Re: PATCH: kernel-2.4 brlock livelock

From: Anton Blanchard
Date: Wed Sep 03 2003 - 14:57:34 EST



Hi,

> The patch changes the non-atomic code. It grabs the write lock, and
> then spins, waiting for all of the existing readers to finish.
> New readers are held off. This seems (to me) to be a reasonable
> thing to do, based on the following logic:

The problem is with recursive readers. One cpu takes a br read lock then
wants to take the same lock again. It must be allowed to get that read lock.

We need to drop the write spinlock or else we will deadlock.

Anton
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/