Re: What determines VSIZE allocation?
Re: What determines VSIZE allocation?
- Subject: Re: What determines VSIZE allocation?
- From: Bill Bumgarner <email@hidden>
- Date: Wed, 14 Jan 2009 22:59:07 -0800
On Jan 14, 2009, at 9:40 PM, Michael Ash wrote:
On Wed, Jan 14, 2009 at 5:31 PM, Tobias Zimmerman
<email@hidden> wrote:
I know there are people who will say "VSIZE doesn't matter if there
is no
paging",
This is kind of like that famous question, "Have you stopped beating
your wife?" VSIZE doesn't matter, period. Paging doesn't enter into
it.
but if I ever sought to distribute my app people will not want to
install a statusitem that looks like a memory hog.
The solution there is to educate the foolish people who think that
VSIZE is any indication of being a "memory hog", not to artificially
reduce a number that has no bearing on any kind of system resource
usage.
Generally true (though I might choose a slightly different descriptor
of the uselessness), but not always.
VSIZE *can* be a very useful indication that an application is
consuming address space. This is not the same as consuming memory
and, to the user, is an utterly useless distinction to make.
For example, an application's VSIZE might be growing over time because
it is mmap()'ing a bunch of files (or a few small files). If the app
fails to unmap, the VSIZE will grow and the app may likely exhaust its
address space without any paging activity.
Example: for applications that are processing large files -- ID3 tag
editors come to mind -- watching the VSIZE can be a useful way of
determining if your code is properly managing the mapping of said files.
b.bum
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