linux-kernel - Re: + work_on_cpu-rewrite-it-to-create-a-kernel-thread-on-demand.patch added to -mm tree

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: <c62985530902030858y28906b2dh511c5868afabfd17@mail.gmail.com>
Date:	Tue, 3 Feb 2009 17:58:13 +0100
From:	Frédéric Weisbecker <fweisbec@...il.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
	Oleg Nesterov <oleg@...hat.com>, Mike Travis <travis@....com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	mm-commits@...r.kernel.org, rusty@...tcorp.com.au
Subject: Re: + work_on_cpu-rewrite-it-to-create-a-kernel-thread-on-demand.patch 
	added to -mm tree

2009/2/3 Ingo Molnar <mingo@...e.hu>:
>
> * akpm@...ux-foundation.org <akpm@...ux-foundation.org> wrote:
>
>> ------------------------------------------------------
>> Subject: work_on_cpu(): rewrite it to create a kernel thread on demand
>> From: Andrew Morton <akpm@...ux-foundation.org>
>>
>> The various implemetnations and proposed implemetnations of work_on_cpu()
>> are vulnerable to various deadlocks because they all used queues of some
>> form.
>>
>> Unrelated pieces of kernel code thus gained dependencies wherein if one
>> work_on_cpu() caller holds a lock which some other work_on_cpu() callback
>> also takes, the kernel could rarely deadlock.
>>
>> Fix this by creating a short-lived kernel thread for each work_on_cpu()
>> invokation.
>>
>> This is not terribly fast, but the only current caller of work_on_cpu() is
>> pci_call_probe().
>
> hm, it's quite ugly as well, and wasteful with resources.


Sorry I don't see the patch but only the changelog.
So perhaps my answer will be a bit out of sync.

But if pci_call_probe() is the only caller, so it is supposed to be
called only on boot.
Perhaps the work_on_cpu thread can be killed after boot up and then
become a thread created
on the fly after that if needed....

Or perhaps it's too much complex.....
--
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/