Date: Tue, 25 Apr 2000 01:36:48 -0700 (PDT) From: Matthew Dillon <dillon@apollo.backplane.com> To: "Jonathan M. Bresler" <jmb@hub.freebsd.org> Cc: smp@csn.net, current@FreeBSD.ORG Subject: Re: SMP changes and breaking kld object module compatibility Message-ID: <200004250836.BAA76099@apollo.backplane.com> References: <20000425014539.D944E37B7A0@hub.freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
:> The network stack is equally easy to make MP-safe. In this case we
:> have a shared lock to lookup sockets for host/port combinations and
:> then fine-grained exclusive locks within those sockets. Route table
:> and other high level operations could in fact remain BGL'd without
:> interfering with the network stack because the network stack *already*
:> caches route table lookups.
:>
:
: might it be fair to summarize this as: you locks on data
:rather than locks on code.
:
:jmb
In a nutshell, yes. Functional data structure locking such that
things don't trip over each other with a typical heavy load.
For example, it may well be that it makes more sense to lock hash
table chains rather then the structures stored on those chains
in some instances. vm_page_lookup(), for example, and tsleep().
In other cases it may make sense to lock the terminal structures.
For example: vnodes, processes, pmaps, VM objects.
And in still other cases we should be able to get away with no
locking at all (in the steady-state heavy load case). Network
interrupts, for example, can queue packets with fixed-length
bidirectional FIFOs.
-Matt
Matthew Dillon
<dillon@backplane.com>
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-current" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200004250836.BAA76099>