Re: Strange load spikes on 2.4.19 kernel

David S. Miller
2002-10-13T07:51:09Z

From: "Joseph D. Wagner" <wagnerjd@prodigy.net>
Date: Sun, 13 Oct 2002 02:49:55 -0500

> But there is no fundamental reason for that, we just haven't
> gotten around to threading that bit yet.

Oh yes there is. What if an allocation of blocks and/or inodes is
preempted? Another thread could attempt to allocate the same set of
blocks and/or inodes.

That's why we protect the allocation with SMP locking primitives
which under Linux prevent preemption.

This isn't rocket science, the IP networking is fully threaded for
example and I consider that about as hard to thread as something like
ext2/ext3 inode/block allocation.

Also, as Andi Kleen noted, it's actually filesystem dependant whether
the inode/block allocation is threaded or not.