linux-kernel - Re: [patch] queued spinlocks (i386)

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: <75b66ecd0703291906q265f9cc7g486cf65484ba8393@mail.gmail.com>
Date:	Thu, 29 Mar 2007 22:06:41 -0400
From:	"Lee Revell" <rlrevell@...-job.com>
To:	"Davide Libenzi" <davidel@...ilserver.org>
Cc:	"Oleg Nesterov" <oleg@...sign.ru>, "Nick Piggin" <npiggin@...e.de>,
	"Ravikiran G Thirumalai" <kiran@...lex86.org>,
	"Ingo Molnar" <mingo@...e.hu>,
	"Nikita Danilov" <nikita@...sterfs.com>,
	"Andrew Morton" <akpm@...ux-foundation.org>,
	"Linux Kernel Mailing List" <linux-kernel@...r.kernel.org>
Subject: Re: [patch] queued spinlocks (i386)

On 3/29/07, Davide Libenzi <davidel@...ilserver.org> wrote:
> On Thu, 29 Mar 2007, Oleg Nesterov wrote:
>
> > On 03/28, Nick Piggin wrote:
> > >
> > > Well with my queued spinlocks, all that lockbreak stuff can just come out
> > > of the spin_lock, break_lock out of the spinlock structure, and
> > > need_lockbreak just becomes (lock->qhead - lock->qtail > 1).
> >
> > Q: queued spinlocks are not CONFIG_PREEMPT friendly,
>
> Why? Is CONFIG_PREEMPT friendly to anyone? :)

Until someone fixes all the places in the kernel where scheduling can
be held off for tens of milliseconds, CONFIG_PREEMPT will be an
absolute requirement for many applications like audio and gaming.

Many of these were fixed a while back during early -rt development but
at some point the process stalled as the remaining cases were too hard
to fix...

Lee
-
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/