On Fri, 2 Jun 2000, Matthew Dharm wrote:
> Hi! I'm working on the usb mass storage support for linux. For this, we
> have a kernel thread which blocks on a semaphore (used to indicate the
> number of commands in the queue).
>
> The problem is, when I block on the semaphore, the process is still marked
> as runnable, and thus drives the load average up to 1.00. How do I sleep
> so that I don't drive up the load? Or how do I mark the process as
> sleeping on a semaphore for the purposes of load average calculation?
>
[ actually, I don't really know anything about kernel threads but ] my first
guess is that blocking on a semaphore from a kernel thread doesn't set the task
state to TASK_{UN,}INTERRUPTIBLE, this is why it keeps running.
Can you use spinlocks in kernel threads? If yes, /methinks this is what you
should use. My $0.02. Indeed, I'd appreciate being corrected.
-- fg"You can tune a filesystem but you can't tuna fish" (HP/UX' fsck manpage)
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This archive was generated by hypermail 2b29 : Sat Jun 03 2000 - 02:55:30 EDT