[src/trunk]: src/sys/fs/puffs Roll back the change that forced kernel threads...

[manu <manu%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/26f4014e0807
branches:  trunk
changeset: 770460:26f4014e0807
user:      manu <manu%NetBSD.org@localhost>
date:      Mon Oct 17 23:54:01 2011 +0000

description:
Roll back the change that forced kernel threads to not sleep in PUFFS.
The change does not make consensus, since only pagedaemon should need it.
Other threads will tolerate sleeping, and problems here are only symptoms
that something is going wrong in memory management. The cause, not the
symptoms, need to be fixed.

diffstat:

 sys/fs/puffs/puffs_vnops.c |  18 ++++--------------
 1 files changed, 4 insertions(+), 14 deletions(-)

diffs (59 lines):

diff -r 782d81cfe6e1 -r 26f4014e0807 sys/fs/puffs/puffs_vnops.c
--- a/sys/fs/puffs/puffs_vnops.c        Mon Oct 17 23:27:41 2011 +0000
+++ b/sys/fs/puffs/puffs_vnops.c        Mon Oct 17 23:54:01 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: puffs_vnops.c,v 1.157 2011/09/23 01:57:32 manu Exp $   */
+/*     $NetBSD: puffs_vnops.c,v 1.158 2011/10/17 23:54:01 manu Exp $   */
 
 /*
  * Copyright (c) 2005, 2006, 2007  Antti Kantee.  All Rights Reserved.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: puffs_vnops.c,v 1.157 2011/09/23 01:57:32 manu Exp $");
+__KERNEL_RCSID(0, "$NetBSD: puffs_vnops.c,v 1.158 2011/10/17 23:54:01 manu Exp $");
 
 #include <sys/param.h>
 #include <sys/buf.h>
@@ -1357,14 +1357,6 @@
        struct puffs_mount *pmp = MPTOPUFFSMP(vp->v_mount);
        int error, dofaf;
 
-       /*
-        * Make sure kernel threads such as ioflush do not get 
-        * stuck in low memory conditions: they should not wait 
-        * for the mutex.
-        */
-       if (curlwp->l_flag & LW_SYSTEM)
-               KASSERT((ap->a_flags & FSYNC_WAIT) == 0);
-
        if (ap->a_flags & FSYNC_WAIT) {
                mutex_enter(&pn->pn_sizemtx);
        } else {
@@ -2225,13 +2217,12 @@
        struct buf *bp;
        size_t argsize;
        size_t tomove, moved;
-       int error, dofaf, cansleep, dobiodone;
+       int error, dofaf, dobiodone;
 
        pmp = MPTOPUFFSMP(vp->v_mount);
        bp = ap->a_bp;
        error = 0;
        dofaf = 0;
-       cansleep = 0;
        pn = VPTOPP(vp);
        park_rw = NULL; /* explicit */
        dobiodone = 1;
@@ -2279,9 +2270,8 @@
        /* allocate transport structure */
        tomove = PUFFS_TOMOVE(bp->b_bcount, pmp);
        argsize = sizeof(struct puffs_vnmsg_rw);
-       cansleep = (dofaf || (curlwp->l_flag & LW_SYSTEM)) ? 0 : 1; 
        error = puffs_msgmem_alloc(argsize + tomove, &park_rw,
-           (void *)&rw_msg, cansleep);
+           (void *)&rw_msg, dofaf);
        if (error)
                goto out;
        RWARGS(rw_msg, 0, tomove, bp->b_blkno << DEV_BSHIFT, FSCRED);