From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx131.postini.com [74.125.245.131]) by kanga.kvack.org (Postfix) with SMTP id DBD186B0081 for ; Tue, 13 Nov 2012 09:40:31 -0500 (EST) From: "K. Y. Srinivasan" Subject: [PATCH 1/1] mm: Export a function to get vm committed memory Date: Tue, 13 Nov 2012 07:02:37 -0800 Message-Id: <1352818957-9229-1-git-send-email-kys@microsoft.com> Sender: owner-linux-mm@kvack.org List-ID: To: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com, andi@firstfloor.org, akpm@linux-foundation.org, linux-mm@kvack.org, kamezawa.hiroyuki@gmail.com, mhocko@suse.cz, hannes@cmpxchg.org, yinghan@google.com, dan.magenheimer@oracle.com, konrad.wilk@oracle.com Cc: "K. Y. Srinivasan" It will be useful to be able to access global memory commitment from device drivers. On the Hyper-V platform, the host has a policy engine to balance the available physical memory amongst all competing virtual machines hosted on a given node. This policy engine is driven by a number of metrics including the memory commitment reported by the guests. The balloon driver for Linux on Hyper-V will use this function to retrieve guest memory commitment. This function is also used in Xen self ballooning code. Signed-off-by: K. Y. Srinivasan --- drivers/xen/xen-selfballoon.c | 2 +- include/linux/mman.h | 2 ++ mm/mmap.c | 15 +++++++++++++++ mm/nommu.c | 16 ++++++++++++++++ 4 files changed, 34 insertions(+), 1 deletions(-) diff --git a/drivers/xen/xen-selfballoon.c b/drivers/xen/xen-selfballoon.c index 7d041cb..2552d3e 100644 --- a/drivers/xen/xen-selfballoon.c +++ b/drivers/xen/xen-selfballoon.c @@ -222,7 +222,7 @@ static void selfballoon_process(struct work_struct *work) if (xen_selfballooning_enabled) { cur_pages = totalram_pages; tgt_pages = cur_pages; /* default is no change */ - goal_pages = percpu_counter_read_positive(&vm_committed_as) + + goal_pages = vm_memory_committed() + totalreserve_pages + MB2PAGES(selfballoon_reserved_mb); #ifdef CONFIG_FRONTSWAP diff --git a/include/linux/mman.h b/include/linux/mman.h index d09dde1..9aa863d 100644 --- a/include/linux/mman.h +++ b/include/linux/mman.h @@ -11,6 +11,8 @@ extern int sysctl_overcommit_memory; extern int sysctl_overcommit_ratio; extern struct percpu_counter vm_committed_as; +unsigned long vm_memory_committed(void); + static inline void vm_acct_memory(long pages) { percpu_counter_add(&vm_committed_as, pages); diff --git a/mm/mmap.c b/mm/mmap.c index 2d94235..3dd0a17 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -89,6 +89,21 @@ int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp; /* + * The global memory commitment made in the system can be a metric + * that can be used to drive ballooning decisions when Linux is hosted + * as a guest. On Hyper-V, the host implements a policy engine for dynamically + * balancing memory across competing virtual machines that are hosted. + * Several metrics drive this policy engine including the guest reported + * memory commitment. + */ + +unsigned long vm_memory_committed(void) +{ + return percpu_counter_read_positive(&vm_committed_as); +} +EXPORT_SYMBOL_GPL(vm_memory_committed); + +/* * Check that a process has enough memory to allocate a new virtual * mapping. 0 means there is enough memory for the allocation to * succeed and -ENOMEM implies there is not. diff --git a/mm/nommu.c b/mm/nommu.c index 45131b4..f11e703 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -66,6 +66,22 @@ int heap_stack_gap = 0; atomic_long_t mmap_pages_allocated; +/* + * The global memory commitment made in the system can be a metric + * that can be used to drive ballooning decisions when Linux is hosted + * as a guest. On Hyper-V, the host implements a policy engine for dynamically + * balancing memory across competing virtual machines that are hosted. + * Several metrics drive this policy engine including the guest reported + * memory commitment. + */ + +unsigned long vm_memory_committed(void) +{ + return percpu_counter_read_positive(&vm_committed_as); +} + +EXPORT_SYMBOL_GPL(vm_memory_committed); + EXPORT_SYMBOL(mem_map); EXPORT_SYMBOL(num_physpages); -- 1.7.4.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org