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From: Jiri Kosina <jikos@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>,
	Andrew Morton <akpm@linux-foundation.org>,
	live-patching@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	the arch/x86 maintainers <x86@kernel.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>
Subject: Re: [PATCH 7/7] DWARF: add the config option
Date: Sat, 6 May 2017 16:24:47 +0200 (CEST)	[thread overview]
Message-ID: <alpine.LSU.2.20.1705061616010.26873@cbobk.fhfr.pm> (raw)
In-Reply-To: <CA+55aFzEF_A1MzH8P8EX35FSci7UFj_+5LdsEFVai1DYtCk-Hg@mail.gmail.com>


[ adding Josh to CC ]

On Fri, 5 May 2017, Linus Torvalds wrote:

> > The DWARF unwinder is in place and ready. So introduce the config option
> > to allow users to enable it. It is by default off due to missing
> > assembly annotations.
> 
> Who actually ends up using this?

As a datapoint -- we've been using dwarf unwinder in SUSE kernels since 
stone age, because we do not enable frame pointer, as it adds up to 10% of 
runtime slowdown for certain workloads, but we want reliable stacktraces 
so that we can actually debug user reports.

Now that we have nicely reliable stacktraces thanks to Josh's objtool for 
FP-enabled builds, we'd like to bring comparably understandable traces 
also to non-FP enabled builds.

> Put another way; the last time we did crazy stuff like this, it got
> reverted. For a damn good reason, despite some people being in denial
> about those reasons.

There had been personal issues involved previously, no questions about 
that :)

Thanks,

-- 
Jiri Kosina
SUSE Labs

  parent reply	other threads:[~2017-05-06 14:24 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-05 12:21 [PATCH 1/7] DWARF: add option to preserve unwind info Jiri Slaby
2017-05-05 12:21 ` [PATCH 2/7] DWARF: EH-frame based stack unwinding Jiri Slaby
2017-05-05 12:21 ` [PATCH 3/7] vmlinux.lds: preserve eh_frame for DWARF unwinder Jiri Slaby
2017-05-05 12:21 ` [PATCH 4/7] DWARF: initialize structures for kernel and modules Jiri Slaby
2017-05-05 12:21 ` [PATCH 5/7] unwinder: show_stack, check also ret_addr_p's contents Jiri Slaby
2017-05-05 12:21 ` [PATCH 6/7] unwinder: plug in the DWARF unwinder Jiri Slaby
2017-05-05 12:22 ` [PATCH 7/7] DWARF: add the config option Jiri Slaby
2017-05-05 19:57   ` Linus Torvalds
2017-05-06  7:19     ` Ingo Molnar
2017-05-10  7:46       ` Jiri Slaby
2017-05-06 14:24     ` Jiri Kosina [this message]
2017-05-07 16:55     ` Josh Poimboeuf
2017-05-07 17:59       ` Ingo Molnar
2017-05-07 18:08         ` hpa
2017-05-07 21:48           ` Josh Poimboeuf
2017-05-08  7:50             ` Vojtech Pavlik
2017-05-08 13:14               ` Josh Poimboeuf
2017-05-08  5:35       ` Andy Lutomirski
2017-05-08  6:15         ` Ingo Molnar
2017-05-08 14:40         ` Josh Poimboeuf
2017-05-08 18:57           ` hpa
2017-05-09  0:21       ` Andy Lutomirski
2017-05-09  1:38         ` Josh Poimboeuf
2017-05-09  2:31           ` Andy Lutomirski
2017-05-09  3:38             ` Josh Poimboeuf
2017-05-09 10:00               ` hpa
2017-05-09 14:58                 ` Josh Poimboeuf
2017-05-09 16:46                   ` H.J. Lu
2017-05-10  8:15                 ` Jiri Slaby
2017-05-10 13:09                   ` Josh Poimboeuf
2017-05-10 16:23                     ` H.J. Lu
2017-05-09 18:47       ` Jiri Kosina
2017-05-09 19:22         ` Josh Poimboeuf
2017-05-10  8:32           ` Jiri Slaby
2017-05-10 13:13             ` Josh Poimboeuf
2017-05-23  7:07             ` Peter Zijlstra
2017-05-23  7:27               ` Ingo Molnar
2017-05-19 20:53       ` Josh Poimboeuf
2017-05-19 20:57         ` H. Peter Anvin
2017-05-19 20:59         ` H. Peter Anvin
2017-05-19 21:29           ` Josh Poimboeuf
2017-05-19 21:35             ` Josh Poimboeuf
2017-05-20  5:23               ` Andy Lutomirski
2017-05-20 16:20                 ` Josh Poimboeuf
2017-05-20 17:19                   ` Josh Poimboeuf
2017-05-20 20:01                   ` H.J. Lu
2017-05-20 21:58                     ` Andy Lutomirski
2017-05-20 22:20                       ` H.J. Lu
2017-05-22 11:34                         ` Jiri Kosina
2017-05-22 14:39                           ` H.J. Lu
2017-05-22 21:07                     ` H. Peter Anvin
2017-05-22 21:37                       ` H. Peter Anvin
2017-05-22 22:11                         ` Josh Poimboeuf
2017-05-20 20:16                 ` Linus Torvalds
2017-05-20 21:56                   ` Andy Lutomirski
2017-05-20 23:00                     ` Linus Torvalds
2017-05-20 23:29                       ` Linus Torvalds
2017-05-26  6:54               ` Jiri Slaby
2017-05-26 11:29                 ` Jiri Slaby
2017-05-26 12:14                   ` Josh Poimboeuf
2017-05-22 11:12             ` Ingo Molnar
2017-05-22 21:16               ` H. Peter Anvin
2017-05-22 23:23                 ` Jiri Kosina
2017-05-23  5:49                 ` Ingo Molnar
2017-05-26 19:16                   ` hpa
2017-05-28  9:12                     ` Ingo Molnar
2017-05-10  7:39     ` Jiri Slaby
2017-05-10 12:42       ` Josh Poimboeuf
2017-05-10 12:47         ` Jiri Slaby
2017-05-10 18:11       ` Linus Torvalds

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