Re: Linux-2.4.5

Rik van Riel
2001-05-26T15:27:45Z

On Sat, 26 May 2001, Andrea Arcangeli wrote:

> @@ -1416,11 +1416,9 @@
> */
> run_task_queue(&tq_disk);
>
> - /*
> - * Set our state for sleeping, then check again for buffer heads.
> - * This ensures we won't miss a wake_up from an interrupt.
> - */
> - wait_event(buffer_wait, nr_unused_buffer_heads >= MAX_BUF_PER_PAGE);
> + current->policy |= SCHED_YIELD;
> + __set_current_state(TASK_RUNNING);
> + schedule();
> goto try_again;
> }

This cannot possibly fix the problem because this code is
never reached.

What was observed in the backtraces by arjan, ben, marcelo
and people at IBM was:

create_buffers -> get_unused_buffer_head -> __alloc_pages

with the system looping infinitely in __alloc_pages. The
code you are changing above ONLY gets reached in case the
__alloc_pages (and thus, get_unused_buffer_head) returns
failure.

Rik
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