Re: [Crash-utility] [PATCH] add arm support for libgcore

----- Original Message ----- ... > > > The reason why I've included the ``page fault'' in the default warning > > > message is to avoid the situation where users get confused they have > > > successfully got complete user-space coredump. > > > > > > GDB tends to work well because part of user stack necessary for > > > backtrace is not paged out most of time; of course, the backtrace > > > would fail if paged-out. > > > > > > Thanks. > > > HATAYAMA, Daisuke > > > > > > > I see, thanks for detailed explanation. > > My another curious is whether we could refill those missing swapped page, if > > we provide whole swap partition data? > > > > Thanks, > > Lei > > Aren't most of those "page fault" references that you see > during a gcore operation typically referring to pages that > exist in the target task's virtual memory map but have not > been referenced? For example, none of these pages are swapped out: crash> gcore 1951 gcore: WARNING: FPU may be inaccurate: 1951 gcore: WARNING: page fault at 386df98000 gcore: WARNING: page fault at 386df99000 gcore: WARNING: page fault at 386df9e000 gcore: WARNING: page fault at 386df9f000 gcore: WARNING: page fault at 7fff632f3000 gcore: WARNING: page fault at 7fff632f4000 gcore: WARNING: page fault at 7fff632f5000 gcore: WARNING: page fault at 7fff632f6000 gcore: WARNING: page fault at 7fff632f7000 gcore: WARNING: page fault at 7fff632f8000 gcore: WARNING: page fault at 7fff632f9000 gcore: WARNING: page fault at 7fff632fa000 gcore: WARNING: page fault at 7fff632fb000 gcore: WARNING: page fault at 7fff632fc000 gcore: WARNING: page fault at 7fff632fd000 gcore: WARNING: page fault at 7fff632fe000 gcore: WARNING: page fault at 7fff632ff000 gcore: WARNING: page fault at 7fff63300000 gcore: WARNING: page fault at 7fff63301000 gcore: WARNING: page fault at 7fff63302000 gcore: WARNING: page fault at 7fff63303000 gcore: WARNING: page fault at 7fff63304000 gcore: WARNING: page fault at 7fff63305000 Saved core.1951.system_crash crash> In fact, no swap was used at all: crash> swap FILENAME TYPE SIZE USED PCT PRIORITY /dm-1 PARTITION 5439480k 0k 0% -1 crash> And here are the "page fault" pages from above, all either unreferenced file-backed pages or unreferenced data pages: crash> vm -p ... [ cut ] ... VIRTUAL PHYSICAL ... [ cut ] ... 386df98000 FILE: /lib64/libc-2.12.so OFFSET: 198000 386df99000 FILE: /lib64/libc-2.12.so OFFSET: 199000 ... [ cut ] ... 386df9e000 (not mapped) 386df9f000 (not mapped) ... [ cut ] ... 7fff632f3000 (not mapped) 7fff632f4000 (not mapped) 7fff632f5000 (not mapped) 7fff632f6000 (not mapped) 7fff632f7000 (not mapped) 7fff632f8000 (not mapped) 7fff632f9000 (not mapped) 7fff632fa000 (not mapped) 7fff632fb000 (not mapped) 7fff632fc000 (not mapped) 7fff632fd000 (not mapped) 7fff632fe000 (not mapped) 7fff632ff000 (not mapped) 7fff63300000 (not mapped) 7fff63301000 (not mapped) 7fff63302000 (not mapped) 7fff63303000 (not mapped) 7fff63304000 (not mapped) 7fff63305000 (not mapped) ... Dave