Xen devel - Feb 2010 - tools/xenbaked: fix bug of getting trace buffer size

Size of t_info pages is regarded as trace buffer size now,
it is wrong. This size should be t_info->tbuf_size * XC_PAGE_SIZE.

Signed-off-by: Yu Zhiguo <yuzg@cn.fujitsu.com>

diff --git a/tools/xenmon/xenbaked.c b/tools/xenmon/xenbaked.c
--- a/tools/xenmon/xenbaked.c
+++ b/tools/xenmon/xenbaked.c
@@ -469,6 +469,40 @@
     return physinfo.nr_cpus;
 }
 
+/**
+ * get_tbuf_size - get the size in pages of each trace buffer
+ */
+uint16_t get_tbuf_size(unsigned long tbufs_mfn, unsigned long tinfo_size)
+{
+    struct t_info *t_info;
+    int xc_handle;
+
+    xc_handle = xc_interface_open();
+    if ( xc_handle < 0 ) 
+    {
+        exit(EXIT_FAILURE);
+    }
+
+    t_info = xc_map_foreign_range(xc_handle, DOMID_XEN,
+                    tinfo_size, PROT_READ | PROT_WRITE,
+                    tbufs_mfn);
+
+    if ( t_info == 0 ) 
+    {
+        PERROR("Failed to mmap trace buffers");
+        exit(EXIT_FAILURE);
+    }
+
+    if ( t_info->tbuf_size == 0 )
+    {
+        fprintf(stderr, "%s: tbuf_size 0!\n", __func__);
+        exit(EXIT_FAILURE);
+    }
+
+    xc_interface_close(xc_handle);
+
+    return t_info->tbuf_size;
+}
 
 /**
  * monitor_tbufs - monitor the contents of tbufs
@@ -483,6 +517,8 @@
                                   * where they are mapped into user space.   */
     unsigned long tbufs_mfn;     /* mfn of the tbufs                         */
     unsigned int  num;           /* number of trace buffers / logical CPUS   */
+    unsigned long tinfo_size;    /* size of t_info metadata map              */
+    uint16_t tbuf_size;          /* Size in pages of each trace buffer       */
     unsigned long size;          /* size of a single trace buffer            */
 
     unsigned long data_size, rec_size;
@@ -496,9 +532,12 @@
     printf("CPU Frequency = %7.2f\n", opts.cpu_freq);
     
     /* setup access to trace buffers */
-    get_tbufs(&tbufs_mfn, &size);
+    get_tbufs(&tbufs_mfn, &tinfo_size);
 
-    tbufs_mapped = map_tbufs(tbufs_mfn, num, size);
+    tbufs_mapped = map_tbufs(tbufs_mfn, num, tinfo_size);
+
+    tbuf_size = get_tbuf_size(tbufs_mfn, tinfo_size);
+    size = tbuf_size * XC_PAGE_SIZE;
 
     data_size = size - sizeof(struct t_buf);
 



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Hi, Keir

 Please ignore this patch.

 Run xenbaked will occur Segmentation fault, because
some other bugs exist: the tbuf''s meta&data which be gotten
is wrong, so SIGSEGV occurs in routine process_record()

static int process_record(int cpu, struct t_rec *r)
{
...snip...
    if ( r->cycles_included )    --- SIGSEGV

 The method to get tbuf''s meta is wrong, I think it can be
fixed according to xentrace and I''ll make a new patch.


regards,
Yu


Yu Zhiguo wrote:
> Size of t_info pages is regarded as trace buffer size now,
> it is wrong. This size should be t_info->tbuf_size * XC_PAGE_SIZE.
> 
> Signed-off-by: Yu Zhiguo <yuzg@cn.fujitsu.com>
> 
> diff --git a/tools/xenmon/xenbaked.c b/tools/xenmon/xenbaked.c
> --- a/tools/xenmon/xenbaked.c
> +++ b/tools/xenmon/xenbaked.c
> @@ -469,6 +469,40 @@
>      return physinfo.nr_cpus;
>  }
>  
> +/**
> + * get_tbuf_size - get the size in pages of each trace buffer
> + */
> +uint16_t get_tbuf_size(unsigned long tbufs_mfn, unsigned long tinfo_size)
> +{
> +    struct t_info *t_info;
> +    int xc_handle;
> +
> +    xc_handle = xc_interface_open();
> +    if ( xc_handle < 0 ) 
> +    {
> +        exit(EXIT_FAILURE);
> +    }
> +
> +    t_info = xc_map_foreign_range(xc_handle, DOMID_XEN,
> +                    tinfo_size, PROT_READ | PROT_WRITE,
> +                    tbufs_mfn);
> +
> +    if ( t_info == 0 ) 
> +    {
> +        PERROR("Failed to mmap trace buffers");
> +        exit(EXIT_FAILURE);
> +    }
> +
> +    if ( t_info->tbuf_size == 0 )
> +    {
> +        fprintf(stderr, "%s: tbuf_size 0!\n", __func__);
> +        exit(EXIT_FAILURE);
> +    }
> +
> +    xc_interface_close(xc_handle);
> +
> +    return t_info->tbuf_size;
> +}
>  
>  /**
>   * monitor_tbufs - monitor the contents of tbufs
> @@ -483,6 +517,8 @@
>                                    * where they are mapped into user space.
*/
>      unsigned long tbufs_mfn;     /* mfn of the tbufs                      
*/
>      unsigned int  num;           /* number of trace buffers / logical CPUS
*/
> +    unsigned long tinfo_size;    /* size of t_info metadata map           
*/
> +    uint16_t tbuf_size;          /* Size in pages of each trace buffer    
*/
>      unsigned long size;          /* size of a single trace buffer         
*/
>  
>      unsigned long data_size, rec_size;
> @@ -496,9 +532,12 @@
>      printf("CPU Frequency = %7.2f\n", opts.cpu_freq);
>      
>      /* setup access to trace buffers */
> -    get_tbufs(&tbufs_mfn, &size);
> +    get_tbufs(&tbufs_mfn, &tinfo_size);
>  
> -    tbufs_mapped = map_tbufs(tbufs_mfn, num, size);
> +    tbufs_mapped = map_tbufs(tbufs_mfn, num, tinfo_size);
> +
> +    tbuf_size = get_tbuf_size(tbufs_mfn, tinfo_size);
> +    size = tbuf_size * XC_PAGE_SIZE;
>  
>      data_size = size - sizeof(struct t_buf);
>  
> 
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
> 
> 
> 

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