Date: Thu, 29 Jul 1999 11:05:46 -0700 (PDT) From: Matthew Dillon <dillon@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 Message-ID: <199907291805.LAA76909@apollo.backplane.com> References: <199907291756.KAA00408@lestat.nas.nasa.gov>
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:On Thu, 29 Jul 1999 10:52:02 -0700 (PDT)
: Matthew Dillon <dillon@apollo.backplane.com> wrote:
:
: > Yes, we already do this, but only for OBJT_DEFAULT and OBJT_SWAP objects.
: > We do not do this for file objects... it would make me rather nervous
: > if we did :-)
:
:Why? I can think of at least one instance where this is useful: using
:a file in the file system as a shared memory handle.
I was thinking of adding a flag to mmap() for that, to prevent unnecessary
paging. Right now any shared file map will be synced to disk every 30
seconds or so no matter what.
I'm not against the idea, but it isn't front and center for me yet, at
least not until we fix the syncing problem. There are several people
who have already requested a solution to the syncing problem that are
currently being forced to use SysV shared memory (and hating it).
:Seems as if the programmer erroneously MADV_FREE's a file, well ... you
:only supplied the rope.
:
: -- Jason R. Thorpe <thorpej@nas.nasa.gov>
-Matt
Matthew Dillon
<dillon@backplane.com>
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