linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Boqun Feng <boqun.feng@gmail.com>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	linux-api <linux-api@vger.kernel.org>,
	Andy Lutomirski <luto@amacapital.net>,
	Dave Watson <davejwatson@fb.com>, Paul Turner <pjt@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Russell King <linux@arm.linux.org.uk>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Andi Kleen <andi@firstfloor.org>, Chris Lameter <cl@linux.com>,
	Ben Maurer <bmaurer@fb.com>,
	Josh Triplett <josh@joshtriplett.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Michael Kerrisk <mtk.manpages@gmail.com>,
	Joel Fernandes <joelaf@google.com>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Matthew Wilcox <mawilcox@microsoft.com>
Subject: Re: [RFC PATCH for 4.21 03/16] mm: Replace BUG_ON() by WARN_ON() in vm_unmap_ram()
Date: Thu, 1 Nov 2018 15:57:53 -0400 (EDT)	[thread overview]
Message-ID: <278477314.3995.1541102273591.JavaMail.zimbra@efficios.com> (raw)
In-Reply-To: <20181101144623.61d43102@gandalf.local.home>

----- On Nov 1, 2018, at 7:46 PM, rostedt rostedt@goodmis.org wrote:

> On Thu, 1 Nov 2018 13:21:12 +0100 (CET)
> Thomas Gleixner <tglx@linutronix.de> wrote:
> 
>> Mathieu,
>> 
>> On Thu, 1 Nov 2018, Mathieu Desnoyers wrote:
>> 
>> > It is encouraged to warn and return rather than use BUG_ON() when
>> > the condition can be recovered from in ways that are more graceful than
>> > halting the whole system.
>> 
>> You're failing to desribe how that graceful recovery works.
>> 
> 
> I think the graceful recovery is to simply return:
> 
>	if (WARN_ON(cond))
>		return;
> 
> is better than just
> 
>	BUG_ON(cond);
> 
> As that's what Linus made pretty clear at the Maintainer's Summit.

That's it. For an unmap function, this basically boils down to
print a warning and leak the memory on internal unmap error.

I will update the commit message describing this behavior.

Thanks,

Mathieu

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com

  reply	other threads:[~2018-11-01 19:57 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-01  9:58 [RFC PATCH for 4.21 00/16] rseq updates, new cpu_opv system call (v2) Mathieu Desnoyers
2018-11-01  9:58 ` [RFC PATCH for 4.21 01/16] rseq/selftests: Expose reference counter to coexist with glibc (v2) Mathieu Desnoyers
2018-11-01  9:58 ` [RFC PATCH for 4.21 02/16] rseq/selftests: Adapt number of threads to the number of detected cpus Mathieu Desnoyers
2018-11-01  9:58 ` [RFC PATCH for 4.21 03/16] mm: Replace BUG_ON() by WARN_ON() in vm_unmap_ram() Mathieu Desnoyers
2018-11-01 12:21   ` Thomas Gleixner
2018-11-01 18:46     ` Steven Rostedt
2018-11-01 19:57       ` Mathieu Desnoyers [this message]
2018-11-01 22:00         ` Linus Torvalds
2018-11-01 22:17           ` Mathieu Desnoyers
2018-11-01  9:58 ` [RFC PATCH for 4.21 04/16] mm: Introduce vm_map_user_ram, vm_unmap_user_ram (v2) Mathieu Desnoyers
2018-11-01  9:58 ` [RFC PATCH for 4.21 05/16] mm: Provide is_vma_noncached Mathieu Desnoyers
2018-11-01  9:58 ` [RFC PATCH for 4.21 06/16] cpu_opv: Provide cpu_opv system call (v9) Mathieu Desnoyers
2018-11-01  9:58 ` [RFC PATCH for 4.21 07/16] cpu_opv: limit amount of virtual address space used by cpu_opv Mathieu Desnoyers
2018-11-01  9:58 ` [RFC PATCH for 4.21 08/16] x86: Wire up cpu_opv system call Mathieu Desnoyers
2018-11-01  9:58 ` [RFC PATCH for 4.21 09/16] powerpc: " Mathieu Desnoyers
2018-11-01  9:58 ` [RFC PATCH for 4.21 10/16] arm: " Mathieu Desnoyers
2018-11-01  9:58 ` [RFC PATCH for 4.21 11/16] cpu-opv/selftests: Provide cpu-op library Mathieu Desnoyers
2018-11-01  9:58 ` [RFC PATCH for 4.21 12/16] cpu-opv/selftests: Provide basic test Mathieu Desnoyers
2018-11-01  9:58 ` [RFC PATCH for 4.21 13/16] cpu-opv/selftests: Provide percpu_op API Mathieu Desnoyers
2018-11-01  9:58 ` [RFC PATCH for 4.21 14/16] cpu-opv/selftests: Provide basic percpu ops test Mathieu Desnoyers
2018-11-01  9:58 ` [RFC PATCH for 4.21 15/16] cpu-opv/selftests: Provide parametrized tests Mathieu Desnoyers
2018-11-01  9:58 ` [RFC PATCH for 4.21 16/16] cpu-opv/selftests: Provide Makefile, scripts, gitignore Mathieu Desnoyers
2018-11-01 15:33 ` [RFC PATCH for 4.21 00/16] rseq updates, new cpu_opv system call (v2) Linus Torvalds

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=278477314.3995.1541102273591.JavaMail.zimbra@efficios.com \
    --to=mathieu.desnoyers@efficios.com \
    --cc=akpm@linux-foundation.org \
    --cc=andi@firstfloor.org \
    --cc=bmaurer@fb.com \
    --cc=boqun.feng@gmail.com \
    --cc=catalin.marinas@arm.com \
    --cc=cl@linux.com \
    --cc=davejwatson@fb.com \
    --cc=hpa@zytor.com \
    --cc=joelaf@google.com \
    --cc=josh@joshtriplett.org \
    --cc=linux-api@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux@arm.linux.org.uk \
    --cc=luto@amacapital.net \
    --cc=mawilcox@microsoft.com \
    --cc=mingo@redhat.com \
    --cc=mtk.manpages@gmail.com \
    --cc=paulmck@linux.vnet.ibm.com \
    --cc=peterz@infradead.org \
    --cc=pjt@google.com \
    --cc=rostedt@goodmis.org \
    --cc=sergey.senozhatsky@gmail.com \
    --cc=tglx@linutronix.de \
    --cc=torvalds@linux-foundation.org \
    --cc=will.deacon@arm.com \
    /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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).