pm24.git/mm/filemap_xip.c, branch v3.10

lift sb_start_write() out of ->write()

2013-04-09T18:12:56Z

Signed-off-by: Al Viro

mm: move all mmu notifier invocations to be done outside the PT lock

2012-10-09T07:22:58Z

In order to allow sleeping during mmu notifier calls, we need to avoid invoking them under the page table spinlock. This patch solves the problem by calling invalidate_page notification after releasing the lock (but before freeing the page itself), or by wrapping the page invalidation with calls to invalidate_range_begin and invalidate_range_end. To prevent accidental changes to the invalidate_range_end arguments after the call to invalidate_range_begin, the patch introduces a convention of saving the arguments in consistently named locals: unsigned long mmun_start; /* For mmu_notifiers */ unsigned long mmun_end; /* For mmu_notifiers */ ... mmun_start = ... mmun_end = ... mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); ... mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); The patch changes code to use this convention for all calls to mmu_notifier_invalidate_range_start/end, except those where the calls are close enough so that anyone who glances at the code can see the values aren't changing. This patchset is a preliminary step towards on-demand paging design to be added to the RDMA stack. Why do we want on-demand paging for Infiniband? Applications register memory with an RDMA adapter using system calls, and subsequently post IO operations that refer to the corresponding virtual addresses directly to HW. Until now, this was achieved by pinning the memory during the registration calls. The goal of on demand paging is to avoid pinning the pages of registered memory regions (MRs). This will allow users the same flexibility they get when swapping any other part of their processes address spaces. Instead of requiring the entire MR to fit in physical memory, we can allow the MR to be larger, and only fit the current working set in physical memory. Why should anyone care? What problems are users currently experiencing? This can make programming with RDMA much simpler. Today, developers that are working with more data than their RAM can hold need either to deregister and reregister memory regions throughout their process's life, or keep a single memory region and copy the data to it. On demand paging will allow these developers to register a single MR at the beginning of their process's life, and let the operating system manage which pages needs to be fetched at a given time. In the future, we might be able to provide a single memory access key for each process that would provide the entire process's address as one large memory region, and the developers wouldn't need to register memory regions at all. Is there any prospect that any other subsystems will utilise these infrastructural changes? If so, which and how, etc? As for other subsystems, I understand that XPMEM wanted to sleep in MMU notifiers, as Christoph Lameter wrote at http://lkml.indiana.edu/hypermail/linux/kernel/0802.1/0460.html and perhaps Andrea knows about other use cases. Scheduling in mmu notifications is required since we need to sync the hardware with the secondary page tables change. A TLB flush of an IO device is inherently slower than a CPU TLB flush, so our design works by sending the invalidation request to the device, and waiting for an interrupt before exiting the mmu notifier handler. Avi said: kvm may be a buyer. kvm::mmu_lock, which serializes guest page faults, also protects long operations such as destroying large ranges. It would be good to convert it into a spinlock, but as it is used inside mmu notifiers, this cannot be done. (there are alternatives, such as keeping the spinlock and using a generation counter to do the teardown in O(1), which is what the "may" is doing up there). [akpm@linux-foundation.orgpossible speed tweak in hugetlb_cow(), cleanups] Signed-off-by: Andrea Arcangeli Signed-off-by: Sagi Grimberg Signed-off-by: Haggai Eran Cc: Peter Zijlstra Cc: Xiao Guangrong Cc: Or Gerlitz Cc: Haggai Eran Cc: Shachar Raindel Cc: Liran Liss Cc: Christoph Lameter Cc: Avi Kivity Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: replace vma prio_tree with an interval tree

2012-10-09T07:22:39Z

Implement an interval tree as a replacement for the VMA prio_tree. The algorithms are similar to lib/interval_tree.c; however that code can't be directly reused as the interval endpoints are not explicitly stored in the VMA. So instead, the common algorithm is moved into a template and the details (node type, how to get interval endpoints from the node, etc) are filled in using the C preprocessor. Once the interval tree functions are available, using them as a replacement to the VMA prio tree is a relatively simple, mechanical job. Signed-off-by: Michel Lespinasse Cc: Rik van Riel Cc: Hillf Danton Cc: Peter Zijlstra Cc: Catalin Marinas Cc: Andrea Arcangeli Cc: David Woodhouse Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: kill vma flag VM_CAN_NONLINEAR

2012-10-09T07:22:17Z

Move actual pte filling for non-linear file mappings into the new special vma operation: ->remap_pages(). Filesystems must implement this method to get non-linear mapping support, if it uses filemap_fault() then generic_file_remap_pages() can be used. Now device drivers can implement this method and obtain nonlinear vma support. Signed-off-by: Konstantin Khlebnikov Cc: Alexander Viro Cc: Carsten Otte Cc: Chris Metcalf #arch/tile Cc: Cyrill Gorcunov Cc: Eric Paris Cc: H. Peter Anvin Cc: Hugh Dickins Cc: Ingo Molnar Cc: James Morris Cc: Jason Baron Cc: Kentaro Takeda Cc: Matt Helsley Cc: Nick Piggin Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Robert Richter Cc: Suresh Siddha Cc: Tetsuo Handa Cc: Venkatesh Pallipadi Acked-by: Linus Torvalds Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

fs: Protect write paths by sb_start_write - sb_end_write

2012-07-31T05:45:47Z

There are several entry points which dirty pages in a filesystem. mmap (handled by block_page_mkwrite()), buffered write (handled by __generic_file_aio_write()), splice write (generic_file_splice_write), truncate, and fallocate (these can dirty last partial page - handled inside each filesystem separately). Protect these places with sb_start_write() and sb_end_write(). ->page_mkwrite() calls are particularly complex since they are called with mmap_sem held and thus we cannot use standard sb_start_write() due to lock ordering constraints. We solve the problem by using a special freeze protection sb_start_pagefault() which ranks below mmap_sem. BugLink: https://bugs.launchpad.net/bugs/897421 Tested-by: Kamal Mostafa Tested-by: Peter M. Petrakis Tested-by: Dann Frazier Tested-by: Massimo Morana Signed-off-by: Jan Kara Signed-off-by: Al Viro

mm: Make default vm_ops provide ->page_mkwrite handler

2012-07-30T21:02:48Z

Make default vm_ops provide ->page_mkwrite handler. Currently it only updates file's modification times and gets locked page but later it will also handle filesystem freezing. BugLink: https://bugs.launchpad.net/bugs/897421 Tested-by: Kamal Mostafa Tested-by: Peter M. Petrakis Tested-by: Dann Frazier Tested-by: Massimo Morana Signed-off-by: Jan Kara Signed-off-by: Al Viro

fs: introduce inode operation ->update_time

2012-06-01T16:07:25Z

Btrfs has to make sure we have space to allocate new blocks in order to modify the inode, so updating time can fail. We've gotten around this by having our own file_update_time but this is kind of a pain, and Christoph has indicated he would like to make xfs do something different with atime updates. So introduce ->update_time, where we will deal with i_version an a/m/c time updates and indicate which changes need to be made. The normal version just does what it has always done, updates the time and marks the inode dirty, and then filesystems can choose to do something different. I've gone through all of the users of file_update_time and made them check for errors with the exception of the fault code since it's complicated and I wasn't quite sure what to do there, also Jan is going to be pushing the file time updates into page_mkwrite for those who have it so that should satisfy btrfs and make it not a big deal to check the file_update_time() return code in the generic fault path. Thanks, Signed-off-by: Josef Bacik

mm/filemap_xip.c: fix race condition in xip_file_fault()

2012-02-04T00:16:41Z

Fix a race condition that shows in conjunction with xip_file_fault() when two threads of the same user process fault on the same memory page. In this case, the race winner will install the page table entry and the unlucky loser will cause an oops: xip_file_fault calls vm_insert_pfn (via vm_insert_mixed) which drops out at this check: retval = -EBUSY; if (!pte_none(*pte)) goto out_unlock; The resulting -EBUSY return value will trigger a BUG_ON() in xip_file_fault. This fix simply considers the fault as fixed in this case, because the race winner has successfully installed the pte. [akpm@linux-foundation.org: use conventional (and consistent) comment layout] Reported-by: David Sadler Signed-off-by: Carsten Otte Reported-by: Louis Alex Eisner Cc: Hugh Dickins Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: Map most files to use export.h instead of module.h

2011-10-31T13:20:12Z

The files changed within are only using the EXPORT_SYMBOL macro variants. They are not using core modular infrastructure and hence don't need module.h but only the export.h header. Signed-off-by: Paul Gortmaker

mm: Convert i_mmap_lock to a mutex

2011-05-25T15:39:18Z

Straightforward conversion of i_mmap_lock to a mutex. Signed-off-by: Peter Zijlstra Acked-by: Hugh Dickins Cc: Benjamin Herrenschmidt Cc: David Miller Cc: Martin Schwidefsky Cc: Russell King Cc: Paul Mundt Cc: Jeff Dike Cc: Richard Weinberger Cc: Tony Luck Cc: KAMEZAWA Hiroyuki Cc: Mel Gorman Cc: KOSAKI Motohiro Cc: Nick Piggin Cc: Namhyung Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds