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VMware balloon: add batching to the vmw_balloon.

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Introduce a new capability to the driver that allow sending 512 pages in
one hypervisor call. This reduce the cost of the driver when reclaiming
memory.

Signed-off-by: Xavier Deguillard <xdeguillard@vmware.com>
Acked-by: Dmitry Torokhov <dtor@vmware.com>
Signed-off-by: Philip P. Moltmann <moltmann@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Xavier Deguillard 2015-08-06 15:17:58 -07:00 committed by Greg Kroah-Hartman
parent 4d4896a507
commit f220a80f0c
1 changed files with 353 additions and 53 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

388
drivers/misc/vmw_balloon.c
View file

@ -1,7 +1,7 @@
/*
* VMware Balloon driver.
*
* Copyright (C) 2000-2010, VMware, Inc. All Rights Reserved.
* Copyright (C) 2000-2013, VMware, Inc. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
@ -37,6 +37,7 @@
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/workqueue.h>
@ -46,7 +47,7 @@
MODULE_AUTHOR("VMware, Inc.");
MODULE_DESCRIPTION("VMware Memory Control (Balloon) Driver");
MODULE_VERSION("1.3.0.0-k");
MODULE_VERSION("1.3.1.0-k");
MODULE_ALIAS("dmi:*:svnVMware*:*");
MODULE_ALIAS("vmware_vmmemctl");
MODULE_LICENSE("GPL");
@ -120,13 +121,26 @@ enum vmwballoon_capabilities {
VMW_BALLOON_BATCHED_CMDS = (1 << 2)
};
#define VMW_BALLOON_CAPABILITIES (VMW_BALLOON_BASIC_CMDS)
#define VMW_BALLOON_CAPABILITIES (VMW_BALLOON_BASIC_CMDS \
| VMW_BALLOON_BATCHED_CMDS)
/*
* Backdoor commands availability:
*
* START, GET_TARGET and GUEST_ID are always available,
*
* VMW_BALLOON_BASIC_CMDS:
* LOCK and UNLOCK commands,
* VMW_BALLOON_BATCHED_CMDS:
* BATCHED_LOCK and BATCHED_UNLOCK commands.
*/
#define VMW_BALLOON_CMD_START 0
#define VMW_BALLOON_CMD_GET_TARGET 1
#define VMW_BALLOON_CMD_LOCK 2
#define VMW_BALLOON_CMD_UNLOCK 3
#define VMW_BALLOON_CMD_GUEST_ID 4
#define VMW_BALLOON_CMD_BATCHED_LOCK 6
#define VMW_BALLOON_CMD_BATCHED_UNLOCK 7
/* error codes */
#define VMW_BALLOON_SUCCESS 0
@ -142,18 +156,63 @@ enum vmwballoon_capabilities {
#define VMW_BALLOON_SUCCESS_WITH_CAPABILITIES (0x03000000)
#define VMWARE_BALLOON_CMD(cmd, data, result) \
/* Batch page description */
/*
* Layout of a page in the batch page:
*
* +-------------+----------+--------+
* | | | |
* | Page number | Reserved | Status |
* | | | |
* +-------------+----------+--------+
* 64 PAGE_SHIFT 6 0
*
* For now only 4K pages are supported, but we can easily support large pages
* by using bits in the reserved field.
*
* The reserved field should be set to 0.
*/
#define VMW_BALLOON_BATCH_MAX_PAGES (PAGE_SIZE / sizeof(u64))
#define VMW_BALLOON_BATCH_STATUS_MASK ((1UL << 5) - 1)
#define VMW_BALLOON_BATCH_PAGE_MASK (~((1UL << PAGE_SHIFT) - 1))
struct vmballoon_batch_page {
u64 pages[VMW_BALLOON_BATCH_MAX_PAGES];
};
static u64 vmballoon_batch_get_pa(struct vmballoon_batch_page *batch, int idx)
{
return batch->pages[idx] & VMW_BALLOON_BATCH_PAGE_MASK;
}
static int vmballoon_batch_get_status(struct vmballoon_batch_page *batch,
int idx)
{
return (int)(batch->pages[idx] & VMW_BALLOON_BATCH_STATUS_MASK);
}
static void vmballoon_batch_set_pa(struct vmballoon_batch_page *batch, int idx,
u64 pa)
{
batch->pages[idx] = pa;
}
#define VMWARE_BALLOON_CMD(cmd, arg1, arg2, result) \
({ \
unsigned long __status, __dummy1, __dummy2; \
unsigned long __status, __dummy1, __dummy2, __dummy3; \
__asm__ __volatile__ ("inl %%dx" : \
"=a"(__status), \
"=c"(__dummy1), \
"=d"(__dummy2), \
"=b"(result) : \
"=b"(result), \
"=S" (__dummy3) : \
"0"(VMW_BALLOON_HV_MAGIC), \
"1"(VMW_BALLOON_CMD_##cmd), \
"2"(VMW_BALLOON_HV_PORT), \
"3"(data) : \
"3"(arg1), \
"4" (arg2) : \
"memory"); \
if (VMW_BALLOON_CMD_##cmd == VMW_BALLOON_CMD_START) \
result = __dummy1; \
@ -192,6 +251,14 @@ struct vmballoon_stats {
#define STATS_INC(stat)
#endif
struct vmballoon;
struct vmballoon_ops {
void (*add_page)(struct vmballoon *b, int idx, struct page *p);
int (*lock)(struct vmballoon *b, unsigned int num_pages);
int (*unlock)(struct vmballoon *b, unsigned int num_pages);
};
struct vmballoon {
/* list of reserved physical pages */
@ -215,6 +282,14 @@ struct vmballoon {
/* slowdown page allocations for next few cycles */
unsigned int slow_allocation_cycles;
unsigned long capabilities;
struct vmballoon_batch_page *batch_page;
unsigned int batch_max_pages;
struct page *page;
const struct vmballoon_ops *ops;
#ifdef CONFIG_DEBUG_FS
/* statistics */
struct vmballoon_stats stats;
@ -234,16 +309,22 @@ static struct vmballoon balloon;
* Send "start" command to the host, communicating supported version
* of the protocol.
*/
static bool vmballoon_send_start(struct vmballoon *b)
static bool vmballoon_send_start(struct vmballoon *b, unsigned long req_caps)
{
unsigned long status, capabilities;
unsigned long status, capabilities, dummy = 0;
STATS_INC(b->stats.start);
status = VMWARE_BALLOON_CMD(START, VMW_BALLOON_CAPABILITIES,
capabilities);
if (status == VMW_BALLOON_SUCCESS)
status = VMWARE_BALLOON_CMD(START, req_caps, dummy, capabilities);
switch (status) {
case VMW_BALLOON_SUCCESS_WITH_CAPABILITIES:
b->capabilities = capabilities;
return true;
case VMW_BALLOON_SUCCESS:
b->capabilities = VMW_BALLOON_BASIC_CMDS;
return true;
}
pr_debug("%s - failed, hv returns %ld\n", __func__, status);
STATS_INC(b->stats.start_fail);
@ -273,9 +354,10 @@ static bool vmballoon_check_status(struct vmballoon *b, unsigned long status)
*/
static bool vmballoon_send_guest_id(struct vmballoon *b)
{
unsigned long status, dummy;
unsigned long status, dummy = 0;
status = VMWARE_BALLOON_CMD(GUEST_ID, VMW_BALLOON_GUEST_ID, dummy);
status = VMWARE_BALLOON_CMD(GUEST_ID, VMW_BALLOON_GUEST_ID, dummy,
dummy);
STATS_INC(b->stats.guest_type);
@ -295,6 +377,7 @@ static bool vmballoon_send_get_target(struct vmballoon *b, u32 *new_target)
unsigned long status;
unsigned long target;
unsigned long limit;
unsigned long dummy = 0;
u32 limit32;
/*
@ -313,7 +396,7 @@ static bool vmballoon_send_get_target(struct vmballoon *b, u32 *new_target)
/* update stats */
STATS_INC(b->stats.target);
status = VMWARE_BALLOON_CMD(GET_TARGET, limit, target);
status = VMWARE_BALLOON_CMD(GET_TARGET, limit, dummy, target);
if (vmballoon_check_status(b, status)) {
*new_target = target;
return true;
@ -332,7 +415,7 @@ static bool vmballoon_send_get_target(struct vmballoon *b, u32 *new_target)
static int vmballoon_send_lock_page(struct vmballoon *b, unsigned long pfn,
unsigned int *hv_status)
{
unsigned long status, dummy;
unsigned long status, dummy = 0;
u32 pfn32;
pfn32 = (u32)pfn;
@ -341,7 +424,7 @@ static int vmballoon_send_lock_page(struct vmballoon *b, unsigned long pfn,
STATS_INC(b->stats.lock);
*hv_status = status = VMWARE_BALLOON_CMD(LOCK, pfn, dummy);
*hv_status = status = VMWARE_BALLOON_CMD(LOCK, pfn, dummy, dummy);
if (vmballoon_check_status(b, status))
return 0;
@ -350,13 +433,30 @@ static int vmballoon_send_lock_page(struct vmballoon *b, unsigned long pfn,
return 1;
}
static int vmballoon_send_batched_lock(struct vmballoon *b,
unsigned int num_pages)
{
unsigned long status, dummy;
unsigned long pfn = page_to_pfn(b->page);
STATS_INC(b->stats.lock);
status = VMWARE_BALLOON_CMD(BATCHED_LOCK, pfn, num_pages, dummy);
if (vmballoon_check_status(b, status))
return 0;
pr_debug("%s - batch ppn %lx, hv returns %ld\n", __func__, pfn, status);
STATS_INC(b->stats.lock_fail);
return 1;
}
/*
* Notify the host that guest intends to release given page back into
* the pool of available (to the guest) pages.
*/
static bool vmballoon_send_unlock_page(struct vmballoon *b, unsigned long pfn)
{
unsigned long status, dummy;
unsigned long status, dummy = 0;
u32 pfn32;
pfn32 = (u32)pfn;
@ -365,7 +465,7 @@ static bool vmballoon_send_unlock_page(struct vmballoon *b, unsigned long pfn)
STATS_INC(b->stats.unlock);
status = VMWARE_BALLOON_CMD(UNLOCK, pfn, dummy);
status = VMWARE_BALLOON_CMD(UNLOCK, pfn, dummy, dummy);
if (vmballoon_check_status(b, status))
return true;
@ -374,6 +474,23 @@ static bool vmballoon_send_unlock_page(struct vmballoon *b, unsigned long pfn)
return false;
}
static bool vmballoon_send_batched_unlock(struct vmballoon *b,
unsigned int num_pages)
{
unsigned long status, dummy;
unsigned long pfn = page_to_pfn(b->page);
STATS_INC(b->stats.unlock);
status = VMWARE_BALLOON_CMD(BATCHED_UNLOCK, pfn, num_pages, dummy);
if (vmballoon_check_status(b, status))
return true;
pr_debug("%s - batch ppn %lx, hv returns %ld\n", __func__, pfn, status);
STATS_INC(b->stats.unlock_fail);
return false;
}
/*
* Quickly release all pages allocated for the balloon. This function is
* called when host decides to "reset" balloon for one reason or another.
@ -396,22 +513,13 @@ static void vmballoon_pop(struct vmballoon *b)
cond_resched();
}
}
}
/*
* Perform standard reset sequence by popping the balloon (in case it
* is not empty) and then restarting protocol. This operation normally
* happens when host responds with VMW_BALLOON_ERROR_RESET to a command.
*/
static void vmballoon_reset(struct vmballoon *b)
{
/* free all pages, skipping monitor unlock */
vmballoon_pop(b);
if ((b->capabilities & VMW_BALLOON_BATCHED_CMDS) != 0) {
if (b->batch_page)
vunmap(b->batch_page);
if (vmballoon_send_start(b)) {
b->reset_required = false;
if (!vmballoon_send_guest_id(b))
pr_err("failed to send guest ID to the host\n");
if (b->page)
__free_page(b->page);
}
}
@ -420,9 +528,10 @@ static void vmballoon_reset(struct vmballoon *b)
* refuse list, those refused page are then released at the end of the
* inflation cycle.
*/
static int vmballoon_lock_page(struct vmballoon *b, struct page *page)
static int vmballoon_lock_page(struct vmballoon *b, unsigned int num_pages)
{
int locked, hv_status;
struct page *page = b->page;
locked = vmballoon_send_lock_page(b, page_to_pfn(page), &hv_status);
if (locked > 0) {
@ -457,17 +566,68 @@ static int vmballoon_lock_page(struct vmballoon *b, struct page *page)
return 0;
}
static int vmballoon_lock_batched_page(struct vmballoon *b,
unsigned int num_pages)
{
int locked, i;
locked = vmballoon_send_batched_lock(b, num_pages);
if (locked > 0) {
for (i = 0; i < num_pages; i++) {
u64 pa = vmballoon_batch_get_pa(b->batch_page, i);
struct page *p = pfn_to_page(pa >> PAGE_SHIFT);
__free_page(p);
}
return -EIO;
}
for (i = 0; i < num_pages; i++) {
u64 pa = vmballoon_batch_get_pa(b->batch_page, i);
struct page *p = pfn_to_page(pa >> PAGE_SHIFT);
locked = vmballoon_batch_get_status(b->batch_page, i);
switch (locked) {
case VMW_BALLOON_SUCCESS:
list_add(&p->lru, &b->pages);
b->size++;
break;
case VMW_BALLOON_ERROR_PPN_PINNED:
case VMW_BALLOON_ERROR_PPN_INVALID:
if (b->n_refused_pages < VMW_BALLOON_MAX_REFUSED) {
list_add(&p->lru, &b->refused_pages);
b->n_refused_pages++;
break;
}
/* Fallthrough */
case VMW_BALLOON_ERROR_RESET:
case VMW_BALLOON_ERROR_PPN_NOTNEEDED:
__free_page(p);
break;
default:
/* This should never happen */
WARN_ON_ONCE(true);
}
}
return 0;
}
/*
* Release the page allocated for the balloon. Note that we first notify
* the host so it can make sure the page will be available for the guest
* to use, if needed.
*/
static int vmballoon_release_page(struct vmballoon *b, struct page *page)
static int vmballoon_unlock_page(struct vmballoon *b, unsigned int num_pages)
{
if (!vmballoon_send_unlock_page(b, page_to_pfn(page)))
return -EIO;
struct page *page = b->page;
list_del(&page->lru);
if (!vmballoon_send_unlock_page(b, page_to_pfn(page))) {
list_add(&page->lru, &b->pages);
return -EIO;
}
/* deallocate page */
__free_page(page);
@ -479,6 +639,41 @@ static int vmballoon_release_page(struct vmballoon *b, struct page *page)
return 0;
}
static int vmballoon_unlock_batched_page(struct vmballoon *b,
unsigned int num_pages)
{
int locked, i, ret = 0;
bool hv_success;
hv_success = vmballoon_send_batched_unlock(b, num_pages);
if (!hv_success)
ret = -EIO;
for (i = 0; i < num_pages; i++) {
u64 pa = vmballoon_batch_get_pa(b->batch_page, i);
struct page *p = pfn_to_page(pa >> PAGE_SHIFT);
locked = vmballoon_batch_get_status(b->batch_page, i);
if (!hv_success || locked != VMW_BALLOON_SUCCESS) {
/*
* That page wasn't successfully unlocked by the
* hypervisor, re-add it to the list of pages owned by
* the balloon driver.
*/
list_add(&p->lru, &b->pages);
} else {
/* deallocate page */
__free_page(p);
STATS_INC(b->stats.free);
/* update balloon size */
b->size--;
}
}
return ret;
}
/*
* Release pages that were allocated while attempting to inflate the
* balloon but were refused by the host for one reason or another.
@ -496,6 +691,18 @@ static void vmballoon_release_refused_pages(struct vmballoon *b)
b->n_refused_pages = 0;
}
static void vmballoon_add_page(struct vmballoon *b, int idx, struct page *p)
{
b->page = p;
}
static void vmballoon_add_batched_page(struct vmballoon *b, int idx,
struct page *p)
{
vmballoon_batch_set_pa(b->batch_page, idx,
(u64)page_to_pfn(p) << PAGE_SHIFT);
}
/*
* Inflate the balloon towards its target size. Note that we try to limit
* the rate of allocation to make sure we are not choking the rest of the
@ -507,6 +714,7 @@ static void vmballoon_inflate(struct vmballoon *b)
unsigned int rate;
unsigned int i;
unsigned int allocations = 0;
unsigned int num_pages = 0;
int error = 0;
gfp_t flags = VMW_PAGE_ALLOC_NOSLEEP;
@ -539,14 +747,13 @@ static void vmballoon_inflate(struct vmballoon *b)
__func__, goal, rate, b->rate_alloc);
for (i = 0; i < goal; i++) {
struct page *page;
struct page *page = alloc_page(flags);
if (flags == VMW_PAGE_ALLOC_NOSLEEP)
STATS_INC(b->stats.alloc);
else
STATS_INC(b->stats.sleep_alloc);
page = alloc_page(flags);
if (!page) {
if (flags == VMW_PAGE_ALLOC_CANSLEEP) {
/*
@ -580,9 +787,13 @@ static void vmballoon_inflate(struct vmballoon *b)
continue;
}
error = vmballoon_lock_page(b, page);
b->ops->add_page(b, num_pages++, page);
if (num_pages == b->batch_max_pages) {
error = b->ops->lock(b, num_pages);
num_pages = 0;
if (error)
break;
}
if (++allocations > VMW_BALLOON_YIELD_THRESHOLD) {
cond_resched();
@ -595,6 +806,9 @@ static void vmballoon_inflate(struct vmballoon *b)
}
}
if (num_pages > 0)
b->ops->lock(b, num_pages);
/*
* We reached our goal without failures so try increasing
* allocation rate.
@ -618,6 +832,7 @@ static void vmballoon_deflate(struct vmballoon *b)
struct page *page, *next;
unsigned int i = 0;
unsigned int goal;
unsigned int num_pages = 0;
int error;
pr_debug("%s - size: %d, target %d\n", __func__, b->size, b->target);
@ -629,23 +844,96 @@ static void vmballoon_deflate(struct vmballoon *b)
/* free pages to reach target */
list_for_each_entry_safe(page, next, &b->pages, lru) {
error = vmballoon_release_page(b, page);
list_del(&page->lru);
b->ops->add_page(b, num_pages++, page);
if (num_pages == b->batch_max_pages) {
error = b->ops->unlock(b, num_pages);
num_pages = 0;
if (error) {
/* quickly decrease rate in case of error */
b->rate_free = max(b->rate_free / 2,
VMW_BALLOON_RATE_FREE_MIN);
return;
}
}
if (++i >= goal)
break;
}
if (num_pages > 0)
b->ops->unlock(b, num_pages);
/* slowly increase rate if there were no errors */
if (error == 0)
b->rate_free = min(b->rate_free + VMW_BALLOON_RATE_FREE_INC,
VMW_BALLOON_RATE_FREE_MAX);
}
static const struct vmballoon_ops vmballoon_basic_ops = {
.add_page = vmballoon_add_page,
.lock = vmballoon_lock_page,
.unlock = vmballoon_unlock_page
};
static const struct vmballoon_ops vmballoon_batched_ops = {
.add_page = vmballoon_add_batched_page,
.lock = vmballoon_lock_batched_page,
.unlock = vmballoon_unlock_batched_page
};
static bool vmballoon_init_batching(struct vmballoon *b)
{
b->page = alloc_page(VMW_PAGE_ALLOC_NOSLEEP);
if (!b->page)
return false;
b->batch_page = vmap(&b->page, 1, VM_MAP, PAGE_KERNEL);
if (!b->batch_page) {
__free_page(b->page);
return false;
}
return true;
}
/*
* Perform standard reset sequence by popping the balloon (in case it
* is not empty) and then restarting protocol. This operation normally
* happens when host responds with VMW_BALLOON_ERROR_RESET to a command.
*/
static void vmballoon_reset(struct vmballoon *b)
{
/* free all pages, skipping monitor unlock */
vmballoon_pop(b);
if (!vmballoon_send_start(b, VMW_BALLOON_CAPABILITIES))
return;
if ((b->capabilities & VMW_BALLOON_BATCHED_CMDS) != 0) {
b->ops = &vmballoon_batched_ops;
b->batch_max_pages = VMW_BALLOON_BATCH_MAX_PAGES;
if (!vmballoon_init_batching(b)) {
/*
* We failed to initialize batching, inform the monitor
* about it by sending a null capability.
*
* The guest will retry in one second.
*/
vmballoon_send_start(b, 0);
return;
}
} else if ((b->capabilities & VMW_BALLOON_BASIC_CMDS) != 0) {
b->ops = &vmballoon_basic_ops;
b->batch_max_pages = 1;
}
b->reset_required = false;
if (!vmballoon_send_guest_id(b))
pr_err("failed to send guest ID to the host\n");
}
/*
* Balloon work function: reset protocol, if needed, get the new size and
* adjust balloon as needed. Repeat in 1 sec.
@ -802,11 +1090,23 @@ static int __init vmballoon_init(void)
/*
* Start balloon.
*/
if (!vmballoon_send_start(&balloon)) {
if (!vmballoon_send_start(&balloon, VMW_BALLOON_CAPABILITIES)) {
pr_err("failed to send start command to the host\n");
return -EIO;
}
if ((balloon.capabilities & VMW_BALLOON_BATCHED_CMDS) != 0) {
balloon.ops = &vmballoon_batched_ops;
balloon.batch_max_pages = VMW_BALLOON_BATCH_MAX_PAGES;
if (!vmballoon_init_batching(&balloon)) {
pr_err("failed to init batching\n");
return -EIO;
}
} else if ((balloon.capabilities & VMW_BALLOON_BASIC_CMDS) != 0) {
balloon.ops = &vmballoon_basic_ops;
balloon.batch_max_pages = 1;
}
if (!vmballoon_send_guest_id(&balloon)) {
pr_err("failed to send guest ID to the host\n");
return -EIO;
@ -833,7 +1133,7 @@ static void __exit vmballoon_exit(void)
* Reset connection before deallocating memory to avoid potential for
* additional spurious resets from guest touching deallocated pages.
*/
vmballoon_send_start(&balloon);
vmballoon_send_start(&balloon, VMW_BALLOON_CAPABILITIES);
vmballoon_pop(&balloon);
}
module_exit(vmballoon_exit);