On Tue, 2009-09-29 at 20:54 +0000, Dave Anderson wrote: > ----- "Dave Anderson" <anderson@xxxxxxxxxx> wrote: > > > > > So the fix would be to first determine the cache_cache.buffer_size value, > > and use that to initialize the size_table.kmem_cache_s value used by the > > "SIZE(kmem_cache_s)" macro. Secondly, "vt->kmem_cache_len_nodes", which > > is also based upon the same MAX_NUMNODES array index value, needs to be > > downsized as well. It looks like if the kernel "nr_node_ids" exists as > > symbol (instead of a #define), then it should be used. > > I'm thinking this patch should work: > > http://people.redhat.com/anderson/memory.patch > > Dave Dave, You are faster than me at fixing crash:-) I was just about to start on the part for kmem_cache_len_nodes... The patch fixes the problem on my example dump which previously said: ===== please wait... (gathering kmem slab cache data) crash: page excluded: kernel virtual address: ffff88022457a000 type: "kmem_cache_s buffer" crash: unable to initialize kmem slab cache subsystem ===== It now says: ===== please wait... (gathering kmem slab cache data) kmem_cache_downsize: SIZE(kmem_cache_s): 872 cache_cache.buffer_size: 384 kmem_cache_downsize: nr_node_ids: 2 ===== In the meantime, I remembered "--zero_exclude", which makes for a slightly dangerous workaround for the problem. It fills in the unnecessarily-accessed missing pages with zeros. The output of "kmem -s" and "kmem -S" on my problem dump is the same between your patched version and the old version running with --zero_exclude. (I don't normally think of using zero_exclude because it can mask both kernel bugs and makedumpfile bugs...) Thanks for making that patch. Is there anything left to fix in crash ?-) Bob Montgomery -- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/crash-utility
