/hw_breakpoint.h
+++ b/include/linux/hw_breakpoint.h
@@ -80,7 +80,6 @@ extern int dbg_reserve_bp_slot(struct perf_event *bp);
extern int dbg_release_bp_slot(struct perf_event *bp);
extern int reserve_bp_slot(struct perf_event *bp);
extern void release_bp_slot(struct perf_event *bp);
-int hw_breakpoint_weight(struct perf_event *bp);
int arch_reserve_bp_slot(struct perf_event *bp);
void arch_release_bp_slot(struct perf_event *bp);
void arch_unregister_hw_breakpoint(struct perf_event *bp);