Modules behaving differently on 32-bit and 64-bit systems?

Server NGINX
1

Hi there,

I have built nginx 1.5.6 from source, with a 3rd party module (xtoken -
Google Code Archive - Long-term storage for Google Code Project Hosting.).

I have it working fine on a 32-bit Debian Squeeze system. An identical
build
on a 64-bit Centos 6.4 system, with an identical configuration file
results
in the error: “nginx: [crit] ngx_slab_alloc() failed: no memory” on
startup.

I have narrowed the problem to the xtoken module, in as much as removing
references to it on the 64-bit system results in nginx starting
correctly.

I have had a quick look at the module source code, and can’t see
anything
that is obviously 32-bit -centric, other than a couple of variables that
have been declared as uint32_t.

Is it correct to assume that a properly written module will work
correctly
on both 32 and 64-bit systems?
Is there any additional nginx configuration that needs to be performed
on
64-bit systems?

Thanks,

Andrew

Posted at Nginx Forum:

2

Hello!

On Mon, Oct 21, 2013 at 01:13:56AM -0400, andrewc wrote:

I have narrowed the problem to the xtoken module, in as much as removing
references to it on the 64-bit system results in nginx starting correctly.

I have had a quick look at the module source code, and can’t see anything
that is obviously 32-bit -centric, other than a couple of variables that
have been declared as uint32_t.

Is it correct to assume that a properly written module will work correctly
on both 32 and 64-bit systems?

Yes.

Is there any additional nginx configuration that needs to be performed on
64-bit systems?

In some cases, additional configuration may be required due to
different data sizes.

Quick looks suggests that the problem in xtoken module is likely
here:

https://code.google.com/p/nginx-xtoken-module/source/browse/trunk/ngx_http_xtoken_module.c#660

It tries to estimate size of shared memory zone needed to keep
it’s data, but the estimate likely fails on 64-bit platforms due
to internal structures of slab allocator being bigger on these
platforms.

The same code may also unexpectedly fail in the future on internal
slab allocator changes.

–
Maxim D.
http://nginx.org/en/donation.html

3

Maxim D. Wrote:

Quick looks suggests that the problem in xtoken module is likely
here:

Google Code Archive - Long-term storage for Google Code Project Hosting.
http_xtoken_module.c#660

It tries to estimate size of shared memory zone needed to keep
it’s data, but the estimate likely fails on 64-bit platforms due
to internal structures of slab allocator being bigger on these
platforms.

Thanks for the tip, Maxim. On line 13 of ngx_http_token_module.c I
replaced:

#define XTOKEN_SHM_SIZE (sizeof(ngx_http_xtoken_shctx_t))

with:

#define XTOKEN_SHM_SIZE 65536

and rebuilt. It seems to work fine now.

65536 is purely arbitrary, and obviously not the most efficient use of
memory. I’ll do some reading and see if I can rework that memory
allocation
line.

Thanks,

Andrew

Posted at Nginx Forum:

4

Sorry if im bumping a very old thread but was a more permanent solution
ever
found to this problem?

//Daniel F

Posted at Nginx Forum: