The definitions for page->flags in crash are no longer correct in crash resulting in incorrect output for the kmem -i command. The page flags are currently defined for V22 V24 and one flag for V26. The flag definitions are changing in the 2.6 kernel often, crash will need to update these definitions for each 2.6.x. Yuck! Can we limit the flag definitions to just a few kernel versions? Any suggestions on what versions we should have definitions for?

-- David Wilder IBM Linux Technology Center Beaverton, Oregon, USA dwilder(a)us.ibm.com (503)578-3789 -- Crash-utility mailing list Crash-utility(a)redhat.com https://www.redhat.com/mailman/listinfo/crash-utility

Dave Anderson wrote: > David Wilder wrote: > >> The definitions for page->flags in crash are no longer correct in crash >> resulting in incorrect output for the kmem -i command. The page flags >> are currently defined for V22 V24 and one flag for V26. The flag >> definitions are changing in the 2.6 kernel often, crash will need to >> update these definitions for each 2.6.x. Yuck! Can we limit the flag >> definitions to just a few kernel versions? Any suggestions on what >> versions we should have definitions for? >> > > I've long since been keeping up with these, because most > of the hardwired page flag definitions that are #define'd > in memory.c are not used anymore. For example, there's > this construct in dump_mem_map() which just displays the > hex value: > > if (v22) { > ...translate hardwired flags... > } else if (THIS_KERNEL_VERSION > LINUX(2,4,9)) { > fprintf(fp, "%lx\n", flags); > } else { > ...translate old hardwired 2.4 flags... > } > > But there are a few other places that need to know about > specific flags, like PG_reserved and PG_slab for example, > whose bits get determined in vm_init(). Which one has > changed that upsets "kmem -i"? > > Dave > I was first looking at PG_slab. But I now see this bit in vm_init() if (VALID_MEMBER(page_pte)) { if (THIS_KERNEL_VERSION < LINUX(2,6,0)) vt->PG_slab = 10; else if (THIS_KERNEL_VERSION >= LINUX(2,6,0)) vt->PG_slab = 7; } This would set the correct value for vt->PG_slab = 7 except that pte is not a member of the struct page so vt->PG_slab=0.

vt->PG_reserved is not getting set in PG_reserved_flag_init(). But that looks like a problem resolving the symbol sys_read. So in dump_mem_map() it is falling back to v24_PG_reserved....

case GET_TOTALRAM_PAGES: if (vt->PG_reserved) PG_reserved_flag = vt->PG_reserved; else PG_reserved_flag = v22 ? 1 << v22_PG_reserved : 1 << v24_PG_reserved; .... That should mess up the calculation for total memory for kmem -i. But in my case the number is still correct.. -- David Wilder IBM Linux Technology Center Beaverton, Oregon, USA dwilder(a)us.ibm.com (503)578-3789 -- Crash-utility mailing list Crash-utility(a)redhat.com https://www.redhat.com/mailman/listinfo/crash-utility