From b1713975c31ae20ecc40fd00191ee3fa51445d4a Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Thu, 31 Oct 2019 15:29:31 +0100 Subject: [PATCH] powerpc/pseries/cmm: Simulation mode Let's allow to test the implementation without needing HW support. When "simulate=1" is specified when loading the module, we bypass all HW checks and HW calls. The sysfs file "simulate_loan_target_kb" can be used to simulate HW requests. The simualtion mode can be activated using: modprobe cmm debug=1 simulate=1 And the requested loan target can be changed using: echo X > /sys/devices/system/cmm/cmm0/simulate_loan_target_kb Signed-off-by: David Hildenbrand Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20191031142933.10779-11-david@redhat.com --- arch/powerpc/platforms/pseries/cmm.c | 38 ++++++++++++++++++++++------ 1 file changed, 30 insertions(+), 8 deletions(-) diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c index 86eb845b4737..91571841df8a 100644 --- a/arch/powerpc/platforms/pseries/cmm.c +++ b/arch/powerpc/platforms/pseries/cmm.c @@ -51,6 +51,8 @@ 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 bool __read_mostly simulate; +static unsigned long simulate_loan_target_kb; static struct device cmm_dev; MODULE_AUTHOR("Brian King "); @@ -74,6 +76,8 @@ MODULE_PARM_DESC(min_mem_mb, "Minimum amount of memory (in MB) to not balloon. " module_param_named(debug, cmm_debug, uint, 0644); MODULE_PARM_DESC(debug, "Enable module debugging logging. Set to 1 to enable. " "[Default=" __stringify(CMM_DEBUG) "]"); +module_param_named(simulate, simulate, bool, 0444); +MODULE_PARM_DESC(simulate, "Enable simulation mode (no communication with hw)."); #define cmm_dbg(...) if (cmm_debug) { printk(KERN_INFO "cmm: "__VA_ARGS__); } @@ -94,6 +98,9 @@ static long plpar_page_set_loaned(struct page *page) long rc = 0; int i; + if (unlikely(simulate)) + return 0; + for (i = 0; !rc && i < PAGE_SIZE; i += cmo_page_sz) rc = plpar_hcall_norets(H_PAGE_INIT, H_PAGE_SET_LOANED, vpa + i, 0); @@ -111,6 +118,9 @@ static long plpar_page_set_active(struct page *page) long rc = 0; int i; + if (unlikely(simulate)) + return 0; + for (i = 0; !rc && i < PAGE_SIZE; i += cmo_page_sz) rc = plpar_hcall_norets(H_PAGE_INIT, H_PAGE_SET_ACTIVE, vpa + i, 0); @@ -234,13 +244,17 @@ static void cmm_get_mpp(void) signed long active_pages_target, page_loan_request, target; signed long min_mem_pages = (min_mem_mb * 1024 * 1024) / PAGE_SIZE; - rc = h_get_mpp(&mpp_data); - - if (rc != H_SUCCESS) - return; - - page_loan_request = div_s64((s64)mpp_data.loan_request, PAGE_SIZE); - target = page_loan_request + __loaned_pages; + if (likely(!simulate)) { + rc = h_get_mpp(&mpp_data); + if (rc != H_SUCCESS) + return; + page_loan_request = div_s64((s64)mpp_data.loan_request, + PAGE_SIZE); + target = page_loan_request + __loaned_pages; + } else { + target = KB2PAGES(simulate_loan_target_kb); + page_loan_request = target - __loaned_pages; + } if (target < 0 || total_pages < min_mem_pages) target = 0; @@ -362,6 +376,9 @@ static struct device_attribute *cmm_attrs[] = { &dev_attr_oom_freed_kb, }; +static DEVICE_ULONG_ATTR(simulate_loan_target_kb, 0644, + simulate_loan_target_kb); + static struct bus_type cmm_subsys = { .name = "cmm", .dev_name = "cmm", @@ -396,6 +413,11 @@ static int cmm_sysfs_register(struct device *dev) goto fail; } + if (!simulate) + return 0; + rc = device_create_file(dev, &dev_attr_simulate_loan_target_kb.attr); + if (rc) + goto fail; return 0; fail: @@ -590,7 +612,7 @@ static int cmm_init(void) { int rc; - if (!firmware_has_feature(FW_FEATURE_CMO)) + if (!firmware_has_feature(FW_FEATURE_CMO) && !simulate) return -EOPNOTSUPP; rc = cmm_balloon_compaction_init(); -- 2.30.2