[PATCH]:pthread PTHREAD_STACK_MIN with large PAGE_SIZE

[Kamal Dasu]

Using uClibc 09.30.1  I hit a problem when running timers with SIGEV_THREAD
option on a MIPS system with PAGE_SIZE>=16K.
In uClibc pthread library PTHREAD_STACK_MIN is defined at 16K. This is used
when creating a thread to set the default pthread_attr stack size. However
implementations could have page_size >= 16K in which case the check for the
minimum stack size in _pthread_create() will fail. The only fix seems to be
increasing the value to 2* PAGE_SIZE. However a cleaner way to fix this
would be increasing the PTHREAD_STACK_MIN based on the page size to make
optimal use of resources. The patch below shows the only feasible way I
could find to do this.


Adjust stack size for PAGE_SIZE >= 16K. Needed to make timer uses
SIGEV_THREAD attribute.

---
 .../uClibc/libpthread/nptl/pthread_attr_setstack.c |    2 +-
 .../libpthread/nptl/pthread_attr_setstacksize.c    |    2 +-
 .../libpthread/nptl/sysdeps/pthread/pthread.h      |    1 +
 .../nptl/sysdeps/unix/sysv/linux/bits/local_lim.h  |    3 ++-
 4 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/uclinux-rootfs/lib/uClibc/libpthread/nptl/pthread_attr_setstack.c
b/uclinux-rootfs/lib/uClibc/libpthread/nptl/pthread_attr_setstack.c
index d400f3d..7327e7d 100644
--- a/uclinux-rootfs/lib/uClibc/libpthread/nptl/pthread_attr_setstack.c
+++ b/uclinux-rootfs/lib/uClibc/libpthread/nptl/pthread_attr_setstack.c
@@ -49,7 +49,7 @@ __pthread_attr_setstack (
   return 0;
 }

-#if PTHREAD_STACK_MIN == 16384
+#if PTHREAD_STACK_MIN >= 16384
 strong_alias(__pthread_attr_setstack, pthread_attr_setstack)
 #else
 weak_alias(__pthread_attr_setstack, pthread_attr_setstack)
diff --git a/uclinux-rootfs/lib/uClibc/libpthread/nptl/pthread_attr_setstacksize.c
b/uclinux-rootfs/lib/uClibc/libpthread/nptl/pthread_attr_setstacksize.c
index 24e5b0a..d2ae5fe 100644
--- a/uclinux-rootfs/lib/uClibc/libpthread/nptl/pthread_attr_setstacksize.c
+++ b/uclinux-rootfs/lib/uClibc/libpthread/nptl/pthread_attr_setstacksize.c
@@ -42,7 +42,7 @@ __pthread_attr_setstacksize (
   return 0;
 }

-#if PTHREAD_STACK_MIN == 16384
+#if PTHREAD_STACK_MIN >= 16384
 strong_alias(__pthread_attr_setstacksize, pthread_attr_setstacksize)
 #else
 weak_alias(__pthread_attr_setstacksize, pthread_attr_setstacksize)
diff --git a/uclinux-rootfs/lib/uClibc/libpthread/nptl/sysdeps/pthread/pthread.h
b/uclinux-rootfs/lib/uClibc/libpthread/nptl/sysdeps/pthread/pthread.h
index deb7430..eeeefb7 100644
--- a/uclinux-rootfs/lib/uClibc/libpthread/nptl/sysdeps/pthread/pthread.h
+++ b/uclinux-rootfs/lib/uClibc/libpthread/nptl/sysdeps/pthread/pthread.h
@@ -32,6 +32,7 @@
 #include <bits/wordsize.h>
 #if defined _LIBC && ( defined IS_IN_libc || defined NOT_IN_libc )
 #include <bits/uClibc_pthread.h>
+#include <bits/uClibc_page.h>
 #endif


diff --git a/uclinux-rootfs/lib/uClibc/libpthread/nptl/sysdeps/unix/sysv/linux/bits/local_lim.h
b/uclinux-rootfs/lib/uClibc/libpthread/nptl/sysdeps/unix/sysv/linux/bits/local_lim.h
index 8f0df4f..07cd5bd 100644
--- a/uclinux-rootfs/lib/uClibc/libpthread/nptl/sysdeps/unix/sysv/linux/bits/local_lim.h
+++ b/uclinux-rootfs/lib/uClibc/libpthread/nptl/sysdeps/unix/sysv/linux/bits/local_lim.h
@@ -37,6 +37,7 @@

 /* The kernel sources contain a file with all the needed information.  */
 #include <linux/limits.h>
+#include <pthread.h>

 /* Have to remove NR_OPEN?  */
 #ifdef __undef_NR_OPEN
@@ -79,7 +80,7 @@
 #define AIO_PRIO_DELTA_MAX	20

 /* Minimum size for a thread.  We are free to choose a reasonable value.  */
-#define PTHREAD_STACK_MIN	16384
+#define PTHREAD_STACK_MIN ( (PAGE_SIZE == 4096) ? 16384 : PAGE_SIZE << 1 )

 /* Maximum number of timer expiration overruns.  */
 #define DELAYTIMER_MAX	2147483647
-- 


Kamal