> ---
>   defs.h     | 26 +++++++++++++++++++++
>   diskdump.c | 66 ++++++++++++++++++++++++++++++++++++++++++++----------
>   2 files changed, 80 insertions(+), 12 deletions(-)
>
> diff --git a/defs.h b/defs.h
> index 96a7a2a..2038351 100644
> --- a/defs.h
> +++ b/defs.h
> @@ -2225,6 +2225,7 @@ struct offset_table {                    /* stash of commonly-used offsets */
>      long module_memory_base;
>      long module_memory_size;
>      long irq_data_irq;
> +   long zspage_huge;
>   };
>
>   struct size_table {         /* stash of commonly-used sizes */
> @@ -7210,6 +7211,19 @@ ulong try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong len, ulon
>   #define SECTORS_PER_PAGE        (1 << SECTORS_PER_PAGE_SHIFT)
>   #define ZRAM_FLAG_SHIFT         (1<<24)
>   #define ZRAM_FLAG_SAME_BIT      (1<<25)
> +
> +struct zram_pageflags {
> +    long ZRAM_LOCK;
> +    long ZRAM_SAME;
> +};
> +
> +/*
> + *  diskdump.c
> + */
> +extern struct zram_pageflags zram_pageflags;
> +#define ZRAM_PAGEFLAG_INIT(X, Y) (zram_pageflags.X = Y)
> +#define ZRAM_PAGEFLAG_VALUE(X) (zram_pageflags.X)

Thank you for the update.

I don't think these macros are necessary, so simplified the patch on my
end.  With rethinking the names, kept "ZRAM_FLAG_SHIFT" and
"ZRAM_FLAG_SAME_BIT" as they are, and made some tweaks.

Guanyou and Lianbo, is this attached patch OK?

+static long ZRAM_FLAG_SHIFT;
+static long ZRAM_FLAG_SAME_BIT;

The ulong is good to me.

+
 static void
 zram_init(void)
 {
+       long zram_lock;
+
        MEMBER_OFFSET_INIT(zram_mempoll, "zram", "mem_pool");
        MEMBER_OFFSET_INIT(zram_compressor, "zram", "compressor");
        MEMBER_OFFSET_INIT(zram_table_flag, "zram_table_entry", "flags");
        if (INVALID_MEMBER(zram_table_flag))
                MEMBER_OFFSET_INIT(zram_table_flag, "zram_table_entry", "value");
        STRUCT_SIZE_INIT(zram_table_entry, "zram_table_entry");
+       MEMBER_OFFSET_INIT(zspoll_size_class, "zs_pool", "size_class");
+       MEMBER_OFFSET_INIT(size_class_size, "size_class", "size");
+       MEMBER_OFFSET_INIT(zspage_huge, "zspage", "huge");
+
+       if (enumerator_value("ZRAM_LOCK", &zram_lock))
+               ZRAM_FLAG_SHIFT = 1 << zram_lock;
+       else if (THIS_KERNEL_VERSION >= LINUX(6,1,0))

This depends on kernel version number, it might be more friendly for the distribution to output some debug info as below:

if (CRASHDEBUG(1))

    error(INFO, "ZRAM_FLAG_SHIFT=%lu\n", ZRAM_FLAG_SHIFT);

Once the related kernel patches are backported to an old kernel, the similar checking may fail. But, at least we can know a little more with the crash debug info.

+               ZRAM_FLAG_SHIFT = 1 << (PAGESHIFT() + 1);
+       else
+               ZRAM_FLAG_SHIFT = 1 << 24;
+
+       ZRAM_FLAG_SAME_BIT = ZRAM_FLAG_SHIFT << 1;
 }

I tested this on Linux 6.1.

crash> vtop 00007fb60be00000
VIRTUAL     PHYSICAL
7fb60be00000  (not mapped)

    PGD: 108e807f8 => 1107c4067
    PUD: 1107c46c0 => 106ec9067
    PMD: 106ec92f8 => 1060f2067
    PTE: 1060f2000 => 7fffffffdfffe0a

       PTE           SWAP     OFFSET
7fffffffdfffe0a  /dev/zram0   65536

       VMA           START       END     FLAGS FILE
ffff935206cda980 7fb60bdfe000 7fb64be00000 8100073

SWAP: /dev/zram0  OFFSET: 65536

crash> rd 00007fb60be00000
     7fb60be00000:  0000000000001000                    ........

(Note that it looks like Linux 6.2 and later have other changes related
to zram, so this patch supports up to 6.1.  We can fix them later.)

Thanks,
Kazu