Commit 84af458b authored by Brian King's avatar Brian King Committed by Benjamin Herrenschmidt
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powerpc/pseries: Add collaborative memory manager



Adds a collaborative memory manager, which acts as a simple balloon driver
for System p machines that support cooperative memory overcommitment
(CMO).

Adds a platform configuration option for CMO called PPC_SMLPAR.
Signed-off-by: default avatarBrian King <brking@linux.vnet.ibm.com>
Signed-off-by: default avatarRobert Jennings <rcj@linux.vnet.ibm.com>
Acked-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 86630a32
......@@ -40,3 +40,26 @@ config PPC_PSERIES_DEBUG
depends on PPC_PSERIES && PPC_EARLY_DEBUG
bool "Enable extra debug logging in platforms/pseries"
default y
config PPC_SMLPAR
bool "Support for shared-memory logical partitions"
depends on PPC_PSERIES
select LPARCFG
default n
help
Select this option to enable shared memory partition support.
With this option a system running in an LPAR can be given more
memory than physically available and will allow firmware to
balance memory across many LPARs.
config CMM
tristate "Collaborative memory management"
depends on PPC_SMLPAR
default y
help
Select this option, if you want to enable the kernel interface
to reduce the memory size of the system. This is accomplished
by allocating pages of memory and put them "on hold". This only
makes sense for a system running in an LPAR where the unused pages
will be reused for other LPARs. The interface allows firmware to
balance memory across many LPARs.
......@@ -24,3 +24,4 @@ obj-$(CONFIG_HVC_CONSOLE) += hvconsole.o
obj-$(CONFIG_HVCS) += hvcserver.o
obj-$(CONFIG_HCALL_STATS) += hvCall_inst.o
obj-$(CONFIG_PHYP_DUMP) += phyp_dump.o
obj-$(CONFIG_CMM) += cmm.o
/*
* Collaborative memory management interface.
*
* Copyright (C) 2008 IBM Corporation
* Author(s): Brian King (brking@linux.vnet.ibm.com),
*
* 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 Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/oom.h>
#include <linux/sched.h>
#include <linux/stringify.h>
#include <linux/swap.h>
#include <linux/sysdev.h>
#include <asm/firmware.h>
#include <asm/hvcall.h>
#include <asm/mmu.h>
#include <asm/pgalloc.h>
#include <asm/uaccess.h>
#include "plpar_wrappers.h"
#define CMM_DRIVER_VERSION "1.0.0"
#define CMM_DEFAULT_DELAY 1
#define CMM_DEBUG 0
#define CMM_DISABLE 0
#define CMM_OOM_KB 1024
#define CMM_MIN_MEM_MB 256
#define KB2PAGES(_p) ((_p)>>(PAGE_SHIFT-10))
#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))
static unsigned int delay = CMM_DEFAULT_DELAY;
static unsigned int oom_kb = CMM_OOM_KB;
static unsigned int cmm_debug = CMM_DEBUG;
static unsigned int cmm_disabled = CMM_DISABLE;
static unsigned long min_mem_mb = CMM_MIN_MEM_MB;
static struct sys_device cmm_sysdev;
MODULE_AUTHOR("Brian King <brking@linux.vnet.ibm.com>");
MODULE_DESCRIPTION("IBM System p Collaborative Memory Manager");
MODULE_LICENSE("GPL");
MODULE_VERSION(CMM_DRIVER_VERSION);
module_param_named(delay, delay, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(delay, "Delay (in seconds) between polls to query hypervisor paging requests. "
"[Default=" __stringify(CMM_DEFAULT_DELAY) "]");
module_param_named(oom_kb, oom_kb, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(oom_kb, "Amount of memory in kb to free on OOM. "
"[Default=" __stringify(CMM_OOM_KB) "]");
module_param_named(min_mem_mb, min_mem_mb, ulong, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(min_mem_mb, "Minimum amount of memory (in MB) to not balloon. "
"[Default=" __stringify(CMM_MIN_MEM_MB) "]");
module_param_named(debug, cmm_debug, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Enable module debugging logging. Set to 1 to enable. "
"[Default=" __stringify(CMM_DEBUG) "]");
#define CMM_NR_PAGES ((PAGE_SIZE - sizeof(void *) - sizeof(unsigned long)) / sizeof(unsigned long))
#define cmm_dbg(...) if (cmm_debug) { printk(KERN_INFO "cmm: "__VA_ARGS__); }
struct cmm_page_array {
struct cmm_page_array *next;
unsigned long index;
unsigned long page[CMM_NR_PAGES];
};
static unsigned long loaned_pages;
static unsigned long loaned_pages_target;
static unsigned long oom_freed_pages;
static struct cmm_page_array *cmm_page_list;
static DEFINE_SPINLOCK(cmm_lock);
static struct task_struct *cmm_thread_ptr;
/**
* cmm_alloc_pages - Allocate pages and mark them as loaned
* @nr: number of pages to allocate
*
* Return value:
* number of pages requested to be allocated which were not
**/
static long cmm_alloc_pages(long nr)
{
struct cmm_page_array *pa, *npa;
unsigned long addr;
long rc;
cmm_dbg("Begin request for %ld pages\n", nr);
while (nr) {
addr = __get_free_page(GFP_NOIO | __GFP_NOWARN |
__GFP_NORETRY | __GFP_NOMEMALLOC);
if (!addr)
break;
spin_lock(&cmm_lock);
pa = cmm_page_list;
if (!pa || pa->index >= CMM_NR_PAGES) {
/* Need a new page for the page list. */
spin_unlock(&cmm_lock);
npa = (struct cmm_page_array *)__get_free_page(GFP_NOIO | __GFP_NOWARN |
__GFP_NORETRY | __GFP_NOMEMALLOC);
if (!npa) {
pr_info("%s: Can not allocate new page list\n", __FUNCTION__);
free_page(addr);
break;
}
spin_lock(&cmm_lock);
pa = cmm_page_list;
if (!pa || pa->index >= CMM_NR_PAGES) {
npa->next = pa;
npa->index = 0;
pa = npa;
cmm_page_list = pa;
} else
free_page((unsigned long) npa);
}
if ((rc = plpar_page_set_loaned(__pa(addr)))) {
pr_err("%s: Can not set page to loaned. rc=%ld\n", __FUNCTION__, rc);
spin_unlock(&cmm_lock);
free_page(addr);
break;
}
pa->page[pa->index++] = addr;
loaned_pages++;
totalram_pages--;
spin_unlock(&cmm_lock);
nr--;
}
cmm_dbg("End request with %ld pages unfulfilled\n", nr);
return nr;
}
/**
* cmm_free_pages - Free pages and mark them as active
* @nr: number of pages to free
*
* Return value:
* number of pages requested to be freed which were not
**/
static long cmm_free_pages(long nr)
{
struct cmm_page_array *pa;
unsigned long addr;
cmm_dbg("Begin free of %ld pages.\n", nr);
spin_lock(&cmm_lock);
pa = cmm_page_list;
while (nr) {
if (!pa || pa->index <= 0)
break;
addr = pa->page[--pa->index];
if (pa->index == 0) {
pa = pa->next;
free_page((unsigned long) cmm_page_list);
cmm_page_list = pa;
}
plpar_page_set_active(__pa(addr));
free_page(addr);
loaned_pages--;
nr--;
totalram_pages++;
}
spin_unlock(&cmm_lock);
cmm_dbg("End request with %ld pages unfulfilled\n", nr);
return nr;
}
/**
* cmm_oom_notify - OOM notifier
* @self: notifier block struct
* @dummy: not used
* @parm: returned - number of pages freed
*
* Return value:
* NOTIFY_OK
**/
static int cmm_oom_notify(struct notifier_block *self,
unsigned long dummy, void *parm)
{
unsigned long *freed = parm;
long nr = KB2PAGES(oom_kb);
cmm_dbg("OOM processing started\n");
nr = cmm_free_pages(nr);
loaned_pages_target = loaned_pages;
*freed += KB2PAGES(oom_kb) - nr;
oom_freed_pages += KB2PAGES(oom_kb) - nr;
cmm_dbg("OOM processing complete\n");
return NOTIFY_OK;
}
/**
* cmm_get_mpp - Read memory performance parameters
*
* Makes hcall to query the current page loan request from the hypervisor.
*
* Return value:
* nothing
**/
static void cmm_get_mpp(void)
{
int rc;
struct hvcall_mpp_data mpp_data;
unsigned long active_pages_target;
signed long page_loan_request;
rc = h_get_mpp(&mpp_data);
if (rc != H_SUCCESS)
return;
page_loan_request = div_s64((s64)mpp_data.loan_request, PAGE_SIZE);
loaned_pages_target = page_loan_request + loaned_pages;
if (loaned_pages_target > oom_freed_pages)
loaned_pages_target -= oom_freed_pages;
else
loaned_pages_target = 0;
active_pages_target = totalram_pages + loaned_pages - loaned_pages_target;
if ((min_mem_mb * 1024 * 1024) > (active_pages_target * PAGE_SIZE))
loaned_pages_target = totalram_pages + loaned_pages -
((min_mem_mb * 1024 * 1024) / PAGE_SIZE);
cmm_dbg("delta = %ld, loaned = %lu, target = %lu, oom = %lu, totalram = %lu\n",
page_loan_request, loaned_pages, loaned_pages_target,
oom_freed_pages, totalram_pages);
}
static struct notifier_block cmm_oom_nb = {
.notifier_call = cmm_oom_notify
};
/**
* cmm_thread - CMM task thread
* @dummy: not used
*
* Return value:
* 0
**/
static int cmm_thread(void *dummy)
{
unsigned long timeleft;
while (1) {
timeleft = msleep_interruptible(delay * 1000);
if (kthread_should_stop() || timeleft) {
loaned_pages_target = loaned_pages;
break;
}
cmm_get_mpp();
if (loaned_pages_target > loaned_pages) {
if (cmm_alloc_pages(loaned_pages_target - loaned_pages))
loaned_pages_target = loaned_pages;
} else if (loaned_pages_target < loaned_pages)
cmm_free_pages(loaned_pages - loaned_pages_target);
}
return 0;
}
#define CMM_SHOW(name, format, args...) \
static ssize_t show_##name(struct sys_device *dev, char *buf) \
{ \
return sprintf(buf, format, ##args); \
} \
static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL)
CMM_SHOW(loaned_kb, "%lu\n", PAGES2KB(loaned_pages));
CMM_SHOW(loaned_target_kb, "%lu\n", PAGES2KB(loaned_pages_target));
static ssize_t show_oom_pages(struct sys_device *dev, char *buf)
{
return sprintf(buf, "%lu\n", PAGES2KB(oom_freed_pages));
}
static ssize_t store_oom_pages(struct sys_device *dev,
const char *buf, size_t count)
{
unsigned long val = simple_strtoul (buf, NULL, 10);
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (val != 0)
return -EBADMSG;
oom_freed_pages = 0;
return count;
}
static SYSDEV_ATTR(oom_freed_kb, S_IWUSR| S_IRUGO,
show_oom_pages, store_oom_pages);
static struct sysdev_attribute *cmm_attrs[] = {
&attr_loaned_kb,
&attr_loaned_target_kb,
&attr_oom_freed_kb,
};
static struct sysdev_class cmm_sysdev_class = {
.name = "cmm",
};
/**
* cmm_sysfs_register - Register with sysfs
*
* Return value:
* 0 on success / other on failure
**/
static int cmm_sysfs_register(struct sys_device *sysdev)
{
int i, rc;
if ((rc = sysdev_class_register(&cmm_sysdev_class)))
return rc;
sysdev->id = 0;
sysdev->cls = &cmm_sysdev_class;
if ((rc = sysdev_register(sysdev)))
goto class_unregister;
for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++) {
if ((rc = sysdev_create_file(sysdev, cmm_attrs[i])))
goto fail;
}
return 0;
fail:
while (--i >= 0)
sysdev_remove_file(sysdev, cmm_attrs[i]);
sysdev_unregister(sysdev);
class_unregister:
sysdev_class_unregister(&cmm_sysdev_class);
return rc;
}
/**
* cmm_unregister_sysfs - Unregister from sysfs
*
**/
static void cmm_unregister_sysfs(struct sys_device *sysdev)
{
int i;
for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++)
sysdev_remove_file(sysdev, cmm_attrs[i]);
sysdev_unregister(sysdev);
sysdev_class_unregister(&cmm_sysdev_class);
}
/**
* cmm_init - Module initialization
*
* Return value:
* 0 on success / other on failure
**/
static int cmm_init(void)
{
int rc = -ENOMEM;
if (!firmware_has_feature(FW_FEATURE_CMO))
return -EOPNOTSUPP;
if ((rc = register_oom_notifier(&cmm_oom_nb)) < 0)
return rc;
if ((rc = cmm_sysfs_register(&cmm_sysdev)))
goto out_oom_notifier;
if (cmm_disabled)
return rc;
cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
if (IS_ERR(cmm_thread_ptr)) {
rc = PTR_ERR(cmm_thread_ptr);
goto out_unregister_sysfs;
}
return rc;
out_unregister_sysfs:
cmm_unregister_sysfs(&cmm_sysdev);
out_oom_notifier:
unregister_oom_notifier(&cmm_oom_nb);
return rc;
}
/**
* cmm_exit - Module exit
*
* Return value:
* nothing
**/
static void cmm_exit(void)
{
if (cmm_thread_ptr)
kthread_stop(cmm_thread_ptr);
unregister_oom_notifier(&cmm_oom_nb);
cmm_free_pages(loaned_pages);
cmm_unregister_sysfs(&cmm_sysdev);
}
/**
* cmm_set_disable - Disable/Enable CMM
*
* Return value:
* 0 on success / other on failure
**/
static int cmm_set_disable(const char *val, struct kernel_param *kp)
{
int disable = simple_strtoul(val, NULL, 10);
if (disable != 0 && disable != 1)
return -EINVAL;
if (disable && !cmm_disabled) {
if (cmm_thread_ptr)
kthread_stop(cmm_thread_ptr);
cmm_thread_ptr = NULL;
cmm_free_pages(loaned_pages);
} else if (!disable && cmm_disabled) {
cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
if (IS_ERR(cmm_thread_ptr))
return PTR_ERR(cmm_thread_ptr);
}
cmm_disabled = disable;
return 0;
}
module_param_call(disable, cmm_set_disable, param_get_uint,
&cmm_disabled, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(disable, "Disable CMM. Set to 1 to disable. "
"[Default=" __stringify(CMM_DISABLE) "]");
module_init(cmm_init);
module_exit(cmm_exit);
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