nginx and php5-fpm have stopped working

[winnall]

I am moving a Drupal 7 application on Ubuntu 14.04 from development to
production. I use nginx (1.4.6-1ubuntu3.2) and php5-fpm
(5.5.9+dfsg-1ubuntu4.9).

The production machine is a VPS hosted at 1&1 and was running alright up
until about 4 hours ago. Nginx had been giving some errors on startup:

    2015/05/17 16:21:39 [info] 27859#0: Using 32768KiB of shared memory for
push module in /etc/nginx/nginx.conf:85
    2015/05/17 16:21:39 [alert] 27859#0: mmap(MAP_ANON|MAP_SHARED, 1048576)
failed (12: Cannot allocate memory)

but nginx and php5-fpm were working alright.

Later, however, after I had uploaded some corrected theme data (basically
CSS generated from SASS), nginx went down. Since then I have been unable to
make nginx AND php5-fpm start. I can start one or the other. Unfortunately
php5-fpm has not generated any error messages that I have been able to
find.

Rebooting doesn't solve the problem.

Nginx, however, now generates the following error.

    2015/05/17 23:40:40 [alert] 1559#0: mmap(MAP_ANON|MAP_SHARED, 33554432)
failed (12: Cannot allocate memory)

I'm pretty sure I have enough memory. The command free -m gives:

                        total       used       free     shared    buffers   
 cached
    Mem:          8192        168       8023        126          0       
149
    -/+ buffers/cache:         19       8172
    Swap:               0          0          0

I have seen other discussions with similar symptoms which seem to suggest
that parameters of the VPS need to be adjusted by the provider. Is this such
a case? If so, which parameters do I need to ask to have adjusted?

I'm out of my depth on this, so I'd be grateful for any assistance anyone
could offer.

Steve

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,258946,258946#msg-258946