mirror of
https://github.com/brain-hackers/linux-brain.git
synced 2024-06-08 23:14:51 +09:00
mm: deduplicate memory overcommitment code
Currently we have two copies of the same code which implements memory overcommitment logic. Let's move it into mm/util.c and hence avoid duplication. No functional changes here. Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrey Ryabinin
Linus Torvalds
parent
ea606cf5d8
commit
39a1aa8e19
124
mm/mmap.c
124
mm/mmap.c
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@ -122,130 +122,6 @@ void vma_set_page_prot(struct vm_area_struct *vma)
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}
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}
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int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; /* heuristic overcommit */
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int sysctl_overcommit_ratio __read_mostly = 50; /* default is 50% */
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unsigned long sysctl_overcommit_kbytes __read_mostly;
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int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
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unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */
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unsigned long sysctl_admin_reserve_kbytes __read_mostly = 1UL << 13; /* 8MB */
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/*
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* Make sure vm_committed_as in one cacheline and not cacheline shared with
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* other variables. It can be updated by several CPUs frequently.
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*/
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struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp;
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/*
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* The global memory commitment made in the system can be a metric
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* that can be used to drive ballooning decisions when Linux is hosted
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* as a guest. On Hyper-V, the host implements a policy engine for dynamically
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* balancing memory across competing virtual machines that are hosted.
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* Several metrics drive this policy engine including the guest reported
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* memory commitment.
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*/
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unsigned long vm_memory_committed(void)
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{
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return percpu_counter_read_positive(&vm_committed_as);
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}
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EXPORT_SYMBOL_GPL(vm_memory_committed);
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/*
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* Check that a process has enough memory to allocate a new virtual
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* mapping. 0 means there is enough memory for the allocation to
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* succeed and -ENOMEM implies there is not.
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*
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* We currently support three overcommit policies, which are set via the
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* vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
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*
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* Strict overcommit modes added 2002 Feb 26 by Alan Cox.
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* Additional code 2002 Jul 20 by Robert Love.
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*
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* cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
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*
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* Note this is a helper function intended to be used by LSMs which
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* wish to use this logic.
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*/
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int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
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{
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long free, allowed, reserve;
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VM_WARN_ONCE(percpu_counter_read(&vm_committed_as) <
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-(s64)vm_committed_as_batch * num_online_cpus(),
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"memory commitment underflow");
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vm_acct_memory(pages);
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/*
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* Sometimes we want to use more memory than we have
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*/
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if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
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return 0;
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if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
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free = global_page_state(NR_FREE_PAGES);
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free += global_page_state(NR_FILE_PAGES);
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/*
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* shmem pages shouldn't be counted as free in this
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* case, they can't be purged, only swapped out, and
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* that won't affect the overall amount of available
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* memory in the system.
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*/
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free -= global_page_state(NR_SHMEM);
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free += get_nr_swap_pages();
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/*
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* Any slabs which are created with the
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* SLAB_RECLAIM_ACCOUNT flag claim to have contents
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* which are reclaimable, under pressure. The dentry
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* cache and most inode caches should fall into this
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*/
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free += global_page_state(NR_SLAB_RECLAIMABLE);
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/*
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* Leave reserved pages. The pages are not for anonymous pages.
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*/
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if (free <= totalreserve_pages)
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goto error;
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else
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free -= totalreserve_pages;
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/*
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* Reserve some for root
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*/
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if (!cap_sys_admin)
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free -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
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if (free > pages)
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return 0;
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goto error;
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}
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allowed = vm_commit_limit();
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/*
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* Reserve some for root
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*/
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if (!cap_sys_admin)
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allowed -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
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/*
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* Don't let a single process grow so big a user can't recover
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*/
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if (mm) {
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reserve = sysctl_user_reserve_kbytes >> (PAGE_SHIFT - 10);
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allowed -= min_t(long, mm->total_vm / 32, reserve);
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}
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if (percpu_counter_read_positive(&vm_committed_as) < allowed)
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return 0;
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error:
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vm_unacct_memory(pages);
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return -ENOMEM;
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}
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/*
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* Requires inode->i_mapping->i_mmap_rwsem
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*/
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116
mm/nommu.c
116
mm/nommu.c
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@ -47,33 +47,11 @@ struct page *mem_map;
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unsigned long max_mapnr;
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EXPORT_SYMBOL(max_mapnr);
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unsigned long highest_memmap_pfn;
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struct percpu_counter vm_committed_as;
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int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
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int sysctl_overcommit_ratio = 50; /* default is 50% */
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unsigned long sysctl_overcommit_kbytes __read_mostly;
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int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
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int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
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unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */
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unsigned long sysctl_admin_reserve_kbytes __read_mostly = 1UL << 13; /* 8MB */
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int heap_stack_gap = 0;
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atomic_long_t mmap_pages_allocated;
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/*
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* The global memory commitment made in the system can be a metric
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* that can be used to drive ballooning decisions when Linux is hosted
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* as a guest. On Hyper-V, the host implements a policy engine for dynamically
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* balancing memory across competing virtual machines that are hosted.
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* Several metrics drive this policy engine including the guest reported
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* memory commitment.
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*/
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unsigned long vm_memory_committed(void)
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{
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return percpu_counter_read_positive(&vm_committed_as);
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}
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EXPORT_SYMBOL_GPL(vm_memory_committed);
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EXPORT_SYMBOL(mem_map);
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/* list of mapped, potentially shareable regions */
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@ -1828,100 +1806,6 @@ void unmap_mapping_range(struct address_space *mapping,
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}
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EXPORT_SYMBOL(unmap_mapping_range);
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/*
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* Check that a process has enough memory to allocate a new virtual
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* mapping. 0 means there is enough memory for the allocation to
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* succeed and -ENOMEM implies there is not.
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*
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* We currently support three overcommit policies, which are set via the
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* vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
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*
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* Strict overcommit modes added 2002 Feb 26 by Alan Cox.
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* Additional code 2002 Jul 20 by Robert Love.
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*
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* cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
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*
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* Note this is a helper function intended to be used by LSMs which
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* wish to use this logic.
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*/
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int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
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{
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long free, allowed, reserve;
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vm_acct_memory(pages);
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/*
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* Sometimes we want to use more memory than we have
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*/
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if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
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return 0;
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if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
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free = global_page_state(NR_FREE_PAGES);
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free += global_page_state(NR_FILE_PAGES);
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/*
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* shmem pages shouldn't be counted as free in this
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* case, they can't be purged, only swapped out, and
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* that won't affect the overall amount of available
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* memory in the system.
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*/
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free -= global_page_state(NR_SHMEM);
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free += get_nr_swap_pages();
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/*
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* Any slabs which are created with the
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* SLAB_RECLAIM_ACCOUNT flag claim to have contents
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* which are reclaimable, under pressure. The dentry
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* cache and most inode caches should fall into this
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*/
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free += global_page_state(NR_SLAB_RECLAIMABLE);
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/*
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* Leave reserved pages. The pages are not for anonymous pages.
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*/
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if (free <= totalreserve_pages)
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goto error;
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else
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free -= totalreserve_pages;
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/*
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* Reserve some for root
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*/
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if (!cap_sys_admin)
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free -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
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if (free > pages)
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return 0;
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goto error;
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}
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allowed = vm_commit_limit();
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/*
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* Reserve some 3% for root
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*/
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if (!cap_sys_admin)
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allowed -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
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/*
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* Don't let a single process grow so big a user can't recover
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*/
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if (mm) {
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reserve = sysctl_user_reserve_kbytes >> (PAGE_SHIFT - 10);
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allowed -= min_t(long, mm->total_vm / 32, reserve);
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}
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if (percpu_counter_read_positive(&vm_committed_as) < allowed)
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return 0;
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error:
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vm_unacct_memory(pages);
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return -ENOMEM;
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}
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int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
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{
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BUG();
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124
mm/util.c
124
mm/util.c
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@ -396,6 +396,13 @@ int __page_mapcount(struct page *page)
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}
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EXPORT_SYMBOL_GPL(__page_mapcount);
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int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS;
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int sysctl_overcommit_ratio __read_mostly = 50;
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unsigned long sysctl_overcommit_kbytes __read_mostly;
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int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
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unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */
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unsigned long sysctl_admin_reserve_kbytes __read_mostly = 1UL << 13; /* 8MB */
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int overcommit_ratio_handler(struct ctl_table *table, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos)
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@ -437,6 +444,123 @@ unsigned long vm_commit_limit(void)
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return allowed;
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}
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/*
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* Make sure vm_committed_as in one cacheline and not cacheline shared with
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* other variables. It can be updated by several CPUs frequently.
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*/
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struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp;
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/*
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* The global memory commitment made in the system can be a metric
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* that can be used to drive ballooning decisions when Linux is hosted
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* as a guest. On Hyper-V, the host implements a policy engine for dynamically
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* balancing memory across competing virtual machines that are hosted.
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* Several metrics drive this policy engine including the guest reported
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* memory commitment.
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*/
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unsigned long vm_memory_committed(void)
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{
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return percpu_counter_read_positive(&vm_committed_as);
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}
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EXPORT_SYMBOL_GPL(vm_memory_committed);
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/*
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* Check that a process has enough memory to allocate a new virtual
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* mapping. 0 means there is enough memory for the allocation to
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* succeed and -ENOMEM implies there is not.
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*
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* We currently support three overcommit policies, which are set via the
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* vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
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*
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* Strict overcommit modes added 2002 Feb 26 by Alan Cox.
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* Additional code 2002 Jul 20 by Robert Love.
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*
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* cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
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*
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* Note this is a helper function intended to be used by LSMs which
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* wish to use this logic.
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*/
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int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
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{
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long free, allowed, reserve;
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VM_WARN_ONCE(percpu_counter_read(&vm_committed_as) <
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-(s64)vm_committed_as_batch * num_online_cpus(),
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"memory commitment underflow");
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vm_acct_memory(pages);
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/*
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* Sometimes we want to use more memory than we have
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*/
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if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
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return 0;
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if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
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free = global_page_state(NR_FREE_PAGES);
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free += global_page_state(NR_FILE_PAGES);
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/*
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* shmem pages shouldn't be counted as free in this
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* case, they can't be purged, only swapped out, and
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* that won't affect the overall amount of available
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* memory in the system.
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*/
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free -= global_page_state(NR_SHMEM);
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free += get_nr_swap_pages();
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/*
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* Any slabs which are created with the
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* SLAB_RECLAIM_ACCOUNT flag claim to have contents
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* which are reclaimable, under pressure. The dentry
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* cache and most inode caches should fall into this
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*/
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free += global_page_state(NR_SLAB_RECLAIMABLE);
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/*
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* Leave reserved pages. The pages are not for anonymous pages.
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*/
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if (free <= totalreserve_pages)
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goto error;
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else
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free -= totalreserve_pages;
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/*
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* Reserve some for root
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*/
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if (!cap_sys_admin)
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free -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
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if (free > pages)
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return 0;
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goto error;
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}
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allowed = vm_commit_limit();
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/*
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* Reserve some for root
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*/
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if (!cap_sys_admin)
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allowed -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
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/*
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* Don't let a single process grow so big a user can't recover
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*/
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if (mm) {
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reserve = sysctl_user_reserve_kbytes >> (PAGE_SHIFT - 10);
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allowed -= min_t(long, mm->total_vm / 32, reserve);
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}
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if (percpu_counter_read_positive(&vm_committed_as) < allowed)
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return 0;
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error:
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vm_unacct_memory(pages);
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return -ENOMEM;
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}
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/**
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* get_cmdline() - copy the cmdline value to a buffer.
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* @task: the task whose cmdline value to copy.
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