[Gluster-devel] mem-pool.c magic trailer causes SIGBUS, fix or remove?

[Paul Jakma]

Hi Amar,

So fix is what I did first, but someone was wondering about the 
additional cost of the alignment calculation in the memory allocation 
path. (Though, the unaligned write of the trailer might be as many 
cycles of slowdown as a roundup calculation on platforms that handle 
unaligned access in microcode).

The pull request with the fix is at: 
https://github.com/gluster/glusterfs/pull/2669

With that, glusterd can now run on SPARC64 - without crashing in one of 
the first few memory allocations.

Though, I still can not get glusterd on SPARC64 to sync up with the 
pool. Whether with the trailer fixed, or the trailer removed. I end up 
with cksum errors on /var/lib/glusterfs/ files - starting with a 
completely clean /var/lib/glusterfs on the SPARC64 box.

The 2 big differences between the SPARC64 host and the other hosts that 
are happily synced are:
- distro (SPARC64 is debian; others are Fedora)
- endianness.

Wondering if either of those could be a factor?

Thanks,

Paul

On Thu, 29 Jul 2021, Amar Tumballi wrote:

> Thanks for the initiative Paul. Let me answer the major question from the
> thread.
>
>>> Remove the trailer? Or fix it?
>
> Ideal one is to fix it, as we do use mem-pool info to identify leaks etc
> through statedumps of the process. Remove can be an option on SPARC to
> start with if fixing is time consuming. I recommend removing the trailer
> within a #ifdef codeblock, so it may continue work in places where its
> already working.

regards,
-- 
Paul Jakma | paul at jakma.org | @pjakma | Key ID: 0xD86BF79464A2FF6A
Fortune:
Honesty pays, but it doesn't seem to pay enough to suit some people.
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