Date: Wed, 22 Oct 2014 22:27:52 +0000 (UTC) From: Rick Macklem <rmacklem@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r273486 - head/sys/fs/nfsclient Message-ID: <201410222227.s9MMRqCI012946@svn.freebsd.org>
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Author: rmacklem Date: Wed Oct 22 22:27:51 2014 New Revision: 273486 URL: https://svnweb.freebsd.org/changeset/base/273486 Log: Clip the settings for the NFS rsize, wsize mount options to a power of 2. For non-power of 2 settings, intermittent page faults have been reported. Although the bug that causes these page faults/crashes has not been identified, it does not appear to occur when rsize, wsize is a power of 2. Reported by: tcberner@gmail.com MFC after: 2 weeks Modified: head/sys/fs/nfsclient/nfs_clvfsops.c Modified: head/sys/fs/nfsclient/nfs_clvfsops.c ============================================================================== --- head/sys/fs/nfsclient/nfs_clvfsops.c Wed Oct 22 21:57:35 2014 (r273485) +++ head/sys/fs/nfsclient/nfs_clvfsops.c Wed Oct 22 22:27:51 2014 (r273486) @@ -621,17 +621,27 @@ nfs_decode_args(struct mount *mp, struct if ((argp->flags & NFSMNT_WSIZE) && argp->wsize > 0) { nmp->nm_wsize = argp->wsize; - /* Round down to multiple of blocksize */ - nmp->nm_wsize &= ~(NFS_FABLKSIZE - 1); - if (nmp->nm_wsize <= 0) + /* + * Clip at the power of 2 below the size. There is an + * issue (not isolated) that causes intermittent page + * faults if this is not done. + */ + if (nmp->nm_wsize > NFS_FABLKSIZE) + nmp->nm_wsize = 1 << (fls(nmp->nm_wsize) - 1); + else nmp->nm_wsize = NFS_FABLKSIZE; } if ((argp->flags & NFSMNT_RSIZE) && argp->rsize > 0) { nmp->nm_rsize = argp->rsize; - /* Round down to multiple of blocksize */ - nmp->nm_rsize &= ~(NFS_FABLKSIZE - 1); - if (nmp->nm_rsize <= 0) + /* + * Clip at the power of 2 below the size. There is an + * issue (not isolated) that causes intermittent page + * faults if this is not done. + */ + if (nmp->nm_rsize > NFS_FABLKSIZE) + nmp->nm_rsize = 1 << (fls(nmp->nm_rsize) - 1); + else nmp->nm_rsize = NFS_FABLKSIZE; }
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