From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keir Fraser <keir.xen@gmail.com>
Subject: Re: [PATCH 1 of 5] xentrace: fix t_info_pages calculation
	for the default case
Date: Thu, 24 Mar 2011 12:34:53 +0000
Message-ID: <C9B0EAED.15565%keir.xen@gmail.com>
References: <4D8B347E.3000504@amd.com>
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To: Christoph Egger <Christoph.Egger@amd.com>, xen-devel@lists.xensource.com
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You need c/s 23074


On 24/03/2011 12:09, "Christoph Egger" <Christoph.Egger@amd.com> wrote:

> 
> This patch does not compile for me. There's no <xen/pfn.h>.
> 
> Christoph
> 
> 
> On 03/23/11 18:54, Olaf Hering wrote:
>> # HG changeset patch
>> # User Olaf Hering<olaf@aepfle.de>
>> # Date 1300900084 -3600
>> # Node ID 14ac28e4656d0c235c5edf119426b1bcf3bf33d4
>> # Parent  8e1c737b2c44249dd1c0e4e1b8978d5d35020226
>> xentrace: fix t_info_pages calculation for the default case
>> 
>> The default tracebuffer size of 32 pages was not tested with the previous
>> patch.
>> As a result, t_info_pages will become zero and alloc_xenheap_pages() fails.
>> Catch this case and allocate at least one page.
>> 
>> Signed-off-by: Olaf Hering<olaf@aepfle.de>
>> 
>> diff -r 8e1c737b2c44 -r 14ac28e4656d xen/common/trace.c
>> --- a/xen/common/trace.c Wed Mar 23 15:24:19 2011 +0000
>> +++ b/xen/common/trace.c Wed Mar 23 18:08:04 2011 +0100
>> @@ -29,6 +29,7 @@
>>   #include<xen/init.h>
>>   #include<xen/mm.h>
>>   #include<xen/percpu.h>
>> +#include<xen/pfn.h>
>>   #include<xen/cpu.h>
>>   #include<asm/atomic.h>
>>   #include<public/sysctl.h>
>> @@ -109,6 +110,7 @@
>>   {
>>       struct t_buf dummy;
>>       typeof(dummy.prod) size;
>> +    unsigned int t_info_bytes;
>> 
>>       /* force maximum value for an unsigned type */
>>       size = -1;
>> @@ -122,11 +124,9 @@
>>           pages = size;
>>       }
>> 
>> -    t_info_pages = num_online_cpus() * pages + t_info_first_offset;
>> -    t_info_pages *= sizeof(uint32_t);
>> -    t_info_pages /= PAGE_SIZE;
>> -    if ( t_info_pages % PAGE_SIZE )
>> -        t_info_pages++;
>> +    t_info_bytes = num_online_cpus() * pages + t_info_first_offset;
>> +    t_info_bytes *= sizeof(uint32_t);
>> +    t_info_pages = PFN_UP(t_info_bytes);
>>       return pages;
>>   }