Date: Thu, 02 Dec 2010 14:04:39 -0800 From: Benjamin Lee <ben@b1c1l1.com> To: Mark Terribile <materribile@yahoo.com> Cc: freebsd-questions@freebsd.org Subject: Re: swap pager:indefinite wait buffer: message out of vm.c Message-ID: <4CF817F7.8050005@b1c1l1.com> In-Reply-To: <552239.98378.qm@web110303.mail.gq1.yahoo.com> References: <552239.98378.qm@web110303.mail.gq1.yahoo.com>
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This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigA23BAB3E09BDCCAF43ACD8DF Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 12/01/2010 03:23 PM, Mark Terribile wrote: >=20 > Hi, >=20 > Would some kind soul please tell me the meaning of a message coming > from vm.c (FreeBSD 7.2): > "swap pager: indefinite wait buffer: bufobj: 0, blkno: 2, size: 4096" >=20 > This message occurs after a return from an msleep whose last args are P= SWP, > "swread", and HZ*20 . >=20 > When it occurs, some interactive program is locked up. It recovers > sometime later. >=20 > My best guess is that this is a complaint that swap or paging I/O has b= een > excessively delayed. It is occurring while I am running disk-to-disk > transfers that have deep buffering. Think mbuf(1), but it's my own cod= e, > testing some algorithms. I speculate that if the disk queuing/head mov= ement optimization doesn't let the heads move off the file system > where the file resides (and I only see this with large, single files) > then this problem might result. But that is a guess, and speculation. >=20 > Does anyone know if this can occur under later versions of FreeBSD? Hi Mark, Do you have any test cases that reliably reproduce the problem? I've seen it crop up very infrequently on 8.1-RELEASE but I haven't been able to reproduce it. --=20 Benjamin Lee http://www.b1c1l1.com/ --------------enigA23BAB3E09BDCCAF43ACD8DF Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQIcBAEBAgAGBQJM+Bf8AAoJEDQaOGXZe8jknmcQALOAR5LFb5VI/sSTTjKrjHS1 22FgzsXrW47e+qMPSlIuApGiTNvqIqjvwI7HZmdlVkm0B9nbJjPI+eMvxrSlYSoT huG/v33ia2RfAh0iQhBBVHx9FtOyQ4ybVZbcRyrqVKWXXkdIWdz28VpG4zmWZ4S0 jjpd29BWLqafB1GKO/GehKOzMXwMCvC/Wu6mAHZ/yZBf3eZEGPSGNSERwYFTBcg8 RZewuRE/sueHNTVZtxxnYZvTSFMVjzaCLwn86PsupOL82PMqDmH9qCZKKnQuz4Gw J9Yf9Em3VwC7qFMRr2Hj/Tm8IsXIHSYrXDxWVK79kGxf2GvQOIvZS5Y7KaUP9bkS f3eYdIyl+X4bJvAzTvoBD/p8NDpcEEuoshplNE+x1DaN0407KFLSEUYkmqeDJYAZ U1TFUw/63IUKI9r8degF+HBkSjOsScH1NanqlqznEQIjMevz41EqIjqQBKzIIBLz 8Xq3QviWPtTIwtRy3S2wdFjUghzqCigNybePtREYKLBTbkY0Hr333jcTc0nfG9a/ 4qfbcWelwTXaLAUCvPCfBiae78cptx58wGMv8X9q7cU5Yf2JgTeBfIYLaKJ39K0F 9mBjqWSIKn5bCBfhud39v53q1gZgBxJ9p1ASt3ZtUCgUlfu6fooh1Z2n+PNp9c4O 4ypcYzP5h8hTGFsFhBuf =SfoU -----END PGP SIGNATURE----- --------------enigA23BAB3E09BDCCAF43ACD8DF--
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