From: Jiri Kosina <jkosina@suse.cz>
To: Torsten Duwe <duwe@lst.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
ppc-dev <linuxppc-dev@lists.ozlabs.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] ppc64 ftrace: mark data_access callees "notrace" (pt.1)
Date: Mon, 18 May 2015 14:29:52 +0200 (CEST) [thread overview]
Message-ID: <alpine.LRH.2.00.1505181428360.2306@twin.jikos.cz> (raw)
In-Reply-To: <20150516080534.GA27059@lst.de>
yOn Sat, 16 May 2015, Torsten Duwe wrote:
> > > There's got to be a better solution than this.
> >
> > Can you think of a better approach?
>
> Maybe a per thread variable to lock out a recursion into tracing?
> Thanks for your doubt.
ftrace already handles recursion protection by itself (depending on the
per-ftrace-ops FTRACE_OPS_FL_RECURSION_SAFE flag).
It's however not really well-defined what to do when recursion would
happen. Therefore __notrace__ annotation, that just completely avoid such
situation by making tracing impossible, looks like saner general solution
to me.
--
Jiri Kosina
SUSE Labs
WARNING: multiple messages have this Message-ID (diff)
From: Jiri Kosina <jkosina@suse.cz>
To: Torsten Duwe <duwe@lst.de>
Cc: ppc-dev <linuxppc-dev@lists.ozlabs.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] ppc64 ftrace: mark data_access callees "notrace" (pt.1)
Date: Mon, 18 May 2015 14:29:52 +0200 (CEST) [thread overview]
Message-ID: <alpine.LRH.2.00.1505181428360.2306@twin.jikos.cz> (raw)
In-Reply-To: <20150516080534.GA27059@lst.de>
yOn Sat, 16 May 2015, Torsten Duwe wrote:
> > > There's got to be a better solution than this.
> >
> > Can you think of a better approach?
>
> Maybe a per thread variable to lock out a recursion into tracing?
> Thanks for your doubt.
ftrace already handles recursion protection by itself (depending on the
per-ftrace-ops FTRACE_OPS_FL_RECURSION_SAFE flag).
It's however not really well-defined what to do when recursion would
happen. Therefore __notrace__ annotation, that just completely avoid such
situation by making tracing impossible, looks like saner general solution
to me.
--
Jiri Kosina
SUSE Labs
next prev parent reply other threads:[~2015-05-18 12:30 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-13 16:11 [PATCH] ppc64 ftrace: mark data_access callees "notrace" (pt.1) Torsten Duwe
2015-05-15 1:34 ` Michael Ellerman
2015-05-15 8:45 ` Torsten Duwe
2015-05-16 8:05 ` Torsten Duwe
2015-05-18 12:29 ` Jiri Kosina [this message]
2015-05-18 12:29 ` Jiri Kosina
2015-05-19 3:27 ` Michael Ellerman
2015-05-19 3:27 ` Michael Ellerman
2015-05-19 9:52 ` Jiri Kosina
2015-05-19 9:52 ` Jiri Kosina
2015-06-03 13:02 ` [PATCH 0/4] ppc64 ftrace implementation Torsten Duwe
2015-06-03 13:08 ` [PATCH 1/4] " Torsten Duwe
2015-06-08 15:30 ` Steven Rostedt
2015-06-08 15:57 ` Torsten Duwe
2015-06-03 13:10 ` [PATCH 2/4] ppc64 ftrace configuration Torsten Duwe
2015-06-03 13:15 ` [PATCH 3/4] ppc64 ftrace: spare early boot and low level code Torsten Duwe
2015-06-03 13:22 ` [PATCH 4/4] ppc64 ftrace recursion protection Torsten Duwe
2015-05-20 9:03 ` [PATCH] ppc64 ftrace: mark data_access callees "notrace" (pt.1) Torsten Duwe
2015-05-26 14:34 ` Torsten Duwe
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=alpine.LRH.2.00.1505181428360.2306@twin.jikos.cz \
--to=jkosina@suse.cz \
--cc=duwe@lst.de \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mpe@ellerman.id.au \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.