linux-kernel - Re: [PATCH bpf-next v8 2/3] perf: Refactor get_perf

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAEf4BzbTLqzcrbyfLmhB7b9XZHLPno+YfZtcw12ZbcwwaAP6yw@mail.gmail.com>
Date: Tue, 3 Feb 2026 16:24:22 -0800
From: Andrii Nakryiko <andrii.nakryiko@...il.com>
To: Peter Zijlstra <peterz@...radead.org>
Cc: Tao Chen <chen.dylane@...ux.dev>, mingo@...hat.com, acme@...nel.org, 
	namhyung@...nel.org, mark.rutland@....com, alexander.shishkin@...ux.intel.com, 
	jolsa@...nel.org, irogers@...gle.com, adrian.hunter@...el.com, 
	kan.liang@...ux.intel.com, song@...nel.org, ast@...nel.org, 
	daniel@...earbox.net, andrii@...nel.org, martin.lau@...ux.dev, 
	eddyz87@...il.com, yonghong.song@...ux.dev, john.fastabend@...il.com, 
	kpsingh@...nel.org, sdf@...ichev.me, haoluo@...gle.com, 
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org, 
	bpf@...r.kernel.org
Subject: Re: [PATCH bpf-next v8 2/3] perf: Refactor get_perf_callchain

On Mon, Feb 2, 2026 at 11:59 AM Peter Zijlstra <peterz@...radead.org> wrote:
>
> On Fri, Jan 30, 2026 at 12:04:45PM -0800, Andrii Nakryiko wrote:
>
> > > Also, there appears to be no buildid caching what so ever, surely that
> > > would help some.
> >
> > Jiri Olsa proposed caching build id per file or per inode some time
> > back, there was vehement opposition to it. And doing some locked
> > global resizable hash that might need to be used from NMI sounds
> > horrible, tbh. So we have what we have today.
>
> See kernel/module/tree_lookup.c and include/linux/rbtree_latch.h :-)

Ah, neat idea. Each node is really two parallel nodes for each of the
latched copies. TIL, good to know and thanks!