From owner-freebsd-hackers  Thu Jul 29 11:11:35 1999
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Date: Thu, 29 Jul 1999 11:11:18 -0700 (PDT)
From: Matthew Dillon <dillon@apollo.backplane.com>
Message-Id: <199907291811.LAA77015@apollo.backplane.com>
To: Jason Thorpe <thorpej@nas.nasa.gov>
Cc: "Daniel C. Sobral" <dcs@newsguy.com>, hackers@FreeBSD.ORG
Subject: Re: MADV_SEQUENTIAL and GNU Grep 
References:  <199907291742.KAA00237@lestat.nas.nasa.gov>
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:On Thu, 29 Jul 1999 10:21:52 -0700 (PDT) 
: Matthew Dillon <dillon@apollo.backplane.com> wrote:
:
: >     Shoot, it barely took 10 minutes for me to move the behavior field from
: >     the object to the vm map entry.
:
:...make sure the map entries are clipped properly.  It's easy to miss this
:in the most common test case of advising the entire mapping.
:
:        -- Jason R. Thorpe <thorpej@nas.nasa.gov>

    I believe the code is doing the right thing.  Here is an excerpt from
    vm_map_madvise() in vm_map.c (with the behavior moved to the map entry):

        for(current = entry;
                (current != &map->header) && (current->start < end);
                current = current->next) {
                vm_size_t size;

                if (current->eflags & MAP_ENTRY_IS_SUB_MAP) {
                        continue;
                }

                vm_map_clip_end(map, current, end);
                size = current->end - current->start;
		...

		current->behavior = ...

	...




					-Matt
					Matthew Dillon 
					<dillon@backplane.com>



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