Date: Sat, 23 Feb 2002 17:54:56 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Bruce Evans <bde@zeta.org.au> Cc: Terry Lambert <tlambert2@mindspring.com>, Alfred Perlstein <alfred@FreeBSD.ORG>, Bosko Milekic <bmilekic@unixdaemons.com>, Seigo Tanimura <tanimura@r.dl.itc.u-tokyo.ac.jp>, <current@FreeBSD.ORG>, John Baldwin <jhb@FreeBSD.ORG> Subject: Re: malloc_bucket() idea (was Re: How to fix malloc.) Message-ID: <200202240154.g1O1suv36741@apollo.backplane.com> References: <20020224111043.W30980-100000@gamplex.bde.org>
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:It's too messy and unfinished (doesn't work right for SMP or irqs >= 16),
:and dificult to untangle from my other patches. I posted these partial
:ones to attempt to inhibit() recomplication of the current critical*
:functions in directions that I don't want to go :-).
:...
:
:ipending here works much as in RELENG_4. It is ORed into by sched_ithd()
:if curthread->td_critnest != 0. Nothing special is needed for pci
:(the ICU masks pending interrupts).
:
:Bruce
Ok, I have most of it coded up. Could you explain what 'spending'
was for?
I am doing it slightly different then you. To avoid having to use
locked instructions I have placed ipending in the thread structure:
void
critical_enter(void)
{
struct thread *td = curthread;
++td->td_critnest;
}
void
critical_exit(void)
{
struct thread *td = curthread;
KASSERT(td->td_critnest > 0, ("bad td_critnest value!"));
if (--td->td_critnest == 0) {
if (td->td_ipending)
unpend();
}
}
The apic and icu vector code will do a simple td_critnest test and
OR the irq bit into td->td_ipending (it conveniently already has
the struct thread in %ebx). And the vector code will also check and
handle any non-zero td_ipending if critnest is 0, handling the
1->0 transition/preemption race.
I'll post the patch when it gets a little further along.
How should I deal with fast interrupts?
-Matt
Matthew Dillon
<dillon@backplane.com>
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