On 02/25/2016 07:35 PM, Atsushi Kumagai wrote: > Hello Dave, > >>> Note that PAGE_MAPPING_ANON is now only set in the compound_head page, >>> so when makedumpfile walks though the pages, it will have to look >>> at each page's head page for the bit setting. >> >> Thanks for your report. >> As you said, it seems checking the head page like kernel does is necessary. >> I'll try to work it out, please give me some time. > > Reading head page's page->mapping for each tail page will take extra time, > so I contrived another way. > > It's just skipping compound tail pages for filtering. > If makedumpfile excludes compound pages, it will be done at a time by > exclude_range() at the time of checking the compound head page. We don't > need to check compound tail pages individually. > > I made the patch, could you test the *compound* branch below ? > This version requires a new unexported symbol, you need to specify > -x vmlinux for now. > > https://sourceforge.net/p/makedumpfile/code/ci/compound/tree/ Hi Atsushi, Dave, Running the makedumpfile compound branch on 4.5-rc5 and this kdump.conf setting: core_collector makedumpfile -l --message-level 1 -d 31 -x /kdumproot/var/crash/vmlinux I was able to collect and successfully read a few test dumps without incident. This was inside a VM without any interesting system load, but was regularly giving me issues before the patch. Regards, -- Joe
