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Date:      Thu, 24 Dec 1998 15:17:29 -0500 (EST)
From:      "John S. Dyson" <dyson@iquest.net>
To:        julian@whistle.com (Julian Elischer)
Cc:        dillon@apollo.backplane.com, dyson@iquest.net, hackers@FreeBSD.ORG
Subject:   Re: M_KERNEL in sys/malloc.h ???
Message-ID:  <199812242017.PAA50847@y.dyson.net>
In-Reply-To: <Pine.BSF.3.95.981224115800.12901C-100000@current1.whistle.com> from Julian Elischer at "Dec 24, 98 11:59:46 am"

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Julian Elischer said:
>
> I would rename it to M_RESERVED or something that indicates
> that this is a request that is allowed dip into the emergency reserves
> to satisfy the request.
> 
> > :> 
> > :As I remember, M_KERNEL means that it really needs memory.  waiting
> > :for memory is bad, and dip deeply into the page reserves.  Normally, the
> > :malloc (in vm_kern) code will only dip into the interrupt accessible
> > :free pages.  The M_KERNEL allows it to dip into all of the pages.
> > 
> 
That isn't what it really does.  In reality, malloc normally grabs
memory from the interrupt available queues.  The M_KERNEL relaxes the
restriction so that more memory is available.  M_KERNEL cannot
be used from interrupt time.

-- 
John                  | Never try to teach a pig to sing,
dyson@iquest.net      | it makes one look stupid
jdyson@nc.com         | and it irritates the pig.

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