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Date: Tue, 28 May 2002 21:29:47 -0400 (EDT)
From: Garrett Wollman <wollman@khavrinen.lcs.mit.edu>
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To: John Baldwin <jhb@FreeBSD.org>
Cc: cvs-all@FreeBSD.org, cvs-committers@FreeBSD.org
Subject: Re: cvs commit: src/sys/kern uipc_socket.c
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<<On Tue, 28 May 2002 20:00:19 -0400 (EDT), John Baldwin <jhb@FreeBSD.org> said:

> And you are being completely vague about what the current strategy actually
> is.

Non-blocking synchronization.  Or rather, semi-non-blocking
synchronization.  As written, except for this (minor) race, and given
the requirement for type-stable memory, we do not need any mutual
exclusion except for the initial construction of the list of sockets
to copy out.  (If a better data structure were used for the list of
sockets, we would not need any mutual exclusion at all.)  We can
provide to applications a limited form of consistency which was not
possible with the old (grovel in KVM) implementation, without blocking
network activity for an inordinate length of time.

One would prefer that an appropriate constructor were used instead of
simply hoping for the best.  (It's highly unlikely that the race would
be lost undetectably, so it's not a huge concern, but it is worthy of
a comment.)

-GAWollman


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