* Re: [PATCH v2 2/2] memblock: do not start bottom-up allocations with kernel_end
[not found] <20201220064959.GB392325@kernel.org>
@ 2021-01-22 4:37 ` Thiago Jung Bauermann
2021-01-24 2:09 ` Andrew Morton
0 siblings, 1 reply; 5+ messages in thread
From: Thiago Jung Bauermann @ 2021-01-22 4:37 UTC (permalink / raw)
To: rppt
Cc: riel, kernel-team, Ram Pai, linux-kernel, guro, linux-mm,
Satheesh Rajendran, Konrad Rzeszutek Wilk, iamjoonsoo.kim,
mhocko, linuxppc-dev, akpm, Thiago Jung Bauermann
Mike Rapoport <rppt@kernel.org> writes:
> > Signed-off-by: Roman Gushchin <guro@fb.com>
>
> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
I've seen a couple of spurious triggers of the WARN_ONCE() removed by this
patch. This happens on some ppc64le bare metal (powernv) server machines with
CONFIG_SWIOTLB=y and crashkernel=4G, as described in a candidate patch I posted
to solve this issue in a different way:
https://lore.kernel.org/linuxppc-dev/20201218062103.76102-1-bauerman@linux.ibm.com/
Since this patch solves that problem, is it possible to include it in the next
feasible v5.11-rcX, with the following tag?
Fixes: 8fabc623238e ("powerpc: Ensure that swiotlb buffer is allocated from low memory")
This is because reverting the commit above also solves the problem on the
machines where I've seen this issue.
--
Thiago Jung Bauermann
IBM Linux Technology Center
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2 2/2] memblock: do not start bottom-up allocations with kernel_end
2021-01-22 4:37 ` [PATCH v2 2/2] memblock: do not start bottom-up allocations with kernel_end Thiago Jung Bauermann
@ 2021-01-24 2:09 ` Andrew Morton
2021-01-24 7:34 ` Mike Rapoport
0 siblings, 1 reply; 5+ messages in thread
From: Andrew Morton @ 2021-01-24 2:09 UTC (permalink / raw)
To: Thiago Jung Bauermann
Cc: riel, kernel-team, Ram Pai, linux-kernel, mhocko, linux-mm,
Satheesh Rajendran, Konrad Rzeszutek Wilk, iamjoonsoo.kim,
linuxppc-dev, guro, rppt
On Fri, 22 Jan 2021 01:37:14 -0300 Thiago Jung Bauermann <bauerman@linux.ibm.com> wrote:
> Mike Rapoport <rppt@kernel.org> writes:
>
> > > Signed-off-by: Roman Gushchin <guro@fb.com>
> >
> > Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
>
> I've seen a couple of spurious triggers of the WARN_ONCE() removed by this
> patch. This happens on some ppc64le bare metal (powernv) server machines with
> CONFIG_SWIOTLB=y and crashkernel=4G, as described in a candidate patch I posted
> to solve this issue in a different way:
>
> https://lore.kernel.org/linuxppc-dev/20201218062103.76102-1-bauerman@linux.ibm.com/
>
> Since this patch solves that problem, is it possible to include it in the next
> feasible v5.11-rcX, with the following tag?
We could do this, if we're confident that this patch doesn't depend on
[1/2] "mm: cma: allocate cma areas bottom-up"? I think it is...
> Fixes: 8fabc623238e ("powerpc: Ensure that swiotlb buffer is allocated from low memory")
I added that.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2 2/2] memblock: do not start bottom-up allocations with kernel_end
2021-01-24 2:09 ` Andrew Morton
@ 2021-01-24 7:34 ` Mike Rapoport
2021-01-26 0:30 ` Thiago Jung Bauermann
2021-02-08 23:58 ` Thiago Jung Bauermann
0 siblings, 2 replies; 5+ messages in thread
From: Mike Rapoport @ 2021-01-24 7:34 UTC (permalink / raw)
To: Andrew Morton
Cc: riel, kernel-team, Ram Pai, linux-kernel, mhocko, linux-mm,
Satheesh Rajendran, Konrad Rzeszutek Wilk, iamjoonsoo.kim,
linuxppc-dev, guro, Thiago Jung Bauermann
On Sat, Jan 23, 2021 at 06:09:11PM -0800, Andrew Morton wrote:
> On Fri, 22 Jan 2021 01:37:14 -0300 Thiago Jung Bauermann <bauerman@linux.ibm.com> wrote:
>
> > Mike Rapoport <rppt@kernel.org> writes:
> >
> > > > Signed-off-by: Roman Gushchin <guro@fb.com>
> > >
> > > Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
> >
> > I've seen a couple of spurious triggers of the WARN_ONCE() removed by this
> > patch. This happens on some ppc64le bare metal (powernv) server machines with
> > CONFIG_SWIOTLB=y and crashkernel=4G, as described in a candidate patch I posted
> > to solve this issue in a different way:
> >
> > https://lore.kernel.org/linuxppc-dev/20201218062103.76102-1-bauerman@linux.ibm.com/
> >
> > Since this patch solves that problem, is it possible to include it in the next
> > feasible v5.11-rcX, with the following tag?
>
> We could do this, if we're confident that this patch doesn't depend on
> [1/2] "mm: cma: allocate cma areas bottom-up"? I think it is...
A think it does not depend on cma bottom-up allocation, it's rather the other
way around: without this CMA bottom-up allocation could fail with KASLR
enabled.
Still, this patch may need updates to the way x86 does early reservations:
https://lore.kernel.org/lkml/20210115083255.12744-1-rppt@kernel.org
> > Fixes: 8fabc623238e ("powerpc: Ensure that swiotlb buffer is allocated from low memory")
>
> I added that.
>
>
--
Sincerely yours,
Mike.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2 2/2] memblock: do not start bottom-up allocations with kernel_end
2021-01-24 7:34 ` Mike Rapoport
@ 2021-01-26 0:30 ` Thiago Jung Bauermann
2021-02-08 23:58 ` Thiago Jung Bauermann
1 sibling, 0 replies; 5+ messages in thread
From: Thiago Jung Bauermann @ 2021-01-26 0:30 UTC (permalink / raw)
To: Mike Rapoport
Cc: riel, kernel-team, Ram Pai, linux-kernel, guro, linux-mm,
Satheesh Rajendran, Konrad Rzeszutek Wilk, iamjoonsoo.kim,
mhocko, linuxppc-dev, Andrew Morton
Mike Rapoport <rppt@kernel.org> writes:
> On Sat, Jan 23, 2021 at 06:09:11PM -0800, Andrew Morton wrote:
>> On Fri, 22 Jan 2021 01:37:14 -0300 Thiago Jung Bauermann <bauerman@linux.ibm.com> wrote:
>>
>> > Mike Rapoport <rppt@kernel.org> writes:
>> >
>> > > > Signed-off-by: Roman Gushchin <guro@fb.com>
>> > >
>> > > Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
>> >
>> > I've seen a couple of spurious triggers of the WARN_ONCE() removed by this
>> > patch. This happens on some ppc64le bare metal (powernv) server machines with
>> > CONFIG_SWIOTLB=y and crashkernel=4G, as described in a candidate patch I posted
>> > to solve this issue in a different way:
>> >
>> > https://lore.kernel.org/linuxppc-dev/20201218062103.76102-1-bauerman@linux.ibm.com/
>> >
>> > Since this patch solves that problem, is it possible to include it in the next
>> > feasible v5.11-rcX, with the following tag?
>>
>> We could do this,
Thanks!
>> if we're confident that this patch doesn't depend on
>> [1/2] "mm: cma: allocate cma areas bottom-up"? I think it is...
>
> A think it does not depend on cma bottom-up allocation, it's rather the other
> way around: without this CMA bottom-up allocation could fail with KASLR
> enabled.
I agree. Conceptually, this could have been patch 1 in this series.
> Still, this patch may need updates to the way x86 does early reservations:
>
> https://lore.kernel.org/lkml/20210115083255.12744-1-rppt@kernel.org
Ah, I wasn't aware of this. Thanks for fixing those issues. That series
seems to be well accepted.
>> > Fixes: 8fabc623238e ("powerpc: Ensure that swiotlb buffer is allocated from low memory")
>>
>> I added that.
Thanks!
--
Thiago Jung Bauermann
IBM Linux Technology Center
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2 2/2] memblock: do not start bottom-up allocations with kernel_end
2021-01-24 7:34 ` Mike Rapoport
2021-01-26 0:30 ` Thiago Jung Bauermann
@ 2021-02-08 23:58 ` Thiago Jung Bauermann
1 sibling, 0 replies; 5+ messages in thread
From: Thiago Jung Bauermann @ 2021-02-08 23:58 UTC (permalink / raw)
To: Mike Rapoport
Cc: riel, iamjoonsoo.kim, Ram Pai, linux-kernel, mhocko, linux-mm,
Satheesh Rajendran, guro, Konrad Rzeszutek Wilk, Andrew Morton,
linuxppc-dev, kernel-team
Mike Rapoport <rppt@kernel.org> writes:
> On Sat, Jan 23, 2021 at 06:09:11PM -0800, Andrew Morton wrote:
>> On Fri, 22 Jan 2021 01:37:14 -0300 Thiago Jung Bauermann <bauerman@linux.ibm.com> wrote:
>>
>> > Mike Rapoport <rppt@kernel.org> writes:
>> >
>> > > > Signed-off-by: Roman Gushchin <guro@fb.com>
>> > >
>> > > Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
>> >
>> > I've seen a couple of spurious triggers of the WARN_ONCE() removed by this
>> > patch. This happens on some ppc64le bare metal (powernv) server machines with
>> > CONFIG_SWIOTLB=y and crashkernel=4G, as described in a candidate patch I posted
>> > to solve this issue in a different way:
>> >
>> > https://lore.kernel.org/linuxppc-dev/20201218062103.76102-1-bauerman@linux.ibm.com/
>> >
>> > Since this patch solves that problem, is it possible to include it in the next
>> > feasible v5.11-rcX, with the following tag?
>>
>> We could do this, if we're confident that this patch doesn't depend on
>> [1/2] "mm: cma: allocate cma areas bottom-up"? I think it is...
>
> A think it does not depend on cma bottom-up allocation, it's rather the other
> way around: without this CMA bottom-up allocation could fail with KASLR
> enabled.
I noticed that this patch is now upstream as:
2dcb39645441 memblock: do not start bottom-up allocations with kernel_end
> Still, this patch may need updates to the way x86 does early reservations:
>
> https://lore.kernel.org/lkml/20210115083255.12744-1-rppt@kernel.org
... but the patches from this link still aren't. Isn't this a potential
problem for x86?
The patch series on the link above is now superseded by v2:
https://lore.kernel.org/linux-mm/20210128105711.10428-1-rppt@kernel.org/
--
Thiago Jung Bauermann
IBM Linux Technology Center
^ permalink raw reply [flat|nested] 5+ messages in thread
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2021-01-22 4:37 ` [PATCH v2 2/2] memblock: do not start bottom-up allocations with kernel_end Thiago Jung Bauermann
2021-01-24 2:09 ` Andrew Morton
2021-01-24 7:34 ` Mike Rapoport
2021-01-26 0:30 ` Thiago Jung Bauermann
2021-02-08 23:58 ` Thiago Jung Bauermann
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