Revert "[PATCH] mm: micro optimise zone_watermark_ok"
authorLinus Torvalds <torvalds@woody.linux-foundation.org>
Thu, 1 Feb 2007 00:43:36 +0000 (16:43 -0800)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Thu, 1 Feb 2007 00:46:40 +0000 (16:46 -0800)
This reverts commit e80ee884ae0e3794ef2b65a18a767d502ad712ee.

Pawel Sikora had a boot-time oops due to it - because the sign change
invalidates the following comparisons, since 'free_pages' can be
negative.

The micro-optimization just isn't worth it.

Bisected-by: Pawel Sikora <pluto@agmk.net>
Acked-by: Andrew Morton <akpm@osdl.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/page_alloc.c

index fc5b5442e9421efc9044eed23e3a188fffe5cce7..2c606cc922a50cc212b6f4abd6e8635356ebb99e 100644 (file)
@@ -989,8 +989,7 @@ int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
                      int classzone_idx, int alloc_flags)
 {
        /* free_pages my go negative - that's OK */
-       unsigned long min = mark;
-       long free_pages = z->free_pages - (1 << order) + 1;
+       long min = mark, free_pages = z->free_pages - (1 << order) + 1;
        int o;
 
        if (alloc_flags & ALLOC_HIGH)