Date: Tue, 14 Jul 2015 17:44:42 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: Boris Ostrovsky <boris.ostrovsky@oracle.com>
cc: LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>, Peter Anvin <hpa@zytor.com>,
        xiao jin <jin.xiao@intel.com>, Joerg Roedel <jroedel@suse.de>,
        Borislav Petkov <bp@suse.de>,
        Yanmin Zhang <yanmin_zhang@linux.intel.com>,
        xen-devel <xen-devel@lists.xenproject.org>
Subject: Re: [patch 1/4] hotplug: Prevent alloc/free of irq descriptors during
 cpu up/down
In-Reply-To: <55A51F10.7010407@oracle.com>
Message-ID: <alpine.DEB.2.11.1507141743150.18576@nanos>
References: <20150705170530.849428850@linutronix.de> <20150705171102.063519515@linutronix.de> <55A51F10.7010407@oracle.com>
User-Agent: Alpine 2.11 (DEB 23 2013-08-11)
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 742
Lines: 26

On Tue, 14 Jul 2015, Boris Ostrovsky wrote:
> > Prevent allocation and freeing of interrupt descriptors accross cpu
> > hotplug.
> 
> 
> This breaks Xen guests that allocate interrupt descriptors in .cpu_up().

And where exactly does XEN allocate those descriptors?
 
> Any chance this locking can be moved into arch code?

No.

> (The patch doesn't appear to have any side effects for the down path since Xen
> guests deallocate descriptors in __cpu_die()).
 
Exact place please.

Thanks,

	tglx
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/