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authorSiddhesh Poyarekar <siddhesh@redhat.com>2015-07-24 06:09:47 +0530
committerSiddhesh Poyarekar <siddhesh@redhat.com>2015-07-24 06:09:47 +0530
commita81a00ff94a43af85f7aefceb6d31f3c0f11151d (patch)
treedabb84f77f81948b442e8dc25e7fa6845934ff02 /stdlib
parentb301e68e4b027340743d050aa32651039c1cb7bc (diff)
downloadglibc-a81a00ff94a43af85f7aefceb6d31f3c0f11151d.tar.gz
Mention dl_load_lock by name in the comments
Mention dl_load_lock by name instead of just 'load lock' in the comments. This makes it unambigious which lock we're talking about.
Diffstat (limited to 'stdlib')
-rw-r--r--stdlib/cxa_thread_atexit_impl.c19
1 files changed, 10 insertions, 9 deletions
diff --git a/stdlib/cxa_thread_atexit_impl.c b/stdlib/cxa_thread_atexit_impl.c
index 8e26380799..2d5d56a7fa 100644
--- a/stdlib/cxa_thread_atexit_impl.c
+++ b/stdlib/cxa_thread_atexit_impl.c
@@ -25,14 +25,15 @@
combinations of all three functions are the link map list, a link map for a
DSO and the link map member l_tls_dtor_count.
- __cxa_thread_atexit_impl acquires the load_lock before accessing any shared
- state and hence multiple of its instances can safely execute concurrently.
+ __cxa_thread_atexit_impl acquires the dl_load_lock before accessing any
+ shared state and hence multiple of its instances can safely execute
+ concurrently.
- _dl_close_worker acquires the load_lock before accessing any shared state as
- well and hence can concurrently execute multiple of its own instances as
+ _dl_close_worker acquires the dl_load_lock before accessing any shared state
+ as well and hence can concurrently execute multiple of its own instances as
well as those of __cxa_thread_atexit_impl safely. Not all accesses to
- l_tls_dtor_count are protected by the load lock, so we need to synchronize
- using atomics.
+ l_tls_dtor_count are protected by the dl_load_lock, so we need to
+ synchronize using atomics.
__call_tls_dtors accesses the l_tls_dtor_count without taking the lock; it
decrements the value by one. It does not need the big lock because it does
@@ -51,8 +52,8 @@
it is safe to unload the DSO. Hence, to ensure that this does not happen,
the following conditions must be met:
- 1. In _dl_close_worker, the l_tls_dtor_count load happens before the DSO
- is unload and its link map is freed
+ 1. In _dl_close_worker, the l_tls_dtor_count load happens before the DSO is
+ unloaded and its link map is freed
2. The link map dereference in __call_tls_dtors happens before the
l_tls_dtor_count dereference.
@@ -122,7 +123,7 @@ __cxa_thread_atexit_impl (dtor_func func, void *obj, void *dso_symbol)
/* This increment may only be concurrently observed either by the decrement
in __call_tls_dtors since the other l_tls_dtor_count access in
- _dl_close_worker is protected by the load lock. The execution in
+ _dl_close_worker is protected by the dl_load_lock. The execution in
__call_tls_dtors does not really depend on this value beyond the fact that
it should be atomic, so Relaxed MO should be sufficient. */
atomic_fetch_add_relaxed (&lm_cache->l_tls_dtor_count, 1);