Drivers: hv: balloon: Implement hot-add functionality

Implement the memory hot-add functionality. With this, Linux guests can fully
participate in the Dynamic Memory protocol implemented in the Windows hosts.

In this version of the patch, based Olaf Herring's feedback, I have gotten
rid of the module level dependency on MEMORY_HOTPLUG. Instead the code within
the driver that depends on MEMORY_HOTPLUG has the appropriate compilation
switches. This would allow this driver to support pure ballooning in cases
where the kernel does not support memory hotplug.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
K. Y. Srinivasan 2013-03-15 12:25:43 -07:00 committed by Greg Kroah-Hartman
parent 0cf40a3e66
commit 1cac8cd4d1
1 changed files with 387 additions and 21 deletions

View File

@ -412,6 +412,27 @@ struct dm_info_msg {
* End protocol definitions.
*/
/*
* State to manage hot adding memory into the guest.
* The range start_pfn : end_pfn specifies the range
* that the host has asked us to hot add. The range
* start_pfn : ha_end_pfn specifies the range that we have
* currently hot added. We hot add in multiples of 128M
* chunks; it is possible that we may not be able to bring
* online all the pages in the region. The range
* covered_start_pfn : covered_end_pfn defines the pages that can
* be brough online.
*/
struct hv_hotadd_state {
struct list_head list;
unsigned long start_pfn;
unsigned long covered_start_pfn;
unsigned long covered_end_pfn;
unsigned long ha_end_pfn;
unsigned long end_pfn;
};
struct balloon_state {
__u32 num_pages;
struct work_struct wrk;
@ -419,16 +440,17 @@ struct balloon_state {
struct hot_add_wrk {
union dm_mem_page_range ha_page_range;
union dm_mem_page_range ha_region_range;
struct work_struct wrk;
};
static bool hot_add;
static bool hot_add = true;
static bool do_hot_add;
/*
* Delay reporting memory pressure by
* the specified number of seconds.
*/
static uint pressure_report_delay = 30;
static uint pressure_report_delay = 45;
module_param(hot_add, bool, (S_IRUGO | S_IWUSR));
MODULE_PARM_DESC(hot_add, "If set attempt memory hot_add");
@ -456,6 +478,7 @@ enum hv_dm_state {
static __u8 recv_buffer[PAGE_SIZE];
static __u8 *send_buffer;
#define PAGES_IN_2M 512
#define HA_CHUNK (32 * 1024)
struct hv_dynmem_device {
struct hv_device *dev;
@ -478,6 +501,17 @@ struct hv_dynmem_device {
*/
struct hot_add_wrk ha_wrk;
/*
* This state tracks if the host has specified a hot-add
* region.
*/
bool host_specified_ha_region;
/*
* State to synchronize hot-add.
*/
struct completion ol_waitevent;
bool ha_waiting;
/*
* This thread handles hot-add
* requests from the host as well as notifying
@ -486,6 +520,11 @@ struct hv_dynmem_device {
*/
struct task_struct *thread;
/*
* A list of hot-add regions.
*/
struct list_head ha_region_list;
/*
* We start with the highest version we can support
* and downgrade based on the host; we save here the
@ -496,35 +535,329 @@ struct hv_dynmem_device {
static struct hv_dynmem_device dm_device;
static void hot_add_req(struct work_struct *dummy)
#ifdef CONFIG_MEMORY_HOTPLUG
void hv_bring_pgs_online(unsigned long start_pfn, unsigned long size)
{
int i;
struct dm_hot_add_response resp;
for (i = 0; i < size; i++) {
struct page *pg;
pg = pfn_to_page(start_pfn + i);
__online_page_set_limits(pg);
__online_page_increment_counters(pg);
__online_page_free(pg);
}
}
if (do_hot_add) {
static void hv_mem_hot_add(unsigned long start, unsigned long size,
unsigned long pfn_count,
struct hv_hotadd_state *has)
{
int ret = 0;
int i, nid, t;
unsigned long start_pfn;
unsigned long processed_pfn;
unsigned long total_pfn = pfn_count;
pr_info("Memory hot add not supported\n");
for (i = 0; i < (size/HA_CHUNK); i++) {
start_pfn = start + (i * HA_CHUNK);
has->ha_end_pfn += HA_CHUNK;
if (total_pfn > HA_CHUNK) {
processed_pfn = HA_CHUNK;
total_pfn -= HA_CHUNK;
} else {
processed_pfn = total_pfn;
total_pfn = 0;
}
has->covered_end_pfn += processed_pfn;
init_completion(&dm_device.ol_waitevent);
dm_device.ha_waiting = true;
nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn));
ret = add_memory(nid, PFN_PHYS((start_pfn)),
(HA_CHUNK << PAGE_SHIFT));
if (ret) {
pr_info("hot_add memory failed error is %d\n", ret);
has->ha_end_pfn -= HA_CHUNK;
has->covered_end_pfn -= processed_pfn;
break;
}
/*
* Currently we do not support hot add.
* Just fail the request.
* Wait for the memory block to be onlined.
*/
t = wait_for_completion_timeout(&dm_device.ol_waitevent, 5*HZ);
if (t == 0) {
pr_info("hot_add memory timedout\n");
has->ha_end_pfn -= HA_CHUNK;
has->covered_end_pfn -= processed_pfn;
break;
}
}
return;
}
static void hv_online_page(struct page *pg)
{
struct list_head *cur;
struct hv_hotadd_state *has;
unsigned long cur_start_pgp;
unsigned long cur_end_pgp;
if (dm_device.ha_waiting) {
dm_device.ha_waiting = false;
complete(&dm_device.ol_waitevent);
}
list_for_each(cur, &dm_device.ha_region_list) {
has = list_entry(cur, struct hv_hotadd_state, list);
cur_start_pgp = (unsigned long)
pfn_to_page(has->covered_start_pfn);
cur_end_pgp = (unsigned long)pfn_to_page(has->covered_end_pfn);
if (((unsigned long)pg >= cur_start_pgp) &&
((unsigned long)pg < cur_end_pgp)) {
/*
* This frame is currently backed; online the
* page.
*/
__online_page_set_limits(pg);
__online_page_increment_counters(pg);
__online_page_free(pg);
has->covered_start_pfn++;
}
}
}
static bool pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt)
{
struct list_head *cur;
struct hv_hotadd_state *has;
unsigned long residual, new_inc;
if (list_empty(&dm_device.ha_region_list))
return false;
list_for_each(cur, &dm_device.ha_region_list) {
has = list_entry(cur, struct hv_hotadd_state, list);
/*
* If the pfn range we are dealing with is not in the current
* "hot add block", move on.
*/
if ((start_pfn >= has->end_pfn))
continue;
/*
* If the current hot add-request extends beyond
* our current limit; extend it.
*/
if ((start_pfn + pfn_cnt) > has->end_pfn) {
residual = (start_pfn + pfn_cnt - has->end_pfn);
/*
* Extend the region by multiples of HA_CHUNK.
*/
new_inc = (residual / HA_CHUNK) * HA_CHUNK;
if (residual % HA_CHUNK)
new_inc += HA_CHUNK;
has->end_pfn += new_inc;
}
/*
* If the current start pfn is not where the covered_end
* is, update it.
*/
if (has->covered_end_pfn != start_pfn) {
has->covered_end_pfn = start_pfn;
has->covered_start_pfn = start_pfn;
}
return true;
}
return false;
}
static unsigned long handle_pg_range(unsigned long pg_start,
unsigned long pg_count)
{
unsigned long start_pfn = pg_start;
unsigned long pfn_cnt = pg_count;
unsigned long size;
struct list_head *cur;
struct hv_hotadd_state *has;
unsigned long pgs_ol = 0;
unsigned long old_covered_state;
if (list_empty(&dm_device.ha_region_list))
return 0;
list_for_each(cur, &dm_device.ha_region_list) {
has = list_entry(cur, struct hv_hotadd_state, list);
/*
* If the pfn range we are dealing with is not in the current
* "hot add block", move on.
*/
if ((start_pfn >= has->end_pfn))
continue;
old_covered_state = has->covered_end_pfn;
if (start_pfn < has->ha_end_pfn) {
/*
* This is the case where we are backing pages
* in an already hot added region. Bring
* these pages online first.
*/
pgs_ol = has->ha_end_pfn - start_pfn;
if (pgs_ol > pfn_cnt)
pgs_ol = pfn_cnt;
hv_bring_pgs_online(start_pfn, pgs_ol);
has->covered_end_pfn += pgs_ol;
has->covered_start_pfn += pgs_ol;
pfn_cnt -= pgs_ol;
}
if ((has->ha_end_pfn < has->end_pfn) && (pfn_cnt > 0)) {
/*
* We have some residual hot add range
* that needs to be hot added; hot add
* it now. Hot add a multiple of
* of HA_CHUNK that fully covers the pages
* we have.
*/
size = (has->end_pfn - has->ha_end_pfn);
if (pfn_cnt <= size) {
size = ((pfn_cnt / HA_CHUNK) * HA_CHUNK);
if (pfn_cnt % HA_CHUNK)
size += HA_CHUNK;
} else {
pfn_cnt = size;
}
hv_mem_hot_add(has->ha_end_pfn, size, pfn_cnt, has);
}
/*
* If we managed to online any pages that were given to us,
* we declare success.
*/
return has->covered_end_pfn - old_covered_state;
}
return 0;
}
static unsigned long process_hot_add(unsigned long pg_start,
unsigned long pfn_cnt,
unsigned long rg_start,
unsigned long rg_size)
{
struct hv_hotadd_state *ha_region = NULL;
if (pfn_cnt == 0)
return 0;
if (!dm_device.host_specified_ha_region)
if (pfn_covered(pg_start, pfn_cnt))
goto do_pg_range;
/*
* If the host has specified a hot-add range; deal with it first.
*/
if ((rg_size != 0) && (!dm_device.host_specified_ha_region)) {
ha_region = kzalloc(sizeof(struct hv_hotadd_state), GFP_KERNEL);
if (!ha_region)
return 0;
INIT_LIST_HEAD(&ha_region->list);
list_add_tail(&ha_region->list, &dm_device.ha_region_list);
ha_region->start_pfn = rg_start;
ha_region->ha_end_pfn = rg_start;
ha_region->covered_start_pfn = pg_start;
ha_region->covered_end_pfn = pg_start;
ha_region->end_pfn = rg_start + rg_size;
}
do_pg_range:
/*
* Process the page range specified; bringing them
* online if possible.
*/
return handle_pg_range(pg_start, pfn_cnt);
}
#endif
static void hot_add_req(struct work_struct *dummy)
{
struct dm_hot_add_response resp;
#ifdef CONFIG_MEMORY_HOTPLUG
unsigned long pg_start, pfn_cnt;
unsigned long rg_start, rg_sz;
#endif
struct hv_dynmem_device *dm = &dm_device;
memset(&resp, 0, sizeof(struct dm_hot_add_response));
resp.hdr.type = DM_MEM_HOT_ADD_RESPONSE;
resp.hdr.size = sizeof(struct dm_hot_add_response);
resp.hdr.trans_id = atomic_inc_return(&trans_id);
resp.page_count = 0;
resp.result = 0;
#ifdef CONFIG_MEMORY_HOTPLUG
pg_start = dm->ha_wrk.ha_page_range.finfo.start_page;
pfn_cnt = dm->ha_wrk.ha_page_range.finfo.page_cnt;
dm_device.state = DM_INITIALIZED;
vmbus_sendpacket(dm_device.dev->channel, &resp,
rg_start = dm->ha_wrk.ha_region_range.finfo.start_page;
rg_sz = dm->ha_wrk.ha_region_range.finfo.page_cnt;
if ((rg_start == 0) && (!dm->host_specified_ha_region)) {
unsigned long region_size;
unsigned long region_start;
/*
* The host has not specified the hot-add region.
* Based on the hot-add page range being specified,
* compute a hot-add region that can cover the pages
* that need to be hot-added while ensuring the alignment
* and size requirements of Linux as it relates to hot-add.
*/
region_start = pg_start;
region_size = (pfn_cnt / HA_CHUNK) * HA_CHUNK;
if (pfn_cnt % HA_CHUNK)
region_size += HA_CHUNK;
region_start = (pg_start / HA_CHUNK) * HA_CHUNK;
rg_start = region_start;
rg_sz = region_size;
}
resp.page_count = process_hot_add(pg_start, pfn_cnt,
rg_start, rg_sz);
#endif
if (resp.page_count > 0)
resp.result = 1;
else
resp.result = 0;
if (!do_hot_add || (resp.page_count == 0))
pr_info("Memory hot add failed\n");
dm->state = DM_INITIALIZED;
vmbus_sendpacket(dm->dev->channel, &resp,
sizeof(struct dm_hot_add_response),
(unsigned long)NULL,
VM_PKT_DATA_INBAND, 0);
}
static void process_info(struct hv_dynmem_device *dm, struct dm_info_msg *msg)
@ -867,6 +1200,7 @@ static void balloon_onchannelcallback(void *context)
struct dm_balloon *bal_msg;
struct dm_hot_add *ha_msg;
union dm_mem_page_range *ha_pg_range;
union dm_mem_page_range *ha_region;
memset(recv_buffer, 0, sizeof(recv_buffer));
vmbus_recvpacket(dev->channel, recv_buffer,
@ -907,8 +1241,26 @@ static void balloon_onchannelcallback(void *context)
pr_warn("Currently hot-adding\n");
dm->state = DM_HOT_ADD;
ha_msg = (struct dm_hot_add *)recv_buffer;
ha_pg_range = &ha_msg->range;
dm_device.ha_wrk.ha_page_range = *ha_pg_range;
if (ha_msg->hdr.size == sizeof(struct dm_hot_add)) {
/*
* This is a normal hot-add request specifying
* hot-add memory.
*/
ha_pg_range = &ha_msg->range;
dm->ha_wrk.ha_page_range = *ha_pg_range;
dm->ha_wrk.ha_region_range.page_range = 0;
} else {
/*
* Host is specifying that we first hot-add
* a region and then partially populate this
* region.
*/
dm->host_specified_ha_region = true;
ha_pg_range = &ha_msg->range;
ha_region = &ha_pg_range[1];
dm->ha_wrk.ha_page_range = *ha_pg_range;
dm->ha_wrk.ha_region_range = *ha_region;
}
schedule_work(&dm_device.ha_wrk.wrk);
break;
@ -952,8 +1304,10 @@ static int balloon_probe(struct hv_device *dev,
dm_device.next_version = DYNMEM_PROTOCOL_VERSION_WIN7;
init_completion(&dm_device.host_event);
init_completion(&dm_device.config_event);
INIT_LIST_HEAD(&dm_device.ha_region_list);
INIT_WORK(&dm_device.balloon_wrk.wrk, balloon_up);
INIT_WORK(&dm_device.ha_wrk.wrk, hot_add_req);
dm_device.host_specified_ha_region = false;
dm_device.thread =
kthread_run(dm_thread_func, &dm_device, "hv_balloon");
@ -962,6 +1316,10 @@ static int balloon_probe(struct hv_device *dev,
goto probe_error1;
}
#ifdef CONFIG_MEMORY_HOTPLUG
set_online_page_callback(&hv_online_page);
#endif
hv_set_drvdata(dev, &dm_device);
/*
* Initiate the hand shake with the host and negotiate
@ -1006,12 +1364,6 @@ static int balloon_probe(struct hv_device *dev,
cap_msg.hdr.trans_id = atomic_inc_return(&trans_id);
cap_msg.caps.cap_bits.balloon = 1;
/*
* While we currently don't support hot-add,
* we still advertise this capability since the
* host requires that guests partcipating in the
* dynamic memory protocol support hot add.
*/
cap_msg.caps.cap_bits.hot_add = 1;
/*
@ -1049,6 +1401,9 @@ static int balloon_probe(struct hv_device *dev,
return 0;
probe_error2:
#ifdef CONFIG_MEMORY_HOTPLUG
restore_online_page_callback(&hv_online_page);
#endif
kthread_stop(dm_device.thread);
probe_error1:
@ -1061,15 +1416,26 @@ probe_error0:
static int balloon_remove(struct hv_device *dev)
{
struct hv_dynmem_device *dm = hv_get_drvdata(dev);
struct list_head *cur, *tmp;
struct hv_hotadd_state *has;
if (dm->num_pages_ballooned != 0)
pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned);
cancel_work_sync(&dm->balloon_wrk.wrk);
cancel_work_sync(&dm->ha_wrk.wrk);
vmbus_close(dev->channel);
kthread_stop(dm->thread);
kfree(send_buffer);
#ifdef CONFIG_MEMORY_HOTPLUG
restore_online_page_callback(&hv_online_page);
#endif
list_for_each_safe(cur, tmp, &dm->ha_region_list) {
has = list_entry(cur, struct hv_hotadd_state, list);
list_del(&has->list);
kfree(has);
}
return 0;
}