Re: [PATCH, GIT] xen: avoid allocation causing potential swap activity on the resume path

[Jeremy Fitzhardinge <jeremy@goop.org>]

On 06/02/2010 05:23 AM, Ian Campbell wrote:
> Jeremy,
>
> are you happy for me to send this +
> 5c6aea17c9692e6c12f198573ef640a9dfb2b431 ("xen: ensure timer tick is
> resumed even on CPU driving the resume") to Linus as bugfixes for 2.6.35
> (+stable backport)?
>   

Yep, ACK.

    J

> Ian.
>
> On Tue, 2010-05-25 at 13:34 +0100, Ian Campbell wrote:
>   
>> The following changes since commit 5c6aea17c9692e6c12f198573ef640a9dfb2b431:
>>   Ian Campbell (1):
>>         xen: ensure timer tick is resumed even on CPU driving the resume
>>
>> are available in the git repository at:
>>
>>   git://xenbits.xensource.com/people/ianc/linux-2.6.git for-jeremy/saverestore
>>
>> Ian Campbell (1):
>>       xen: avoid allocation causing potential swap activity on the resume path
>>
>>  drivers/xen/xenbus/xenbus_xs.c |    2 +-
>>  1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> Subject: [PATCH] xen: avoid allocation causing potential swap activity on the resume path
>>
>> Since the device we are resuming could be the device containing the
>> swap device we should ensure that the allocation cannot cause
>> IO.
>>
>> On resume, this path is triggered when the running system tries to
>> continue using its devices.  If it cannot then the resume will fail;
>> to try to avoid this we let it dip into the emergency pools.
>>
>> The majority of these changes were made when linux-2.6.18-xen.hg
>> changeset e8b49cfbdac0 was ported upstream in
>> a144ff09bc52ef3f3684ed23eadc9c7c0e57b3aa but somehow this hunk was
>> dropped.
>>
>> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
>> Cc: Jeremy Fitzhardinge <jeremy@goop.org>
>> Cc: Stable Kernel <stable@kernel.org>
>> ---
>>  drivers/xen/xenbus/xenbus_xs.c |    2 +-
>>  1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
>> index 6f91e8c..5534690 100644
>> --- a/drivers/xen/xenbus/xenbus_xs.c
>> +++ b/drivers/xen/xenbus/xenbus_xs.c
>> @@ -534,7 +534,7 @@ int xenbus_printf(struct xenbus_transaction t,
>>  #define PRINTF_BUFFER_SIZE 4096
>>  	char *printf_buffer;
>>  
>> -	printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL);
>> +	printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_NOIO | __GFP_HIGH);
>>  	if (printf_buffer == NULL)
>>  		return -ENOMEM;
>>  
>>     
>
>