On 05/18/2013 02:27 PM, Michael L. Semon wrote:
> On 05/18/2013 01:07 AM, Jeff Liu wrote:
>> Looks our test for 32-bit system is insufficient. There has another bug
>> reports regarding 32-bit yesterday:
> I read this and did not chime in because I don't know about the "no
> space left on device" error.
> The first issue the customer had, though, was one I had on a 2.8GHz
> Pentium 4. The idea of using a tunable to increase vmalloc space made
> me think, "What, am I using FreeBSD or something? Why didn't Linux
> auto-tune this?" so I dug deeper. [Disclaimer: I use FreeBSD and find
> value in it, but it requires at least some sysctl tuning for things that
> Linux will tune automatically.]
> Basically, I had vmalloc space to have an environment set up perfectly
> in 768 MB of RAM. Then I added another 512 MB, and Linux saw only 896
> MB for lack of highmem support. At that point I enabled highmem
> support, Linux decided to auto-tune my vmalloc space down to 128 MB,
> which was not enough to handle an xfsdump of a 30 GB device-mapper crypt
> partition. The PC, when left alone, could develop those same oops-y
> messages while doing incremental xfsdumps overnight, and if left alone
> for days, even simple cp commands could cause issues. My resolution was
> to use the CONFIG_VMSPLIT_2G kernel option and reduce the things
> reported by /proc/vmallocinfo that are vmalloc items. Some ioremap
> items in /proc/vmallocinfo were removed where convenient. Despite
> warnings on the Internet like "this breaks ELF" and "this breaks binary
> modules," I've had no issues with it in the nine months in which the
> kernel has operated this way. [Note: I don't use binary modules. For
> that matter, only that PC uses modules at all.] Ultimately, I got rid
> of the crypts as well, but not before verifying that the above setup did
> indeed solve the problem at hand.
> It's only my two cents, one person trying to balance Internet research
> against what actually works in testing on one PC. If the solution is
> sane sane to you, feel free to forward this story to your customer to
> see if anything in it will help.
>> So I'm going to setup a 32-bit test environment for such tests together
>> with Michael.
> Excellent! Let me know a little about your test environment and whether
> it's a VM or bare metal.
VM running via virtual box.
The kernel is based on the updated xfs-next tree.
root@linux32bit:/home/jeff# uname -a
Linux linux32bit 3.10.0-rc1+ #1 SMP Sat May 18 15:30:11 CST 2013 i686
i686 i386 GNU/Linux