Re: [BUG] perf kmem: Broken because of missing tracepoints

[Ravi Bangoria <ravi.bangoria@amd.com>]

On 06-Jan-23 10:52 AM, Leo Yan wrote:
> Hi Ravi, Arnaldo,
> 
> On Thu, Jan 05, 2023 at 01:27:30PM -0300, Arnaldo Carvalho de Melo wrote:
>> Em Thu, Jan 05, 2023 at 07:03:25PM +0530, Ravi Bangoria escreveu:
>>> Hello,
>>>
>>> Two tracepoints, kmem:kmalloc_node and kmem:kmem_cache_alloc_node used by perf-
>>> kmem tool were removed from kernel by commit 11e9734bcb6a7 ("mm/slab_common:
>>> unify NUMA and UMA version of tracepoints"). This causes issue while running
>>> perf kmem on latest kernel:
>>>
>>>   $ sudo ./perf kmem record
>>>   event syntax error: 'kmem:kmalloc_node'
>>>                        \___ unknown tracepoint
>>>
>>>   $ sudo ./perf kmem record
>>>   event syntax error: 'kmem:kmem_cache_alloc_node'
>>>                        \___ unknown tracepoint
>>>
>>> Haven't got a chance to debug further. Anyone aware of this?
>>
>> I didn't notice this so far, would be good to have a fix soon.
> 
> I looked a bit for the issue, so wrote a fix and verified on my
> Arm64 machine.  Please let me know if this works for you or not,
> thanks!
> 
> From b7d26f5543401924ae4ad93daeba66cd7d58eb39 Mon Sep 17 00:00:00 2001
> From: Leo Yan <leo.yan@linaro.org>
> Date: Fri, 6 Jan 2023 11:16:27 +0800
> Subject: [PATCH] perf kmem: Fix tracepoints breakage
> 
> Commit 11e9734bcb6a ("mm/slab_common: unify NUMA and UMA version of
> tracepoints") removed tracepoints 'kmalloc_node' and
> 'kmem_cache_alloc_node'; the tracepoints 'kmalloc'
> and 'kmem_cache_alloc' add an extra field 'node' to present the
> memory node to be allocated and replace the two removed tracepoints
> respectively.
> 
> The commit introduces ABI breakage, both for the dropped tracepoints and
> for the updated tracepoints.
> 
> To fix this issue, perf tool removes the support for the tracepoints
> 'kmalloc_node' and 'kmem_cache_alloc_node'; for the two updated
> tracepoints this patch reads out the new field 'node', if its value is
> NUMA_NO_NODE (-1), we doesn't take it as a cross memory allocation.
> 
> Reported-by: Ravi Bangoria <ravi.bangoria@amd.com>
> Fixes: 11e9734bcb6a ("mm/slab_common: unify NUMA and UMA version of tracepoints")
> Signed-off-by: Leo Yan <leo.yan@linaro.org>

Thanks Leo. A quick test shows it fixes the issue.

Tested-by: Ravi Bangoria <ravi.bangoria@amd.com>

Thanks,
Ravi