[Crash-utility] crash version 4.0-2.22 is available

[Dave Anderson]

Sharyathi Nagesh wrote:

  Dave
      You were right it should be buffer_size instead of objectsize.(As obj_size is the size of debugging information).
  I modified function vm_init() and do_slab_chain_percpu_v2() to make it work with current dumps. This is just a code
  part to show how to fix the problem but it is not a patch as such...
     Please go through and let me know would it be good idea to write a new function (as you have suggested earlier) or
  is it possible to accommodate by calling do_slab_chain_percpu_v2() iteratively with different nodes by passing them as

  parameter.

  Changes to vm_init()

                          if(MEMBER_EXISTS("kmem_cache","objsize"))
                                  MEMBER_OFFSET_INIT(kmem_cache_s_objsize,  "kmem_cache",
                                  "objsize");
                          else if(MEMBER_EXISTS("kmem_cache","buffer_size"))
                                  MEMBER_OFFSET_INIT(kmem_cache_s_objsize,  "kmem_cache",
                                  "buffer_size")

  Changes to do_slab_chain_percpu_v2()

          ulong start_address[MAX_NUMNODES];

          if (!readmem(si->cache+OFFSET(kmem_cache_s_lists),
                      KVADDR, &start_address[0],
                      sizeof(ulong) * MAX_NUMNODES,
                      "array nodelist array", RETURN_ON_ERROR))
                          {printf("\n Error encountered with readmem  \n");exit(0);}

           for (i =  0; i < MAX_NUMNODES ; i++) {
                  slab_chains[0] = start_address[i] + OFFSET(kmem_list3_slabs_partial);
                  slab_chains[1] = start_address[i] + OFFSET(kmem_list3_slabs_full);
                  slab_chains[2] = start_address[i] + OFFSET(kmem_list3_slabs_free);




The vm_init() change is fine, but it would also need:

(1) the same kind of offset initializer to handle the kmem_cache
    structure's "lists"-to-"nodelist" name change.
(2) A new flag in vt->flags to signal this node-enhanced version
    of the kmem_cache struct.
(3) a check of the dimension of some processor-neutral, always-there,
    kernel array indexed by MAX_NUMNODES, so that you can determine
    what MAX_NUMNODES is equal to, and then store that value in a
    new vm_table entry.

With respect to do_slab_chain_percpu_v2(), I would prefer that
it be left as is, and either

(1) at the top of the function, check for your new "node-enhanced"
    flag, and call a new do_slab_chain_percpu_v2_nodes() function, or
(2) alternatively, the two locations where do_slab_chain_percpu_v2()
    gets called could be qualified based upon the new flag, and the
    appropriate function called.

In that new function, the usage of a static start_address[] array
as you indicate above would have to be replaced with dynamically
allocated and freed with GETBUF() and FREEBUF(), based upon
the predetermined size of MAX_NUMNODES.

Doing it that way leaves the current functionality untouched, makes
me a lot less nervous, and should make your task a bit easier.

Make sense?

Dave
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