[PATCH v2 18/29] virtio-mem: memory block states are specific to Sub Block Mode (SBM)

David Hildenbrand
2020-11-12T13:39:30Z

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: Wei Yang <richard.weiyang@linux.alibaba.com>
Reviewed-by: Pankaj 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: David Hildenbrand <david@redhat.com>
---
drivers/virtio/virtio_mem.c | 215 ++++++++++++++++++------------------
1 file changed, 109 insertions(+), 106 deletions(-)

diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index 4234bfc0cf52..c6cc301c78e1 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -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;

- /*
- * 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).
- *
- * With 128MB memory blocks, we have states for 512GB of memory in one
- * page.
- */
- uint8_t *mb_state;
+ 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().
+ * Resized (alloc+copy+free) on demand.
+ *
+ * With 128 MiB memory blocks, we have states for 512 GiB of
+ * memory in one 4 KiB page.
+ */
+ 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,
- unsigned long mb_id)
+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 @@ static int virtio_mem_mb_unplug_any_sb_online(struct virtio_mem *vm,
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 */
--
2.26.2