Re: [Crash-utility] enhance bt command

On Mon, 2008-03-03 at 14:04 -0500, Dave Anderson wrote: > Ming Zhang wrote: > >> my English sucks... >> >> this is what i got. my side size-512 or size-1024 also works. just stuff >> like dentry cache or inode cache does not work. >> >> >> crash> rd 10078b2bca0 2 >> 10078b2bca0: 000001007877c8d4 00000100710fd5c8 ..wx.......q.... >> crash> rd -S 10078b2bca0 2 >> 10078b2bca0: [dentry_cache] 00000100710fd5c8 >> crash> kmem -s 10078b2bca0 >> kmem: address is not allocated in slab subsystem: 10078b2bca0 > No, your English is fine -- it's your command-entering that sucks! > > Above, when you entered "kmem -s 10078b2bca0", you're incorrectly entering > the *address* where the dentry_cache reference (1007877c8d4) is located. > And so it's telling you that 10078b2bca0 is not allocated in the slab > subsystem, which it isn't... > > But if you entered "kmem -s 1007877c8d4", you'd see the dentry_cache > information. yes. i noticed that. need some tea when handling 3 bugs at the same time... so here is my understanding. it actually shows the slab object that contain that address. it might not be the address of that object. so here is what i need to do crash> rd -x 10078b2bca0 10078b2bca0: 000001007877c8d4 crash> rd -S 10078b2bca0 10078b2bca0: [dentry_cache] crash> kmem -s 000001007877c8d4 CACHE NAME OBJSIZE ALLOCATED TOTAL SLABS SSIZE 10037ffc080 dentry_cache 240 9429 10560 660 4k SLAB MEMORY TOTAL ALLOCATED FREE 1007877c040 1007877c088 16 9 7 FREE / [ALLOCATED] [1007877c8d4] this only tell me that it belongs to one dentry object, but no idea which one then i have to use kmem -S dentry_cache, find out this piece SLAB MEMORY TOTAL ALLOCATED FREE 1007877c040 1007877c088 16 9 7 FREE / [ALLOCATED] [1007877c088] [1007877c178] 1007877c268 (cpu 1 cache) 1007877c358 (cpu 1 cache) [1007877c448] 1007877c538 (cpu 1 cache) [1007877c628] [1007877c718] [1007877c808] ~~~~~~~~~~~~~~~~~~~~ then find out it is here. [1007877c8f8] 1007877c9e8 (cpu 1 cache) 1007877cad8 (cpu 1 cache) [1007877cbc8] [1007877ccb8] 1007877cda8 (cpu 1 cache) 1007877ce98 (cpu 1 cache) then i know the object contain this address is 1007877c808. then crash> dentry.d_iname struct dentry { [0xcc] unsigned char d_iname[36]; } crash> eval c808+cc hexadecimal: c8d4 decimal: 51412 octal: 144324 show me that variable in stack actually is d_iname. then can we have the output format as 10078b2bca0: [000001007877c808+cc: dentry_cache] so we know the object address, which slab it is in, and the offset, (thus can derive the raw value), all in one shot?