[PATCH] s390: add read_mostly optimization
Add a read_mostly section and define __read_mostly to prevent cache line
pollution due to writes for mostly read variables. In addition fix the
incorrect alignment of the cache_line_aligned data section. s390 has a
cacheline size of 256 bytes.
Signed-off-by: Christian Borntraeger <cborntra@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S
index 9289fac..9f34bb5 100644
--- a/arch/s390/kernel/vmlinux.lds.S
+++ b/arch/s390/kernel/vmlinux.lds.S
@@ -58,9 +58,11 @@
. = ALIGN(4096);
.data.page_aligned : { *(.data.idt) }
- . = ALIGN(32);
+ . = ALIGN(256);
.data.cacheline_aligned : { *(.data.cacheline_aligned) }
+ . = ALIGN(256);
+ .data.read_mostly : { *(.data.read_mostly) }
_edata = .; /* End of data section */
. = ALIGN(8192); /* init_task */
diff --git a/include/asm-s390/cache.h b/include/asm-s390/cache.h
index e20cdd9..cdf431b 100644
--- a/include/asm-s390/cache.h
+++ b/include/asm-s390/cache.h
@@ -16,4 +16,6 @@
#define ARCH_KMALLOC_MINALIGN 8
+#define __read_mostly __attribute__((__section__(".data.read_mostly")))
+
#endif