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authorJosh Poimboeuf <jpoimboe@redhat.com>2020-08-18 16:57:42 +0300
committerIngo Molnar <mingo@kernel.org>2020-09-01 10:58:04 +0300
commit9183c3f9ed710a8edf1a61e8a96d497258d26e08 (patch)
treeb3434e44f45bb98d2decb831e77c3e2c48329663 /kernel/module.c
parent115284d89a436e9b66da0c6c4f6efded806874b2 (diff)
downloadlinux-9183c3f9ed710a8edf1a61e8a96d497258d26e08.tar.xz
static_call: Add inline static call infrastructure
Add infrastructure for an arch-specific CONFIG_HAVE_STATIC_CALL_INLINE option, which is a faster version of CONFIG_HAVE_STATIC_CALL. At runtime, the static call sites are patched directly, rather than using the out-of-line trampolines. Compared to out-of-line static calls, the performance benefits are more modest, but still measurable. Steven Rostedt did some tracepoint measurements: https://lkml.kernel.org/r/20181126155405.72b4f718@gandalf.local.home This code is heavily inspired by the jump label code (aka "static jumps"), as some of the concepts are very similar. For more details, see the comments in include/linux/static_call.h. [peterz: simplified interface; merged trampolines] Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20200818135804.684334440@infradead.org
Diffstat (limited to 'kernel/module.c')
-rw-r--r--kernel/module.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 3c465cf31d08..c075a18103fb 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3275,6 +3275,11 @@ static int find_module_sections(struct module *mod, struct load_info *info)
sizeof(unsigned long),
&mod->num_kprobe_blacklist);
#endif
+#ifdef CONFIG_HAVE_STATIC_CALL_INLINE
+ mod->static_call_sites = section_objs(info, ".static_call_sites",
+ sizeof(*mod->static_call_sites),
+ &mod->num_static_call_sites);
+#endif
mod->extable = section_objs(info, "__ex_table",
sizeof(*mod->extable), &mod->num_exentries);