linux-kernel - Re: kernel BUGs when removing largish files with the SLOB allocator

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Date:	Tue, 12 Sep 2006 18:53:28 +0800
From:	Aubrey <aubreylee@...il.com>
To:	"David Howells" <dhowells@...hat.com>
Cc:	"Nick Piggin" <nickpiggin@...oo.com.au>,
	linux-kernel@...r.kernel.org, mpm@...enic.com, davidm@...pgear.com,
	gerg@...pgear.com
Subject: Re: kernel BUGs when removing largish files with the SLOB allocator

On 9/12/06, David Howells <dhowells@...hat.com> wrote:
> Aubrey <aubreylee@...il.com> wrote:
>
> > OK. Here is the patch and work properly on my side.
> > Welcome any suggestions and comments.
>
> It looks reasonable.  Don't forget to sign off the patch.
>
> > void kmem_cache_init(void)
> > {
> > +#if 0
> >       void *p = slob_alloc(PAGE_SIZE, 0, PAGE_SIZE-1);
> >
> >       if (p)
> >               free_page((unsigned long)p);
> > +#endif
>
> Any idea what that's about?
>
IMHO kmem_cache_init() needn't to do anything for the slob allocation.

In addition, the original code allocate one page and then free it.
Here, with the patch, slob_alloc() will set the SLAB flag on the page,
and the page with this flag can't pass the free_pages_check(), if so,
the kernel will run into bad_page() panic.

So, I removed this piece of code for the draft of the patch.
Welcome any better idea.

Regards,
-Aubrey
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