From 532a6086e35fa3b5761e68af36d4e42a550eba15 Mon Sep 17 00:00:00 2001 From: Anthony Liguori Date: Mon, 18 Aug 2008 17:15:31 -0500 Subject: [PATCH 1/4] virtio_balloon: fix towards_target when deflating balloon Both v and vb->num_pages are u32 and unsigned int respectively. If v is less than vb->num_pages (and it is, when deflating the balloon), the result is a very large 32-bit number. Since we're returning a s64, instead of getting the same negative number we desire, we get a very large positive number. This handles the case where v < vb->num_pages and ensures we get a small, negative, s64 as the result. Rusty: please push this for 2.6.27-rc4. It's probably appropriate for the stable tree too as it will cause an unexpected OOM when ballooning. Signed-off-by: Anthony Liguori Signed-off-by: Rusty Russell (simplified) --- drivers/virtio/virtio_balloon.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index bfef604160d1..62eab43152d2 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -158,7 +158,7 @@ static inline s64 towards_target(struct virtio_balloon *vb) vb->vdev->config->get(vb->vdev, offsetof(struct virtio_balloon_config, num_pages), &v, sizeof(v)); - return v - vb->num_pages; + return (s64)v - vb->num_pages; } static void update_balloon_size(struct virtio_balloon *vb) From 37a7c0f3e3e808b8d24f2187a25d2de39e46d822 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 26 Aug 2008 00:19:26 -0500 Subject: [PATCH 2/4] stop_machine: wean Xen off stop_machine_run This is the last use of (the deprecated) stop_machine_run in the tree. Signed-off-by: Rusty Russell Acked-by: Jeremy Fitzhardinge --- drivers/xen/manage.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c index a5bc91ae6ff6..d0e87cbe157c 100644 --- a/drivers/xen/manage.c +++ b/drivers/xen/manage.c @@ -102,7 +102,7 @@ static void do_suspend(void) /* XXX use normal device tree? */ xenbus_suspend(); - err = stop_machine_run(xen_suspend, &cancelled, 0); + err = stop_machine(xen_suspend, &cancelled, &cpumask_of_cpu(0)); if (err) { printk(KERN_ERR "failed to start xen_suspend: %d\n", err); goto out; From bf2002967775cbb233876d51ff94e8daa7e77858 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 26 Aug 2008 00:19:27 -0500 Subject: [PATCH 3/4] stop_machine: Remove deprecated stop_machine_run Everyone should be using stop_machine() now. The staged API transition helped life in linux-next. Signed-off-by: Rusty Russell --- include/linux/stop_machine.h | 19 +------------------ 1 file changed, 1 insertion(+), 18 deletions(-) diff --git a/include/linux/stop_machine.h b/include/linux/stop_machine.h index f1cb0ba6d715..faf1519b5adc 100644 --- a/include/linux/stop_machine.h +++ b/include/linux/stop_machine.h @@ -3,16 +3,13 @@ /* "Bogolock": stop the entire machine, disable interrupts. This is a very heavy lock, which is equivalent to grabbing every spinlock (and more). So the "read" side to such a lock is anything which - diables preeempt. */ + disables preeempt. */ #include #include #include #if defined(CONFIG_STOP_MACHINE) && defined(CONFIG_SMP) -/* Deprecated, but useful for transition. */ -#define ALL_CPUS ~0U - /** * stop_machine: freeze the machine on all CPUs and run this function * @fn: the function to run @@ -50,18 +47,4 @@ static inline int stop_machine(int (*fn)(void *), void *data, return ret; } #endif /* CONFIG_SMP */ - -static inline int __deprecated stop_machine_run(int (*fn)(void *), void *data, - unsigned int cpu) -{ - /* If they don't care which cpu fn runs on, just pick one. */ - if (cpu == NR_CPUS) - return stop_machine(fn, data, NULL); - else if (cpu == ~0U) - return stop_machine(fn, data, &cpu_possible_map); - else { - cpumask_t cpus = cpumask_of_cpu(cpu); - return stop_machine(fn, data, &cpus); - } -} #endif /* _LINUX_STOP_MACHINE */ From 1dc3e3bcbfe335843ec938bfdddb34d10f4dd278 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 26 Aug 2008 00:19:27 -0500 Subject: [PATCH 4/4] lguest: update commentry Signed-off-by: Rusty Russell --- Documentation/lguest/lguest.c | 8 ++++++++ drivers/lguest/lguest_device.c | 8 ++++++++ 2 files changed, 16 insertions(+) diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index 655414821edc..7228369d1014 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -895,6 +895,9 @@ static void handle_console_output(int fd, struct virtqueue *vq, bool timeout) } } +/* This is called when we no longer want to hear about Guest changes to a + * virtqueue. This is more efficient in high-traffic cases, but it means we + * have to set a timer to check if any more changes have occurred. */ static void block_vq(struct virtqueue *vq) { struct itimerval itm; @@ -939,6 +942,11 @@ static void handle_net_output(int fd, struct virtqueue *vq, bool timeout) if (!timeout && num) block_vq(vq); + /* We never quite know how long should we wait before we check the + * queue again for more packets. We start at 500 microseconds, and if + * we get fewer packets than last time, we assume we made the timeout + * too small and increase it by 10 microseconds. Otherwise, we drop it + * by one microsecond every time. It seems to work well enough. */ if (timeout) { if (num < last_timeout_num) timeout_usec += 10; diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c index 37344aaee22f..a661bbdae3d6 100644 --- a/drivers/lguest/lguest_device.c +++ b/drivers/lguest/lguest_device.c @@ -98,6 +98,10 @@ static u32 lg_get_features(struct virtio_device *vdev) return features; } +/* The virtio core takes the features the Host offers, and copies the + * ones supported by the driver into the vdev->features array. Once + * that's all sorted out, this routine is called so we can tell the + * Host which features we understand and accept. */ static void lg_finalize_features(struct virtio_device *vdev) { unsigned int i, bits; @@ -108,6 +112,10 @@ static void lg_finalize_features(struct virtio_device *vdev) /* Give virtio_ring a chance to accept features. */ vring_transport_features(vdev); + /* The vdev->feature array is a Linux bitmask: this isn't the + * same as a the simple array of bits used by lguest devices + * for features. So we do this slow, manual conversion which is + * completely general. */ memset(out_features, 0, desc->feature_len); bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8; for (i = 0; i < bits; i++) {