Date: Wed, 1 Apr 2009 22:08:29 GMT From: Stephen Sanders <ssanders@opnet.com> To: freebsd-gnats-submit@FreeBSD.org Subject: misc/133286: dd can fill system memory Message-ID: <200904012208.n31M8TK6018668@www.freebsd.org> Resent-Message-ID: <200904012210.n31MA1PL018141@freefall.freebsd.org>
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>Number: 133286 >Category: misc >Synopsis: dd can fill system memory >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Wed Apr 01 22:10:01 UTC 2009 >Closed-Date: >Last-Modified: >Originator: Stephen Sanders >Release: 6.3 >Organization: OPNET >Environment: FreeBSD alt-4100-1.opnet.com 6.3-RELEASE FreeBSD 6.3-RELEASE #0: Tue Mar 31 18:47:07 EDT 2009 root@vm6-3-64-dev.opnet.com:/root/Projects/FreeBSD/package/NPbabkernel/bld-tmp/sys/amd64/compile/NPBAB amd64 CPU: Intel(R) Xeon(R) CPU X5450 @ 3.00GHz (2414.49-MHz K8-class CPU) FreeBSD/SMP: Multiprocessor System Detected: 8 CPUs 16GB RAM 3ware 9650SE-16ML 16 750GB drives 16 GB swap >Description: Attempting to write very large files using the following command line leads to very sluggish behavior or sometimes the system will restart itself. Dependent on how large the file is, one may see "out of swap" in the dmesg log. dd if=/dev/zero of=/tmp/bigFile bs=128K count=200000 vmstat shows freemem going to 0 and swapping commences. It would appear that the file system cache is growing without bound and/or pages are not being ejected from the cache fast enough. Adding O_DIRECT to the opens on lines 141 and 148 of /usr/src/bin/dd/dd.c will fix this problem. >How-To-Repeat: Run the command : dd if=/dev/zero of=/tmp/bigFile bs=128K count=200000 One may need to use a larger count than 200000. >Fix: Adding O_DIRECT to the opens on lines 141 and 148 of /usr/src/bin/dd/dd.c will fix this problem. >Release-Note: >Audit-Trail: >Unformatted:
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