The patch titled
Subject: mm/nommu.c: drop unlikely inside BUG_ON()
has been added to the -mm tree. Its filename is
mm-nommu-drop-unlikely-behind-bug_on.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-nommu-drop-unlikely-behind-bug_on.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-nommu-drop-unlikely-behind-bug_on.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Geliang Tang <geliangtang@xxxxxxx>
Subject: mm/nommu.c: drop unlikely inside BUG_ON()
(1) For !CONFIG_BUG cases, the bug call is a no-op, so we couldn't
care less and the change is ok.
(2) ppc and mips, which HAVE_ARCH_BUG_ON, do not rely on branch
predictions as it seems to be pointless[1] and thus callers should not
be trying to push an optimization in the first place.
(3) For CONFIG_BUG and !HAVE_ARCH_BUG_ON cases, BUG_ON() contains an
unlikely compiler flag already.
Hence, we can drop unlikely behind BUG_ON().
[1] http://lkml.iu.edu/hypermail/linux/kernel/1101.3/02289.html
Signed-off-by: Geliang Tang <geliangtang@xxxxxxx>
Acked-by: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/nommu.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff -puN mm/nommu.c~mm-nommu-drop-unlikely-behind-bug_on mm/nommu.c
--- a/mm/nommu.c~mm-nommu-drop-unlikely-behind-bug_on
+++ a/mm/nommu.c
@@ -578,16 +578,16 @@ static noinline void validate_nommu_regi
return;
last = rb_entry(lastp, struct vm_region, vm_rb);
- BUG_ON(unlikely(last->vm_end <= last->vm_start));
- BUG_ON(unlikely(last->vm_top < last->vm_end));
+ BUG_ON(last->vm_end <= last->vm_start);
+ BUG_ON(last->vm_top < last->vm_end);
while ((p = rb_next(lastp))) {
region = rb_entry(p, struct vm_region, vm_rb);
last = rb_entry(lastp, struct vm_region, vm_rb);
- BUG_ON(unlikely(region->vm_end <= region->vm_start));
- BUG_ON(unlikely(region->vm_top < region->vm_end));
- BUG_ON(unlikely(region->vm_start < last->vm_top));
+ BUG_ON(region->vm_end <= region->vm_start);
+ BUG_ON(region->vm_top < region->vm_end);
+ BUG_ON(region->vm_start < last->vm_top);
lastp = p;
}
_
Patches currently in -mm which might be from geliangtang@xxxxxxx are
mm-nommu-drop-unlikely-behind-bug_on.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
