* [PATCH 0/4] various cleanups and fixes from the Ruby side
@ 2022-09-03 11:18 Eric Wong
2022-09-03 11:18 ` [PATCH 1/4] favor _Thread_local under C11 Eric Wong
` (3 more replies)
0 siblings, 4 replies; 6+ messages in thread
From: Eric Wong @ 2022-09-03 11:18 UTC (permalink / raw)
To: mwrap-perl
Eric Wong (4):
favor _Thread_local under C11
cleanup some FreeBSD-related workarounds
use macro to quiet uninitialized and unused variable warnings
workaround breakage from urcu v0.11.4
Mwrap.xs | 77 ++++++++++++++++++++++++++++++++++----------------------
1 file changed, 47 insertions(+), 30 deletions(-)
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 1/4] favor _Thread_local under C11
2022-09-03 11:18 [PATCH 0/4] various cleanups and fixes from the Ruby side Eric Wong
@ 2022-09-03 11:18 ` Eric Wong
2022-09-03 11:18 ` [PATCH 2/4] cleanup some FreeBSD-related workarounds Eric Wong
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Eric Wong @ 2022-09-03 11:18 UTC (permalink / raw)
To: mwrap-perl
__thread is a gcc-ism which clang supports, but _Thread_local is
part of C11 and more likely to be supported by future compilers.
---
Mwrap.xs | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/Mwrap.xs b/Mwrap.xs
index bb51930..e888a1c 100644
--- a/Mwrap.xs
+++ b/Mwrap.xs
@@ -26,6 +26,14 @@
#include <urcu/rculist.h>
#include "jhash.h"
+#if __STDC_VERSION__ >= 201112
+# define MWRAP_TSD _Thread_local
+#elif defined(__GNUC__)
+# define MWRAP_TSD __thread
+#else
+# error _Thread_local nor __thread supported
+#endif
+
/*
* Perl doesn't have a GC the same way (C) Ruby does, so no GC count.
* Instead, the relative age of an object is the number of total bytes
@@ -62,7 +70,7 @@ static int resolving_malloc;
} \
} while (0)
-static __thread size_t locating;
+static MWRAP_TSD size_t locating;
#ifndef PERL_IMPLICIT_CONTEXT
static size_t *root_locating; /* determines if PL_curcop is our thread */
#endif
@@ -237,7 +245,7 @@ struct alloc_hdr {
size_t size;
};
-static __thread char kbuf[
+static MWRAP_TSD char kbuf[
PATH_MAX + INT2STR_MAX + sizeof(struct alloc_hdr) + 2
];
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 2/4] cleanup some FreeBSD-related workarounds
2022-09-03 11:18 [PATCH 0/4] various cleanups and fixes from the Ruby side Eric Wong
2022-09-03 11:18 ` [PATCH 1/4] favor _Thread_local under C11 Eric Wong
@ 2022-09-03 11:18 ` Eric Wong
2022-09-04 7:01 ` Eric Wong
2022-09-03 11:18 ` [PATCH 3/4] use macro to quiet uninitialized and unused variable warnings Eric Wong
2022-09-03 11:18 ` [PATCH 4/4] workaround breakage from urcu v0.11.4 Eric Wong
3 siblings, 1 reply; 6+ messages in thread
From: Eric Wong @ 2022-09-03 11:18 UTC (permalink / raw)
To: mwrap-perl
This is to keep up with the Ruby version.
---
Mwrap.xs | 35 +++++++++++++++++++++--------------
1 file changed, 21 insertions(+), 14 deletions(-)
diff --git a/Mwrap.xs b/Mwrap.xs
index e888a1c..3392fee 100644
--- a/Mwrap.xs
+++ b/Mwrap.xs
@@ -84,9 +84,16 @@ union padded_mutex {
/* a round-robin pool of mutexes */
#define MUTEX_NR (1 << 6)
#define MUTEX_MASK (MUTEX_NR - 1)
+#ifdef __FreeBSD__
+# define STATIC_MTX_INIT_OK (0)
+#else /* only tested on Linux + glibc */
+# define STATIC_MTX_INIT_OK (1)
+#endif
static size_t mutex_i;
static union padded_mutex mutexes[MUTEX_NR] = {
+#if STATIC_MTX_INIT_OK
[0 ... (MUTEX_NR-1)].mtx = PTHREAD_MUTEX_INITIALIZER
+#endif
};
static pthread_mutex_t *mutex_assign(void)
@@ -106,12 +113,11 @@ __attribute__((constructor)) static void resolve_malloc(void)
++locating;
-#ifdef __FreeBSD__
/*
* PTHREAD_MUTEX_INITIALIZER on FreeBSD means lazy initialization,
* which happens at pthread_mutex_lock, and that calls calloc
*/
- {
+ if (!STATIC_MTX_INIT_OK) {
size_t i;
for (i = 0; i < MUTEX_NR; i++) {
@@ -124,19 +130,20 @@ __attribute__((constructor)) static void resolve_malloc(void)
/* initialize mutexes used by urcu-bp */
rcu_read_lock();
rcu_read_unlock();
+#ifndef __FreeBSD__
+ } else {
+ if (!real_malloc) {
+ resolving_malloc = 1;
+ real_malloc = dlsym(RTLD_NEXT, "malloc");
+ }
+ real_free = dlsym(RTLD_NEXT, "free");
+ if (!real_malloc || !real_free) {
+ fprintf(stderr, "missing malloc/aligned_alloc/free\n"
+ "\t%p %p\n", real_malloc, real_free);
+ _exit(1);
+ }
}
-#else /* !FreeBSD (tested on GNU/Linux) */
- if (!real_malloc) {
- resolving_malloc = 1;
- real_malloc = dlsym(RTLD_NEXT, "malloc");
- }
- real_free = dlsym(RTLD_NEXT, "free");
- if (!real_malloc || !real_free) {
- fprintf(stderr, "missing malloc/aligned_alloc/free\n"
- "\t%p %p\n", real_malloc, real_free);
- _exit(1);
- }
-#endif /* !FreeBSD */
+#endif /* !__FreeBSD__ */
err = pthread_atfork(call_rcu_before_fork,
call_rcu_after_fork_parent,
call_rcu_after_fork_child);
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 3/4] use macro to quiet uninitialized and unused variable warnings
2022-09-03 11:18 [PATCH 0/4] various cleanups and fixes from the Ruby side Eric Wong
2022-09-03 11:18 ` [PATCH 1/4] favor _Thread_local under C11 Eric Wong
2022-09-03 11:18 ` [PATCH 2/4] cleanup some FreeBSD-related workarounds Eric Wong
@ 2022-09-03 11:18 ` Eric Wong
2022-09-03 11:18 ` [PATCH 4/4] workaround breakage from urcu v0.11.4 Eric Wong
3 siblings, 0 replies; 6+ messages in thread
From: Eric Wong @ 2022-09-03 11:18 UTC (permalink / raw)
To: mwrap-perl
This allows us to avoid some #ifdefs inside function bodies.
This cleanup comes from the Ruby version.
---
Mwrap.xs | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/Mwrap.xs b/Mwrap.xs
index 3392fee..9e9f571 100644
--- a/Mwrap.xs
+++ b/Mwrap.xs
@@ -153,14 +153,18 @@ __attribute__((constructor)) static void resolve_malloc(void)
--locating;
}
+#ifdef NDEBUG
+#define QUIET_CC_WARNING(var) (void)var;
+#else
+#define QUIET_CC_WARNING(var)
+#endif
+
static void
mutex_lock(pthread_mutex_t *m)
{
int err = pthread_mutex_lock(m);
assert(err == 0);
-#ifdef NDEBUG
- (void)err; /* quiet gcc warning */
-#endif
+ QUIET_CC_WARNING(err)
}
static void
@@ -168,9 +172,7 @@ mutex_unlock(pthread_mutex_t *m)
{
int err = pthread_mutex_unlock(m);
assert(err == 0);
-#ifdef NDEBUG
- (void)err; /* quiet gcc warning */
-#endif
+ QUIET_CC_WARNING(err)
}
#ifndef HAVE_MEMPCPY
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 4/4] workaround breakage from urcu v0.11.4
2022-09-03 11:18 [PATCH 0/4] various cleanups and fixes from the Ruby side Eric Wong
` (2 preceding siblings ...)
2022-09-03 11:18 ` [PATCH 3/4] use macro to quiet uninitialized and unused variable warnings Eric Wong
@ 2022-09-03 11:18 ` Eric Wong
3 siblings, 0 replies; 6+ messages in thread
From: Eric Wong @ 2022-09-03 11:18 UTC (permalink / raw)
To: mwrap-perl
urcu v0.11.4+ introduced commit
7ca7fe9c03 (Make temporary variable in _rcu_dereference non-const, 2021-07-29)
which conflicts with our use of _LGPL_SOURCE. In retrospect,
CMM_LOAD_SHARED and CMM_STORE_SHARED seem sufficient for our use
of the `totals' cds_lfht pointer since the constructur should always
fire before any threads are running.
This is fixed in urcu v0.12.4 and v0.13.2 (released 2022-08-18)
but I suspect older versions will live on in enterprise/LTS
distros for a long while.
Link: https://lore.kernel.org/lttng-dev/20220809181927.GA3718@dcvr/
---
Mwrap.xs | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/Mwrap.xs b/Mwrap.xs
index 9e9f571..9a85f36 100644
--- a/Mwrap.xs
+++ b/Mwrap.xs
@@ -298,7 +298,7 @@ static struct src_loc *totals_add_rcu(struct src_loc *k)
struct cds_lfht *t;
again:
- t = rcu_dereference(totals);
+ t = CMM_LOAD_SHARED(totals);
if (!t) goto out_unlock;
cds_lfht_lookup(t, k->hval, loc_eq, k, &iter);
cur = cds_lfht_iter_get_node(&iter);
@@ -341,7 +341,7 @@ update_stats_rcu_lock(size_t *generation, size_t size, uintptr_t caller)
static const size_t xlen = sizeof(caller);
char *dst;
const COP *cop;
- struct cds_lfht *t = rcu_dereference(totals);
+ struct cds_lfht *t = CMM_LOAD_SHARED(totals);
if (caa_unlikely(!t)) return 0;
if (locating++) goto out; /* do not recurse into another *alloc */
@@ -684,7 +684,7 @@ static void *dump_to_file(struct dump_arg *a)
++locating;
rcu_read_lock();
- t = rcu_dereference(totals);
+ t = CMM_LOAD_SHARED(totals);
if (!t)
goto out_unlock;
cds_lfht_for_each_entry(t, &iter, l, hnode) {
@@ -805,8 +805,8 @@ BOOT:
#ifndef PERL_IMPLICIT_CONTEXT
root_locating = &locating;
#endif
- totals = lfht_new();
- if (!totals)
+ CMM_STORE_SHARED(totals, lfht_new());
+ if (!CMM_LOAD_SHARED(totals))
fprintf(stderr, "failed to allocate totals table\n");
PROTOTYPES: ENABLE
@@ -851,7 +851,7 @@ PREINIT:
CODE:
++locating;
rcu_read_lock();
- t = rcu_dereference(totals);
+ t = CMM_LOAD_SHARED(totals);
if (t) {
bool err = false;
@@ -903,7 +903,7 @@ CODE:
uatomic_set(&total_bytes_dec, 0);
rcu_read_lock();
- t = rcu_dereference(totals);
+ t = CMM_LOAD_SHARED(totals);
cds_lfht_for_each_entry(t, &iter, l, hnode) {
uatomic_set(&l->total, 0);
uatomic_set(&l->allocations, 0);
@@ -949,7 +949,7 @@ CODE:
XSRETURN_UNDEF;
rcu_read_lock();
- t = rcu_dereference(totals);
+ t = CMM_LOAD_SHARED(totals);
if (!t) goto out_unlock;
cds_lfht_lookup(t, k->hval, loc_eq, k, &iter);
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 2/4] cleanup some FreeBSD-related workarounds
2022-09-03 11:18 ` [PATCH 2/4] cleanup some FreeBSD-related workarounds Eric Wong
@ 2022-09-04 7:01 ` Eric Wong
0 siblings, 0 replies; 6+ messages in thread
From: Eric Wong @ 2022-09-04 7:01 UTC (permalink / raw)
To: Eric Wong
Eric Wong <mwrap-perl@80x24.org> wrote:
> diff --git a/Mwrap.xs b/Mwrap.xs
> index e888a1c..3392fee 100644
> --- a/Mwrap.xs
> +++ b/Mwrap.xs
> @@ -124,19 +130,20 @@ __attribute__((constructor)) static void resolve_malloc(void)
> /* initialize mutexes used by urcu-bp */
> rcu_read_lock();
> rcu_read_unlock();
> +#ifndef __FreeBSD__
> + } else {
> + if (!real_malloc) {
> + resolving_malloc = 1;
> + real_malloc = dlsym(RTLD_NEXT, "malloc");
> + }
> + real_free = dlsym(RTLD_NEXT, "free");
> + if (!real_malloc || !real_free) {
> + fprintf(stderr, "missing malloc/aligned_alloc/free\n"
> + "\t%p %p\n", real_malloc, real_free);
> + _exit(1);
> + }
> }
> -#else /* !FreeBSD (tested on GNU/Linux) */
> - if (!real_malloc) {
> - resolving_malloc = 1;
> - real_malloc = dlsym(RTLD_NEXT, "malloc");
> - }
> - real_free = dlsym(RTLD_NEXT, "free");
> - if (!real_malloc || !real_free) {
> - fprintf(stderr, "missing malloc/aligned_alloc/free\n"
> - "\t%p %p\n", real_malloc, real_free);
> - _exit(1);
> - }
> -#endif /* !FreeBSD */
> +#endif /* !__FreeBSD__ */
> err = pthread_atfork(call_rcu_before_fork,
> call_rcu_after_fork_parent,
> call_rcu_after_fork_child);
Will squash this in so that it actually compiles :x
diff --git a/Mwrap.xs b/Mwrap.xs
index 3392fee..bec4664 100644
--- a/Mwrap.xs
+++ b/Mwrap.xs
@@ -142,8 +142,8 @@ __attribute__((constructor)) static void resolve_malloc(void)
"\t%p %p\n", real_malloc, real_free);
_exit(1);
}
- }
#endif /* !__FreeBSD__ */
+ }
err = pthread_atfork(call_rcu_before_fork,
call_rcu_after_fork_parent,
call_rcu_after_fork_child);
^ permalink raw reply related [flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-09-04 7:01 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2022-09-03 11:18 [PATCH 0/4] various cleanups and fixes from the Ruby side Eric Wong
2022-09-03 11:18 ` [PATCH 1/4] favor _Thread_local under C11 Eric Wong
2022-09-03 11:18 ` [PATCH 2/4] cleanup some FreeBSD-related workarounds Eric Wong
2022-09-04 7:01 ` Eric Wong
2022-09-03 11:18 ` [PATCH 3/4] use macro to quiet uninitialized and unused variable warnings Eric Wong
2022-09-03 11:18 ` [PATCH 4/4] workaround breakage from urcu v0.11.4 Eric Wong
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