Re: [ckrm-tech] [PATCH 5/13] BC: user interface (syscalls)

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Pavel Emelianov wrote:
Balbir Singh wrote:
Pavel Emelianov wrote:
Balbir Singh wrote:
+
+asmlinkage long sys_set_bcid(bcid_t id)
+{
+    int error;
+    struct beancounter *bc;
+    struct task_beancounter *task_bc;
+
+    task_bc = &current->task_bc;
I was playing around with the bc patches and found that to make
use of bc's, I had to actually call set_bcid() and then exec() a
task/shell so that the id would stick around. Would you consider
That sounds very strange as sys_set_bcid() actually changes current's
exec_bc.
One note is about mm's bc - mm obtains new bc only after fork or exec -
that's
true. But kmemsize starts charging right after the sys_set_bcid.
I was playing around only with kmemsize. I think the reason for my
observation
is this

bash --> (my utility) --> set_bcid()

Since bash spawns my utility in a separate process, it creates and
assigns
a bean counter to it and then my utility exits. Unless it
spawns/exec()'s a
new shell, the beancounter is freed when the task exits (my utility).
Well, beancounter is not "inherited" by parent task :)
After setting bcid you need to spawn/exec a new shell.
But seeting limits and getting stats is possible from the old shell
as well as from the new one.

That's what I suspected. I suggest changing the system call to allow adding any
task to a particular id (not necessarily only the current one). It would help us
group tasks to a particular id. It would also solve my problem of spawning a
shell each time I decide to use a task with a beancounter and limits.

changing sys_set_bcid to sys_set_task_bcid() or adding a new
system call sys_set_task_bcid()? We could pass the pid that we
intend to associate with the new id. This also means we'll need
locking around to protect task->task_bc.


--

	Balbir Singh,
	Linux Technology Center,
	IBM Software Labs
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux