summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorFlorian Weimer <fweimer@redhat.com>2021-06-28 15:48:58 +0200
committerFlorian Weimer <fweimer@redhat.com>2021-06-28 16:41:58 +0200
commitdd45734e322a03287d34d8af9b7da7b35cfddb8e (patch)
tree368647bd8c34ea5d1ea1f3cfa74ef52fb3271e67
parentfef400a2f976d1fd6a4639e6980f6c50ee13fbf5 (diff)
downloadglibc-arm/morello/master.tar.gz
nptl: Add glibc.pthread.stack_cache_size tunablearm/morello/master
The valgrind/helgrind test suite needs a way to make stack dealloction more prompt, and this feature seems to be generally useful. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
-rw-r--r--NEWS3
-rw-r--r--manual/tunables.texi9
-rw-r--r--nptl/nptl-stack.c8
-rw-r--r--nptl/nptl-stack.h3
-rw-r--r--nptl/pthread_mutex_conf.c9
-rw-r--r--sysdeps/nptl/dl-tunables.list4
6 files changed, 32 insertions, 4 deletions
diff --git a/NEWS b/NEWS
index 37ba4334c6..6931135ab9 100644
--- a/NEWS
+++ b/NEWS
@@ -49,6 +49,9 @@ Major new features:
with names ending with .conf to logically classify the converter modules in
that directory.
+* On Linux, a new tunable, glibc.pthread.stack_cache_size, can be used
+ to configure the size of the thread stack cache.
+
Deprecated and removed features, and other changes affecting compatibility:
* The function pthread_mutex_consistent_np has been deprecated; programs
diff --git a/manual/tunables.texi b/manual/tunables.texi
index fe7c1313cc..d5d957fb5b 100644
--- a/manual/tunables.texi
+++ b/manual/tunables.texi
@@ -402,6 +402,15 @@ is acquired.
The default value of this tunable is @samp{100}.
@end deftp
+@deftp Tunable glibc.pthread.stack_cache_size
+This tunable configures the maximum size of the stack cache. Once the
+stack cache exceeds this size, unused thread stacks are returned to
+the kernel, to bring the cache size below this limit.
+
+The value is measured in bytes. The default is @samp{41943040}
+(fourty mibibytes).
+@end deftp
+
@node Hardware Capability Tunables
@section Hardware Capability Tunables
@cindex hardware capability tunables
diff --git a/nptl/nptl-stack.c b/nptl/nptl-stack.c
index 1a0c460ba8..3f33a4c20b 100644
--- a/nptl/nptl-stack.c
+++ b/nptl/nptl-stack.c
@@ -21,8 +21,7 @@
#include <ldsodefs.h>
#include <pthreadP.h>
-/* Maximum size in kB of cache. 40MiBi by default. */
-static const size_t stack_cache_maxsize = 40 * 1024 * 1024;
+size_t __nptl_stack_cache_maxsize = 40 * 1024 * 1024;
void
__nptl_stack_list_del (list_t *elem)
@@ -103,8 +102,9 @@ queue_stack (struct pthread *stack)
__nptl_stack_list_add (&stack->list, &GL (dl_stack_cache));
GL (dl_stack_cache_actsize) += stack->stackblock_size;
- if (__glibc_unlikely (GL (dl_stack_cache_actsize) > stack_cache_maxsize))
- __nptl_free_stacks (stack_cache_maxsize);
+ if (__glibc_unlikely (GL (dl_stack_cache_actsize)
+ > __nptl_stack_cache_maxsize))
+ __nptl_free_stacks (__nptl_stack_cache_maxsize);
}
void
diff --git a/nptl/nptl-stack.h b/nptl/nptl-stack.h
index a6bd8df77f..8bcfde7ec5 100644
--- a/nptl/nptl-stack.h
+++ b/nptl/nptl-stack.h
@@ -25,6 +25,9 @@
#include <list.h>
#include <stdbool.h>
+/* Maximum size of the cache, in bytes. 40 MiB by default. */
+extern size_t __nptl_stack_cache_maxsize attribute_hidden;
+
/* Check whether the stack is still used or not. */
static inline bool
__nptl_stack_in_use (struct pthread *pd)
diff --git a/nptl/pthread_mutex_conf.c b/nptl/pthread_mutex_conf.c
index e6235dea47..c8f171c995 100644
--- a/nptl/pthread_mutex_conf.c
+++ b/nptl/pthread_mutex_conf.c
@@ -23,6 +23,7 @@
#include <stdbool.h>
#include <unistd.h> /* Get STDOUT_FILENO for _dl_printf. */
#include <elf/dl-tunables.h>
+#include <nptl-stack.h>
struct mutex_config __mutex_aconf =
{
@@ -38,10 +39,18 @@ TUNABLE_CALLBACK (set_mutex_spin_count) (tunable_val_t *valp)
__mutex_aconf.spin_count = (int32_t) (valp)->numval;
}
+static void
+TUNABLE_CALLBACK (set_stack_cache_size) (tunable_val_t *valp)
+{
+ __nptl_stack_cache_maxsize = valp->numval;
+}
+
void
__pthread_tunables_init (void)
{
TUNABLE_GET (mutex_spin_count, int32_t,
TUNABLE_CALLBACK (set_mutex_spin_count));
+ TUNABLE_GET (stack_cache_size, size_t,
+ TUNABLE_CALLBACK (set_stack_cache_size));
}
#endif
diff --git a/sysdeps/nptl/dl-tunables.list b/sysdeps/nptl/dl-tunables.list
index e3f6432e60..ac5d053298 100644
--- a/sysdeps/nptl/dl-tunables.list
+++ b/sysdeps/nptl/dl-tunables.list
@@ -23,5 +23,9 @@ glibc {
maxval: 32767
default: 100
}
+ stack_cache_size {
+ type: SIZE_T
+ default: 41943040
+ }
}
}