On Sat, Dec 08, 2007 at 10:30:39AM +0100, Ingo Molnar wrote:
> 
> * Rafael J. Wysocki <[EMAIL PROTECTED]> wrote:
> 
> > Subject             : tipc_init(), WARNING: at arch/x86/mm/highmem_32.c:52 
> > kmap_atomic_prot()
> > Submitter   : Ingo Molnar <[EMAIL PROTECTED]>
> > References  : http://lkml.org/lkml/2007/11/29/157
> >               http://bugzilla.kernel.org/show_bug.cgi?id=9497
> > Handled-By  : Matt Mackall <[EMAIL PROTECTED]>
> > Patch               : http://lkml.org/lkml/2007/11/29/387
> 
> Matt, the above bug is still occuring en masse during random bootups:
> 

I was hoping for some discussion about whether it was the best fix.
The current kzalloc thing strikes me as a step backwards for all
allocators. We'd do better to have a single non-inline kzalloc
function rather than an extra branch in the normal kmalloc fast path.

But here's the patch again, with my sign-off:


Avoid calling page allocator with __GFP_ZERO, as we might be in atomic
context and this will make thing unhappy on highmem systems. Instead,
manually zero allocations from the page allocator.

Signed-off-by: Matt Mackall <[EMAIL PROTECTED]>

diff -r f7edf7226317 mm/slob.c
--- a/mm/slob.c Wed Dec 05 15:57:06 2007 -0600
+++ b/mm/slob.c Wed Dec 05 15:57:51 2007 -0600
@@ -223,6 +231,7 @@ static void *slob_new_page(gfp_t gfp, in
 {
        void *page;
 
+       gfp &= ~__GFP_ZERO;
 #ifdef CONFIG_NUMA
        if (node != -1)
                page = alloc_pages_node(node, gfp, order);
@@ -457,6 +470,8 @@ void *__kmalloc_node(size_t size, gfp_t 
                        page = virt_to_page(ret);
                        page->private = size;
                }
+               if (unlikely((gfp & __GFP_ZERO) && ret))
+                       memset(ret, 0, size);
                return ret;
        }
 }


-- 
Mathematics is the supreme nostalgia of our time.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to