On 08/02/2018 04:45 AM, Kazuhito Hagio wrote:
> Hi Pingfan,
>
> Thank you for the patch.
>
> On 7/31/2018 4:44 AM, Pingfan Liu wrote:
>> When refiltering on kdump format file, there is no info about pt_load[] for
>> exclude_nodata_pages(), and also we can not expect more data than the kdump
>> file can provide, hence this patch suggests to initialize the refiltered
>> bitmap1 from the kdump file's bitmap2.
>
> I understood the issue (I don't have any vmcore which can reproduce it,
> though), but since the bitmap1 is written to the refiltered dump file,
> I think that we should not change the meaning of bitmap1 if possible,
> which is "a page on memory hole".
>
> For instance, with the patch, crash using the bitmaps prints a different
> message for the same "excluded" paddr:
>
> -read_diskdump: PAGE_EXCLUDED: paddr/pfn: 2613e130/2613e
> +read_diskdump: SEEK_ERROR: paddr/pfn: 2613e130/2613e !page_is_ram
>
> and makedumpfile's -e option using the bitmap1 cannot be utilized when
> refiltering, these are not favorable.
>
> So how about initializing the refiltered *bitmap2* from the kdump file's
> bitmap2 ? I'm checking if this works.
>
Yes, it sounds a good idea.
Thanks,
Pingfan
> Thanks,
> Kazu
>
>>
>> Note about the bug reported by the following ops:
>> makedumpfile -l --message-level 1 -d 31 /proc/vmcore /path/to/vmcore
>> makedumpfile --split -d 31 ./vmcore dumpfile_{1,2,3} 2>&1
>> and hit the following error:
>> Excluding unnecessary pages : [100.0 %] \
>> readpage_kdump_compressed: pfn(9b) is excluded from /var/crash/127.0.0.1-2018-07-02-22:10:38/vmcore.
>> readmem: type_addr: 1, addr:9b000, size:4096
>> read_pfn: Can't get the page data.
>> writeout_multiple_dumpfiles: Child process(2277) finished incompletely.(256)
>> Copying data : [ 24.6 %] - eta: 2s
>> makedumpfile Failed.
>>
>> Signed-off-by: Pingfan Liu <piliu@xxxxxxxxxx>
>> ---
>> makedumpfile.c | 6 +++++-
>> 1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/makedumpfile.c b/makedumpfile.c
>> index 101fa7c..af24359 100644
>> --- a/makedumpfile.c
>> +++ b/makedumpfile.c
>> @@ -5544,6 +5544,7 @@ copy_1st_bitmap_from_memory(void)
>>
>> bitmap_offset = (DISKDUMP_HEADER_BLOCKS + dh->sub_hdr_size)
>> * dh->block_size;
>> + bitmap_offset += info->len_bitmap / 2;
>>
>> if (lseek(info->fd_memory, bitmap_offset, SEEK_SET) < 0) {
>> ERRMSG("Can't seek %s. %s\n",
>> @@ -5593,8 +5594,11 @@ create_1st_bitmap_file(void)
>> struct timespec ts_start;
>> off_t offset_page;
>>
>> - if (info->flag_refiltering)
>> + if (info->flag_refiltering) {
>> + /* no hole info in kdump file, set it as 0 for refiltering */
>> + pfn_memhole = 0;
>> return copy_1st_bitmap_from_memory();
>> + }
>>
>> if (info->flag_sadump)
>> return sadump_copy_1st_bitmap_from_memory();
>> --
>> 2.7.4
>>
>
>
>
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