It's not clear how broken an incomplete dump from the existing debugging
prints. Aggregate number of valid pages helps to figure out approximate
size of the dump. Size of a complete dump is roughly:

  EXPECTED_CORE_SIZE = a few pages (kdump headers + bitmaps + descriptors) +
                       (total_valid_pages * block_size) * compression rate

An incomplete core would be significantly smaller than:

        total_valid_pages * block_size

Signed-off-by: Roman Bolshakov <[email protected]>
---
 diskdump.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/diskdump.c b/diskdump.c
index c05f1ec..1428141 100644
--- a/diskdump.c
+++ b/diskdump.c
@@ -74,6 +74,7 @@ struct diskdump_data {
        ulong   evictions;              /* total evictions done */
        ulong   cached_reads;
        ulong  *valid_pages;
+       ulong   total_valid_pages;      /* expected number of dumpable pages */
        ulong   accesses;
        ulong   snapshot_task;
 };
@@ -877,11 +878,14 @@ restart:
        }
 
        dd->valid_pages = calloc(sizeof(ulong), max_sect_len + 1);
+       dd->total_valid_pages = 0;
        for (i = 1; i < max_sect_len + 1; i++) {
                dd->valid_pages[i] = dd->valid_pages[i - 1];
                for (j = 0; j < BITMAP_SECT_LEN; j++, pfn++)
-                       if (page_is_dumpable(pfn))
+                       if (page_is_dumpable(pfn)) {
                                dd->valid_pages[i]++;
+                               dd->total_valid_pages++;
+                       }
        }
 
         return TRUE;
@@ -2090,6 +2094,7 @@ __diskdump_memory_dump(FILE *fp)
        else
                fprintf(fp, "\n");
        fprintf(fp, "       valid_pages: %lx\n", (ulong)dd->valid_pages);
+       fprintf(fp, " total_valid_pages: %lx\n", dd->total_valid_pages);
 
        return 0;
 }
-- 
2.31.1


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