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
| ||
|
Date: Thu, 16 Dec 2010 21:56:25 +0100 From: Peter Zijlstra <peterz@...radead.org> To: Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca> Cc: Jason Baron <jbaron@...hat.com>, hpa@...or.com, rostedt@...dmis.org, mingo@...e.hu, tglx@...utronix.de, andi@...stfloor.org, roland@...hat.com, rth@...hat.com, masami.hiramatsu.pt@...achi.com, fweisbec@...il.com, avi@...hat.com, davem@...emloft.net, sam@...nborg.org, ddaney@...iumnetworks.com, michael@...erman.id.au, linux-kernel@...r.kernel.org Subject: Re: [PATCH/RFC 1/2] jump label: make enable/disable o(1) On Thu, 2010-12-16 at 15:50 -0500, Mathieu Desnoyers wrote: > * Peter Zijlstra (peterz@...radead.org) wrote: > > On Thu, 2010-12-16 at 15:36 -0500, Mathieu Desnoyers wrote: > > > Tracepoints keep their own reference counts for enable/disable, so a > > > simple "enable/disable" is fine as far as tracepoints are concerned. Why > > > does perf need that refcounting done by the static jumps ? > > > > Because the refcount is all we have... Why not replace that tracepoint > > refcount with the jumplabel thing? > > The reason why tracepoints need to keep their own refcount is because > they support dynamically loadable modules, and hence the refcount must > be kept outside of the modules, in a table internal to tracepoints, > so we can attach a probe to a yet unloaded module. Therefore, relying on > this lower level jump label to keep the refcount is not appropriate for > tracepoints, because the refcount only exists when the module is live. That's not a logical conclusion, you can keep these jump_label keys outside of the module just fine. > I know that your point of view is "let users of modules suffer", but > this represents a very large portion of Linux users I am not willing to > let suffer knowingly. Feh, I'd argue to remove this special tracepoint crap, the only in-kernel user (ftrace) doesn't even make use of it. This weird ass tracepoint semantic being different from the ftrace trace_event semantics has caused trouble before. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists