From 8be8cf5b47f72096e42bf88cc3afff7a942a346c Mon Sep 17 00:00:00 2001 From: Brian King Date: Mon, 19 Oct 2009 05:51:34 +0000 Subject: [PATCH] powerpc: Add kdump support to Collaborative Memory Manager When running Active Memory Sharing, the Collaborative Memory Manager (CMM) may mark some pages as "loaned" with the hypervisor. Periodically, the CMM will query the hypervisor for a loan request, which is a single signed value. When kexec'ing into a kdump kernel, the CMM driver in the kdump kernel is not aware of the pages the previous kernel had marked as "loaned", so the hypervisor and the CMM driver are out of sync. Fix the CMM driver to handle this scenario by ignoring requests to decrease the number of loaned pages if we don't think we have any pages loaned. Pages that are marked as "loaned" which are not in the balloon will automatically get switched to "active" the next time we touch the page. This also fixes the case where totalram_pages is smaller than min_mem_mb, which can occur during kdump. Signed-off-by: Brian King Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/platforms/pseries/Kconfig | 2 +- arch/powerpc/platforms/pseries/cmm.c | 29 +++++++++++++++++--------- 2 files changed, 20 insertions(+), 11 deletions(-) diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig index 26a24bd92623..27554c807fd5 100644 --- a/arch/powerpc/platforms/pseries/Kconfig +++ b/arch/powerpc/platforms/pseries/Kconfig @@ -60,7 +60,7 @@ config PPC_SMLPAR config CMM tristate "Collaborative memory management" - depends on PPC_SMLPAR && !CRASH_DUMP + depends on PPC_SMLPAR default y help Select this option, if you want to enable the kernel interface diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c index 6567439fe78d..bcdcf0ccc8d7 100644 --- a/arch/powerpc/platforms/pseries/cmm.c +++ b/arch/powerpc/platforms/pseries/cmm.c @@ -229,8 +229,9 @@ static void cmm_get_mpp(void) { int rc; struct hvcall_mpp_data mpp_data; - unsigned long active_pages_target; - signed long page_loan_request; + signed long active_pages_target, page_loan_request, target; + signed long total_pages = totalram_pages + loaned_pages; + signed long min_mem_pages = (min_mem_mb * 1024 * 1024) / PAGE_SIZE; rc = h_get_mpp(&mpp_data); @@ -238,17 +239,25 @@ static void cmm_get_mpp(void) 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; + target = page_loan_request + (signed long)loaned_pages; + + if (target < 0 || total_pages < min_mem_pages) + target = 0; + + if (target > oom_freed_pages) + target -= oom_freed_pages; else - loaned_pages_target = 0; + target = 0; + + active_pages_target = total_pages - target; + + if (min_mem_pages > active_pages_target) + target = total_pages - min_mem_pages; - active_pages_target = totalram_pages + loaned_pages - loaned_pages_target; + if (target < 0) + target = 0; - 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); + loaned_pages_target = target; cmm_dbg("delta = %ld, loaned = %lu, target = %lu, oom = %lu, totalram = %lu\n", page_loan_request, loaned_pages, loaned_pages_target, -- 2.20.1