From 84638335900f1995495838fe1bd4870c43ec1f67 Mon Sep 17 00:00:00 2001 From: Konstantin Khlebnikov Date: Thu, 14 Jan 2016 15:22:07 -0800 Subject: [PATCH] mm: rework virtual memory accounting When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which testing the RLIMIT_DATA value to figure out if we're allowed to assign new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been commited that RLIMIT_DATA in a form it's implemented now doesn't do anything useful because most of user-space libraries use mmap() syscall for dynamic memory allocations. Linus suggested to convert RLIMIT_DATA rlimit into something suitable for anonymous memory accounting. But in this patch we go further, and the changes are bundled together as: * keep vma counting if CONFIG_PROC_FS=n, will be used for limits * replace mm->shared_vm with better defined mm->data_vm * account anonymous executable areas as executable * account file-backed growsdown/up areas as stack * drop struct file* argument from vm_stat_account * enforce RLIMIT_DATA for size of data areas This way code looks cleaner: now code/stack/data classification depends only on vm_flags state: VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc) VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk) VM_WRITE & ~VM_SHARED & !stack -> data (VmData) The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called "shared", but that might be strange beast like readonly-private or VM_IO area. - RLIMIT_AS limits whole address space "VmSize" - RLIMIT_STACK limits stack "VmStk" (but each vma individually) - RLIMIT_DATA now limits "VmData" Signed-off-by: Konstantin Khlebnikov Signed-off-by: Cyrill Gorcunov Cc: Quentin Casasnovas Cc: Vegard Nossum Acked-by: Linus Torvalds Cc: Willy Tarreau Cc: Andy Lutomirski Cc: Kees Cook Cc: Vladimir Davydov Cc: Pavel Emelyanov Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/ia64/kernel/perfmon.c | 3 +- fs/proc/task_mmu.c | 7 ++--- include/linux/mm.h | 13 ++------ include/linux/mm_types.h | 2 +- kernel/fork.c | 5 ++- mm/debug.c | 4 +-- mm/mmap.c | 63 +++++++++++++++++++------------------- mm/mprotect.c | 8 +++-- mm/mremap.c | 7 +++-- 9 files changed, 54 insertions(+), 58 deletions(-) diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c index 60e02f7747ff..9cd607b06964 100644 --- a/arch/ia64/kernel/perfmon.c +++ b/arch/ia64/kernel/perfmon.c @@ -2332,8 +2332,7 @@ pfm_smpl_buffer_alloc(struct task_struct *task, struct file *filp, pfm_context_t */ insert_vm_struct(mm, vma); - vm_stat_account(vma->vm_mm, vma->vm_flags, vma->vm_file, - vma_pages(vma)); + vm_stat_account(vma->vm_mm, vma->vm_flags, vma_pages(vma)); up_write(&task->mm->mmap_sem); /* diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 46d9619d0aea..a353b4c6e86e 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -23,7 +23,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm) { - unsigned long data, text, lib, swap, ptes, pmds, anon, file, shmem; + unsigned long text, lib, swap, ptes, pmds, anon, file, shmem; unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss; anon = get_mm_counter(mm, MM_ANONPAGES); @@ -44,7 +44,6 @@ void task_mem(struct seq_file *m, struct mm_struct *mm) if (hiwater_rss < mm->hiwater_rss) hiwater_rss = mm->hiwater_rss; - data = mm->total_vm - mm->shared_vm - mm->stack_vm; text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK)) >> 10; lib = (mm->exec_vm << (PAGE_SHIFT-10)) - text; swap = get_mm_counter(mm, MM_SWAPENTS); @@ -76,7 +75,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm) anon << (PAGE_SHIFT-10), file << (PAGE_SHIFT-10), shmem << (PAGE_SHIFT-10), - data << (PAGE_SHIFT-10), + mm->data_vm << (PAGE_SHIFT-10), mm->stack_vm << (PAGE_SHIFT-10), text, lib, ptes >> 10, pmds >> 10, @@ -97,7 +96,7 @@ unsigned long task_statm(struct mm_struct *mm, get_mm_counter(mm, MM_SHMEMPAGES); *text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK)) >> PAGE_SHIFT; - *data = mm->total_vm - mm->shared_vm; + *data = mm->data_vm + mm->stack_vm; *resident = *shared + get_mm_counter(mm, MM_ANONPAGES); return mm->total_vm; } diff --git a/include/linux/mm.h b/include/linux/mm.h index ec9d4559514d..839d9e9a1c38 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1929,7 +1929,9 @@ extern void mm_drop_all_locks(struct mm_struct *mm); extern void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file); extern struct file *get_mm_exe_file(struct mm_struct *mm); -extern int may_expand_vm(struct mm_struct *mm, unsigned long npages); +extern bool may_expand_vm(struct mm_struct *, vm_flags_t, unsigned long npages); +extern void vm_stat_account(struct mm_struct *, vm_flags_t, long npages); + extern struct vm_area_struct *_install_special_mapping(struct mm_struct *mm, unsigned long addr, unsigned long len, unsigned long flags, @@ -2147,15 +2149,6 @@ typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr, extern int apply_to_page_range(struct mm_struct *mm, unsigned long address, unsigned long size, pte_fn_t fn, void *data); -#ifdef CONFIG_PROC_FS -void vm_stat_account(struct mm_struct *, unsigned long, struct file *, long); -#else -static inline void vm_stat_account(struct mm_struct *mm, - unsigned long flags, struct file *file, long pages) -{ - mm->total_vm += pages; -} -#endif /* CONFIG_PROC_FS */ #ifdef CONFIG_DEBUG_PAGEALLOC extern bool _debug_pagealloc_enabled; diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 207890be93c8..6bc9a0ce2253 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -427,7 +427,7 @@ struct mm_struct { unsigned long total_vm; /* Total pages mapped */ unsigned long locked_vm; /* Pages that have PG_mlocked set */ unsigned long pinned_vm; /* Refcount permanently increased */ - unsigned long shared_vm; /* Shared pages (files) */ + unsigned long data_vm; /* VM_WRITE & ~VM_SHARED/GROWSDOWN */ unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE */ unsigned long stack_vm; /* VM_GROWSUP/DOWN */ unsigned long def_flags; diff --git a/kernel/fork.c b/kernel/fork.c index 51915842f1c0..2e391c754ae7 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -414,7 +414,7 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) RCU_INIT_POINTER(mm->exe_file, get_mm_exe_file(oldmm)); mm->total_vm = oldmm->total_vm; - mm->shared_vm = oldmm->shared_vm; + mm->data_vm = oldmm->data_vm; mm->exec_vm = oldmm->exec_vm; mm->stack_vm = oldmm->stack_vm; @@ -433,8 +433,7 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) struct file *file; if (mpnt->vm_flags & VM_DONTCOPY) { - vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file, - -vma_pages(mpnt)); + vm_stat_account(mm, mpnt->vm_flags, -vma_pages(mpnt)); continue; } charge = 0; diff --git a/mm/debug.c b/mm/debug.c index 668aa35191ca..5d2072ed8d5e 100644 --- a/mm/debug.c +++ b/mm/debug.c @@ -175,7 +175,7 @@ void dump_mm(const struct mm_struct *mm) "mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n" "pgd %p mm_users %d mm_count %d nr_ptes %lu nr_pmds %lu map_count %d\n" "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n" - "pinned_vm %lx shared_vm %lx exec_vm %lx stack_vm %lx\n" + "pinned_vm %lx data_vm %lx exec_vm %lx stack_vm %lx\n" "start_code %lx end_code %lx start_data %lx end_data %lx\n" "start_brk %lx brk %lx start_stack %lx\n" "arg_start %lx arg_end %lx env_start %lx env_end %lx\n" @@ -209,7 +209,7 @@ void dump_mm(const struct mm_struct *mm) mm_nr_pmds((struct mm_struct *)mm), mm->map_count, mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm, - mm->pinned_vm, mm->shared_vm, mm->exec_vm, mm->stack_vm, + mm->pinned_vm, mm->data_vm, mm->exec_vm, mm->stack_vm, mm->start_code, mm->end_code, mm->start_data, mm->end_data, mm->start_brk, mm->brk, mm->start_stack, mm->arg_start, mm->arg_end, mm->env_start, mm->env_end, diff --git a/mm/mmap.c b/mm/mmap.c index f32b84ad621a..b3f00b616b81 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1220,24 +1220,6 @@ none: return NULL; } -#ifdef CONFIG_PROC_FS -void vm_stat_account(struct mm_struct *mm, unsigned long flags, - struct file *file, long pages) -{ - const unsigned long stack_flags - = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN); - - mm->total_vm += pages; - - if (file) { - mm->shared_vm += pages; - if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC) - mm->exec_vm += pages; - } else if (flags & stack_flags) - mm->stack_vm += pages; -} -#endif /* CONFIG_PROC_FS */ - /* * If a hint addr is less than mmap_min_addr change hint to be as * low as possible but still greater than mmap_min_addr @@ -1556,7 +1538,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, unsigned long charged = 0; /* Check against address space limit. */ - if (!may_expand_vm(mm, len >> PAGE_SHIFT)) { + if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) { unsigned long nr_pages; /* @@ -1565,7 +1547,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr, */ nr_pages = count_vma_pages_range(mm, addr, addr + len); - if (!may_expand_vm(mm, (len >> PAGE_SHIFT) - nr_pages)) + if (!may_expand_vm(mm, vm_flags, + (len >> PAGE_SHIFT) - nr_pages)) return -ENOMEM; } @@ -1664,7 +1647,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, out: perf_event_mmap(vma); - vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); + vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT); if (vm_flags & VM_LOCKED) { if (!((vm_flags & VM_SPECIAL) || is_vm_hugetlb_page(vma) || vma == get_gate_vma(current->mm))) @@ -2111,7 +2094,7 @@ static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, uns unsigned long new_start, actual_size; /* address space limit tests */ - if (!may_expand_vm(mm, grow)) + if (!may_expand_vm(mm, vma->vm_flags, grow)) return -ENOMEM; /* Stack limit test */ @@ -2208,8 +2191,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address) spin_lock(&mm->page_table_lock); if (vma->vm_flags & VM_LOCKED) mm->locked_vm += grow; - vm_stat_account(mm, vma->vm_flags, - vma->vm_file, grow); + vm_stat_account(mm, vma->vm_flags, grow); anon_vma_interval_tree_pre_update_vma(vma); vma->vm_end = address; anon_vma_interval_tree_post_update_vma(vma); @@ -2284,8 +2266,7 @@ int expand_downwards(struct vm_area_struct *vma, spin_lock(&mm->page_table_lock); if (vma->vm_flags & VM_LOCKED) mm->locked_vm += grow; - vm_stat_account(mm, vma->vm_flags, - vma->vm_file, grow); + vm_stat_account(mm, vma->vm_flags, grow); anon_vma_interval_tree_pre_update_vma(vma); vma->vm_start = address; vma->vm_pgoff -= grow; @@ -2399,7 +2380,7 @@ static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma) if (vma->vm_flags & VM_ACCOUNT) nr_accounted += nrpages; - vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages); + vm_stat_account(mm, vma->vm_flags, -nrpages); vma = remove_vma(vma); } while (vma); vm_unacct_memory(nr_accounted); @@ -2769,7 +2750,7 @@ static unsigned long do_brk(unsigned long addr, unsigned long len) } /* Check against address space limits *after* clearing old maps... */ - if (!may_expand_vm(mm, len >> PAGE_SHIFT)) + if (!may_expand_vm(mm, flags, len >> PAGE_SHIFT)) return -ENOMEM; if (mm->map_count > sysctl_max_map_count) @@ -2804,6 +2785,7 @@ static unsigned long do_brk(unsigned long addr, unsigned long len) out: perf_event_mmap(vma); mm->total_vm += len >> PAGE_SHIFT; + mm->data_vm += len >> PAGE_SHIFT; if (flags & VM_LOCKED) mm->locked_vm += (len >> PAGE_SHIFT); vma->vm_flags |= VM_SOFTDIRTY; @@ -2995,9 +2977,28 @@ out: * Return true if the calling process may expand its vm space by the passed * number of pages */ -int may_expand_vm(struct mm_struct *mm, unsigned long npages) +bool may_expand_vm(struct mm_struct *mm, vm_flags_t flags, unsigned long npages) { - return mm->total_vm + npages <= rlimit(RLIMIT_AS) >> PAGE_SHIFT; + if (mm->total_vm + npages > rlimit(RLIMIT_AS) >> PAGE_SHIFT) + return false; + + if ((flags & (VM_WRITE | VM_SHARED | (VM_STACK_FLAGS & + (VM_GROWSUP | VM_GROWSDOWN)))) == VM_WRITE) + return mm->data_vm + npages <= rlimit(RLIMIT_DATA); + + return true; +} + +void vm_stat_account(struct mm_struct *mm, vm_flags_t flags, long npages) +{ + mm->total_vm += npages; + + if ((flags & (VM_EXEC | VM_WRITE)) == VM_EXEC) + mm->exec_vm += npages; + else if (flags & (VM_STACK_FLAGS & (VM_GROWSUP | VM_GROWSDOWN))) + mm->stack_vm += npages; + else if ((flags & (VM_WRITE | VM_SHARED)) == VM_WRITE) + mm->data_vm += npages; } static int special_mapping_fault(struct vm_area_struct *vma, @@ -3079,7 +3080,7 @@ static struct vm_area_struct *__install_special_mapping( if (ret) goto out; - mm->total_vm += len >> PAGE_SHIFT; + vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT); perf_event_mmap(vma); diff --git a/mm/mprotect.c b/mm/mprotect.c index ef5be8eaab00..c764402c464f 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -278,6 +278,10 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, * even if read-only so there is no need to account for them here */ if (newflags & VM_WRITE) { + /* Check space limits when area turns into data. */ + if (!may_expand_vm(mm, newflags, nrpages) && + may_expand_vm(mm, oldflags, nrpages)) + return -ENOMEM; if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB| VM_SHARED|VM_NORESERVE))) { charged = nrpages; @@ -334,8 +338,8 @@ success: populate_vma_page_range(vma, start, end, NULL); } - vm_stat_account(mm, oldflags, vma->vm_file, -nrpages); - vm_stat_account(mm, newflags, vma->vm_file, nrpages); + vm_stat_account(mm, oldflags, -nrpages); + vm_stat_account(mm, newflags, nrpages); perf_event_mmap(vma); return 0; diff --git a/mm/mremap.c b/mm/mremap.c index de824e72c3e8..e55b157865d5 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -317,7 +317,7 @@ static unsigned long move_vma(struct vm_area_struct *vma, * If this were a serious issue, we'd add a flag to do_munmap(). */ hiwater_vm = mm->hiwater_vm; - vm_stat_account(mm, vma->vm_flags, vma->vm_file, new_len>>PAGE_SHIFT); + vm_stat_account(mm, vma->vm_flags, new_len >> PAGE_SHIFT); /* Tell pfnmap has moved from this vma */ if (unlikely(vma->vm_flags & VM_PFNMAP)) @@ -383,7 +383,8 @@ static struct vm_area_struct *vma_to_resize(unsigned long addr, return ERR_PTR(-EAGAIN); } - if (!may_expand_vm(mm, (new_len - old_len) >> PAGE_SHIFT)) + if (!may_expand_vm(mm, vma->vm_flags, + (new_len - old_len) >> PAGE_SHIFT)) return ERR_PTR(-ENOMEM); if (vma->vm_flags & VM_ACCOUNT) { @@ -545,7 +546,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, goto out; } - vm_stat_account(mm, vma->vm_flags, vma->vm_file, pages); + vm_stat_account(mm, vma->vm_flags, pages); if (vma->vm_flags & VM_LOCKED) { mm->locked_vm += pages; locked = true; -- 2.20.1