diff options
author | dyson <dyson@FreeBSD.org> | 1996-07-02 13:38:10 +0000 |
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committer | dyson <dyson@FreeBSD.org> | 1996-07-02 13:38:10 +0000 |
commit | 835bc691899baa57585dbef6035920f4905812a7 (patch) | |
tree | ab1b99af6754c4b6e8ef302b788761bfeb831979 /sys/fs/procfs/procfs_subr.c | |
parent | c6eea469894d2b98f6429e24f655d896dcd2a026 (diff) | |
download | FreeBSD-src-835bc691899baa57585dbef6035920f4905812a7.zip FreeBSD-src-835bc691899baa57585dbef6035920f4905812a7.tar.gz |
Implement locking for pfs nodes, when at the leaf. Concurrent access
to information from a single process causes hangs. Specifically, this
fixes problems (hangs) with concurrent ps commands, when the system is under
heavy memory load.
Reviewed by: davidg
Diffstat (limited to 'sys/fs/procfs/procfs_subr.c')
-rw-r--r-- | sys/fs/procfs/procfs_subr.c | 39 |
1 files changed, 29 insertions, 10 deletions
diff --git a/sys/fs/procfs/procfs_subr.c b/sys/fs/procfs/procfs_subr.c index 872a4e9..7d0de04 100644 --- a/sys/fs/procfs/procfs_subr.c +++ b/sys/fs/procfs/procfs_subr.c @@ -36,7 +36,7 @@ * * @(#)procfs_subr.c 8.4 (Berkeley) 1/27/94 * - * $Id: procfs_subr.c,v 1.7 1996/06/17 22:43:35 dyson Exp $ + * $Id: procfs_subr.c,v 1.8 1996/06/18 05:15:59 dyson Exp $ */ #include <sys/param.h> @@ -130,6 +130,7 @@ loop: pfs->pfs_type = pfs_type; pfs->pfs_vnode = *vpp; pfs->pfs_flags = 0; + pfs->pfs_lockowner = 0; pfs->pfs_fileno = PROCFS_FILENO(pid, pfs_type); switch (pfs_type) { @@ -230,40 +231,58 @@ procfs_rw(ap) struct proc *curp = uio->uio_procp; struct pfsnode *pfs = VTOPFS(vp); struct proc *p; + int rtval; p = PFIND(pfs->pfs_pid); if (p == 0) return (EINVAL); + while (pfs->pfs_lockowner) { + tsleep(&pfs->pfs_lockowner, PRIBIO, "pfslck", 0); + } + pfs->pfs_lockowner = curproc->p_pid; + switch (pfs->pfs_type) { case Pnote: case Pnotepg: - return (procfs_donote(curp, p, pfs, uio)); + rtval = procfs_donote(curp, p, pfs, uio); + break; case Pregs: - return (procfs_doregs(curp, p, pfs, uio)); + rtval = procfs_doregs(curp, p, pfs, uio); + break; case Pfpregs: - return (procfs_dofpregs(curp, p, pfs, uio)); + rtval = procfs_dofpregs(curp, p, pfs, uio); + break; case Pctl: - return (procfs_doctl(curp, p, pfs, uio)); + rtval = procfs_doctl(curp, p, pfs, uio); + break; case Pstatus: - return (procfs_dostatus(curp, p, pfs, uio)); + rtval = procfs_dostatus(curp, p, pfs, uio); + break; case Pmap: - return (procfs_domap(curp, p, pfs, uio)); + rtval = procfs_domap(curp, p, pfs, uio); + break; case Pmem: - return (procfs_domem(curp, p, pfs, uio)); + rtval = procfs_domem(curp, p, pfs, uio); + break; case Ptype: - return (procfs_dotype(curp, p, pfs, uio)); + rtval = procfs_dotype(curp, p, pfs, uio); + break; default: - return (EOPNOTSUPP); + rtval = EOPNOTSUPP; + break; } + pfs->pfs_lockowner = 0; + wakeup(&pfs->pfs_lockowner); + return rtval; } /* |