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Implement locking for pfs nodes, when at the leaf. Concurrent access

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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
This commit is contained in:
John Dyson 1996-07-02 13:38:10 +00:00
parent dd74699f76
commit 688bbd5b76
4 changed files with 62 additions and 22 deletions
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3
sys/fs/procfs/procfs.h
View File

@ -36,7 +36,7 @@
*
* @(#)procfs.h 8.6 (Berkeley) 2/3/94
*
* $Id: procfs.h,v 1.10 1996/06/17 22:43:35 dyson Exp $
* $Id: procfs.h,v 1.11 1996/06/18 05:15:58 dyson Exp $
*/
/*
@ -68,6 +68,7 @@ struct pfsnode {
u_short pfs_mode; /* mode bits for stat() */
u_long pfs_flags; /* open flags */
u_long pfs_fileno; /* unique file id */
pid_t pfs_lockowner; /* pfs lock owner */
};
#define PROCFS_NOTELEN 64 /* max length of a note (/proc/$pid/note) */

39
sys/fs/procfs/procfs_subr.c
View File

@ -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 @@ procfs_allocvp(mp, vpp, pid, pfs_type)
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;
}
/*

3
sys/miscfs/procfs/procfs.h
View File

@ -36,7 +36,7 @@
*
* @(#)procfs.h 8.6 (Berkeley) 2/3/94
*
* $Id: procfs.h,v 1.10 1996/06/17 22:43:35 dyson Exp $
* $Id: procfs.h,v 1.11 1996/06/18 05:15:58 dyson Exp $
*/
/*
@ -68,6 +68,7 @@ struct pfsnode {
u_short pfs_mode; /* mode bits for stat() */
u_long pfs_flags; /* open flags */
u_long pfs_fileno; /* unique file id */
pid_t pfs_lockowner; /* pfs lock owner */
};
#define PROCFS_NOTELEN 64 /* max length of a note (/proc/$pid/note) */

39
sys/miscfs/procfs/procfs_subr.c
View File

@ -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 @@ procfs_allocvp(mp, vpp, pid, pfs_type)
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;
}
/*