From 14f966e79445015cd89d0fa0ceb6b33702e951b6 Mon Sep 17 00:00:00 2001 From: Robert Jennings Date: Wed, 15 Apr 2009 05:55:32 +0000 Subject: powerpc/pseries: CMO unused page hinting Adds support for the "unused" page hint which can be used in shared memory partitions to flag pages not in use, which will then be stolen before active pages by the hypervisor when memory needs to be moved to LPARs in need of additional memory. Failure to mark pages as 'unused' makes the LPAR slower to give up unused memory to other partitions. This adds the kernel parameter 'cmo_free_hint' to disable this functionality. Signed-off-by: Brian King Signed-off-by: Robert Jennings Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/platforms/pseries/lpar.c | 52 +++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) (limited to 'arch/powerpc/platforms/pseries') diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c index 52a80e5840e..e3139fa5e55 100644 --- a/arch/powerpc/platforms/pseries/lpar.c +++ b/arch/powerpc/platforms/pseries/lpar.c @@ -609,3 +609,55 @@ void __init hpte_init_lpar(void) ppc_md.flush_hash_range = pSeries_lpar_flush_hash_range; ppc_md.hpte_clear_all = pSeries_lpar_hptab_clear; } + +#ifdef CONFIG_PPC_SMLPAR +#define CMO_FREE_HINT_DEFAULT 1 +static int cmo_free_hint_flag = CMO_FREE_HINT_DEFAULT; + +static int __init cmo_free_hint(char *str) +{ + char *parm; + parm = strstrip(str); + + if (strcasecmp(parm, "no") == 0 || strcasecmp(parm, "off") == 0) { + printk(KERN_INFO "cmo_free_hint: CMO free page hinting is not active.\n"); + cmo_free_hint_flag = 0; + return 1; + } + + cmo_free_hint_flag = 1; + printk(KERN_INFO "cmo_free_hint: CMO free page hinting is active.\n"); + + if (strcasecmp(parm, "yes") == 0 || strcasecmp(parm, "on") == 0) + return 1; + + return 0; +} + +__setup("cmo_free_hint=", cmo_free_hint); + +static void pSeries_set_page_state(struct page *page, int order, + unsigned long state) +{ + int i, j; + unsigned long cmo_page_sz, addr; + + cmo_page_sz = cmo_get_page_size(); + addr = __pa((unsigned long)page_address(page)); + + for (i = 0; i < (1 << order); i++, addr += PAGE_SIZE) { + for (j = 0; j < PAGE_SIZE; j += cmo_page_sz) + plpar_hcall_norets(H_PAGE_INIT, state, addr + j, 0); + } +} + +void arch_free_page(struct page *page, int order) +{ + if (!cmo_free_hint_flag || !firmware_has_feature(FW_FEATURE_CMO)) + return; + + pSeries_set_page_state(page, order, H_PAGE_SET_UNUSED); +} +EXPORT_SYMBOL(arch_free_page); + +#endif -- cgit v1.2.3