Thread (27 messages) 27 messages, 7 authors, 2024-11-21

Re: [PATCH v4 tip/perf/core 0/4] uprobes,mm: speculative lockless VMA-to-uprobe lookup

From: Andrii Nakryiko <hidden>
Date: 2024-11-20 17:23:49
Also in: bpf, linux-arm-kernel, linux-mm, lkml

On Wed, Nov 20, 2024 at 8:03 AM Ingo Molnar [off-list ref] wrote:

* Peter Zijlstra [off-list ref] wrote:
quoted
On Wed, Nov 20, 2024 at 07:40:15AM -0800, Andrii Nakryiko wrote:
quoted
Linus,

I'm not sure what's going on here, this patch set seems to be in some
sort of "ignore list" on Peter's side with no indication on its
destiny.
*sigh* it is not, but my inbox is like drinking from a firehose :/
And I've been considering that particular series WIP for two reasons:

 1) Oleg was still unconvinced about patch 5/5 in the v2 discussion.
    Upon re-reading it I think he might have come around and has agreed
    to the current approach - but sending a v3 & not seeing Oleg object
    would ascertain that.
Is this about Liao's siglock patch set? We are at v4 (!) already (see
[0]) with Oleg's Acked-by added.
 2) There was a build failure reported against -v2 at:

       https://lore.kernel.org/all/202410050745.2Nuvusy4-lkp@intel.com/t.mbox.gz (local)

    We cannot and will not merge patches with build failures.
This one is about this patch set (speculative uprobe lookup), right?
It is already at v4 ([1]), while you are mentioning v2 as the reason
for this to not yet be applied. Those build failures were fixed *a
long time ago*, v4 itself has been sitting idle for almost a month
(since Oct 27). If there are any other problems, do bring them up,
don't wait for weeks.
Andrii did get some other uprobes scalability work merged in v6.13:

    - Switch to RCU Tasks Trace flavor for better performance (Andrii Nakryiko)

    - Massively increase uretprobe SMP scalability by SRCU-protecting
      the uretprobe lifetime (Andrii Nakryiko)

So we've certainly not been ignoring his patches, to the contrary ...
Yes, and as I mentioned, this one is a) ready, reviewed, tested and b)
complements the other work you mention. It removes mmap_lock which
limits scalability of the rest of the work. Is there some rule that I
get to land only two patch sets in a single release?
Thanks,

        Ingo

[0] https://lore.kernel.org/linux-trace-kernel/20241022073141.3291245-1-liaochang1@huawei.com/ (local)
[1] https://lore.kernel.org/linux-trace-kernel/20241028010818.2487581-1-andrii@kernel.org/ (local)
[2] https://lore.kernel.org/linux-trace-kernel/CAEf4BzYPajbgyvcvm7z1EiPgkee1D1r=a8gaqxzd7k13gh9Uzw@mail.gmail.com/ (local)
[3] https://lore.kernel.org/linux-trace-kernel/CAEf4Bza=pwrZvd+3dz-a7eiAQMk9rwBDO1Kk_iwXSCM70CAARw@mail.gmail.com/ (local)
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