PATCH: increase heap size for (gpt)zfsboot

[Matt Reimer]

On Wed, Dec 9, 2009 at 12:31 PM, John Baldwin <jhb at freebsd.org> wrote:
> On Wednesday 09 December 2009 1:00:47 pm Matt Reimer wrote:
>> On Wed, Dec 9, 2009 at 7:15 AM, John Baldwin <jhb at freebsd.org> wrote:
>> > On Tuesday 08 December 2009 6:06:14 pm Matt Reimer wrote:
>> >> On Tue, Dec 8, 2009 at 5:13 AM, John Baldwin <jhb at freebsd.org> wrote:
>> >> > On Monday 07 December 2009 7:01:03 pm Matt Reimer wrote:
>> >> >> Enlarge the heap size for gptzfsboot and zfsboot. This is necessary so
>> >> >> the ZFS code has enough memory to handle decompression and error
>> >> >> recovery.
>> >> >>
>> >> >> Before this patch the heap grew from the end of the (gpt)zfsboot code
>> >> >> and static data up to 640KB, possibly overrunning the stack. Now the
>> >> >> heap is located at 16MB-64MB.
>> >> >>
>> >> >> Note that this requires machines with at least 64MB RAM, but this is
>> >> >> not likely to be a problem on any machine running ZFS.
>> >> >>
>> >> >> Sponsored by: VPOP Technologies, Inc.
>> >> >>
>> >> >> Matt Reimer
>> >> >
>> >> > Unfortunately the 16M - 64M range may not all be useable RAM.  It may contain
>> >> > ACPI tables, etc.  A robust approach would involve walking the SMAP, etc.  I
>> >> > just committed some changes to sys/boot/i386/loader/biosmem.c that make it
>> >> > smarter about choosing a heap region.  I suggest adopting that algorithm for
>> >> > figuring out a safe heap range.  zfsboot and gptzfsboot should have enough
>> >> > free space to take the bios_getmem() function.  You can increase the minimum
>> >> > heap size beyond 3M if desired (though 3M is the minimum the loader will
>> >> > guarantee currently, and if ZFS needs more than that it likely needs to be
>> >> > changed in both places).
>> >>
>> >> Thanks John. I dropped the bios_getmem() into zfsboot.c and it works
>> >> for me. How's the attached patch look to you?
>> >
>> > I tweaked it slightly (memtop* aren't needed for gptboot, and memsize() isn't
>> > used anymore).  Can you test the updated version below?
>>
>> It works. But making bios_getmem() inline causes a compiler warning:
>>
>> /usr/src/sys/boot/i386/gptzfsboot/../zfsboot/zfsboot.c: In function 'main':
>> /usr/src/sys/boot/i386/gptzfsboot/../zfsboot/zfsboot.c:353: warning:
>> inlining failed in call to 'bios_getmem': --param
>> max-inline-insns-single limit reached
>> /usr/src/sys/boot/i386/gptzfsboot/../zfsboot/zfsboot.c:620: warning:
>> called from here
>
> Ok, the inline is probably not needed for zfsboot since it isn't quite as
> space constrained.  I will commit it w/o the inline.

Thanks for committing this John.

Matt