From: JoonSoo Kim <js1304@gmail.com>
To: Sasha Levin <sasha.levin@oracle.com>
Cc: David Rientjes <rientjes@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
"David S. Miller" <davem@davemloft.net>,
Tejun Heo <tj@kernel.org>, Yinghai Lu <yinghai@kernel.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] mm, bootmem: panic in bootmem alloc functions even if slab is available
Date: Fri, 28 Dec 2012 23:42:24 +0900 [thread overview]
Message-ID: <CAAmzW4MhCyYkdpOaHnJtoMoJeFsXQJXN=Cpo3s67=s+id-hrMg@mail.gmail.com> (raw)
In-Reply-To: <50DCD4CB.50205@oracle.com>
Hello, Sasha.
2012/12/28 Sasha Levin <sasha.levin@oracle.com>:
> On 12/27/2012 06:04 PM, David Rientjes wrote:
>> On Thu, 27 Dec 2012, Sasha Levin wrote:
>>
>>> That's exactly what happens with the patch. Note that in the current upstream
>>> version there are several slab checks scattered all over.
>>>
>>> In this case for example, I'm removing it from __alloc_bootmem_node(), but the
>>> first code line of__alloc_bootmem_node_nopanic() is:
>>>
>>> if (WARN_ON_ONCE(slab_is_available()))
>>> return kzalloc(size, GFP_NOWAIT);
>>>
>>
>> You're only talking about mm/bootmem.c and not mm/nobootmem.c, and notice
>> that __alloc_bootmem_node() does not call __alloc_bootmem_node_nopanic(),
>> it calls ___alloc_bootmem_node_nopanic().
>
> Holy cow, this is an underscore hell.
>
>
> Thanks,
> Sasha
>
I have a different idea.
How about removing fallback allocation in bootmem.c completely?
I don't know why it is there exactly.
But, warning for 'slab_is_available()' is there for a long time.
So, most people who misuse fallback allocation change their code adequately.
I think that removing fallback at this time is valid. Isn't it?
Fallback allocation may cause possible bug.
If someone free a memory from fallback allocation,
it can't be handled properly.
So, IMHO, at this time, we should remove fallback allocation in
bootmem.c entirely.
Please let me know what I misunderstand.
Thanks.
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next prev parent reply other threads:[~2012-12-28 14:42 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-23 20:15 [PATCH 1/3] mm, sparse: allocate bootmem without panicing in sparse_mem_maps_populate_node Sasha Levin
2012-12-23 20:15 ` [PATCH 2/3] mm, bootmem: panic in bootmem alloc functions even if slab is available Sasha Levin
2012-12-27 22:25 ` David Rientjes
2012-12-27 22:27 ` Pekka Enberg
2012-12-27 22:31 ` David Rientjes
2012-12-27 22:38 ` Pekka Enberg
2012-12-27 22:40 ` Sasha Levin
2012-12-27 23:04 ` David Rientjes
2012-12-27 23:07 ` Sasha Levin
2012-12-28 14:42 ` JoonSoo Kim [this message]
2012-12-28 19:16 ` Yinghai Lu
2012-12-23 20:15 ` [PATCH 3/3] mm, sparse: don't check return value of alloc_bootmem calls Sasha Levin
2012-12-27 22:28 ` David Rientjes
2012-12-27 22:23 ` [PATCH 1/3] mm, sparse: allocate bootmem without panicing in sparse_mem_maps_populate_node David Rientjes
2012-12-27 22:41 ` Sasha Levin
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