diff options
| -rw-r--r-- | drivers/virtio/virtio_mem.c | 95 |
1 files changed, 63 insertions, 32 deletions
diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index f86654af8b6b..cbd0aa5eb95c 100644 --- a/drivers/virtio/virtio_mem.c +++ b/drivers/virtio/virtio_mem.c @@ -51,6 +51,7 @@ struct virtio_mem { /* Workqueue that processes the plug/unplug requests. */ struct work_struct wq; + atomic_t wq_active; atomic_t config_changed; /* Virtqueue for guest->host requests. */ @@ -99,7 +100,15 @@ struct virtio_mem { /* Summary of all memory block states. */ unsigned long nb_mb_state[VIRTIO_MEM_MB_STATE_COUNT]; -#define VIRTIO_MEM_NB_OFFLINE_THRESHOLD 10 + + /* + * We don't want to add too much memory if it's not getting onlined, + * to avoid running OOM. Besides this threshold, we allow to have at + * least two offline blocks at a time (whatever is bigger). + */ +#define VIRTIO_MEM_DEFAULT_OFFLINE_THRESHOLD (1024 * 1024 * 1024) + atomic64_t offline_size; + uint64_t offline_threshold; /* * One byte state per memory block. @@ -406,6 +415,18 @@ static int virtio_mem_sb_bitmap_prepare_next_mb(struct virtio_mem *vm) } /* + * Test if we could add memory without creating too much offline memory - + * to avoid running OOM if memory is getting onlined deferred. + */ +static bool virtio_mem_could_add_memory(struct virtio_mem *vm, uint64_t size) +{ + if (WARN_ON_ONCE(size > vm->offline_threshold)) + return false; + + return atomic64_read(&vm->offline_size) + size <= vm->offline_threshold; +} + +/* * Try to add a memory block to Linux. This will usually only fail * if out of memory. * @@ -417,6 +438,8 @@ static int virtio_mem_sb_bitmap_prepare_next_mb(struct virtio_mem *vm) static int virtio_mem_mb_add(struct virtio_mem *vm, unsigned long mb_id) { const uint64_t addr = virtio_mem_mb_id_to_phys(mb_id); + const uint64_t size = memory_block_size_bytes(); + int rc; /* * When force-unloading the driver and we still have memory added to @@ -430,10 +453,13 @@ static int virtio_mem_mb_add(struct virtio_mem *vm, unsigned long mb_id) } dev_dbg(&vm->vdev->dev, "adding memory block: %lu\n", mb_id); - return add_memory_driver_managed(vm->nid, addr, - memory_block_size_bytes(), - vm->resource_name, - MEMHP_MERGE_RESOURCE); + /* Memory might get onlined immediately. */ + atomic64_add(size, &vm->offline_size); + rc = add_memory_driver_managed(vm->nid, addr, size, vm->resource_name, + MEMHP_MERGE_RESOURCE); + if (rc) + atomic64_sub(size, &vm->offline_size); + return rc; } /* @@ -448,16 +474,19 @@ static int virtio_mem_mb_add(struct virtio_mem *vm, unsigned long mb_id) static int virtio_mem_mb_remove(struct virtio_mem *vm, unsigned long mb_id) { const uint64_t addr = virtio_mem_mb_id_to_phys(mb_id); + const uint64_t size = memory_block_size_bytes(); int rc; dev_dbg(&vm->vdev->dev, "removing memory block: %lu\n", mb_id); - rc = remove_memory(vm->nid, addr, memory_block_size_bytes()); - if (!rc) + rc = remove_memory(vm->nid, addr, size); + if (!rc) { + atomic64_sub(size, &vm->offline_size); /* * We might have freed up memory we can now unplug, retry * immediately instead of waiting. */ virtio_mem_retry(vm); + } return rc; } @@ -473,18 +502,20 @@ static int virtio_mem_mb_offline_and_remove(struct virtio_mem *vm, unsigned long mb_id) { const uint64_t addr = virtio_mem_mb_id_to_phys(mb_id); + const uint64_t size = memory_block_size_bytes(); int rc; dev_dbg(&vm->vdev->dev, "offlining and removing memory block: %lu\n", mb_id); - rc = offline_and_remove_memory(vm->nid, addr, - memory_block_size_bytes()); - if (!rc) + rc = offline_and_remove_memory(vm->nid, addr, size); + if (!rc) { + atomic64_sub(size, &vm->offline_size); /* * We might have freed up memory we can now unplug, retry * immediately instead of waiting. */ virtio_mem_retry(vm); + } return rc; } @@ -567,8 +598,6 @@ static void virtio_mem_notify_offline(struct virtio_mem *vm, static void virtio_mem_notify_online(struct virtio_mem *vm, unsigned long mb_id) { - unsigned long nb_offline; - switch (virtio_mem_mb_get_state(vm, mb_id)) { case VIRTIO_MEM_MB_STATE_OFFLINE_PARTIAL: virtio_mem_mb_set_state(vm, mb_id, @@ -581,12 +610,6 @@ static void virtio_mem_notify_online(struct virtio_mem *vm, unsigned long mb_id) BUG(); break; } - nb_offline = vm->nb_mb_state[VIRTIO_MEM_MB_STATE_OFFLINE] + - vm->nb_mb_state[VIRTIO_MEM_MB_STATE_OFFLINE_PARTIAL]; - - /* see if we can add new blocks now that we onlined one block */ - if (nb_offline == VIRTIO_MEM_NB_OFFLINE_THRESHOLD - 1) - virtio_mem_retry(vm); } static void virtio_mem_notify_going_offline(struct virtio_mem *vm, @@ -681,6 +704,7 @@ static int virtio_mem_memory_notifier_cb(struct notifier_block *nb, case MEM_OFFLINE: virtio_mem_notify_offline(vm, mb_id); + atomic64_add(size, &vm->offline_size); /* * Trigger the workqueue. Now that we have some offline memory, * maybe we can handle pending unplug requests. @@ -693,6 +717,18 @@ static int virtio_mem_memory_notifier_cb(struct notifier_block *nb, break; case MEM_ONLINE: virtio_mem_notify_online(vm, mb_id); + + atomic64_sub(size, &vm->offline_size); + /* + * Start adding more memory once we onlined half of our + * threshold. Don't trigger if it's possibly due to our actipn + * (e.g., us adding memory which gets onlined immediately from + * the core). + */ + if (!atomic_read(&vm->wq_active) && + virtio_mem_could_add_memory(vm, vm->offline_threshold / 2)) + virtio_mem_retry(vm); + vm->hotplug_active = false; mutex_unlock(&vm->hotplug_mutex); break; @@ -1152,18 +1188,6 @@ static int virtio_mem_prepare_next_mb(struct virtio_mem *vm, } /* - * Don't add too many blocks that are not onlined yet to avoid running OOM. - */ -static bool virtio_mem_too_many_mb_offline(struct virtio_mem *vm) -{ - unsigned long nb_offline; - - nb_offline = vm->nb_mb_state[VIRTIO_MEM_MB_STATE_OFFLINE] + - vm->nb_mb_state[VIRTIO_MEM_MB_STATE_OFFLINE_PARTIAL]; - return nb_offline >= VIRTIO_MEM_NB_OFFLINE_THRESHOLD; -} - -/* * Try to plug the desired number of subblocks and add the memory block * to Linux. * @@ -1316,7 +1340,7 @@ static int virtio_mem_plug_request(struct virtio_mem *vm, uint64_t diff) /* Try to plug and add unused blocks */ virtio_mem_for_each_mb_state(vm, mb_id, VIRTIO_MEM_MB_STATE_UNUSED) { - if (virtio_mem_too_many_mb_offline(vm)) + if (!virtio_mem_could_add_memory(vm, memory_block_size_bytes())) return -ENOSPC; rc = virtio_mem_mb_plug_and_add(vm, mb_id, &nb_sb); @@ -1327,7 +1351,7 @@ static int virtio_mem_plug_request(struct virtio_mem *vm, uint64_t diff) /* Try to prepare, plug and add new blocks */ while (nb_sb) { - if (virtio_mem_too_many_mb_offline(vm)) + if (!virtio_mem_could_add_memory(vm, memory_block_size_bytes())) return -ENOSPC; rc = virtio_mem_prepare_next_mb(vm, &mb_id); @@ -1620,6 +1644,7 @@ static void virtio_mem_run_wq(struct work_struct *work) if (vm->broken) return; + atomic_set(&vm->wq_active, 1); retry: rc = 0; @@ -1680,6 +1705,8 @@ retry: "unknown error, marking device broken: %d\n", rc); vm->broken = true; } + + atomic_set(&vm->wq_active, 0); } static enum hrtimer_restart virtio_mem_timer_expired(struct hrtimer *timer) @@ -1788,6 +1815,10 @@ static int virtio_mem_init(struct virtio_mem *vm) memory_block_size_bytes()); vm->next_mb_id = vm->first_mb_id; + /* Prepare the offline threshold - make sure we can add two blocks. */ + vm->offline_threshold = max_t(uint64_t, 2 * memory_block_size_bytes(), + VIRTIO_MEM_DEFAULT_OFFLINE_THRESHOLD); + dev_info(&vm->vdev->dev, "start address: 0x%llx", vm->addr); dev_info(&vm->vdev->dev, "region size: 0x%llx", vm->region_size); dev_info(&vm->vdev->dev, "device block size: 0x%llx", |