Commit 997071bc authored by K. Y. Srinivasan's avatar K. Y. Srinivasan Committed by Greg Kroah-Hartman
Browse files

mm: export a function to get vm committed memory 



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.

[akpm@linux-foundation.org: coding-style tweak]
Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Acked-by: default avatarDavid Rientjes <rientjes@google.com>
Acked-by: default avatarDan Magenheimer <dan.magenheimer@oracle.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d892de8d

drivers/xen/xen-selfballoon.c

+1 −1
Original line number Diff line number Diff line
@@ -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

include/linux/mman.h

+2 −0
Original line number Diff line number Diff line
@@ -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);

mm/mmap.c

+14 −0
Original line number Diff line number Diff line
@@ -88,6 +88,20 @@ 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

mm/nommu.c

+15 −0
Original line number Diff line number Diff line
@@ -66,6 +66,21 @@ 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);

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