31 Oct, 2011

1 commit


25 May, 2011

1 commit

  • 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

    Peter Zijlstra
     

30 Mar, 2010

1 commit

  • …it slab.h inclusion from percpu.h

    percpu.h is included by sched.h and module.h and thus ends up being
    included when building most .c files. percpu.h includes slab.h which
    in turn includes gfp.h making everything defined by the two files
    universally available and complicating inclusion dependencies.

    percpu.h -> slab.h dependency is about to be removed. Prepare for
    this change by updating users of gfp and slab facilities include those
    headers directly instead of assuming availability. As this conversion
    needs to touch large number of source files, the following script is
    used as the basis of conversion.

    http://userweb.kernel.org/~tj/misc/slabh-sweep.py

    The script does the followings.

    * Scan files for gfp and slab usages and update includes such that
    only the necessary includes are there. ie. if only gfp is used,
    gfp.h, if slab is used, slab.h.

    * When the script inserts a new include, it looks at the include
    blocks and try to put the new include such that its order conforms
    to its surrounding. It's put in the include block which contains
    core kernel includes, in the same order that the rest are ordered -
    alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
    doesn't seem to be any matching order.

    * If the script can't find a place to put a new include (mostly
    because the file doesn't have fitting include block), it prints out
    an error message indicating which .h file needs to be added to the
    file.

    The conversion was done in the following steps.

    1. The initial automatic conversion of all .c files updated slightly
    over 4000 files, deleting around 700 includes and adding ~480 gfp.h
    and ~3000 slab.h inclusions. The script emitted errors for ~400
    files.

    2. Each error was manually checked. Some didn't need the inclusion,
    some needed manual addition while adding it to implementation .h or
    embedding .c file was more appropriate for others. This step added
    inclusions to around 150 files.

    3. The script was run again and the output was compared to the edits
    from #2 to make sure no file was left behind.

    4. Several build tests were done and a couple of problems were fixed.
    e.g. lib/decompress_*.c used malloc/free() wrappers around slab
    APIs requiring slab.h to be added manually.

    5. The script was run on all .h files but without automatically
    editing them as sprinkling gfp.h and slab.h inclusions around .h
    files could easily lead to inclusion dependency hell. Most gfp.h
    inclusion directives were ignored as stuff from gfp.h was usually
    wildly available and often used in preprocessor macros. Each
    slab.h inclusion directive was examined and added manually as
    necessary.

    6. percpu.h was updated not to include slab.h.

    7. Build test were done on the following configurations and failures
    were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
    distributed build env didn't work with gcov compiles) and a few
    more options had to be turned off depending on archs to make things
    build (like ipr on powerpc/64 which failed due to missing writeq).

    * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
    * powerpc and powerpc64 SMP allmodconfig
    * sparc and sparc64 SMP allmodconfig
    * ia64 SMP allmodconfig
    * s390 SMP allmodconfig
    * alpha SMP allmodconfig
    * um on x86_64 SMP allmodconfig

    8. percpu.h modifications were reverted so that it could be applied as
    a separate patch and serve as bisection point.

    Given the fact that I had only a couple of failures from tests on step
    6, I'm fairly confident about the coverage of this conversion patch.
    If there is a breakage, it's likely to be something in one of the arch
    headers which should be easily discoverable easily on most builds of
    the specific arch.

    Signed-off-by: Tejun Heo <tj@kernel.org>
    Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

    Tejun Heo
     

07 Mar, 2010

1 commit

  • Presently, per-mm statistics counter is defined by macro in sched.h

    This patch modifies it to
    - defined in mm.h as inlinf functions
    - use array instead of macro's name creation.

    This patch is for reducing patch size in future patch to modify
    implementation of per-mm counter.

    Signed-off-by: KAMEZAWA Hiroyuki
    Reviewed-by: Minchan Kim
    Cc: Christoph Lameter
    Cc: Lee Schermerhorn
    Cc: David Rientjes
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    KAMEZAWA Hiroyuki
     

28 Sep, 2009

1 commit


03 Apr, 2009

1 commit

  • The calculation of the value nr in do_xip_mapping_read is incorrect. If
    the copy required more than one iteration in the do while loop the copies
    variable will be non-zero. The maximum length that may be passed to the
    call to copy_to_user(buf+copied, xip_mem+offset, nr) is len-copied but the
    check only compares against (nr > len).

    This bug is the cause for the heap corruption Carsten has been chasing
    for so long:

    *** glibc detected *** /bin/bash: free(): invalid next size (normal): 0x00000000800e39f0 ***
    ======= Backtrace: =========
    /lib64/libc.so.6[0x200000b9b44]
    /lib64/libc.so.6(cfree+0x8e)[0x200000bdade]
    /bin/bash(free_buffered_stream+0x32)[0x80050e4e]
    /bin/bash(close_buffered_stream+0x1c)[0x80050ea4]
    /bin/bash(unset_bash_input+0x2a)[0x8001c366]
    /bin/bash(make_child+0x1d4)[0x8004115c]
    /bin/bash[0x8002fc3c]
    /bin/bash(execute_command_internal+0x656)[0x8003048e]
    /bin/bash(execute_command+0x5e)[0x80031e1e]
    /bin/bash(execute_command_internal+0x79a)[0x800305d2]
    /bin/bash(execute_command+0x5e)[0x80031e1e]
    /bin/bash(reader_loop+0x270)[0x8001efe0]
    /bin/bash(main+0x1328)[0x8001e960]
    /lib64/libc.so.6(__libc_start_main+0x100)[0x200000592a8]
    /bin/bash(clearerr+0x5e)[0x8001c092]

    With this bug fix the commit 0e4a9b59282914fe057ab17027f55123964bc2e2
    "ext2/xip: refuse to change xip flag during remount with busy inodes" can
    be removed again.

    Cc: Carsten Otte
    Cc: Nick Piggin
    Cc: Jared Hulbert
    Cc:
    Signed-off-by: Martin Schwidefsky
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Martin Schwidefsky
     

07 Jan, 2009

1 commit

  • Remove page_remove_rmap()'s vma arg, which was only for the Eeek message.
    And remove the BUG_ON(page_mapcount(page) == 0) from CONFIG_DEBUG_VM's
    page_dup_rmap(): we're trying to be more resilient about that than BUGs.

    Signed-off-by: Hugh Dickins
    Cc: Nick Piggin
    Cc: Christoph Lameter
    Cc: Mel Gorman
    Cc: Rik van Riel
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Hugh Dickins
     

21 Aug, 2008

3 commits

  • XIP can call into get_xip_mem concurrently with the same file,offset with
    create=1. This usually maps down to get_block, which expects the page
    lock to prevent such a situation. This causes ext2 to explode for one
    reason or another.

    Serialise those calls for the moment. For common usages today, I suspect
    get_xip_mem rarely is called to create new blocks. In future as XIP
    technologies evolve we might need to look at which operations require
    scalability, and rework the locking to suit.

    Signed-off-by: Nick Piggin
    Cc: Jared Hulbert
    Acked-by: Carsten Otte
    Cc: Hugh Dickins
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     
  • XIP has a race between sparse pages being inserted into page tables, and
    sparse pages being zapped when its time to put a non-sparse page in.

    What can happen is that a process can be left with a dangling sparse page
    in a MAP_SHARED mapping, while the rest of the world sees the non-sparse
    version. Ie. data corruption.

    Guard these operations with a seqlock, making fault-in-sparse-pages the
    slowpath, and try-to-unmap-sparse-pages the fastpath.

    Signed-off-by: Nick Piggin
    Cc: Jared Hulbert
    Acked-by: Carsten Otte
    Cc: Hugh Dickins
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     
  • There is a race with dirty page accounting where a page may not properly
    be accounted for.

    clear_page_dirty_for_io() calls page_mkclean; then TestClearPageDirty.

    page_mkclean walks the rmaps for that page, and for each one it cleans and
    write protects the pte if it was dirty. It uses page_check_address to
    find the pte. That function has a shortcut to avoid the ptl if the pte is
    not present. Unfortunately, the pte can be switched to not-present then
    back to present by other code while holding the page table lock -- this
    should not be a signal for page_mkclean to ignore that pte, because it may
    be dirty.

    For example, powerpc64's set_pte_at will clear a previously present pte
    before setting it to the desired value. There may also be other code in
    core mm or in arch which do similar things.

    The consequence of the bug is loss of data integrity due to msync, and
    loss of dirty page accounting accuracy. XIP's __xip_unmap could easily
    also be unreliable (depending on the exact XIP locking scheme), which can
    lead to data corruption.

    Fix this by having an option to always take ptl to check the pte in
    page_check_address.

    It's possible to retain this optimization for page_referenced and
    try_to_unmap.

    Signed-off-by: Nick Piggin
    Cc: Jared Hulbert
    Cc: Carsten Otte
    Cc: Hugh Dickins
    Acked-by: Peter Zijlstra
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     

29 Jul, 2008

1 commit

  • With KVM/GFP/XPMEM there isn't just the primary CPU MMU pointing to pages.
    There are secondary MMUs (with secondary sptes and secondary tlbs) too.
    sptes in the kvm case are shadow pagetables, but when I say spte in
    mmu-notifier context, I mean "secondary pte". In GRU case there's no
    actual secondary pte and there's only a secondary tlb because the GRU
    secondary MMU has no knowledge about sptes and every secondary tlb miss
    event in the MMU always generates a page fault that has to be resolved by
    the CPU (this is not the case of KVM where the a secondary tlb miss will
    walk sptes in hardware and it will refill the secondary tlb transparently
    to software if the corresponding spte is present). The same way
    zap_page_range has to invalidate the pte before freeing the page, the spte
    (and secondary tlb) must also be invalidated before any page is freed and
    reused.

    Currently we take a page_count pin on every page mapped by sptes, but that
    means the pages can't be swapped whenever they're mapped by any spte
    because they're part of the guest working set. Furthermore a spte unmap
    event can immediately lead to a page to be freed when the pin is released
    (so requiring the same complex and relatively slow tlb_gather smp safe
    logic we have in zap_page_range and that can be avoided completely if the
    spte unmap event doesn't require an unpin of the page previously mapped in
    the secondary MMU).

    The mmu notifiers allow kvm/GRU/XPMEM to attach to the tsk->mm and know
    when the VM is swapping or freeing or doing anything on the primary MMU so
    that the secondary MMU code can drop sptes before the pages are freed,
    avoiding all page pinning and allowing 100% reliable swapping of guest
    physical address space. Furthermore it avoids the code that teardown the
    mappings of the secondary MMU, to implement a logic like tlb_gather in
    zap_page_range that would require many IPI to flush other cpu tlbs, for
    each fixed number of spte unmapped.

    To make an example: if what happens on the primary MMU is a protection
    downgrade (from writeable to wrprotect) the secondary MMU mappings will be
    invalidated, and the next secondary-mmu-page-fault will call
    get_user_pages and trigger a do_wp_page through get_user_pages if it
    called get_user_pages with write=1, and it'll re-establishing an updated
    spte or secondary-tlb-mapping on the copied page. Or it will setup a
    readonly spte or readonly tlb mapping if it's a guest-read, if it calls
    get_user_pages with write=0. This is just an example.

    This allows to map any page pointed by any pte (and in turn visible in the
    primary CPU MMU), into a secondary MMU (be it a pure tlb like GRU, or an
    full MMU with both sptes and secondary-tlb like the shadow-pagetable layer
    with kvm), or a remote DMA in software like XPMEM (hence needing of
    schedule in XPMEM code to send the invalidate to the remote node, while no
    need to schedule in kvm/gru as it's an immediate event like invalidating
    primary-mmu pte).

    At least for KVM without this patch it's impossible to swap guests
    reliably. And having this feature and removing the page pin allows
    several other optimizations that simplify life considerably.

    Dependencies:

    1) mm_take_all_locks() to register the mmu notifier when the whole VM
    isn't doing anything with "mm". This allows mmu notifier users to keep
    track if the VM is in the middle of the invalidate_range_begin/end
    critical section with an atomic counter incraese in range_begin and
    decreased in range_end. No secondary MMU page fault is allowed to map
    any spte or secondary tlb reference, while the VM is in the middle of
    range_begin/end as any page returned by get_user_pages in that critical
    section could later immediately be freed without any further
    ->invalidate_page notification (invalidate_range_begin/end works on
    ranges and ->invalidate_page isn't called immediately before freeing
    the page). To stop all page freeing and pagetable overwrites the
    mmap_sem must be taken in write mode and all other anon_vma/i_mmap
    locks must be taken too.

    2) It'd be a waste to add branches in the VM if nobody could possibly
    run KVM/GRU/XPMEM on the kernel, so mmu notifiers will only enabled if
    CONFIG_KVM=m/y. In the current kernel kvm won't yet take advantage of
    mmu notifiers, but this already allows to compile a KVM external module
    against a kernel with mmu notifiers enabled and from the next pull from
    kvm.git we'll start using them. And GRU/XPMEM will also be able to
    continue the development by enabling KVM=m in their config, until they
    submit all GRU/XPMEM GPLv2 code to the mainline kernel. Then they can
    also enable MMU_NOTIFIERS in the same way KVM does it (even if KVM=n).
    This guarantees nobody selects MMU_NOTIFIER=y if KVM and GRU and XPMEM
    are all =n.

    The mmu_notifier_register call can fail because mm_take_all_locks may be
    interrupted by a signal and return -EINTR. Because mmu_notifier_reigster
    is used when a driver startup, a failure can be gracefully handled. Here
    an example of the change applied to kvm to register the mmu notifiers.
    Usually when a driver startups other allocations are required anyway and
    -ENOMEM failure paths exists already.

    struct kvm *kvm_arch_create_vm(void)
    {
    struct kvm *kvm = kzalloc(sizeof(struct kvm), GFP_KERNEL);
    + int err;

    if (!kvm)
    return ERR_PTR(-ENOMEM);

    INIT_LIST_HEAD(&kvm->arch.active_mmu_pages);

    + kvm->arch.mmu_notifier.ops = &kvm_mmu_notifier_ops;
    + err = mmu_notifier_register(&kvm->arch.mmu_notifier, current->mm);
    + if (err) {
    + kfree(kvm);
    + return ERR_PTR(err);
    + }
    +
    return kvm;
    }

    mmu_notifier_unregister returns void and it's reliable.

    The patch also adds a few needed but missing includes that would prevent
    kernel to compile after these changes on non-x86 archs (x86 didn't need
    them by luck).

    [akpm@linux-foundation.org: coding-style fixes]
    [akpm@linux-foundation.org: fix mm/filemap_xip.c build]
    [akpm@linux-foundation.org: fix mm/mmu_notifier.c build]
    Signed-off-by: Andrea Arcangeli
    Signed-off-by: Nick Piggin
    Signed-off-by: Christoph Lameter
    Cc: Jack Steiner
    Cc: Robin Holt
    Cc: Nick Piggin
    Cc: Peter Zijlstra
    Cc: Kanoj Sarcar
    Cc: Roland Dreier
    Cc: Steve Wise
    Cc: Avi Kivity
    Cc: Hugh Dickins
    Cc: Rusty Russell
    Cc: Anthony Liguori
    Cc: Chris Wright
    Cc: Marcelo Tosatti
    Cc: Eric Dumazet
    Cc: "Paul E. McKenney"
    Cc: Izik Eidus
    Cc: Anthony Liguori
    Cc: Rik van Riel
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Andrea Arcangeli
     

27 Jul, 2008

1 commit


28 Apr, 2008

1 commit

  • Convert XIP to support non-struct page backed memory, using VM_MIXEDMAP for
    the user mappings.

    This requires the get_xip_page API to be changed to an address based one.
    Improve the API layering a little bit too, while we're here.

    This is required in order to support XIP filesystems on memory that isn't
    backed with struct page (but memory with struct page is still supported too).

    Signed-off-by: Nick Piggin
    Acked-by: Carsten Otte
    Cc: Jared Hulbert
    Cc: Martin Schwidefsky
    Cc: Heiko Carstens
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     

09 Feb, 2008

1 commit


06 Feb, 2008

1 commit

  • Simplify page cache zeroing of segments of pages through 3 functions

    zero_user_segments(page, start1, end1, start2, end2)

    Zeros two segments of the page. It takes the position where to
    start and end the zeroing which avoids length calculations and
    makes code clearer.

    zero_user_segment(page, start, end)

    Same for a single segment.

    zero_user(page, start, length)

    Length variant for the case where we know the length.

    We remove the zero_user_page macro. Issues:

    1. Its a macro. Inline functions are preferable.

    2. The KM_USER0 macro is only defined for HIGHMEM.

    Having to treat this special case everywhere makes the
    code needlessly complex. The parameter for zeroing is always
    KM_USER0 except in one single case that we open code.

    Avoiding KM_USER0 makes a lot of code not having to be dealing
    with the special casing for HIGHMEM anymore. Dealing with
    kmap is only necessary for HIGHMEM configurations. In those
    configurations we use KM_USER0 like we do for a series of other
    functions defined in highmem.h.

    Since KM_USER0 is depends on HIGHMEM the existing zero_user_page
    function could not be a macro. zero_user_* functions introduced
    here can be be inline because that constant is not used when these
    functions are called.

    Also extract the flushing of the caches to be outside of the kmap.

    [akpm@linux-foundation.org: fix nfs and ntfs build]
    [akpm@linux-foundation.org: fix ntfs build some more]
    Signed-off-by: Christoph Lameter
    Cc: Steven French
    Cc: Michael Halcrow
    Cc:
    Cc: Steven Whitehouse
    Cc: Trond Myklebust
    Cc: "J. Bruce Fields"
    Cc: Anton Altaparmakov
    Cc: Mark Fasheh
    Cc: David Chinner
    Cc: Michael Halcrow
    Cc: Steven French
    Cc: Steven Whitehouse
    Cc: Trond Myklebust
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christoph Lameter
     

09 Jan, 2008

1 commit

  • The use of get_zeroed_page() with __GFP_HIGHMEM is invalid. Use
    alloc_page() with __GFP_ZERO instead of invalid get_zeroed_page().

    (This patch is only compile tested)

    Cc: Carsten Otte
    Signed-off-by: Akinobu Mita
    Acked-by: Hugh Dickins
    Acked-by: Carsten Otte
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Akinobu Mita
     

06 Dec, 2007

1 commit

  • Writing to XIP files at a non-page-aligned offset results in data corruption
    because the writes were always sent to the start of the page.

    Signed-off-by: Nick Piggin
    Cc: Christian Borntraeger
    Acked-by: Carsten Otte
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     

17 Oct, 2007

1 commit

  • Hide some of the open-coded nr_segs tests into the iovec helpers. This is all
    to simplify generic_file_buffered_write, because that gets more complex in the
    next patch.

    Signed-off-by: Nick Piggin
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     

20 Jul, 2007

3 commits

  • This patch completes Linus's wish that the fault return codes be made into
    bit flags, which I agree makes everything nicer. This requires requires
    all handle_mm_fault callers to be modified (possibly the modifications
    should go further and do things like fault accounting in handle_mm_fault --
    however that would be for another patch).

    [akpm@linux-foundation.org: fix alpha build]
    [akpm@linux-foundation.org: fix s390 build]
    [akpm@linux-foundation.org: fix sparc build]
    [akpm@linux-foundation.org: fix sparc64 build]
    [akpm@linux-foundation.org: fix ia64 build]
    Signed-off-by: Nick Piggin
    Cc: Richard Henderson
    Cc: Ivan Kokshaysky
    Cc: Russell King
    Cc: Ian Molton
    Cc: Bryan Wu
    Cc: Mikael Starvik
    Cc: David Howells
    Cc: Yoshinori Sato
    Cc: "Luck, Tony"
    Cc: Hirokazu Takata
    Cc: Geert Uytterhoeven
    Cc: Roman Zippel
    Cc: Greg Ungerer
    Cc: Matthew Wilcox
    Cc: Paul Mackerras
    Cc: Benjamin Herrenschmidt
    Cc: Heiko Carstens
    Cc: Martin Schwidefsky
    Cc: Paul Mundt
    Cc: Kazumoto Kojima
    Cc: Richard Curnow
    Cc: William Lee Irwin III
    Cc: "David S. Miller"
    Cc: Jeff Dike
    Cc: Paolo 'Blaisorblade' Giarrusso
    Cc: Miles Bader
    Cc: Chris Zankel
    Acked-by: Kyle McMartin
    Acked-by: Haavard Skinnemoen
    Acked-by: Ralf Baechle
    Acked-by: Andi Kleen
    Signed-off-by: Andrew Morton
    [ Still apparently needs some ARM and PPC loving - Linus ]
    Signed-off-by: Linus Torvalds

    Nick Piggin
     
  • Change ->fault prototype. We now return an int, which contains
    VM_FAULT_xxx code in the low byte, and FAULT_RET_xxx code in the next byte.
    FAULT_RET_ code tells the VM whether a page was found, whether it has been
    locked, and potentially other things. This is not quite the way he wanted
    it yet, but that's changed in the next patch (which requires changes to
    arch code).

    This means we no longer set VM_CAN_INVALIDATE in the vma in order to say
    that a page is locked which requires filemap_nopage to go away (because we
    can no longer remain backward compatible without that flag), but we were
    going to do that anyway.

    struct fault_data is renamed to struct vm_fault as Linus asked. address
    is now a void __user * that we should firmly encourage drivers not to use
    without really good reason.

    The page is now returned via a page pointer in the vm_fault struct.

    Signed-off-by: Nick Piggin
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     
  • Nonlinear mappings are (AFAIKS) simply a virtual memory concept that encodes
    the virtual address -> file offset differently from linear mappings.

    ->populate is a layering violation because the filesystem/pagecache code
    should need to know anything about the virtual memory mapping. The hitch here
    is that the ->nopage handler didn't pass down enough information (ie. pgoff).
    But it is more logical to pass pgoff rather than have the ->nopage function
    calculate it itself anyway (because that's a similar layering violation).

    Having the populate handler install the pte itself is likewise a nasty thing
    to be doing.

    This patch introduces a new fault handler that replaces ->nopage and
    ->populate and (later) ->nopfn. Most of the old mechanism is still in place
    so there is a lot of duplication and nice cleanups that can be removed if
    everyone switches over.

    The rationale for doing this in the first place is that nonlinear mappings are
    subject to the pagefault vs invalidate/truncate race too, and it seemed stupid
    to duplicate the synchronisation logic rather than just consolidate the two.

    After this patch, MAP_NONBLOCK no longer sets up ptes for pages present in
    pagecache. Seems like a fringe functionality anyway.

    NOPAGE_REFAULT is removed. This should be implemented with ->fault, and no
    users have hit mainline yet.

    [akpm@linux-foundation.org: cleanup]
    [randy.dunlap@oracle.com: doc. fixes for readahead]
    [akpm@linux-foundation.org: build fix]
    Signed-off-by: Nick Piggin
    Signed-off-by: Randy Dunlap
    Cc: Mark Fasheh
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     

10 Jul, 2007

1 commit

  • This patch removes xip_file_sendfile, the sendfile implementation for
    xip without replacement. Those customers that use xip on s390 are not
    using sendfile() as far as we know, and so far s390 is the only platform
    this could potentially be used on so far.
    Having sendfile is not a popular feature for execute in place file
    systems, however we have a working implementation of splice_read() based
    on fs/splice.c if anyone asks for it.
    At this point in time, it does not seem preferable to merge
    splice_read() for xip because it causes extra maintenence effort due to
    code duplication and it requires struct page behind the xip memory
    segment. We'd like to get rid of that in favor of supporting flash based
    embedded platforms (Monta Vista work) soon.

    Signed-off-by: Carsten Otte
    Signed-off-by: Jens Axboe

    Carsten Otte
     

22 May, 2007

1 commit

  • First thing mm.h does is including sched.h solely for can_do_mlock() inline
    function which has "current" dereference inside. By dealing with can_do_mlock()
    mm.h can be detached from sched.h which is good. See below, why.

    This patch
    a) removes unconditional inclusion of sched.h from mm.h
    b) makes can_do_mlock() normal function in mm/mlock.c
    c) exports can_do_mlock() to not break compilation
    d) adds sched.h inclusions back to files that were getting it indirectly.
    e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were
    getting them indirectly

    Net result is:
    a) mm.h users would get less code to open, read, preprocess, parse, ... if
    they don't need sched.h
    b) sched.h stops being dependency for significant number of files:
    on x86_64 allmodconfig touching sched.h results in recompile of 4083 files,
    after patch it's only 3744 (-8.3%).

    Cross-compile tested on

    all arm defconfigs, all mips defconfigs, all powerpc defconfigs,
    alpha alpha-up
    arm
    i386 i386-up i386-defconfig i386-allnoconfig
    ia64 ia64-up
    m68k
    mips
    parisc parisc-up
    powerpc powerpc-up
    s390 s390-up
    sparc sparc-up
    sparc64 sparc64-up
    um-x86_64
    x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig

    as well as my two usual configs.

    Signed-off-by: Alexey Dobriyan
    Signed-off-by: Linus Torvalds

    Alexey Dobriyan
     

10 May, 2007

1 commit

  • It's very common for file systems to need to zero part or all of a page,
    the simplist way is just to use kmap_atomic() and memset(). There's
    actually a library function in include/linux/highmem.h that does exactly
    that, but it's confusingly named memclear_highpage_flush(), which is
    descriptive of *how* it does the work rather than what the *purpose* is.
    So this patchset renames the function to zero_user_page(), and calls it
    from the various places that currently open code it.

    This first patch introduces the new function call, and converts all the
    core kernel callsites, both the open-coded ones and the old
    memclear_highpage_flush() ones. Following this patch is a series of
    conversions for each file system individually, per AKPM, and finally a
    patch deprecating the old call. The diffstat below shows the entire
    patchset.

    [akpm@linux-foundation.org: fix a few things]
    Signed-off-by: Nate Diller
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nate Diller
     

29 Mar, 2007

1 commit

  • Fix the bug, that reading into xip mapping from /dev/zero fills the user
    page table with ZERO_PAGE() entries. Later on, xip cannot tell which pages
    have been ZERO_PAGE() filled by access to a sparse mapping, and which ones
    origin from /dev/zero. It will unmap ZERO_PAGE from all mappings when
    filling the sparse hole with data. xip does now use its own zeroed page
    for its sparse mappings. Please apply.

    Signed-off-by: Carsten Otte
    Signed-off-by: Hugh Dickins
    Cc: Nick Piggin
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Carsten Otte
     

31 Jan, 2007

1 commit

  • Nick Piggin points out that page accounting on MIPS multiple ZERO_PAGEs
    is not maintained by its move_pte, and could lead to freeing a ZERO_PAGE.

    Instead of complicating that move_pte, just forget the minor optimization
    when mremapping, and change the one thing which needed it for correctness
    - filemap_xip use ZERO_PAGE(0) throughout instead of according to address.

    [ "There is no block device driver one could use for XIP on mips
    platforms" - Carsten Otte ]

    Signed-off-by: Hugh Dickins
    Cc: Nick Piggin
    Cc: Andrew Morton
    Cc: Ralf Baechle
    Cc: Carsten Otte
    Signed-off-by: Linus Torvalds

    Hugh Dickins
     

23 Dec, 2006

1 commit


09 Dec, 2006

1 commit


29 Jun, 2006

1 commit


11 Jan, 2006

1 commit

  • To allow various options to work per-mount instead of per-sb we need a
    struct vfsmount when updating ctime and mtime. This preparation patch
    replaces the inode_update_time routine with a file_update_atime routine so
    we can easily get at the vfsmount. (and the file makes more sense in this
    context anyway). Also get rid of the unused second argument - we always
    want to update the ctime when calling this routine.

    Signed-off-by: Christoph Hellwig
    Cc: Al Viro
    Cc: Anton Altaparmakov
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christoph Hellwig
     

10 Jan, 2006

1 commit


30 Oct, 2005

3 commits

  • rmap's page_check_address descend without page_table_lock. First just
    pte_offset_map in case there's no pte present worth locking for, then take
    page_table_lock for the full check, and pass ptl back to caller in the same
    style as pte_offset_map_lock. __xip_unmap, page_referenced_one and
    try_to_unmap_one use pte_unmap_unlock. try_to_unmap_cluster also.

    page_check_address reformatted to avoid progressive indentation. No use is
    made of its one error code, return NULL when it fails.

    Signed-off-by: Hugh Dickins
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Hugh Dickins
     
  • Small fix to the PageReserved patch: the mips ZERO_PAGE(address) depends on
    address, so __xip_unmap is wrong to initialize page with that before address
    is initialized; and in fact must re-evaluate it each iteration.

    Signed-off-by: Hugh Dickins
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Hugh Dickins
     
  • Remove PageReserved() calls from core code by tightening VM_RESERVED
    handling in mm/ to cover PageReserved functionality.

    PageReserved special casing is removed from get_page and put_page.

    All setting and clearing of PageReserved is retained, and it is now flagged
    in the page_alloc checks to help ensure we don't introduce any refcount
    based freeing of Reserved pages.

    MAP_PRIVATE, PROT_WRITE of VM_RESERVED regions is tentatively being
    deprecated. We never completely handled it correctly anyway, and is be
    reintroduced in future if required (Hugh has a proof of concept).

    Once PageReserved() calls are removed from kernel/power/swsusp.c, and all
    arch/ and driver code, the Set and Clear calls, and the PG_reserved bit can
    be trivially removed.

    Last real user of PageReserved is swsusp, which uses PageReserved to
    determine whether a struct page points to valid memory or not. This still
    needs to be addressed (a generic page_is_ram() should work).

    A last caveat: the ZERO_PAGE is now refcounted and managed with rmap (and
    thus mapcounted and count towards shared rss). These writes to the struct
    page could cause excessive cacheline bouncing on big systems. There are a
    number of ways this could be addressed if it is an issue.

    Signed-off-by: Nick Piggin

    Refcount bug fix for filemap_xip.c

    Signed-off-by: Carsten Otte
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     

16 Jul, 2005

1 commit

  • This patch includes feedback from Andrew and Christoph. Thanks for
    taking time to review.

    Use of empty_zero_page was eliminated to fix compilation for architectures
    that don't have it.

    This patch removes setting pages up-to-date in ext2_get_xip_page and all
    bug checks to verify that the page is indeed up to date. Setting the page
    state on mapping to userland is bogus. None of the code patchs involved
    with these pages in mm cares about the page state.

    still on my ToDo list: identify a place outside second extended where
    __inode_direct_access should reside

    Signed-off-by: Carsten Otte
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Carsten Otte
     

13 Jul, 2005

1 commit

  • mm/filemap_xip.c: In function `__xip_unmap':
    mm/filemap_xip.c:194: request for member `pte' in something not a structure or union

    Apparently pte_pfn() takes a pte_t, not a pointer to a pte_t. From looking
    at asm/page.h, it seems to be the same on ia32 or ppc (iff
    STRICT_MM_TYPECHECKS is enabled, which is disabled by default on ppc).

    Acked-by: Carsten Otte
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Geert Uytterhoeven
     

24 Jun, 2005

2 commits

  • This patch reworks filemap_xip.c with the goal to reduce code duplication
    from mm/filemap.c. It applies agains 2.6.12-rc6-mm1. Instead of
    implementing the aio functions, this one implements the synchronous
    read/write functions only. For readv and writev, the generic fallback is
    used. For aio, we rely on the application doing the fallback. Since our
    "synchronous" function does memcpy immediately anyway, there is no
    performance difference between using the fallbacks or implementing each
    operation.

    Signed-off-by: Carsten Otte
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Carsten Otte
     
  • - generic_file* file operations do no longer have a xip/non-xip split
    - filemap_xip.c implements a new set of fops that require get_xip_page
    aop to work proper. all new fops are exported GPL-only (don't like to
    see whatever code use those except GPL modules)
    - __xip_unmap now uses page_check_address, which is no longer static
    in rmap.c, and defined in linux/rmap.h
    - mm/filemap.h is now much more clean, plainly having just Linus'
    inline funcs moved here from filemap.c
    - fix includes in filemap_xip to make it build cleanly on i386

    Signed-off-by: Carsten Otte
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Carsten Otte