Re: vm_unmap_aliases and Xen - Jeremy Fitzhardinge

All of lore.kernel.org
 help / color / mirror / Atom feed

From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: vm_unmap_aliases and Xen
Date: Tue, 28 Oct 2008 19:04:25 +1100	[thread overview]
Message-ID: <4906C789.7060408@goop.org> (raw)
In-Reply-To: <200810281619.10388.nickpiggin@yahoo.com.au>

Nick Piggin wrote:
> On Friday 24 October 2008 10:48, Jeremy Fitzhardinge wrote:
>   
>> I've been having a few problems with Xen, I suspect as a result of the
>> lazy unmapping in vmalloc.c.
>>
>> One immediate one is that vm_unmap_aliases() will oops if you call it
>> before vmalloc_init() is called, which can happen in the Xen case.  RFC
>> patch below.
>>     
>
> Sure, we could do that. If you add an unlikely, and a __read_mostly,
> I'd ack it. Thanks for picking this up.
>   

OK, will respin accordingly.

>> But the bigger problem I'm seeing is that despite calling
>> vm_unmap_aliases() at the pertinent places, I'm still seeing errors
>> resulting from stray aliases.  Is it possible that vm_unmap_aliases()
>> could be missing some, or not completely synchronous?
>>     
>
> It's possible, but of course that would not be by design ;)
>
> I've had another look over it, and nothing obvious comes to
> mind.
>   

I found the problem and fixed it; I was just doing the operations in the 
wrong order.

Thanks,
    J

WARNING: multiple messages have this Message-ID (diff)

From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: vm_unmap_aliases and Xen
Date: Tue, 28 Oct 2008 19:04:25 +1100	[thread overview]
Message-ID: <4906C789.7060408@goop.org> (raw)
In-Reply-To: <200810281619.10388.nickpiggin@yahoo.com.au>

Nick Piggin wrote:
> On Friday 24 October 2008 10:48, Jeremy Fitzhardinge wrote:
>   
>> I've been having a few problems with Xen, I suspect as a result of the
>> lazy unmapping in vmalloc.c.
>>
>> One immediate one is that vm_unmap_aliases() will oops if you call it
>> before vmalloc_init() is called, which can happen in the Xen case.  RFC
>> patch below.
>>     
>
> Sure, we could do that. If you add an unlikely, and a __read_mostly,
> I'd ack it. Thanks for picking this up.
>   

OK, will respin accordingly.

>> But the bigger problem I'm seeing is that despite calling
>> vm_unmap_aliases() at the pertinent places, I'm still seeing errors
>> resulting from stray aliases.  Is it possible that vm_unmap_aliases()
>> could be missing some, or not completely synchronous?
>>     
>
> It's possible, but of course that would not be by design ;)
>
> I've had another look over it, and nothing obvious comes to
> mind.
>   

I found the problem and fixed it; I was just doing the operations in the 
wrong order.

Thanks,
    J

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

next prev parent reply	other threads:[~2008-10-28  8:04 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-23 23:48 vm_unmap_aliases and Xen Jeremy Fitzhardinge
2008-10-23 23:48 ` Jeremy Fitzhardinge
2008-10-28  5:19 ` Nick Piggin
2008-10-28  5:19   ` Nick Piggin
2008-10-28  8:04   ` Jeremy Fitzhardinge [this message]
2008-10-28  8:04     ` Jeremy Fitzhardinge
2008-10-28  8:22   ` [PATCH 1/2] vmap: cope with vm_unmap_aliases before vmalloc_init() Jeremy Fitzhardinge
2008-10-28  8:22     ` Jeremy Fitzhardinge
2008-11-05 18:52     ` Jeremy Fitzhardinge
2008-11-05 18:52       ` Jeremy Fitzhardinge
2008-11-06 10:02       ` Ingo Molnar
2008-11-06 10:02         ` Ingo Molnar
2008-11-06 10:41         ` Nick Piggin
2008-11-06 10:41           ` Nick Piggin
2008-11-06 14:51           ` Ingo Molnar
2008-11-06 14:51             ` Ingo Molnar
2008-10-28  8:23   ` [PATCH 2/2] xen: make sure stray alias mappings are gone before pinning Jeremy Fitzhardinge
2008-10-28  8:23     ` Jeremy Fitzhardinge

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=4906C789.7060408@goop.org \
    --to=jeremy@goop.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=nickpiggin@yahoo.com.au \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.