[PATCH 2/2] makedumpfile: Use max_pfn from mem_map array

[Atsushi Kumagai]

>On Tue, 1 Apr 2014 05:06:33 +0000
>Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp> wrote:
>
>[...]
>
>> >OTOH, Michal's patch is still neded to fix non-Xen non-cyclic dumps.
>>
>> Yes, the fix for create_1st_bitmap() is still necessary.
>>
>> Michael, could you fix your patch ? We need to add the conditional
>> check for Xen like below:
>>
>> +	if (!is_xen_memory()) {
>> +	       for (i = 0; i < info->num_mem_map; i++) {
>> +   	            if (info->mem_map_data[i].mem_map == NOT_MEMMAP_ADDR)
>> +       	                continue;
>> +           	    max_pfn = MAX(max_pfn, info->mem_map_data[i].pfn_end);
>> +       	}
>> +       	info->max_mapnr = MIN(info->max_mapnr, max_pfn);
>> +	}
>
>Hello Atsushi and Petr,
>
>Based on the discussion I removed the checks in exclude_xen3_user_domain()
>and exclude_xen4_user_domain() and added the is_xen_memory() check
>int get_mem_map().
>
>Here the updated patch:

Good, I'll merge this into v1.5.6.
Thanks for your work, Michael and Petr !


Atsushi Kumagai

>---
>[PATCH] makedumpfile: Fix bitmap create for adjusted info->max_mapnr
>
>If info->max_mapnr has been adjusted, for example because the dumped
>system has specified the "mem=" kernel parameter, makedumpfile writes
>the following error messages for Xen dumps or when the "--non-cyclic"
>option has been specified:
>
>set_bitmap: Can't read the bitmap(/tmp/kdump_bitmapBsKAUe). Invalid argument
>
>Fix this and consider "info->max_mapnr" in the create_1st_bitmap() function.
>
>In addition to this, do not adjust max_mapnr for Xen dumps.
>For Xen info->max_mapnr gives the maximum machine PFN and the data
>in mem_section describes the Dom0 kernel memory map that gets
>initialized from info->dom0_mapnr. It may be substantially smaller
>than info->max_mapnr.
>
>Signed-off-by: Michael Holzheu <holzheu at linux.vnet.ibm.com>
>---
> makedumpfile.c |   15 ++++++++++-----
> 1 file changed, 10 insertions(+), 5 deletions(-)
>
>--- a/makedumpfile.c
>+++ b/makedumpfile.c
>@@ -2868,12 +2868,14 @@ get_mem_map(void)
> 	 * than is dumped. For example when "mem=" has been used for the
> 	 * dumped system.
> 	 */
>-	for (i = 0; i < info->num_mem_map; i++) {
>-		if (info->mem_map_data[i].mem_map == NOT_MEMMAP_ADDR)
>-			continue;
>-		max_pfn = MAX(max_pfn, info->mem_map_data[i].pfn_end);
>+	if (!is_xen_memory()) {
>+		for (i = 0; i < info->num_mem_map; i++) {
>+			if (info->mem_map_data[i].mem_map == NOT_MEMMAP_ADDR)
>+				continue;
>+			max_pfn = MAX(max_pfn, info->mem_map_data[i].pfn_end);
>+		}
>+		info->max_mapnr = MIN(info->max_mapnr, max_pfn);
> 	}
>-	info->max_mapnr = MIN(info->max_mapnr, max_pfn);
> 	return ret;
> }
>
>@@ -4402,6 +4404,9 @@ create_1st_bitmap(void)
>
> 		pfn_start = paddr_to_pfn(phys_start);
> 		pfn_end   = paddr_to_pfn(phys_end);
>+		if (pfn_start > info->max_mapnr)
>+			continue;
>+		pfn_end = MIN(pfn_end, info->max_mapnr);
>
> 		for (pfn = pfn_start; pfn < pfn_end; pfn++) {
> 			set_bit_on_1st_bitmap(pfn);