It turns out we were using the CPU accounting
cgroups for keeping track of processes that were
forked by an app without the framework's knowledge,
so we could kill all of them reliably (see b/15313911
for context).
Since we want to use memory cgroups for other purposes,
we might as well use memory cgroups for tracking forked
PIDs if they're enabled. This also gets us automatic cleanup
of empty mem cgroups.
Also, removed old mem cgroup mount point that is no
longer used, as well as cgroup release agent code that
we're not using.
Change-Id: I69d5cc31c162ffa49ef6945755f41381e306cc8b
It looks like there were a couple problems in the code:
- It would not 0-terminate the string it read, to make sure we didn't
see garbage at the end.
- It didn't reduce buf_len as it processes data in the buffer, so if
we need to read more we will increase the buffer length to be longer
than the actual available data.
Also put in some logs about every thing we kill, so we can see what
is going on when debugging. And add a special check for us trying
to kill pid 0 for any reason, since doing so seem to be terminal to
the caller.
Change-Id: I2fe29bfef08938b8a2eb182475c0705c14d8d84f
libprocessgroup will allow Zygote to place processes
in a cgroup, and then kill the process and all forked processes
later. lmkd will also kill all forked processes.
Bug: 15313911
Change-Id: I20404d0dbe448f1c475d2f4c61cccca462f9e544
