Date: Tue, 21 Jan 2003 15:08:28 -0700 (MST) From: "M. Warner Losh" <imp@bsdimp.com> To: bmilekic@unixdaemons.com Cc: arch@freebsd.org Subject: Re: Alfre's malloc changes: the next step Message-ID: <20030121.150828.121894335.imp@bsdimp.com> In-Reply-To: <20030121170319.B74210@unixdaemons.com> References: <20030121.144243.52206100.imp@bsdimp.com> <20030121170319.B74210@unixdaemons.com>
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In message: <20030121170319.B74210@unixdaemons.com>
Bosko Milekic <bmilekic@unixdaemons.com> writes:
: > 1) Make M_WAITOK and M_NOWAIT mandatory and exclusive in malloc.c.
: > You must specify one or the other, but not both.
: > 2) We assign both M_WAITOK and M_NOWAIT values that aren't 0, let's
: > say 0x10 and 0x20.
: > 3) We assign both M_DONTWAIT and M_TRYWAIT from mbuf.h values 0x40
: > and 0x80.
: > 4) We back out the bulk of the changes made, except where they were
: > real bugs.
: > 5) Hack the mbuf routines to reject M_DONTWAIT and M_TRYWAIT that
: > aren't the right value in flags.
:
: I'm not sure I understand point (5) here. What do you mean "that
: aren't the right value in flags?"
if (flags & ~(M_DONTWAIT | M_TRYWAIT))
panic("you used the interface wrong");
if ((flags & (M_DONTWAIT | M_TRYWAIT)) == 0)
panic("you used the interface wrong");
if ((flags & (M_DONTWAIT | M_TRYWAIT)) == (M_DONTWAIT | M_TRYWAIT))
panic("you used the interface wrong");
Maybe ifdef's INVARIANT or some such.
Similarly in malloc and M_WAITOK and M_NOWAIT
Warner
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