On Sun, Sep 27, 2015 at 09:04:16PM +0000, Alexandru Moise wrote: > Their stored values come from zone_page_state() which returns > an unsigned long. To improve code correctness we should avoid > mixing signed and unsigned integers. > > Signed-off-by: Alexandru Moise <00moses.alexander00@xxxxxxxxx> > --- > mm/page_alloc.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 48aaf7b..f55e3a2 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -2242,7 +2242,7 @@ static bool __zone_watermark_ok(struct zone *z, unsigned int order, > /* free_pages may go negative - that's OK */ > long min = mark; > int o; > - long free_cma = 0; > + unsigned long free_cma = 0; > NAK. free_cma is used with free_pages which is explicitly commented as saying it can go negative. With your patch, there is a signed/unsigned operation where the unsigned type cannot fit into the signed type which casts them both to unsigned which is then broken for the comparison. This patch looks broken for very subtle reasons. Please do not do any similar style patches to this because they can introduce subtle breakage if issues are not caught at review. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>