[src/trunk]: src/sys/arch/xen/xen Provide and accept memory reservation infor...

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

details:   https://anonhg.NetBSD.org/src/rev/340c87a21a93
branches:  trunk
changeset: 756276:340c87a21a93
user:      cherry <cherry%NetBSD.org@localhost>
date:      Sat Jul 10 11:20:48 2010 +0000

description:
Provide and accept memory reservation information from the hypervisor
in KiloBytes. This is valid both for the xenbus interface, as well as
the dom0 only sysctl interface.

Thanks cegger@ for testing.

diffstat:

 sys/arch/xen/xen/balloon.c |  48 ++++++++++++++++++++++++++-------------------
 1 files changed, 28 insertions(+), 20 deletions(-)

diffs (159 lines):

diff -r 32b9d3b03143 -r 340c87a21a93 sys/arch/xen/xen/balloon.c
--- a/sys/arch/xen/xen/balloon.c        Sat Jul 10 10:12:07 2010 +0000
+++ b/sys/arch/xen/xen/balloon.c        Sat Jul 10 11:20:48 2010 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: balloon.c,v 1.3 2010/07/08 14:51:14 cherry Exp $ */
+/* $NetBSD: balloon.c,v 1.4 2010/07/10 11:20:48 cherry Exp $ */
 
 /*-
  * Copyright (c) 2010 The NetBSD Foundation, Inc.
@@ -55,7 +55,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: balloon.c,v 1.3 2010/07/08 14:51:14 cherry Exp $");
+__KERNEL_RCSID(0, "$NetBSD: balloon.c,v 1.4 2010/07/10 11:20:48 cherry Exp $");
 
 #include <sys/inttypes.h>
 #include <sys/param.h>
@@ -91,6 +91,11 @@
 #define XEN_RESERVATION_MIN (uvmexp.freemin + BALLOON_BALLAST) /* In pages */
 #define XEN_RESERVATION_MAX nkmempages /* In pages */
 
+/* KB <-> PAGEs */
+#define BALLOON_PAGES_TO_KB(_pg) (_pg * PAGE_SIZE / 1024)
+#define BALLOON_KB_TO_PAGES(_kb) (_kb * 1024 / PAGE_SIZE)
+#define BALLOON_PAGE_FLOOR(_kb) (_kb & PAGE_MASK)
+
 /* Forward declaration */
 static void xenbus_balloon_watcher(struct xenbus_watch *, const char **,
                                   unsigned int);
@@ -193,18 +198,16 @@
                return 0;
        }
 
-       /* Convert to npages */
+       /* Returned in KB */
 
-       return new_target * 1024 / PAGE_SIZE;
+       return new_target;
 }
 
 static void
 xenbus_balloon_write_target(unsigned long long new_target)
 {
 
-       /* Convert to KB */
-       new_target = new_target * PAGE_SIZE / 1024;
-
+       /* new_target is in KB */
        if (0 != xenbus_printf(NULL, "memory", "target", "%llu", new_target)) {
                printf("error, couldn't write xenbus target node\n");
        }
@@ -247,9 +250,9 @@
 balloon_feedback_target(size_t newtarget)
 {
        /* Notify XenStore. */
-       xenbus_balloon_write_target(newtarget);
+       xenbus_balloon_write_target(BALLOON_PAGES_TO_KB(newtarget));
        /* Update sysctl value XXX: Locking ? */
-       sysctl_target = newtarget;
+       sysctl_target = BALLOON_PAGES_TO_KB(newtarget);
 
        /* Finally update our private copy */
        balloon_set_target(newtarget);
@@ -651,15 +654,18 @@
 xenbus_balloon_watcher(struct xenbus_watch *watch, const char **vec,
                       unsigned int len)
 {
-       size_t new_target;
+       size_t new_target; /* In KB */
 
        if (0 == (new_target = (size_t) xenbus_balloon_read_target())) {
                /* Don't update target value */
                return;
        }
+
+       new_target = BALLOON_PAGE_FLOOR(new_target);
+
 #if BALLOONDEBUG 
-       if (new_target < balloon_conf.xen_res_min ||
-           new_target > balloon_conf.xen_res_max) {
+       if (new_target < BALLOON_KB_TO_PAGES(balloon_conf.xen_res_min) ||
+           new_target > BALLOON_KB_TO_PAGES(balloon_conf.xen_res_max)) {
                printf("Requested target is unacceptable.\n");
                return;
        }
@@ -669,7 +675,7 @@
         * balloon_set_target() calls
         * xenbus_balloon_write_target(). Not sure if this is racy 
         */
-       balloon_set_target(new_target);
+       balloon_set_target(BALLOON_KB_TO_PAGES(new_target));
 
 #if BALLOONDEBUG
        printf("Setting target to %zu\n", new_target);
@@ -727,7 +733,8 @@
         * Initialise the sysctl_xxx copies of target and current
         * as above, because sysctl inits before balloon_xenbus_setup()
         */
-       sysctl_target = sysctl_current = currentpages;
+       sysctl_current = currentpages;
+       sysctl_target = BALLOON_PAGES_TO_KB(currentpages);
 
        /* Setup xenbus node watch callback */
        if (register_xenbus_watch(&xenbus_balloon_watch)) {
@@ -780,7 +787,7 @@
        node = *rnode;
 
        if (strcmp(node.sysctl_name, "current") == 0) {
-               node_val = xenmem_get_currentreservation();
+               node_val = BALLOON_PAGES_TO_KB(xenmem_get_currentreservation());
                node.sysctl_data = &node_val;
                return sysctl_lookup(SYSCTLFN_CALL(&node));
 #ifndef XEN_BALLOON /* Read only, if balloon is disabled */
@@ -788,7 +795,7 @@
                if (newp != NULL || newlen != 0) {
                        return (EPERM);
                }
-               node_val = xenmem_get_currentreservation();
+               node_val = BALLOON_PAGES_TO_KB(xenmem_get_currentreservation());
                node.sysctl_data = &node_val;
                error = sysctl_lookup(SYSCTLFN_CALL(&node));
                return error;
@@ -796,6 +803,7 @@
 #else
        } else if (strcmp(node.sysctl_name, "target") == 0) {
                node_val = * (int64_t *) rnode->sysctl_data;
+               node_val = BALLOON_PAGE_FLOOR(node_val);
                node.sysctl_data = &node_val;
                error = sysctl_lookup(SYSCTLFN_CALL(&node));
                if (error != 0) {
@@ -803,8 +811,8 @@
                }
 
                /* Sanity check new size */
-               if (node_val < XEN_RESERVATION_MIN || 
-                   node_val > XEN_RESERVATION_MAX ) {
+               if (node_val < BALLOON_PAGES_TO_KB(XEN_RESERVATION_MIN) || 
+                   node_val > BALLOON_PAGES_TO_KB(XEN_RESERVATION_MAX) ) {
 #if BALLOONDEBUG
                        printf("node_val out of range.\n");
                        printf("node_val = %"PRIu64"\n", node_val);
@@ -816,14 +824,14 @@
                printf("node_val = %"PRIu64"\n", node_val);
 #endif
 
-               if (node_val != balloon_get_target()) {
+               if (node_val != BALLOON_PAGES_TO_KB(balloon_get_target())) {
                        * (int64_t *) rnode->sysctl_data = node_val;
 
 #if BALLOONDEBUG
                        printf("setting to %" PRIu64"\n", node_val);
 #endif
 
-                       balloon_set_target(node_val);
+                       balloon_set_target(BALLOON_KB_TO_PAGES(node_val));
 
                        /* Notify balloon thread, if we can. */
                        if (mutex_tryenter(&balloon_conf.flaglock)) {