http://phk.freebsd.dk/misc/p_args.patch
The p_args.patch patch implements a cache of the commandline arguments
in the process structure and makes ps(1) pick it up from there with
sysctl rather than by groping around in the target process memory.
This patch:
Speeds up ps(1).
Reduces the risk of some hairy races in procfs/proc_mem.c
when multiple ps(1) processes are running on a SMP system
Moves us closer to makeing procfs optional again (this is
a nice thing for chroot and jails).
There is a new sysctl: kern.ps_arg_cache_limit which defaults to
(PAGE_SIZE / 8). This is the max amount of RAM we will use *PER
PROCESS* to cache commandlines in. If the commandline is longer
*OR* of the process calls setproctitle(3) then nothing will be
cached and ps(1) will have to take the long way though the process
memory to find the command line for it.
Things which need more work:
Examine if locking will be needed for p->p_args, in particular
for the refcount element.
Decide how setproctitle(3) should work. Do we want to keep
the "real" commandline around in addition to the proctitle
or do we just overwrite it as we do now. I'd like to hear
input from people on this one. One option is "as today",
the other would allow us to see the actual commandline
in addition to any proctitle the process have set. The
down side is that the process nolonger can erase a password
or similar sensitive arguments.
Test, test, test...
Poul-Henning
/19991115
--
Poul-Henning Kamp FreeBSD coreteam member
[EMAIL PROTECTED] "Real hackers run -current on their laptop."
FreeBSD -- It will take a long time before progress goes too far!
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