Make the storage low-water mark a function of the number of threads.

2008-12-16  Neal H. Walfield  <neal@gnu.org>

	* storage.c (num_threads): New function.
	(FREE_PAGES_LOW_WATER): Make it a function of the number of
	threads.
	(FREE_PAGES_SERIALIZE): Likewise.

2 files changed, 21 insertions, 4 deletions

diff --git a/libhurd-mm/ChangeLog b/libhurd-mm/ChangeLog
index f8fb701..ac6dace 100644
--- a/libhurd-mm/ChangeLog
+++ b/libhurd-mm/ChangeLog
@@ -1,5 +1,12 @@
 2008-12-16  Neal H. Walfield  <neal@gnu.org>
 
+	* storage.c (num_threads): New function.
+	(FREE_PAGES_LOW_WATER): Make it a function of the number of
+	threads.
+	(FREE_PAGES_SERIALIZE): Likewise.
+
+2008-12-16  Neal H. Walfield  <neal@gnu.org>
+
 	* storage.c (struct storage_desc) [!NDEBUG]: Add field owner.
 	(shadow_setup): Set DESC->OWNER appropriately.
 	(storage_alloc): Likewise.
diff --git a/libhurd-mm/storage.c b/libhurd-mm/storage.c
index cfdb6ed..3f774e1 100644
--- a/libhurd-mm/storage.c
+++ b/libhurd-mm/storage.c
@@ -325,14 +325,24 @@ storage_shadow_setup (struct cap *cap, addr_t folio)
 
 static bool storage_init_done;
 
-/* The minimum number of pages that should be available.  This should
-   probably be per-thread (or at least per-CPU).  */
-#define FREE_PAGES_LOW_WATER 64
+static int
+num_threads (void)
+{
+  extern int __pthread_num_threads __attribute__ ((weak));
+
+  if (&__pthread_num_threads)
+    return __pthread_num_threads;
+  else
+    return 1;
+}
+
+/* The minimum number of pages that should be available.  */
+#define FREE_PAGES_LOW_WATER (32 + 16 * num_threads ())
 /* If the number of free pages drops below this amount, the we might
    soon have a problem.  In this case, we serialize access to the pool
    of available pages to allow some thread that is able to allocate
    more pages the chance to do so.  */
-#define FREE_PAGES_SERIALIZE 32
+#define FREE_PAGES_SERIALIZE (16 + 8 * num_threads ())
 
 static pthread_mutex_t storage_low_mutex
   = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;