* [PATCH] use __attribute__((weak)) instead of dlsym
@ 2018-07-09 10:21 Eric Wong
0 siblings, 0 replies; only message in thread
From: Eric Wong @ 2018-07-09 10:21 UTC (permalink / raw)
To: mwrap-public
This should avoid indirect function call overhead as the
symbol can be resolved at link time instead of at runtime
with a constructor.
---
ext/mwrap/mwrap.c | 33 +++++++++++++++------------------
1 file changed, 15 insertions(+), 18 deletions(-)
diff --git a/ext/mwrap/mwrap.c b/ext/mwrap/mwrap.c
index e6449d7..3f59f11 100644
--- a/ext/mwrap/mwrap.c
+++ b/ext/mwrap/mwrap.c
@@ -22,7 +22,14 @@
static ID id_uminus;
const char *rb_source_location_cstr(int *line); /* requires 2.6.0dev */
-static int *(*has_gvl_p)(void);
+extern int __attribute__((weak)) ruby_thread_has_gvl_p(void);
+extern void * __attribute__((weak)) ruby_current_execution_context_ptr;
+
+int __attribute__((weak)) ruby_thread_has_gvl_p(void)
+{
+ return 0;
+}
+
#ifdef __FreeBSD__
void *__malloc(size_t);
void *__calloc(size_t, size_t);
@@ -51,13 +58,6 @@ static void *(*real_realloc)(void *, size_t);
#endif /* !FreeBSD */
-/*
- * rb_source_location_cstr relies on GET_EC(), and it's possible
- * to have a native thread but no EC during the early and late
- * (teardown) phases of the Ruby process
- */
-static void **ec_loc;
-
static struct cds_lfht *totals;
static struct cds_lfht *
@@ -91,14 +91,6 @@ __attribute__((constructor)) static void resolve_malloc(void)
call_rcu_after_fork_child);
if (err)
fprintf(stderr, "pthread_atfork failed: %s\n", strerror(err));
-
- has_gvl_p = dlsym(RTLD_DEFAULT, "ruby_thread_has_gvl_p");
-
- /*
- * resolve dynamically so it doesn't break when LD_PRELOAD-ed
- * into non-Ruby binaries
- */
- ec_loc = dlsym(RTLD_DEFAULT, "ruby_current_execution_context_ptr");
}
#ifndef HAVE_MEMPCPY
@@ -143,9 +135,14 @@ static char *int2str(int num, char *dst, size_t * size)
return NULL;
}
+/*
+ * rb_source_location_cstr relies on GET_EC(), and it's possible
+ * to have a native thread but no EC during the early and late
+ * (teardown) phases of the Ruby process
+ */
static int has_ec_p(void)
{
- return (ec_loc && *ec_loc);
+ return (ruby_thread_has_gvl_p() && ruby_current_execution_context_ptr);
}
struct src_loc {
@@ -224,7 +221,7 @@ static void update_stats(size_t size, uintptr_t caller)
if (locating++) goto out; /* do not recurse into another *alloc */
- if (has_gvl_p && has_gvl_p() && has_ec_p()) {
+ if (has_ec_p()) {
int line;
const char *ptr = rb_source_location_cstr(&line);
size_t len;
--
EW
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2018-07-09 10:21 [PATCH] use __attribute__((weak)) instead of dlsym Eric Wong
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