[PATCH] Optimize D-cache alias handling on fork

Virtually index, physically tagged cache architectures can get away
without cache flushing when forking.  This patch adds a new cache
flushing function flush_cache_dup_mm(struct mm_struct *) which for the
moment I've implemented to do the same thing on all architectures
except on MIPS where it's a no-op.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/asm-mips/cacheflush.h b/include/asm-mips/cacheflush.h
index e3c9925876a3..0ddada3bb0b6 100644
--- a/include/asm-mips/cacheflush.h
+++ b/include/asm-mips/cacheflush.h
@@ -17,6 +17,7 @@
  *
  *  - flush_cache_all() flushes entire cache
  *  - flush_cache_mm(mm) flushes the specified mm context's cache lines
+ *  - flush_cache_dup mm(mm) handles cache flushing when forking
  *  - flush_cache_page(mm, vmaddr, pfn) flushes a single page
  *  - flush_cache_range(vma, start, end) flushes a range of pages
  *  - flush_icache_range(start, end) flush a range of instructions
@@ -31,6 +32,7 @@
 extern void (*flush_cache_all)(void);
 extern void (*__flush_cache_all)(void);
 extern void (*flush_cache_mm)(struct mm_struct *mm);
+#define flush_cache_dup_mm(mm)  do { (void) (mm); } while (0)
 extern void (*flush_cache_range)(struct vm_area_struct *vma,
         unsigned long start, unsigned long end);
 extern void (*flush_cache_page)(struct vm_area_struct *vma, unsigned long page, unsigned long pfn);