Messages in this thread | | | Date | Sun, 06 Sep 2009 18:14:57 +0200 | From | devzero@web ... | Subject | Re: block_dump - full path ? |
| |
Hi,
i just (too blindly) copied a tiny part of the log to this mail and kjournald and pdflush are indeed bad examples - sure there is no path for kernel threads.
> What do you mean by "the full path of the process"? Do you mean the > full path of the process' executable?
yes! certainly this applies to userspace processes only :)
> What exactly are you trying to do?
determine which processes did read/write.
> There might be a more efficient > way of gathering whatever data you are trying to get for your experiment.
i think that depends. if you have a trace of lots of temporary processes doing reads/writes in dmesg, it could be hard to correctly associate a pid with a process-binary /somewhere/deep/inside. furthermore you can`t assume that binary names are unique on a system.
regards roland
> On Sat, Sep 05, 2009 at 11:44:35PM +0200, devzero@web.de wrote: > > Hi, > > > > i came across the nice debugging feature sysctl vm.block_dump=1 which leaves information on read/write in dmesg for every process. > > > > Sep 5 20:11:15 neoware kernel: kjournald(423): WRITE block 155542512 on sda2 > > Sep 5 20:11:15 neoware kernel: kjournald(423): WRITE block 155542520 on sda2 > > Sep 5 20:11:15 neoware kernel: kjournald(423): WRITE block 155542528 on sda2 > > Sep 5 20:11:19 neoware kernel: pdflush(14): WRITE block 144498288 on sda2 > > Sep 5 20:11:19 neoware kernel: pdflush(14): WRITE block 144916496 on sda2 > > Sep 5 20:11:19 neoware kernel: pdflush(14): WRITE block 144917376 on sda2 > > Sep 5 20:11:19 neoware kernel: pdflush(14): WRITE block 144704600 on sda2 > > > > is it possible to log the full path of the process ? > > What do you mean by "the full path of the process"? Do you mean the > full path of the process' executable? (In this case kjournald and > pdflush are kernel threads so there is no executable, and thus there > is no "full path". unless you mean pathname to the kernel, i.e., /vmlinux.) > > Or did you mean the full path name of the file associated with the > block number? In this case, kjournald is writing to the file system > journal, which has no pathname. pdflush is writing dirty pages from > the page cache, which could be mapped to file names, but it would take > up a huge amount of space in the log -- but to what effect? > > What exactly are you trying to do? There might be a more efficient > way of gathering whatever data you are trying to get for your experiment. > > - Ted >
________________________________________________________________ Neu: WEB.DE Doppel-FLAT mit Internet-Flatrate + Telefon-Flatrate für nur 19,99 Euro/mtl.!* http://produkte.web.de/go/02/
-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |