Commit 99f0b55e authored by David Hildenbrand's avatar David Hildenbrand Committed by Michael S. Tsirkin
Browse files

virtio-mem: memory block states are specific to Sub Block Mode (SBM) 



let's use a new "sbm" sub-struct to hold SBM-specific state and rename +
move applicable definitions, functions, and variables (related to
memory block states).

While at it:
- Drop the "_STATE" part from memory block states
- Rename "nb_mb_state" to "mb_count"
- "set_mb_state" / "get_mb_state" vs. "mb_set_state" / "mb_get_state"
- Don't use lengthy "enum virtio_mem_smb_mb_state", simply use "uint8_t"

Reviewed-by: default avatarWei Yang <richard.weiyang@linux.alibaba.com>
Reviewed-by: default avatarPankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20201112133815.13332-19-david@redhat.com


Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent d5614944

drivers/virtio/virtio_mem.c

+109 −106
Original line number Diff line number Diff line
@@ -42,20 +42,23 @@ MODULE_PARM_DESC(unplug_online, "Try to unplug online memory"); 
 * onlined to the same zone - virtio-mem relies on this behavior.

 */



enum virtio_mem_mb_state {

/*

 * State of a Linux memory block in SBM.

 */

enum virtio_mem_sbm_mb_state {

	/* Unplugged, not added to Linux. Can be reused later. */

	VIRTIO_MEM_MB_STATE_UNUSED = 0,

	VIRTIO_MEM_SBM_MB_UNUSED = 0,

	/* (Partially) plugged, not added to Linux. Error on add_memory(). */

	VIRTIO_MEM_MB_STATE_PLUGGED,

	VIRTIO_MEM_SBM_MB_PLUGGED,

	/* Fully plugged, fully added to Linux, offline. */

	VIRTIO_MEM_MB_STATE_OFFLINE,

	VIRTIO_MEM_SBM_MB_OFFLINE,

	/* Partially plugged, fully added to Linux, offline. */

	VIRTIO_MEM_MB_STATE_OFFLINE_PARTIAL,

	VIRTIO_MEM_SBM_MB_OFFLINE_PARTIAL,

	/* Fully plugged, fully added to Linux, online. */

	VIRTIO_MEM_MB_STATE_ONLINE,

	VIRTIO_MEM_SBM_MB_ONLINE,

	/* Partially plugged, fully added to Linux, online. */

	VIRTIO_MEM_MB_STATE_ONLINE_PARTIAL,

	VIRTIO_MEM_MB_STATE_COUNT

	VIRTIO_MEM_SBM_MB_ONLINE_PARTIAL,

	VIRTIO_MEM_SBM_MB_COUNT

};



struct virtio_mem {
@@ -113,9 +116,6 @@ struct virtio_mem { 
	 */

	const char *resource_name;



	/* Summary of all memory block states. */

	unsigned long nb_mb_state[VIRTIO_MEM_MB_STATE_COUNT];



	/*

	 * 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
@@ -125,27 +125,29 @@ struct virtio_mem { 
	atomic64_t offline_size;

	uint64_t offline_threshold;



	struct {

		/* Summary of all memory block states. */

		unsigned long mb_count[VIRTIO_MEM_SBM_MB_COUNT];



		/*

	 * One byte state per memory block.

	 *

	 * Allocated via vmalloc(). When preparing new blocks, resized

	 * (alloc+copy+free) when needed (crossing pages with the next mb).

	 * (when crossing pages).

		 * One byte state per memory block. Allocated via vmalloc().

		 * Resized (alloc+copy+free) on demand.

		 *

	 * With 128MB memory blocks, we have states for 512GB of memory in one

	 * page.

		 * With 128 MiB memory blocks, we have states for 512 GiB of

		 * memory in one 4 KiB page.

		 */

	uint8_t *mb_state;

		uint8_t *mb_states;

	} sbm;



	/*

	 * $nb_sb_per_mb bit per memory block. Handled similar to mb_state.

	 * $nb_sb_per_mb bit per memory block. Handled similar to sbm.mb_states.

	 *

	 * With 4MB subblocks, we manage 128GB of memory in one page.

	 */

	unsigned long *sb_bitmap;



	/*

	 * Mutex that protects the nb_mb_state, mb_state, and sb_bitmap.

	 * Mutex that protects the sbm.mb_count, sbm.mb_states, and sb_bitmap.

	 *

	 * When this lock is held the pointers can't change, ONLINE and

	 * OFFLINE blocks can't change the state and no subblocks will get
@@ -254,68 +256,68 @@ static unsigned long virtio_mem_phys_to_sb_id(struct virtio_mem *vm, 
/*

 * Set the state of a memory block, taking care of the state counter.

 */

static void virtio_mem_mb_set_state(struct virtio_mem *vm, unsigned long mb_id,

				    enum virtio_mem_mb_state state)

static void virtio_mem_sbm_set_mb_state(struct virtio_mem *vm,

					unsigned long mb_id, uint8_t state)

{

	const unsigned long idx = mb_id - vm->first_mb_id;

	enum virtio_mem_mb_state old_state;

	uint8_t old_state;



	old_state = vm->mb_state[idx];

	vm->mb_state[idx] = state;

	old_state = vm->sbm.mb_states[idx];

	vm->sbm.mb_states[idx] = state;



	BUG_ON(vm->nb_mb_state[old_state] == 0);

	vm->nb_mb_state[old_state]--;

	vm->nb_mb_state[state]++;

	BUG_ON(vm->sbm.mb_count[old_state] == 0);

	vm->sbm.mb_count[old_state]--;

	vm->sbm.mb_count[state]++;

}



/*

 * Get the state of a memory block.

 */

static enum virtio_mem_mb_state virtio_mem_mb_get_state(struct virtio_mem *vm,

static uint8_t virtio_mem_sbm_get_mb_state(struct virtio_mem *vm,

					   unsigned long mb_id)

{

	const unsigned long idx = mb_id - vm->first_mb_id;



	return vm->mb_state[idx];

	return vm->sbm.mb_states[idx];

}



/*

 * Prepare the state array for the next memory block.

 */

static int virtio_mem_mb_state_prepare_next_mb(struct virtio_mem *vm)

static int virtio_mem_sbm_mb_states_prepare_next_mb(struct virtio_mem *vm)

{

	int old_pages = PFN_UP(vm->next_mb_id - vm->first_mb_id);

	int new_pages = PFN_UP(vm->next_mb_id - vm->first_mb_id + 1);

	uint8_t *new_mb_state;

	uint8_t *new_array;



	if (vm->mb_state && old_pages == new_pages)

	if (vm->sbm.mb_states && old_pages == new_pages)

		return 0;



	new_mb_state = vzalloc(new_pages * PAGE_SIZE);

	if (!new_mb_state)

	new_array = vzalloc(new_pages * PAGE_SIZE);

	if (!new_array)

		return -ENOMEM;



	mutex_lock(&vm->hotplug_mutex);

	if (vm->mb_state)

		memcpy(new_mb_state, vm->mb_state, old_pages * PAGE_SIZE);

	vfree(vm->mb_state);

	vm->mb_state = new_mb_state;

	if (vm->sbm.mb_states)

		memcpy(new_array, vm->sbm.mb_states, old_pages * PAGE_SIZE);

	vfree(vm->sbm.mb_states);

	vm->sbm.mb_states = new_array;

	mutex_unlock(&vm->hotplug_mutex);



	return 0;

}



#define virtio_mem_for_each_mb_state(_vm, _mb_id, _state) \

#define virtio_mem_sbm_for_each_mb(_vm, _mb_id, _state) \

	for (_mb_id = _vm->first_mb_id; \

	     _mb_id < _vm->next_mb_id && _vm->nb_mb_state[_state]; \

	     _mb_id < _vm->next_mb_id && _vm->sbm.mb_count[_state]; \

	     _mb_id++) \

		if (virtio_mem_mb_get_state(_vm, _mb_id) == _state)

		if (virtio_mem_sbm_get_mb_state(_vm, _mb_id) == _state)



#define virtio_mem_for_each_mb_state_rev(_vm, _mb_id, _state) \

#define virtio_mem_sbm_for_each_mb_rev(_vm, _mb_id, _state) \

	for (_mb_id = _vm->next_mb_id - 1; \

	     _mb_id >= _vm->first_mb_id && _vm->nb_mb_state[_state]; \

	     _mb_id >= _vm->first_mb_id && _vm->sbm.mb_count[_state]; \

	     _mb_id--) \

		if (virtio_mem_mb_get_state(_vm, _mb_id) == _state)

		if (virtio_mem_sbm_get_mb_state(_vm, _mb_id) == _state)



/*

 * Calculate the bit number in the subblock bitmap for the given subblock
@@ -581,9 +583,9 @@ static bool virtio_mem_contains_range(struct virtio_mem *vm, uint64_t start, 
static int virtio_mem_notify_going_online(struct virtio_mem *vm,

					  unsigned long mb_id)

{

	switch (virtio_mem_mb_get_state(vm, mb_id)) {

	case VIRTIO_MEM_MB_STATE_OFFLINE_PARTIAL:

	case VIRTIO_MEM_MB_STATE_OFFLINE:

	switch (virtio_mem_sbm_get_mb_state(vm, mb_id)) {

	case VIRTIO_MEM_SBM_MB_OFFLINE_PARTIAL:

	case VIRTIO_MEM_SBM_MB_OFFLINE:

		return NOTIFY_OK;

	default:

		break;
@@ -596,14 +598,14 @@ static int virtio_mem_notify_going_online(struct virtio_mem *vm, 
static void virtio_mem_notify_offline(struct virtio_mem *vm,

				      unsigned long mb_id)

{

	switch (virtio_mem_mb_get_state(vm, mb_id)) {

	case VIRTIO_MEM_MB_STATE_ONLINE_PARTIAL:

		virtio_mem_mb_set_state(vm, mb_id,

					VIRTIO_MEM_MB_STATE_OFFLINE_PARTIAL);

	switch (virtio_mem_sbm_get_mb_state(vm, mb_id)) {

	case VIRTIO_MEM_SBM_MB_ONLINE_PARTIAL:

		virtio_mem_sbm_set_mb_state(vm, mb_id,

					    VIRTIO_MEM_SBM_MB_OFFLINE_PARTIAL);

		break;

	case VIRTIO_MEM_MB_STATE_ONLINE:

		virtio_mem_mb_set_state(vm, mb_id,

					VIRTIO_MEM_MB_STATE_OFFLINE);

	case VIRTIO_MEM_SBM_MB_ONLINE:

		virtio_mem_sbm_set_mb_state(vm, mb_id,

					    VIRTIO_MEM_SBM_MB_OFFLINE);

		break;

	default:

		BUG();
@@ -613,13 +615,14 @@ static void virtio_mem_notify_offline(struct virtio_mem *vm, 


static void virtio_mem_notify_online(struct virtio_mem *vm, unsigned long mb_id)

{

	switch (virtio_mem_mb_get_state(vm, mb_id)) {

	case VIRTIO_MEM_MB_STATE_OFFLINE_PARTIAL:

		virtio_mem_mb_set_state(vm, mb_id,

					VIRTIO_MEM_MB_STATE_ONLINE_PARTIAL);

	switch (virtio_mem_sbm_get_mb_state(vm, mb_id)) {

	case VIRTIO_MEM_SBM_MB_OFFLINE_PARTIAL:

		virtio_mem_sbm_set_mb_state(vm, mb_id,

					VIRTIO_MEM_SBM_MB_ONLINE_PARTIAL);

		break;

	case VIRTIO_MEM_MB_STATE_OFFLINE:

		virtio_mem_mb_set_state(vm, mb_id, VIRTIO_MEM_MB_STATE_ONLINE);

	case VIRTIO_MEM_SBM_MB_OFFLINE:

		virtio_mem_sbm_set_mb_state(vm, mb_id,

					    VIRTIO_MEM_SBM_MB_ONLINE);

		break;

	default:

		BUG();
@@ -1188,7 +1191,7 @@ static int virtio_mem_prepare_next_mb(struct virtio_mem *vm, 
		return -ENOSPC;



	/* Resize the state array if required. */

	rc = virtio_mem_mb_state_prepare_next_mb(vm);

	rc = virtio_mem_sbm_mb_states_prepare_next_mb(vm);

	if (rc)

		return rc;
@@ -1197,7 +1200,7 @@ static int virtio_mem_prepare_next_mb(struct virtio_mem *vm, 
	if (rc)

		return rc;



	vm->nb_mb_state[VIRTIO_MEM_MB_STATE_UNUSED]++;

	vm->sbm.mb_count[VIRTIO_MEM_SBM_MB_UNUSED]++;

	*mb_id = vm->next_mb_id++;

	return 0;

}
@@ -1231,16 +1234,16 @@ static int virtio_mem_mb_plug_and_add(struct virtio_mem *vm, 
	 * so the memory notifiers will find the block in the right state.

	 */

	if (count == vm->nb_sb_per_mb)

		virtio_mem_mb_set_state(vm, mb_id,

					VIRTIO_MEM_MB_STATE_OFFLINE);

		virtio_mem_sbm_set_mb_state(vm, mb_id,

					    VIRTIO_MEM_SBM_MB_OFFLINE);

	else

		virtio_mem_mb_set_state(vm, mb_id,

					VIRTIO_MEM_MB_STATE_OFFLINE_PARTIAL);

		virtio_mem_sbm_set_mb_state(vm, mb_id,

					    VIRTIO_MEM_SBM_MB_OFFLINE_PARTIAL);



	/* Add the memory block to linux - if that fails, try to unplug. */

	rc = virtio_mem_mb_add(vm, mb_id);

	if (rc) {

		enum virtio_mem_mb_state new_state = VIRTIO_MEM_MB_STATE_UNUSED;

		int new_state = VIRTIO_MEM_SBM_MB_UNUSED;



		dev_err(&vm->vdev->dev,

			"adding memory block %lu failed with %d\n", mb_id, rc);
@@ -1250,8 +1253,8 @@ static int virtio_mem_mb_plug_and_add(struct virtio_mem *vm, 
		 * where adding of memory failed - especially on -ENOMEM.

		 */

		if (virtio_mem_mb_unplug_sb(vm, mb_id, 0, count))

			new_state = VIRTIO_MEM_MB_STATE_PLUGGED;

		virtio_mem_mb_set_state(vm, mb_id, new_state);

			new_state = VIRTIO_MEM_SBM_MB_PLUGGED;

		virtio_mem_sbm_set_mb_state(vm, mb_id, new_state);

		return rc;

	}
@@ -1304,11 +1307,11 @@ static int virtio_mem_mb_plug_any_sb(struct virtio_mem *vm, unsigned long mb_id, 


	if (virtio_mem_mb_test_sb_plugged(vm, mb_id, 0, vm->nb_sb_per_mb)) {

		if (online)

			virtio_mem_mb_set_state(vm, mb_id,

						VIRTIO_MEM_MB_STATE_ONLINE);

			virtio_mem_sbm_set_mb_state(vm, mb_id,

						    VIRTIO_MEM_SBM_MB_ONLINE);

		else

			virtio_mem_mb_set_state(vm, mb_id,

						VIRTIO_MEM_MB_STATE_OFFLINE);

			virtio_mem_sbm_set_mb_state(vm, mb_id,

						    VIRTIO_MEM_SBM_MB_OFFLINE);

	}



	return 0;
@@ -1330,8 +1333,8 @@ static int virtio_mem_plug_request(struct virtio_mem *vm, uint64_t diff) 
	mutex_lock(&vm->hotplug_mutex);



	/* Try to plug subblocks of partially plugged online blocks. */

	virtio_mem_for_each_mb_state(vm, mb_id,

				     VIRTIO_MEM_MB_STATE_ONLINE_PARTIAL) {

	virtio_mem_sbm_for_each_mb(vm, mb_id,

				   VIRTIO_MEM_SBM_MB_ONLINE_PARTIAL) {

		rc = virtio_mem_mb_plug_any_sb(vm, mb_id, &nb_sb, true);

		if (rc || !nb_sb)

			goto out_unlock;
@@ -1339,8 +1342,8 @@ static int virtio_mem_plug_request(struct virtio_mem *vm, uint64_t diff) 
	}



	/* Try to plug subblocks of partially plugged offline blocks. */

	virtio_mem_for_each_mb_state(vm, mb_id,

				     VIRTIO_MEM_MB_STATE_OFFLINE_PARTIAL) {

	virtio_mem_sbm_for_each_mb(vm, mb_id,

				   VIRTIO_MEM_SBM_MB_OFFLINE_PARTIAL) {

		rc = virtio_mem_mb_plug_any_sb(vm, mb_id, &nb_sb, false);

		if (rc || !nb_sb)

			goto out_unlock;
@@ -1354,7 +1357,7 @@ static int virtio_mem_plug_request(struct virtio_mem *vm, uint64_t diff) 
	mutex_unlock(&vm->hotplug_mutex);



	/* Try to plug and add unused blocks */

	virtio_mem_for_each_mb_state(vm, mb_id, VIRTIO_MEM_MB_STATE_UNUSED) {

	virtio_mem_sbm_for_each_mb(vm, mb_id, VIRTIO_MEM_SBM_MB_UNUSED) {

		if (!virtio_mem_could_add_memory(vm, memory_block_size_bytes()))

			return -ENOSPC;
@@ -1403,8 +1406,8 @@ static int virtio_mem_mb_unplug_any_sb_offline(struct virtio_mem *vm, 


	/* some subblocks might have been unplugged even on failure */

	if (!virtio_mem_mb_test_sb_plugged(vm, mb_id, 0, vm->nb_sb_per_mb))

		virtio_mem_mb_set_state(vm, mb_id,

					VIRTIO_MEM_MB_STATE_OFFLINE_PARTIAL);

		virtio_mem_sbm_set_mb_state(vm, mb_id,

					    VIRTIO_MEM_SBM_MB_OFFLINE_PARTIAL);

	if (rc)

		return rc;
@@ -1415,8 +1418,8 @@ static int virtio_mem_mb_unplug_any_sb_offline(struct virtio_mem *vm, 
		 * unplugged. Temporarily drop the mutex, so

		 * any pending GOING_ONLINE requests can be serviced/rejected.

		 */

		virtio_mem_mb_set_state(vm, mb_id,

					VIRTIO_MEM_MB_STATE_UNUSED);

		virtio_mem_sbm_set_mb_state(vm, mb_id,

					    VIRTIO_MEM_SBM_MB_UNUSED);



		mutex_unlock(&vm->hotplug_mutex);

		rc = virtio_mem_mb_remove(vm, mb_id);
@@ -1454,8 +1457,8 @@ static int virtio_mem_mb_unplug_sb_online(struct virtio_mem *vm, 
		return rc;

	}



	virtio_mem_mb_set_state(vm, mb_id,

				VIRTIO_MEM_MB_STATE_ONLINE_PARTIAL);

	virtio_mem_sbm_set_mb_state(vm, mb_id,

				    VIRTIO_MEM_SBM_MB_ONLINE_PARTIAL);

	return 0;

}
@@ -1515,8 +1518,8 @@ unplugged: 
		rc = virtio_mem_mb_offline_and_remove(vm, mb_id);

		mutex_lock(&vm->hotplug_mutex);

		if (!rc)

			virtio_mem_mb_set_state(vm, mb_id,

						VIRTIO_MEM_MB_STATE_UNUSED);

			virtio_mem_sbm_set_mb_state(vm, mb_id,

						    VIRTIO_MEM_SBM_MB_UNUSED);

	}



	return 0;
@@ -1542,8 +1545,8 @@ static int virtio_mem_unplug_request(struct virtio_mem *vm, uint64_t diff) 
	mutex_lock(&vm->hotplug_mutex);



	/* Try to unplug subblocks of partially plugged offline blocks. */

	virtio_mem_for_each_mb_state_rev(vm, mb_id,

					 VIRTIO_MEM_MB_STATE_OFFLINE_PARTIAL) {

	virtio_mem_sbm_for_each_mb_rev(vm, mb_id,

				       VIRTIO_MEM_SBM_MB_OFFLINE_PARTIAL) {

		rc = virtio_mem_mb_unplug_any_sb_offline(vm, mb_id,

							 &nb_sb);

		if (rc || !nb_sb)
@@ -1552,8 +1555,7 @@ static int virtio_mem_unplug_request(struct virtio_mem *vm, uint64_t diff) 
	}



	/* Try to unplug subblocks of plugged offline blocks. */

	virtio_mem_for_each_mb_state_rev(vm, mb_id,

					 VIRTIO_MEM_MB_STATE_OFFLINE) {

	virtio_mem_sbm_for_each_mb_rev(vm, mb_id, VIRTIO_MEM_SBM_MB_OFFLINE) {

		rc = virtio_mem_mb_unplug_any_sb_offline(vm, mb_id,

							 &nb_sb);

		if (rc || !nb_sb)
@@ -1567,8 +1569,8 @@ static int virtio_mem_unplug_request(struct virtio_mem *vm, uint64_t diff) 
	}



	/* Try to unplug subblocks of partially plugged online blocks. */

	virtio_mem_for_each_mb_state_rev(vm, mb_id,

					 VIRTIO_MEM_MB_STATE_ONLINE_PARTIAL) {

	virtio_mem_sbm_for_each_mb_rev(vm, mb_id,

				       VIRTIO_MEM_SBM_MB_ONLINE_PARTIAL) {

		rc = virtio_mem_mb_unplug_any_sb_online(vm, mb_id,

							&nb_sb);

		if (rc || !nb_sb)
@@ -1579,8 +1581,7 @@ static int virtio_mem_unplug_request(struct virtio_mem *vm, uint64_t diff) 
	}



	/* Try to unplug subblocks of plugged online blocks. */

	virtio_mem_for_each_mb_state_rev(vm, mb_id,

					 VIRTIO_MEM_MB_STATE_ONLINE) {

	virtio_mem_sbm_for_each_mb_rev(vm, mb_id, VIRTIO_MEM_SBM_MB_ONLINE) {

		rc = virtio_mem_mb_unplug_any_sb_online(vm, mb_id,

							&nb_sb);

		if (rc || !nb_sb)
@@ -1606,11 +1607,12 @@ static int virtio_mem_unplug_pending_mb(struct virtio_mem *vm) 
	unsigned long mb_id;

	int rc;



	virtio_mem_for_each_mb_state(vm, mb_id, VIRTIO_MEM_MB_STATE_PLUGGED) {

	virtio_mem_sbm_for_each_mb(vm, mb_id, VIRTIO_MEM_SBM_MB_PLUGGED) {

		rc = virtio_mem_mb_unplug(vm, mb_id);

		if (rc)

			return rc;

		virtio_mem_mb_set_state(vm, mb_id, VIRTIO_MEM_MB_STATE_UNUSED);

		virtio_mem_sbm_set_mb_state(vm, mb_id,

					    VIRTIO_MEM_SBM_MB_UNUSED);

	}



	return 0;
@@ -2002,11 +2004,12 @@ static void virtio_mem_remove(struct virtio_device *vdev) 
	 * After we unregistered our callbacks, user space can online partially

	 * plugged offline blocks. Make sure to remove them.

	 */

	virtio_mem_for_each_mb_state(vm, mb_id,

				     VIRTIO_MEM_MB_STATE_OFFLINE_PARTIAL) {

	virtio_mem_sbm_for_each_mb(vm, mb_id,

				   VIRTIO_MEM_SBM_MB_OFFLINE_PARTIAL) {

		rc = virtio_mem_mb_remove(vm, mb_id);

		BUG_ON(rc);

		virtio_mem_mb_set_state(vm, mb_id, VIRTIO_MEM_MB_STATE_UNUSED);

		virtio_mem_sbm_set_mb_state(vm, mb_id,

					    VIRTIO_MEM_SBM_MB_UNUSED);

	}

	/*

	 * After we unregistered our callbacks, user space can no longer
@@ -2031,7 +2034,7 @@ static void virtio_mem_remove(struct virtio_device *vdev) 
	}



	/* remove all tracking data - no locking needed */

	vfree(vm->mb_state);

	vfree(vm->sbm.mb_states);

	vfree(vm->sb_bitmap);



	/* reset the device and cleanup the queues */

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