[src/trunk]: src/sys/uvm uvm_pageactivate() needs to be called _after_ code i...

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

details:   https://anonhg.NetBSD.org/src/rev/5563c661a122
branches:  trunk
changeset: 322975:5563c661a122
user:      jdolecek <jdolecek%NetBSD.org@localhost>
date:      Sat May 26 18:57:35 2018 +0000

description:
uvm_pageactivate() needs to be called _after_ code is done with the page, no reason
to bother pdaemon with PG_BUSY pages; also clear the PG_FAKE and PG_CLEAN after
we are done with the write

this does not make any difference on my machine, but maybe it might fix
the machine check panic on Martin's alpha

while here remove UBC_PARTIALOK handling from ubc_zeropage_direct(), just to be sure
it works exactly the same as the non-direct one

diffstat:

 sys/uvm/uvm_bio.c |  50 ++++++++++++++++++++++++++++----------------------
 1 files changed, 28 insertions(+), 22 deletions(-)

diffs (106 lines):

diff -r faeac11b718c -r 5563c661a122 sys/uvm/uvm_bio.c
--- a/sys/uvm/uvm_bio.c Sat May 26 18:18:19 2018 +0000
+++ b/sys/uvm/uvm_bio.c Sat May 26 18:57:35 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_bio.c,v 1.95 2018/05/19 15:13:26 jdolecek Exp $    */
+/*     $NetBSD: uvm_bio.c,v 1.96 2018/05/26 18:57:35 jdolecek Exp $    */
 
 /*
  * Copyright (c) 1998 Chuck Silvers.
@@ -34,7 +34,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_bio.c,v 1.95 2018/05/19 15:13:26 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_bio.c,v 1.96 2018/05/26 18:57:35 jdolecek Exp $");
 
 #include "opt_uvmhist.h"
 #include "opt_ubc.h"
@@ -872,21 +872,33 @@
 
                /* Page must be writable by now */
                KASSERT((pg->flags & PG_RDONLY) == 0 || (flags & UBC_WRITE) == 0);
-
-               mutex_enter(&uvm_pageqlock);
-               uvm_pageactivate(pg);
-               mutex_exit(&uvm_pageqlock);
-
-               /* Page will be changed, no longer clean */
-               /* XXX do this AFTER the write? */
-               if (flags & UBC_WRITE)
-                       pg->flags &= ~(PG_FAKE|PG_CLEAN);
        }
        mutex_exit(uobj->vmobjlock);
 
        return 0;
 }
 
+static void __noinline
+ubc_direct_release(struct uvm_object *uobj,
+       int flags, struct vm_page **pgs, int npages)
+{
+       mutex_enter(uobj->vmobjlock);
+       mutex_enter(&uvm_pageqlock);
+       for (int i = 0; i < npages; i++) {
+               struct vm_page *pg = pgs[i];
+
+               uvm_pageactivate(pg);
+
+               /* Page was changed, no longer fake and neither clean */
+               if (flags & UBC_WRITE)
+                       pg->flags &= ~(PG_FAKE|PG_CLEAN);
+       }
+       mutex_exit(&uvm_pageqlock);
+
+       uvm_page_unbusy(pgs, npages);
+       mutex_exit(uobj->vmobjlock);
+}
+
 static int
 ubc_uiomove_process(void *win, size_t len, void *arg)
 {
@@ -942,9 +954,7 @@
                            ubc_zerorange_process, NULL);
                }
 
-               mutex_enter(uobj->vmobjlock);
-               uvm_page_unbusy(pgs, npages);
-               mutex_exit(uobj->vmobjlock);
+               ubc_direct_release(uobj, flags, pgs, npages);
 
                off += bytelen;
                todo -= bytelen;
@@ -963,12 +973,14 @@
        int error, npages;
        struct vm_page *pgs[ubc_winsize >> PAGE_SHIFT];
 
+       flags |= UBC_WRITE;
+
        error = 0;
        while (todo > 0) {
                vsize_t bytelen = todo;
 
                error = ubc_alloc_direct(uobj, off, &bytelen, UVM_ADV_NORMAL,
-                   UBC_WRITE, pgs, &npages);
+                   flags, pgs, &npages);
                if (error != 0) {
                        /* can't do anything, failed to get the pages */
                        break;
@@ -977,16 +989,10 @@
                error = uvm_direct_process(pgs, npages, off, bytelen,
                    ubc_zerorange_process, NULL);
 
-               mutex_enter(uobj->vmobjlock);
-               uvm_page_unbusy(pgs, npages);
-               mutex_exit(uobj->vmobjlock);
+               ubc_direct_release(uobj, flags, pgs, npages);
 
                off += bytelen;
                todo -= bytelen;
-
-               if (error != 0 && ISSET(flags, UBC_PARTIALOK)) {
-                       break;
-               }
        }
 }