linux-kernel - Re: linux-next: build failure after merge of the final tree (slab tree related)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <alpine.DEB.2.00.1008250846590.13026@router.home>
Date:	Wed, 25 Aug 2010 08:50:52 -0500 (CDT)
From:	Christoph Lameter <cl@...ux.com>
To:	Pekka Enberg <penberg@...helsinki.fi>
cc:	Tejun Heo <tj@...nel.org>, Stephen Rothwell <sfr@...b.auug.org.au>,
	linux-next@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: linux-next: build failure after merge of the final tree (slab
 tree related)

On Wed, 25 Aug 2010, Pekka Enberg wrote:

> On 8/25/10 11:18 AM, Tejun Heo wrote:
> > Hello,
> >
> > On 08/24/2010 08:53 PM, Christoph Lameter wrote:
> > > > [    0.000000] Kernel panic - not syncing: Cannot create slab kmem_cache
> > > > size=232 realsize=256 order=0 offset=0 flags=42000
> > >
> > > alloc per cpu result in kmalloc which fails.
> > >
> > > Tejon: Is there some way we could get a reserved per cpu area under UP
> > > instead of fallback to slab allocations during bootup?
> >
> > Eh... nasty.  Maybe we can create a alloc_percpu_early() function
> > which doesn't allow freeing of allocate memory and just redirect to
> > bootmem on UP?
>
> Yeah, I was thinking about that too.

Another solution is to allocate an order 1 (compound) page for each early
cache. Then resize the kmalloc array after everything is up. kfree() will
then redirect to the page allocator.

But this is a slab allocator specific solution.

We now have the situation that alloc_percpu can only be used on early boot
on SMP machines. A general solution would be better I think.

If the early alloc_percpu stuff would work consistently then it could also
be used to avoid the boot_pageset in the page allocator f.e.

Can we just get rid of the special UP case and just run the percpu
subsystem even for UP?

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/