diff options
Diffstat (limited to 'drivers/xen/xen-selfballoon.c')
| -rw-r--r-- | drivers/xen/xen-selfballoon.c | 142 |
1 files changed, 72 insertions, 70 deletions
diff --git a/drivers/xen/xen-selfballoon.c b/drivers/xen/xen-selfballoon.c index 2552d3e0a70..3b2bffde534 100644 --- a/drivers/xen/xen-selfballoon.c +++ b/drivers/xen/xen-selfballoon.c @@ -53,20 +53,19 @@ * System configuration note: Selfballooning should not be enabled on * systems without a sufficiently large swap device configured; for best * results, it is recommended that total swap be increased by the size - * of the guest memory. Also, while technically not required to be - * configured, it is highly recommended that frontswap also be configured - * and enabled when selfballooning is running. So, selfballooning - * is disabled by default if frontswap is not configured and can only - * be enabled with the "selfballooning" kernel boot option; similarly - * selfballooning is enabled by default if frontswap is configured and - * can be disabled with the "noselfballooning" kernel boot option. Finally, - * when frontswap is configured, frontswap-selfshrinking can be disabled - * with the "noselfshrink" kernel boot option. + * of the guest memory. Note, that selfballooning should be disabled by default + * if frontswap is not configured. Similarly selfballooning should be enabled + * by default if frontswap is configured and can be disabled with the + * "tmem.selfballooning=0" kernel boot option. Finally, when frontswap is + * configured, frontswap-selfshrinking can be disabled with the + * "tmem.selfshrink=0" kernel boot option. * * Selfballooning is disallowed in domain0 and force-disabled. * */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + #include <linux/kernel.h> #include <linux/bootmem.h> #include <linux/swap.h> @@ -120,9 +119,6 @@ static DECLARE_DELAYED_WORK(selfballoon_worker, selfballoon_process); /* Enable/disable with sysfs. */ static bool frontswap_selfshrinking __read_mostly; -/* Enable/disable with kernel boot option. */ -static bool use_frontswap_selfshrink __initdata = true; - /* * The default values for the following parameters were deemed reasonable * by experimentation, may be workload-dependent, and can all be @@ -174,40 +170,13 @@ static void frontswap_selfshrink(void) tgt_frontswap_pages = cur_frontswap_pages - (cur_frontswap_pages / frontswap_hysteresis); frontswap_shrink(tgt_frontswap_pages); + frontswap_inertia_counter = frontswap_inertia; } -static int __init xen_nofrontswap_selfshrink_setup(char *s) -{ - use_frontswap_selfshrink = false; - return 1; -} - -__setup("noselfshrink", xen_nofrontswap_selfshrink_setup); - -/* Disable with kernel boot option. */ -static bool use_selfballooning __initdata = true; - -static int __init xen_noselfballooning_setup(char *s) -{ - use_selfballooning = false; - return 1; -} - -__setup("noselfballooning", xen_noselfballooning_setup); -#else /* !CONFIG_FRONTSWAP */ -/* Enable with kernel boot option. */ -static bool use_selfballooning __initdata = false; - -static int __init xen_selfballooning_setup(char *s) -{ - use_selfballooning = true; - return 1; -} - -__setup("selfballooning", xen_selfballooning_setup); #endif /* CONFIG_FRONTSWAP */ #define MB2PAGES(mb) ((mb) << (20 - PAGE_SHIFT)) +#define PAGES2MB(pages) ((pages) >> (20 - PAGE_SHIFT)) /* * Use current balloon size, the goal (vm_committed_as), and hysteresis @@ -298,8 +267,10 @@ static ssize_t store_selfballooning(struct device *dev, if (!capable(CAP_SYS_ADMIN)) return -EPERM; - err = strict_strtoul(buf, 10, &tmp); - if (err || ((tmp != 0) && (tmp != 1))) + err = kstrtoul(buf, 10, &tmp); + if (err) + return err; + if ((tmp != 0) && (tmp != 1)) return -EINVAL; xen_selfballooning_enabled = !!tmp; @@ -325,8 +296,10 @@ static ssize_t store_selfballoon_interval(struct device *dev, if (!capable(CAP_SYS_ADMIN)) return -EPERM; - err = strict_strtoul(buf, 10, &val); - if (err || val == 0) + err = kstrtoul(buf, 10, &val); + if (err) + return err; + if (val == 0) return -EINVAL; selfballoon_interval = val; return count; @@ -347,8 +320,10 @@ static ssize_t store_selfballoon_downhys(struct device *dev, if (!capable(CAP_SYS_ADMIN)) return -EPERM; - err = strict_strtoul(buf, 10, &val); - if (err || val == 0) + err = kstrtoul(buf, 10, &val); + if (err) + return err; + if (val == 0) return -EINVAL; selfballoon_downhysteresis = val; return count; @@ -370,8 +345,10 @@ static ssize_t store_selfballoon_uphys(struct device *dev, if (!capable(CAP_SYS_ADMIN)) return -EPERM; - err = strict_strtoul(buf, 10, &val); - if (err || val == 0) + err = kstrtoul(buf, 10, &val); + if (err) + return err; + if (val == 0) return -EINVAL; selfballoon_uphysteresis = val; return count; @@ -393,8 +370,10 @@ static ssize_t store_selfballoon_min_usable_mb(struct device *dev, if (!capable(CAP_SYS_ADMIN)) return -EPERM; - err = strict_strtoul(buf, 10, &val); - if (err || val == 0) + err = kstrtoul(buf, 10, &val); + if (err) + return err; + if (val == 0) return -EINVAL; selfballoon_min_usable_mb = val; return count; @@ -417,8 +396,10 @@ static ssize_t store_selfballoon_reserved_mb(struct device *dev, if (!capable(CAP_SYS_ADMIN)) return -EPERM; - err = strict_strtoul(buf, 10, &val); - if (err || val == 0) + err = kstrtoul(buf, 10, &val); + if (err) + return err; + if (val == 0) return -EINVAL; selfballoon_reserved_mb = val; return count; @@ -443,8 +424,10 @@ static ssize_t store_frontswap_selfshrinking(struct device *dev, if (!capable(CAP_SYS_ADMIN)) return -EPERM; - err = strict_strtoul(buf, 10, &tmp); - if (err || ((tmp != 0) && (tmp != 1))) + err = kstrtoul(buf, 10, &tmp); + if (err) + return err; + if ((tmp != 0) && (tmp != 1)) return -EINVAL; frontswap_selfshrinking = !!tmp; if (!was_enabled && !xen_selfballooning_enabled && @@ -470,8 +453,10 @@ static ssize_t store_frontswap_inertia(struct device *dev, if (!capable(CAP_SYS_ADMIN)) return -EPERM; - err = strict_strtoul(buf, 10, &val); - if (err || val == 0) + err = kstrtoul(buf, 10, &val); + if (err) + return err; + if (val == 0) return -EINVAL; frontswap_inertia = val; frontswap_inertia_counter = val; @@ -493,8 +478,10 @@ static ssize_t store_frontswap_hysteresis(struct device *dev, if (!capable(CAP_SYS_ADMIN)) return -EPERM; - err = strict_strtoul(buf, 10, &val); - if (err || val == 0) + err = kstrtoul(buf, 10, &val); + if (err) + return err; + if (val == 0) return -EINVAL; frontswap_hysteresis = val; return count; @@ -537,41 +524,56 @@ int register_xen_selfballooning(struct device *dev) } EXPORT_SYMBOL(register_xen_selfballooning); -static int __init xen_selfballoon_init(void) +int xen_selfballoon_init(bool use_selfballooning, bool use_frontswap_selfshrink) { bool enable = false; + unsigned long reserve_pages; if (!xen_domain()) return -ENODEV; if (xen_initial_domain()) { - pr_info("xen/balloon: Xen selfballooning driver " - "disabled for domain0.\n"); + pr_info("Xen selfballooning driver disabled for domain0\n"); return -ENODEV; } xen_selfballooning_enabled = tmem_enabled && use_selfballooning; if (xen_selfballooning_enabled) { - pr_info("xen/balloon: Initializing Xen " - "selfballooning driver.\n"); + pr_info("Initializing Xen selfballooning driver\n"); enable = true; } #ifdef CONFIG_FRONTSWAP frontswap_selfshrinking = tmem_enabled && use_frontswap_selfshrink; if (frontswap_selfshrinking) { - pr_info("xen/balloon: Initializing frontswap " - "selfshrinking driver.\n"); + pr_info("Initializing frontswap selfshrinking driver\n"); enable = true; } #endif if (!enable) return -ENODEV; + /* + * Give selfballoon_reserved_mb a default value(10% of total ram pages) + * to make selfballoon not so aggressive. + * + * There are mainly two reasons: + * 1) The original goal_page didn't consider some pages used by kernel + * space, like slab pages and memory used by device drivers. + * + * 2) The balloon driver may not give back memory to guest OS fast + * enough when the workload suddenly aquries a lot of physical memory. + * + * In both cases, the guest OS will suffer from memory pressure and + * OOM killer may be triggered. + * By reserving extra 10% of total ram pages, we can keep the system + * much more reliably and response faster in some cases. + */ + if (!selfballoon_reserved_mb) { + reserve_pages = totalram_pages / 10; + selfballoon_reserved_mb = PAGES2MB(reserve_pages); + } schedule_delayed_work(&selfballoon_worker, selfballoon_interval * HZ); return 0; } - -subsys_initcall(xen_selfballoon_init); - -MODULE_LICENSE("GPL"); +EXPORT_SYMBOL(xen_selfballoon_init); |