The patch titled Subject: mm: export a function to get vm committed memory has been added to the -mm tree. Its filename is mm-export-a-function-to-get-vm-committed-memory.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx> Subject: 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. Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> Cc: Greg KH <greg@xxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Acked-by: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx> Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- 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 deletion(-) diff -puN drivers/xen/xen-selfballoon.c~mm-export-a-function-to-get-vm-committed-memory drivers/xen/xen-selfballoon.c --- a/drivers/xen/xen-selfballoon.c~mm-export-a-function-to-get-vm-committed-memory +++ a/drivers/xen/xen-selfballoon.c @@ -222,7 +222,7 @@ static void selfballoon_process(struct w 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 -puN include/linux/mman.h~mm-export-a-function-to-get-vm-committed-memory include/linux/mman.h --- a/include/linux/mman.h~mm-export-a-function-to-get-vm-committed-memory +++ a/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 -puN mm/mmap.c~mm-export-a-function-to-get-vm-committed-memory mm/mmap.c --- a/mm/mmap.c~mm-export-a-function-to-get-vm-committed-memory +++ a/mm/mmap.c @@ -90,6 +90,21 @@ int sysctl_max_map_count __read_mostly = 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 -puN mm/nommu.c~mm-export-a-function-to-get-vm-committed-memory mm/nommu.c --- a/mm/nommu.c~mm-export-a-function-to-get-vm-committed-memory +++ a/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); _ Patches currently in -mm which might be from kys@xxxxxxxxxxxxx are linux-next.patch mm-export-a-function-to-get-vm-committed-memory.patch mm-export-a-function-to-get-vm-committed-memory-fix.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html