use the right memory barriers
diff --git a/src/os/unix/ngx_gcc_atomic_ppc.h b/src/os/unix/ngx_gcc_atomic_ppc.h
index cfa58f9..e82e755 100644
--- a/src/os/unix/ngx_gcc_atomic_ppc.h
+++ b/src/os/unix/ngx_gcc_atomic_ppc.h
@@ -15,6 +15,11 @@
* any register except r0. The r0 register always has a zero value and
* could not be used in "addi r0, r0, 1".
* The "=&b" means that no input registers can be used.
+ *
+ * "sync" read and write barriers
+ * "isync" read barrier, is faster than "sync"
+ * "eieio" write barrier, is faster than "sync"
+ * "lwsync" write barrier, is faster than "eieio" on ppc64
*/
#if (NGX_PTR_SIZE == 8)
@@ -28,6 +33,7 @@
__asm__ volatile (
" li %0, 0 \n" /* preset "0" to "res" */
+ " lwsync \n" /* write barrier */
"1: \n"
" ldarx %1, 0, %2 \n" /* load from [lock] into "temp" */
/* and store reservation */
@@ -36,6 +42,7 @@
" stdcx. %4, 0, %2 \n" /* store "set" into [lock] if reservation */
/* is not cleared */
" bne- 1b \n" /* the reservation was cleared */
+ " isync \n" /* read barrier */
" li %0, 1 \n" /* set "1" to "res" */
"2: \n"
@@ -54,12 +61,14 @@
__asm__ volatile (
+ " lwsync \n" /* write barrier */
"1: ldarx %0, 0, %2 \n" /* load from [value] into "res" */
/* and store reservation */
" add %1, %0, %3 \n" /* "res" + "add" store in "temp" */
" stdcx. %1, 0, %2 \n" /* store "temp" into [value] if reservation */
/* is not cleared */
" bne- 1b \n" /* try again if reservation was cleared */
+ " isync \n" /* read barrier */
: "=&b" (res), "=&b" (temp)
: "b" (value), "b" (add)
@@ -70,7 +79,8 @@
#if (NGX_SMP)
-#define ngx_memory_barrier() __asm__ volatile ("lwsync\n" ::: "memory")
+#define ngx_memory_barrier() \
+ __asm__ volatile ("isync \n lwsync \n" ::: "memory")
#else
#define ngx_memory_barrier() __asm__ volatile ("" ::: "memory")
#endif
@@ -86,6 +96,7 @@
__asm__ volatile (
" li %0, 0 \n" /* preset "0" to "res" */
+ " eieio \n" /* write barrier */
"1: \n"
" lwarx %1, 0, %2 \n" /* load from [lock] into "temp" */
/* and store reservation */
@@ -94,6 +105,7 @@
" stwcx. %4, 0, %2 \n" /* store "set" into [lock] if reservation */
/* is not cleared */
" bne- 1b \n" /* the reservation was cleared */
+ " isync \n" /* read barrier */
" li %0, 1 \n" /* set "1" to "res" */
"2: \n"
@@ -112,12 +124,14 @@
__asm__ volatile (
+ " eieio \n" /* write barrier */
"1: lwarx %0, 0, %2 \n" /* load from [value] into "res" */
/* and store reservation */
" add %1, %0, %3 \n" /* "res" + "add" store in "temp" */
" stwcx. %1, 0, %2 \n" /* store "temp" into [value] if reservation */
/* is not cleared */
" bne- 1b \n" /* try again if reservation was cleared */
+ " isync \n" /* read barrier */
: "=&b" (res), "=&b" (temp)
: "b" (value), "b" (add)
@@ -128,7 +142,8 @@
#if (NGX_SMP)
-#define ngx_memory_barrier() __asm__ volatile ("sync\n" ::: "memory")
+#define ngx_memory_barrier() \
+ __asm__ volatile ("isync \n eieio \n" ::: "memory")
#else
#define ngx_memory_barrier() __asm__ volatile ("" ::: "memory")
#endif
