huge pages on linux and HUGETLB_SHARE and a coredump

[Ganesh Venkitachalam]

Sorry, attached is VERBOSE/DEBUG output:


laddu$ ./myhuge
libhugetlbfs [laddu:14704]: INFO: Detected page sizes:
libhugetlbfs [laddu:14704]: INFO:    Size: 2048 kB (default)  Mount: /mnt/huge
libhugetlbfs [laddu:14704]: INFO: Parsed kernel version: [2] . [6] . [32]  [post-release: 10]
libhugetlbfs [laddu:14704]: INFO: Feature private_reservations is present in this kernel
libhugetlbfs [laddu:14704]: INFO: Kernel has MAP_PRIVATE reservations.  Disabling heap prefaulting.
libhugetlbfs [laddu:14704]: INFO: HUGETLB_SHARE=1, sharing enabled for only read-only segments
libhugetlbfs [laddu:14704]: INFO: Segment 0 (phdr 2): 0x1000000-0x1000954  (filesz=0x954) (prot = 0x5)
libhugetlbfs [laddu:14704]: INFO: Segment 1 (phdr 3): 0x2000000-0x2000208  (filesz=0x1f4) (prot = 0x7)
libhugetlbfs [laddu:14704]: DEBUG: Total memsz = 0xb5c, memsz of largest segment = 0x954
libhugetlbfs [laddu:14704]: INFO: libhugetlbfs version: 2.8
libhugetlbfs [laddu:14705]: INFO: Mapped hugeseg at 0x2aaaaac00000. Copying 0x1f4 bytes and 0 extra bytes from 0x2000000...done
libhugetlbfs [laddu:14704]: INFO: Prepare succeeded
Illegal instruction (core dumped)

--Thanks
Ganesh
~


--- On Fri, 4/23/10, Ganesh Venkitachalam <venkitac@yahoo.com> wrote:

> From: Ganesh Venkitachalam <venkitac@yahoo.com>
> Subject: huge pages on linux and HUGETLB_SHARE and a coredump
> To: binutils@sourceware.org
> Date: Friday, April 23, 2010, 2:38 PM
> 
> So, I finally have large pages working for my app text
> (thanks for then 
> help). I have one more problem I need to fix, though:
> 
> I found that my large app is not sharing text pages when
> using hugepages. 
> In trying to figure this out, I wrote a 3 line while(1)
> program, linked to
> use huge pages, and exported HUGETLB_SHARE=1, and ran the
> program. It
> coredumps on process load. When I unset HUGETLB_SHARE, no
> problem it works 
> fine. 
> 
> I can't find the coredump, Or I'd have tried a backtrace.
> (It seems to be 
> dumping core someplace else other than curdir).
> 
> Thanks for any help!
> 
> --Ganesh
> 
> 
> 
>       
>