27 Jul, 2016

1 commit


18 Mar, 2016

1 commit

  • The define has a comment from Nick Piggin from 2007:

    /* For backwards compat. Remove me quickly. */

    I guess 9 years should not be too hurried sense of 'quickly' even for
    kernel measures.

    Signed-off-by: Jan Kara
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Jan Kara
     

17 Aug, 2015

1 commit


19 May, 2015

1 commit

  • Introduce faulthandler_disabled() and use it to check for irq context and
    disabled pagefaults (via pagefault_disable()) in the pagefault handlers.

    Please note that we keep the in_atomic() checks in place - to detect
    whether in irq context (in which case preemption is always properly
    disabled).

    In contrast, preempt_disable() should never be used to disable pagefaults.
    With !CONFIG_PREEMPT_COUNT, preempt_disable() doesn't modify the preempt
    counter, and therefore the result of in_atomic() differs.
    We validate that condition by using might_fault() checks when calling
    might_sleep().

    Therefore, add a comment to faulthandler_disabled(), describing why this
    is needed.

    faulthandler_disabled() and pagefault_disable() are defined in
    linux/uaccess.h, so let's properly add that include to all relevant files.

    This patch is based on a patch from Thomas Gleixner.

    Reviewed-and-tested-by: Thomas Gleixner
    Signed-off-by: David Hildenbrand
    Signed-off-by: Peter Zijlstra (Intel)
    Cc: David.Laight@ACULAB.COM
    Cc: Linus Torvalds
    Cc: Peter Zijlstra
    Cc: Thomas Gleixner
    Cc: airlied@linux.ie
    Cc: akpm@linux-foundation.org
    Cc: benh@kernel.crashing.org
    Cc: bigeasy@linutronix.de
    Cc: borntraeger@de.ibm.com
    Cc: daniel.vetter@intel.com
    Cc: heiko.carstens@de.ibm.com
    Cc: herbert@gondor.apana.org.au
    Cc: hocko@suse.cz
    Cc: hughd@google.com
    Cc: mst@redhat.com
    Cc: paulus@samba.org
    Cc: ralf@linux-mips.org
    Cc: schwidefsky@de.ibm.com
    Cc: yang.shi@windriver.com
    Link: http://lkml.kernel.org/r/1431359540-32227-7-git-send-email-dahi@linux.vnet.ibm.com
    Signed-off-by: Ingo Molnar

    David Hildenbrand
     

30 Jan, 2015

1 commit

  • The core VM already knows about VM_FAULT_SIGBUS, but cannot return a
    "you should SIGSEGV" error, because the SIGSEGV case was generally
    handled by the caller - usually the architecture fault handler.

    That results in lots of duplication - all the architecture fault
    handlers end up doing very similar "look up vma, check permissions, do
    retries etc" - but it generally works. However, there are cases where
    the VM actually wants to SIGSEGV, and applications _expect_ SIGSEGV.

    In particular, when accessing the stack guard page, libsigsegv expects a
    SIGSEGV. And it usually got one, because the stack growth is handled by
    that duplicated architecture fault handler.

    However, when the generic VM layer started propagating the error return
    from the stack expansion in commit fee7e49d4514 ("mm: propagate error
    from stack expansion even for guard page"), that now exposed the
    existing VM_FAULT_SIGBUS result to user space. And user space really
    expected SIGSEGV, not SIGBUS.

    To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach all those
    duplicate architecture fault handlers about it. They all already have
    the code to handle SIGSEGV, so it's about just tying that new return
    value to the existing code, but it's all a bit annoying.

    This is the mindless minimal patch to do this. A more extensive patch
    would be to try to gather up the mostly shared fault handling logic into
    one generic helper routine, and long-term we really should do that
    cleanup.

    Just from this patch, you can generally see that most architectures just
    copied (directly or indirectly) the old x86 way of doing things, but in
    the meantime that original x86 model has been improved to hold the VM
    semaphore for shorter times etc and to handle VM_FAULT_RETRY and other
    "newer" things, so it would be a good idea to bring all those
    improvements to the generic case and teach other architectures about
    them too.

    Reported-and-tested-by: Takashi Iwai
    Tested-by: Jan Engelhardt
    Acked-by: Heiko Carstens # "s390 still compiles and boots"
    Cc: linux-arch@vger.kernel.org
    Cc: stable@vger.kernel.org
    Signed-off-by: Linus Torvalds

    Linus Torvalds
     

15 Jan, 2014

1 commit

  • This is largely based on SMP code from the xtensa-2.6.29-smp tree by
    Piet Delaney, Marc Gauthier, Joe Taylor, Christian Zankel (and possibly
    other Tensilica folks).

    Signed-off-by: Max Filippov
    Signed-off-by: Chris Zankel

    Max Filippov
     

13 Sep, 2013

1 commit

  • Unlike global OOM handling, memory cgroup code will invoke the OOM killer
    in any OOM situation because it has no way of telling faults occuring in
    kernel context - which could be handled more gracefully - from
    user-triggered faults.

    Pass a flag that identifies faults originating in user space from the
    architecture-specific fault handlers to generic code so that memcg OOM
    handling can be improved.

    Signed-off-by: Johannes Weiner
    Reviewed-by: Michal Hocko
    Cc: David Rientjes
    Cc: KAMEZAWA Hiroyuki
    Cc: azurIt
    Cc: KOSAKI Motohiro
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Johannes Weiner
     

19 Dec, 2012

1 commit


16 Oct, 2012

1 commit


09 Oct, 2012

1 commit

  • .fault now can retry. The retry can break state machine of .fault. In
    filemap_fault, if page is miss, ra->mmap_miss is increased. In the second
    try, since the page is in page cache now, ra->mmap_miss is decreased. And
    these are done in one fault, so we can't detect random mmap file access.

    Add a new flag to indicate .fault is tried once. In the second try, skip
    ra->mmap_miss decreasing. The filemap_fault state machine is ok with it.

    I only tested x86, didn't test other archs, but looks the change for other
    archs is obvious, but who knows :)

    Signed-off-by: Shaohua Li
    Cc: Rik van Riel
    Cc: Wu Fengguang
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Shaohua Li
     

31 Jul, 2012

1 commit

  • Commits d065bd810b6d ("mm: retry page fault when blocking on disk
    transfer") and 37b23e0525d3 ("x86,mm: make pagefault killable")
    introduced changes into the x86 pagefault handler for making the page
    fault handler retryable as well as killable.

    These changes reduce the mmap_sem hold time, which is crucial during OOM
    killer invocation.

    Port these changes to xtensa.

    Signed-off-by: Kautuk Consul
    Acked-by: Chris Zankel
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Kautuk Consul
     

29 Mar, 2012

1 commit


05 Jun, 2010

1 commit

  • As explained in commit 1c0fe6e3bd ("mm: invoke oom-killer from page
    fault") , we want to call the architecture independent oom killer when
    getting an unexplained OOM from handle_mm_fault, rather than simply
    killing current.

    Signed-off-by: Nick Piggin
    Acked-by: David Rientjes
    Cc: Chris Zankel
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     

22 Jun, 2009

1 commit

  • This allows the callers to now pass down the full set of FAULT_FLAG_xyz
    flags to handle_mm_fault(). All callers have been (mechanically)
    converted to the new calling convention, there's almost certainly room
    for architectures to clean up their code and then add FAULT_FLAG_RETRY
    when that support is added.

    Signed-off-by: Linus Torvalds

    Linus Torvalds
     

11 Mar, 2009

1 commit


20 Oct, 2007

1 commit

  • is_init() is an ambiguous name for the pid==1 check. Split it into
    is_global_init() and is_container_init().

    A cgroup init has it's tsk->pid == 1.

    A global init also has it's tsk->pid == 1 and it's active pid namespace
    is the init_pid_ns. But rather than check the active pid namespace,
    compare the task structure with 'init_pid_ns.child_reaper', which is
    initialized during boot to the /sbin/init process and never changes.

    Changelog:

    2.6.22-rc4-mm2-pidns1:
    - Use 'init_pid_ns.child_reaper' to determine if a given task is the
    global init (/sbin/init) process. This would improve performance
    and remove dependence on the task_pid().

    2.6.21-mm2-pidns2:

    - [Sukadev Bhattiprolu] Changed is_container_init() calls in {powerpc,
    ppc,avr32}/traps.c for the _exception() call to is_global_init().
    This way, we kill only the cgroup if the cgroup's init has a
    bug rather than force a kernel panic.

    [akpm@linux-foundation.org: fix comment]
    [sukadev@us.ibm.com: Use is_global_init() in arch/m32r/mm/fault.c]
    [bunk@stusta.de: kernel/pid.c: remove unused exports]
    [sukadev@us.ibm.com: Fix capability.c to work with threaded init]
    Signed-off-by: Serge E. Hallyn
    Signed-off-by: Sukadev Bhattiprolu
    Acked-by: Pavel Emelianov
    Cc: Eric W. Biederman
    Cc: Cedric Le Goater
    Cc: Dave Hansen
    Cc: Herbert Poetzel
    Cc: Kirill Korotaev
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Serge E. Hallyn
     

17 Oct, 2007

1 commit

  • We have had complaints where a threaded application is left in a bad state
    after one of it's threads is killed when we hit a VM: out_of_memory
    condition.

    Killing just one of the process threads can leave the application in a bad
    state, whereas killing the entire process group would allow for the
    application to restart, or be otherwise handled, and makes it very obvious
    that something has gone wrong.

    This change allows the entire process group to be taken down, rather
    than just the one thread.

    Signed-off-by: Will Schmidt
    Cc: Richard Henderson
    Cc: Ivan Kokshaysky
    Cc: Russell King
    Cc: Ian Molton
    Cc: Haavard Skinnemoen
    Cc: Mikael Starvik
    Cc: David Howells
    Cc: Andi Kleen
    Cc: "Luck, Tony"
    Cc: Hirokazu Takata
    Cc: Geert Uytterhoeven
    Cc: Roman Zippel
    Cc: Ralf Baechle
    Cc: Kyle McMartin
    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: Chris Zankel
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Will Schmidt
     

28 Aug, 2007

1 commit

  • Add support for processors that have cache-aliasing issues, such as
    the Stretch S5000 processor. Cache-aliasing means that the size of
    the cache (for one way) is larger than the page size, thus, a page
    can end up in several places in cache depending on the virtual to
    physical translation. The method used here is to map a user page
    temporarily through the auto-refill way 0 and of of the DTLB.
    We probably will want to revisit this issue and use a better
    approach with kmap/kunmap.

    Signed-off-by: Chris Zankel

    Chris Zankel
     

20 Jul, 2007

1 commit

  • 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
     

11 Dec, 2006

1 commit

  • The Xtensa port contained many header files that were never needed. This
    rather lengthy patch removes all those files. Unfortunately, there were
    many dependencies that needed to be updated, so this patch touches quite a
    few source files.

    Signed-off-by: Chris Zankel
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Chris Zankel
     

30 Sep, 2006

1 commit

  • This is an updated version of Eric Biederman's is_init() patch.
    (http://lkml.org/lkml/2006/2/6/280). It applies cleanly to 2.6.18-rc3 and
    replaces a few more instances of ->pid == 1 with is_init().

    Further, is_init() checks pid and thus removes dependency on Eric's other
    patches for now.

    Eric's original description:

    There are a lot of places in the kernel where we test for init
    because we give it special properties. Most significantly init
    must not die. This results in code all over the kernel test
    ->pid == 1.

    Introduce is_init to capture this case.

    With multiple pid spaces for all of the cases affected we are
    looking for only the first process on the system, not some other
    process that has pid == 1.

    Signed-off-by: Eric W. Biederman
    Signed-off-by: Sukadev Bhattiprolu
    Cc: Dave Hansen
    Cc: Serge Hallyn
    Cc: Cedric Le Goater
    Cc:
    Acked-by: Paul Mackerras
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Sukadev Bhattiprolu
     

24 Jun, 2005

1 commit