Date: Thu, 11 Jan 2001 15:05:29 -0500 From: "Brian J. McGovern" <bmcgover@cisco.com> To: hackers@freebsd.org Subject: Question about 'open' files.... Message-ID: <200101112005.f0BK5T406464@bmcgover-pc.cisco.com>
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I'm doing some tests for Greg on vinum (trying to crash it), and I've run
across a problem that is not particular to vinum. I'm hoping someone can
explain it to me and/or tell me how to work around it.
Using the code fragment (note: The code I'm using is actually more complex,
and checks for errors in opening, writing, etc, but I'm keeping it basic
for the discussion):
for (counter = 0; counter < 20000; counter++)
{
x = open(filename,O_CREAT | O_WRONLY);
write(x, buffer, size);
close(x);
}
I will run anywhere between 1-5 instances of the code loop above. After there
are about 2050 files on the disk (it _appears_ to be variations of 2048, plus
files already on the disk, . and .., etc.), the programs crash with "too many
open files".
The problem, in my mind, is that the files are _closed_ (not open). I'm curious
if this is some type of accounting error on a per-login basis, or whether
there is some type of garbage collection not happening. Typically, after all
of the applications die with this error, if I immediately restart, they
die pretty quickly. If I wait like 10+ seconds, they can run again, and
generate the 2048+/- files again before dying, which leads me to believe its
something to do with per-user accounting/garbage collection.
I would be curious to understand this, and its impact, as this does not
appear to be 'good' (tm) behavior, particularly if one wishes to run a program
that opens and closes a lot of small files.
I welcome any thoughts.
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