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

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Fri, Jan 06, 2023 at 06:34:32PM +0530, Ravi Bangoria escreveu:
> 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, applied.

- Arnaldo