kernel.git/mm/mremap.c, branch linux-4.6.y

mm: cleanup pte_alloc interfaces

2016-03-17T22:09:34Z

There are few things about *pte_alloc*() helpers worth cleaning up: - 'vma' argument is unused, let's drop it; - most __pte_alloc() callers do speculative check for pmd_none(), before taking ptl: let's introduce pte_alloc() macro which does the check. The only direct user of __pte_alloc left is userfaultfd, which has different expectation about atomicity wrt pmd. - pte_alloc_map() and pte_alloc_map_lock() are redefined using pte_alloc(). [sudeep.holla@arm.com: fix build for arm64 hugetlbpage] [sfr@canb.auug.org.au: fix arch/arm/mm/mmu.c some more] Signed-off-by: Kirill A. Shutemov Cc: Dave Hansen Signed-off-by: Sudeep Holla Acked-by: Kirill A. Shutemov Signed-off-by: Stephen Rothwell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: move max_map_count bits into mm.h

2016-03-17T22:09:34Z

max_map_count sysctl unrelated to scheduler. Move its bits from include/linux/sched/sysctl.h to include/linux/mm.h. Signed-off-by: Andrey Ryabinin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, dax: check for pmd_none() after split_huge_pmd()

2016-02-12T02:35:48Z

DAX implements split_huge_pmd() by clearing pmd. This simple approach reduces memory overhead, as we don't need to deposit page table on huge page mapping to make split_huge_pmd() never-fail. PTE table can be allocated and populated later on page fault from backing store. But one side effect is that have to check if pmd is pmd_none() after split_huge_pmd(). In most places we do this already to deal with parallel MADV_DONTNEED. But I found two call sites which is not affected by MADV_DONTNEED (due down_write(mmap_sem)), but need to have the check to work with DAX properly. Signed-off-by: Kirill A. Shutemov Cc: Dan Williams Cc: Matthew Wilcox Cc: Andrea Arcangeli Cc: Ross Zwisler Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, thp: remove infrastructure for handling splitting PMDs

2016-01-16T01:56:32Z

With new refcounting we don't need to mark PMDs splitting. Let's drop code to handle this. Signed-off-by: Kirill A. Shutemov Tested-by: Sasha Levin Tested-by: Aneesh Kumar K.V Acked-by: Vlastimil Babka Acked-by: Jerome Marchand Cc: Andrea Arcangeli Cc: Hugh Dickins Cc: Dave Hansen Cc: Mel Gorman Cc: Rik van Riel Cc: Naoya Horiguchi Cc: Steve Capper Cc: Johannes Weiner Cc: Michal Hocko Cc: Christoph Lameter Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

thp: rename split_huge_page_pmd() to split_huge_pmd()

2016-01-16T01:56:32Z

We are going to decouple splitting THP PMD from splitting underlying compound page. This patch renames split_huge_page_pmd*() functions to split_huge_pmd*() to reflect the fact that it doesn't imply page splitting, only PMD. Signed-off-by: Kirill A. Shutemov Tested-by: Sasha Levin Tested-by: Aneesh Kumar K.V Acked-by: Jerome Marchand Acked-by: Vlastimil Babka Cc: Andrea Arcangeli Cc: Hugh Dickins Cc: Dave Hansen Cc: Mel Gorman Cc: Rik van Riel Cc: Naoya Horiguchi Cc: Steve Capper Cc: Johannes Weiner Cc: Michal Hocko Cc: Christoph Lameter Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: rework virtual memory accounting

2016-01-15T00:00:49Z

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

x86/mm/pat: Add untrack_pfn_moved for mremap

2016-01-05T10:10:05Z

mremap() with MREMAP_FIXED on a VM_PFNMAP range causes the following WARN_ON_ONCE() message in untrack_pfn(). WARNING: CPU: 1 PID: 3493 at arch/x86/mm/pat.c:985 untrack_pfn+0xbd/0xd0() Call Trace: [] dump_stack+0x45/0x57 [] warn_slowpath_common+0x86/0xc0 [] warn_slowpath_null+0x1a/0x20 [] untrack_pfn+0xbd/0xd0 [] unmap_single_vma+0x80e/0x860 [] unmap_vmas+0x55/0xb0 [] unmap_region+0xac/0x120 [] do_munmap+0x28a/0x460 [] move_vma+0x1b3/0x2e0 [] SyS_mremap+0x3b3/0x510 [] entry_SYSCALL_64_fastpath+0x12/0x71 MREMAP_FIXED moves a pfnmap from old vma to new vma. untrack_pfn() is called with the old vma after its pfnmap page table has been removed, which causes follow_phys() to fail. The new vma has a new pfnmap to the same pfn & cache type with VM_PAT set. Therefore, we only need to clear VM_PAT from the old vma in this case. Add untrack_pfn_moved(), which clears VM_PAT from a given old vma. move_vma() is changed to call this function with the old vma when VM_PFNMAP is set. move_vma() then calls do_munmap(), and untrack_pfn() is a no-op since VM_PAT is cleared. Reported-by: Stas Sergeev Signed-off-by: Toshi Kani Cc: Thomas Gleixner Cc: Ingo Molnar Cc: H. Peter Anvin Cc: Borislav Petkov Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/1450832064-10093-2-git-send-email-toshi.kani@hpe.com Signed-off-by: Thomas Gleixner

mm/mremap: use offset_in_page macro

2015-11-06T03:34:48Z

linux/mm.h provides offset_in_page() macro. Let's use already predefined macro instead of (addr & ~PAGE_MASK). Signed-off-by: Alexander Kuleshov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mremap: simplify the "overlap" check in mremap_to()

2015-09-04T23:54:41Z

Minor, but this check is overcomplicated. Two half-intervals do NOT overlap if END1 <= START2 || END2 <= START1, mremap_to() just needs to negate this check. Signed-off-by: Oleg Nesterov Acked-by: David Rientjes Cc: Benjamin LaHaise Cc: Hugh Dickins Cc: Jeff Moyer Cc: Kirill A. Shutemov Cc: Laurent Dufour Cc: Pavel Emelyanov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mremap: don't do uneccesary checks if new_len == old_len

2015-09-04T23:54:41Z

The "new_len > old_len" branch in vma_to_resize() looks very confusing. It only covers the VM_DONTEXPAND/pgoff checks but everything below is equally unneeded if new_len == old_len. Change this code to return if "new_len == old_len", new_len < old_len is not possible, otherwise the code below is wrong anyway. Signed-off-by: Oleg Nesterov Acked-by: David Rientjes Cc: Benjamin LaHaise Cc: Hugh Dickins Cc: Jeff Moyer Cc: Kirill A. Shutemov Cc: Laurent Dufour Cc: Pavel Emelyanov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel.git/mm/mremap.c, branch linux-4.6.y

mm: cleanup *pte_alloc* interfaces

mm: move max_map_count bits into mm.h

mm, dax: check for pmd_none() after split_huge_pmd()

mm, thp: remove infrastructure for handling splitting PMDs

thp: rename split_huge_page_pmd() to split_huge_pmd()

mm: rework virtual memory accounting

x86/mm/pat: Add untrack_pfn_moved for mremap

mm/mremap: use offset_in_page macro

mremap: simplify the "overlap" check in mremap_to()

mremap: don't do uneccesary checks if new_len == old_len

mm: cleanup pte_alloc interfaces