16 Jun, 2011

40 commits

  • Commit a77aea92010acf ("cgroup: remove the ns_cgroup") removed the
    ns_cgroup but it forgot to remove the related doc in
    feature-removal-schedule.txt.

    Signed-off-by: WANG Cong
    Cc: Daniel Lezcano
    Cc: Serge E. Hallyn
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    akpm@linux-foundation.org
     
  • Asynchronous compaction is used when promoting to huge pages. This is all
    very nice but if there are a number of processes in compacting memory, a
    large number of pages can be isolated. An "asynchronous" process can
    stall for long periods of time as a result with a user reporting that
    firefox can stall for 10s of seconds. This patch aborts asynchronous
    compaction if too many pages are isolated as it's better to fail a
    hugepage promotion than stall a process.

    [minchan.kim@gmail.com: return COMPACT_PARTIAL for abort]
    Reported-and-tested-by: Ury Stankevich
    Signed-off-by: Mel Gorman
    Reviewed-by: Minchan Kim
    Reviewed-by: Michal Hocko
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Mel Gorman
     
  • It is unsafe to run page_count during the physical pfn scan because
    compound_head could trip on a dangling pointer when reading
    page->first_page if the compound page is being freed by another CPU.

    [mgorman@suse.de: split out patch]
    Signed-off-by: Andrea Arcangeli
    Signed-off-by: Mel Gorman
    Reviewed-by: Michal Hocko
    Reviewed-by: Minchan Kim

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

    Andrea Arcangeli
     
  • Compaction works with two scanners, a migration and a free scanner. When
    the scanners crossover, migration within the zone is complete. The
    location of the scanner is recorded on each cycle to avoid excesive
    scanning.

    When a zone is small and mostly reserved, it's very easy for the migration
    scanner to be close to the end of the zone. Then the following situation
    can occurs

    o migration scanner isolates some pages near the end of the zone
    o free scanner starts at the end of the zone but finds that the
    migration scanner is already there
    o free scanner gets reinitialised for the next cycle as
    cc->migrate_pfn + pageblock_nr_pages
    moving the free scanner into the next zone
    o migration scanner moves into the next zone

    When this happens, NR_ISOLATED accounting goes haywire because some of the
    accounting happens against the wrong zone. One zones counter remains
    positive while the other goes negative even though the overall global
    count is accurate. This was reported on X86-32 with !SMP because !SMP
    allows the negative counters to be visible. The fact that it is the bug
    should theoritically be possible there.

    Signed-off-by: Mel Gorman
    Reviewed-by: Minchan Kim
    Reviewed-by: Michal Hocko
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Mel Gorman
     
  • fragmentation_index() returns -1000 when the allocation might succeed
    This doesn't match the comment and code in compaction_suitable(). I
    thought compaction_suitable should return COMPACT_PARTIAL in -1000
    case, because in this case allocation could succeed depending on
    watermarks.

    The impact of this is that compaction starts and compact_finished() is
    called which rechecks the watermarks and the free lists. It should have
    the same result in that compaction should not start but is more expensive.

    Acked-by: Mel Gorman
    Signed-off-by: Shaohua Li
    Cc: Minchan Kim
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Shaohua Li
     
  • Pages isolated for migration are accounted with the vmstat counters
    NR_ISOLATE_[ANON|FILE]. Callers of migrate_pages() are expected to
    increment these counters when pages are isolated from the LRU. Once the
    pages have been migrated, they are put back on the LRU or freed and the
    isolated count is decremented.

    Memory failure is not properly accounting for pages it isolates causing
    the NR_ISOLATED counters to be negative. On SMP builds, this goes
    unnoticed as negative counters are treated as 0 due to expected per-cpu
    drift. On UP builds, the counter is treated by too_many_isolated() as a
    large value causing processes to enter D state during page reclaim or
    compaction. This patch accounts for pages isolated by memory failure
    correctly.

    [mel@csn.ul.ie: rewrote changelog]
    Reviewed-by: Andrea Arcangeli
    Signed-off-by: Minchan Kim
    Cc: Andi Kleen
    Acked-by: Mel Gorman
    Cc:
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Minchan Kim
     
  • CONFIG_CONSTRUCTORS controls support for running constructor functions at
    kernel init time. According to commit b99b87f70c7785ab ("kernel:
    constructor support"), gcov (CONFIG_GCOV_KERNEL) needs this. However,
    CONFIG_CONSTRUCTORS currently defaults to y, with no option to disable it,
    and CONFIG_GCOV_KERNEL depends on it. Instead, default it to n and have
    CONFIG_GCOV_KERNEL select it, so that the normal case of
    CONFIG_GCOV_KERNEL=n will result in CONFIG_CONSTRUCTORS=n.

    Observed in the short list of =y values in a minimal kernel configuration.

    Signed-off-by: Josh Triplett
    Acked-by: WANG Cong
    Acked-by: Peter Oberparleiter
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Josh Triplett
     
  • I shall maintain the legacy eeprom driver, until we finally get rid of it.

    Signed-off-by: Jean Delvare
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Jean Delvare
     
  • Based on Michal Hocko's comment.

    We are not draining per cpu cached charges during soft limit reclaim
    because background reclaim doesn't care about charges. It tries to free
    some memory and charges will not give any.

    Cached charges might influence only selection of the biggest soft limit
    offender but as the call is done only after the selection has been already
    done it makes no change.

    Signed-off-by: KAMEZAWA Hiroyuki
    Cc: Daisuke Nishimura
    Reviewed-by: Michal Hocko
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    KAMEZAWA Hiroyuki
     
  • For performance, memory cgroup caches some "charge" from res_counter into
    per cpu cache. This works well but because it's cache, it needs to be
    flushed in some cases. Typical cases are

    1. when someone hit limit.

    2. when rmdir() is called and need to charges to be 0.

    But "1" has problem.

    Recently, with large SMP machines, we see many kworker runs because of
    flushing memcg's cache. Bad things in implementation are that even if a
    cpu contains a cache for memcg not related to a memcg which hits limit,
    drain code is called.

    This patch does
    A) check percpu cache contains a useful data or not.
    B) check other asynchronous percpu draining doesn't run.
    C) don't call local cpu callback.

    (*)This patch avoid changing the calling condition with hard-limit.

    When I run "cat 1Gfile > /dev/null" under 300M limit memcg,

    [Before]
    13767 kamezawa 20 0 98.6m 424 416 D 10.0 0.0 0:00.61 cat
    58 root 20 0 0 0 0 S 0.6 0.0 0:00.09 kworker/2:1
    60 root 20 0 0 0 0 S 0.6 0.0 0:00.08 kworker/4:1
    4 root 20 0 0 0 0 S 0.3 0.0 0:00.02 kworker/0:0
    57 root 20 0 0 0 0 S 0.3 0.0 0:00.05 kworker/1:1
    61 root 20 0 0 0 0 S 0.3 0.0 0:00.05 kworker/5:1
    62 root 20 0 0 0 0 S 0.3 0.0 0:00.05 kworker/6:1
    63 root 20 0 0 0 0 S 0.3 0.0 0:00.05 kworker/7:1

    [After]
    2676 root 20 0 98.6m 416 416 D 9.3 0.0 0:00.87 cat
    2626 kamezawa 20 0 15192 1312 920 R 0.3 0.0 0:00.28 top
    1 root 20 0 19384 1496 1204 S 0.0 0.0 0:00.66 init
    2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd
    3 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/0
    4 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kworker/0:0

    [akpm@linux-foundation.org: make percpu_charge_mutex static, tweak comments]
    Signed-off-by: KAMEZAWA Hiroyuki
    Acked-by: Daisuke Nishimura
    Reviewed-by: Michal Hocko
    Tested-by: Ying Han
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    KAMEZAWA Hiroyuki
     
  • Hierarchical reclaim doesn't swap out if memsw and resource limits are
    thye same (memsw_is_minimum == true) because we would hit mem+swap limit
    anyway (during hard limit reclaim).

    If it comes to the soft limit we shouldn't consider memsw_is_minimum at
    all because it doesn't make much sense. Either the soft limit is bellow
    the hard limit and then we cannot hit mem+swap limit or the direct reclaim
    takes a precedence.

    Signed-off-by: KAMEZAWA Hiroyuki
    Reviewed-by: Michal Hocko
    Acked-by: Daisuke Nishimura
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    KAMEZAWA Hiroyuki
     
  • The following crash was reported:

    > Call Trace:
    > [] mem_cgroup_from_task+0x15/0x17
    > [] __mem_cgroup_try_charge+0x148/0x4b4
    > [] ? need_resched+0x23/0x2d
    > [] ? preempt_schedule+0x46/0x4f
    > [] mem_cgroup_charge_common+0x9a/0xce
    > [] mem_cgroup_newpage_charge+0x5d/0x5f
    > [] khugepaged+0x5da/0xfaf
    > [] ? __init_waitqueue_head+0x4b/0x4b
    > [] ? add_mm_counter.constprop.5+0x13/0x13
    > [] kthread+0xa8/0xb0
    > [] ? sub_preempt_count+0xa1/0xb4
    > [] kernel_thread_helper+0x4/0x10
    > [] ? retint_restore_args+0x13/0x13
    > [] ? __init_kthread_worker+0x5a/0x5a

    What happens is that khugepaged tries to charge a huge page against an mm
    whose last possible owner has already exited, and the memory controller
    crashes when the stale mm->owner is used to look up the cgroup to charge.

    mm->owner has never been set to NULL with the last owner going away, but
    nobody cared until khugepaged came along.

    Even then it wasn't a problem because the final mmput() on an mm was
    forced to acquire and release mmap_sem in write-mode, preventing an
    exiting owner to go away while the mmap_sem was held, and until "692e0b3
    mm: thp: optimize memcg charge in khugepaged", the memory cgroup charge
    was protected by mmap_sem in read-mode.

    Instead of going back to relying on the mmap_sem to enforce lifetime of a
    task, this patch ensures that mm->owner is properly set to NULL when the
    last possible owner is exiting, which the memory controller can handle
    just fine.

    [akpm@linux-foundation.org: tweak comments]
    Signed-off-by: Hugh Dickins
    Signed-off-by: KAMEZAWA Hiroyuki
    Signed-off-by: Johannes Weiner
    Reported-by: Hugh Dickins
    Reported-by: Dave Jones
    Reviewed-by: Andrea Arcangeli
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    KAMEZAWA Hiroyuki
     
  • Commit 21a3c9646873 ("memcg: allocate memory cgroup structures in local
    nodes") makes page_cgroup allocation as NUMA aware. But that caused a
    problem https://bugzilla.kernel.org/show_bug.cgi?id=36192.

    The problem was getting a NID from invalid struct pages, which was not
    initialized because it was out-of-node, out of [node_start_pfn,
    node_end_pfn)

    Now, with sparsemem, page_cgroup_init scans pfn from 0 to max_pfn. But
    this may scan a pfn which is not on any node and can access memmap which
    is not initialized.

    This makes page_cgroup_init() for SPARSEMEM node aware and remove a code
    to get nid from page->flags. (Then, we'll use valid NID always.)

    [akpm@linux-foundation.org: try to fix up comments]
    Signed-off-by: KAMEZAWA Hiroyuki
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    KAMEZAWA Hiroyuki
     
  • Commit 406eb0c9ba76 ("memcg: add memory.numastat api for numa
    statistics") adds memory.numa_stat file for memory cgroup. But the file
    permissions are wrong.

    [kamezawa@bluextal linux-2.6]$ ls -l /cgroup/memory/A/memory.numa_stat
    ---------- 1 root root 0 Jun 9 18:36 /cgroup/memory/A/memory.numa_stat

    This patch fixes the permission as

    [root@bluextal kamezawa]# ls -l /cgroup/memory/A/memory.numa_stat
    -r--r--r-- 1 root root 0 Jun 10 16:49 /cgroup/memory/A/memory.numa_stat

    Signed-off-by: KAMEZAWA Hiroyuki
    Acked-by: Ying Han
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    KAMEZAWA Hiroyuki
     
  • Seems when a config option does not have a dependency of the menuconfig,
    it messes the display of the rest configs, even if it's a hidden one.

    Signed-off-by: Eric Miao
    Cc: Richard Purdie
    Cc: Valdis Kletnieks
    Cc: Randy Dunlap
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Eric Miao
     
  • When 1GB hugepages are allocated on a system, free(1) reports less
    available memory than what really is installed in the box. Also, if the
    total size of hugepages allocated on a system is over half of the total
    memory size, CommitLimit becomes a negative number.

    The problem is that gigantic hugepages (order > MAX_ORDER) can only be
    allocated at boot with bootmem, thus its frames are not accounted to
    'totalram_pages'. However, they are accounted to hugetlb_total_pages()

    What happens to turn CommitLimit into a negative number is this
    calculation, in fs/proc/meminfo.c:

    allowed = ((totalram_pages - hugetlb_total_pages())
    * sysctl_overcommit_ratio / 100) + total_swap_pages;

    A similar calculation occurs in __vm_enough_memory() in mm/mmap.c.

    Also, every vm statistic which depends on 'totalram_pages' will render
    confusing values, as if system were 'missing' some part of its memory.

    Impact of this bug:

    When gigantic hugepages are allocated and sysctl_overcommit_memory ==
    OVERCOMMIT_NEVER. In a such situation, __vm_enough_memory() goes through
    the mentioned 'allowed' calculation and might end up mistakenly returning
    -ENOMEM, thus forcing the system to start reclaiming pages earlier than it
    would be ususal, and this could cause detrimental impact to overall
    system's performance, depending on the workload.

    Besides the aforementioned scenario, I can only think of this causing
    annoyances with memory reports from /proc/meminfo and free(1).

    [akpm@linux-foundation.org: standardize comment layout]
    Reported-by: Russ Anderson
    Signed-off-by: Rafael Aquini
    Acked-by: Russ Anderson
    Cc: Andrea Arcangeli
    Cc: Christoph Lameter
    Cc:
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Rafael Aquini
     
  • During memory hotplug we refresh zonelists when we online a page in a new
    zone. It means that the node's zonelist is not initialized until pages
    are onlined. So for example, "nid" passed by MEM_GOING_ONLINE notifier
    will point to NODE_DATA(nid) which has no zone fallback list. Moreover,
    if we hot-add cpu-only nodes, alloc_pages() will do no fallback.

    This patch makes a zonelist when a new pgdata is available.

    Note: in production, at fujitsu, memory should be onlined before cpu
    and our server didn't have any memory-less nodes and had no problems.

    But recent changes in MEM_GOING_ONLINE+page_cgroup
    will access not initialized zonelist of node.
    Anyway, there are memory-less node and we need some care.

    Signed-off-by: KAMEZAWA Hiroyuki
    Cc: Mel Gorman
    Cc: Dave Hansen
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    KAMEZAWA Hiroyuki
     
  • Remove calibrate_delay_direct()'s KERN_DEBUG printk related to bogomips
    calculation as it appears when booting every core on setups with
    'ignore_loglevel' which dmesg people scan for possible issues. As the
    message doesn't show very useful information to the widest audience of
    kernel boot message gazers, it should be removed.

    Introduced by commit d2b463135f84 ("init/calibrate.c: fix for critical
    bogoMIPS intermittent calculation failure").

    Signed-off-by: Borislav Petkov
    Cc: Andrew Worsley
    Cc: Phil Carmody
    Cc: Peter Zijlstra
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Borislav Petkov
     
  • On m68k (which doesn't support generic hardirqs yet):

    drivers/w1/masters/ds1wm.c: In function `ds1wm_probe':
    drivers/w1/masters/ds1wm.c: error: implicit declaration of function `irq_set_irq_type'

    Signed-off-by: Geert Uytterhoeven
    Cc: Evgeniy Polyakov
    Cc: Jean-Franois Dagenais
    Cc: Matt Reimer
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Geert Uytterhoeven
     
  • Signed-off-by: Nicolas Kaiser
    Reviewed-by: Andrea Arcangeli
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nicolas Kaiser
     
  • Add maintainers for the videobuf2 V4L2 driver framework.

    Signed-off-by: Pawel Osciak
    Acked-by: Marek Szyprowski
    Cc: Mauro Carvalho Chehab
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Pawel Osciak
     
  • Commit 4440673a95e6 ("leds: provide helper to register "leds-gpio"
    devices") broke the display of the NEW_LEDS menu as it didn't depend on
    NEW_LEDS and so made "LED drivers" and "LED Triggers" appear at the same
    level as "LED Support" instead of below it as it was before 4440673a.

    Moving LEDS_GPIO_REGISTER out of the menuconfig NEW_LEDS fixes this
    unintended side effect.

    Reported-by: Axel Lin
    Signed-off-by: Uwe Kleine-König
    Cc: Richard Purdie
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Uwe Kleine-König
     
  • We call led_classdev_unregister/led_classdev_register in
    asic3_led_remove/asic3_led_probe, thus make LEDS_ASIC3 depend on
    LEDS_CLASS.

    This patch fixes below build error if LEDS_CLASS is not configured.

    LD .tmp_vmlinux1
    drivers/built-in.o: In function `asic3_led_remove':
    clkdev.c:(.devexit.text+0x1860): undefined reference to `led_classdev_unregister'
    drivers/built-in.o: In function `asic3_led_probe':
    clkdev.c:(.devinit.text+0xcee8): undefined reference to `led_classdev_register'
    make: *** [.tmp_vmlinux1] Error 1

    Signed-off-by: Axel Lin
    Cc: Paul Parsons
    Cc: Richard Purdie
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Axel Lin
     
  • Update my email address. Email will start to the old address bouncing
    soon

    Signed-off-by: Balbir Singh
    Cc: Balbir Singh
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Balbir Singh
     
  • The "hostname" tool falls back to setting the hostname to "localhost" if
    /etc/hostname does not exist. Distribution init scripts have the same
    fallback. However, if userspace never calls sethostname, such as when
    booting with init=/bin/sh, or otherwise booting a minimal system without
    the usual init scripts, the default hostname of "(none)" remains,
    unhelpfully appearing in various places such as prompts ("root@(none):~#")
    and logs. Furthermore, "(none)" doesn't typically resolve to anything
    useful.

    Make the default hostname configurable. This removes the need for the
    standard fallback, provides a useful default for systems that never call
    sethostname, and makes minimal systems that much more useful with less
    configuration. Distributions could choose to use "localhost" here to
    avoid the fallback, while embedded systems may wish to use a specific
    target hostname.

    Signed-off-by: Josh Triplett
    Acked-by: Linus Torvalds
    Acked-by: David Miller
    Cc: Serge Hallyn
    Cc: Kel Modderman
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Josh Triplett
     
  • BUILD_BUG_ON_ZERO and BUILD_BUG_ON_NULL must return values, even in the
    CHECKER case otherwise various users of it become syntactically invalid.

    Signed-off-by: Dr. David Alan Gilbert
    Reviewed-by: KOSAKI Motohiro
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Dr. David Alan Gilbert
     
  • Commit 56de7263fcf3 ("mm: compaction: direct compact when a high-order
    allocation fails") introduced a check for cc->order == -1 in
    compact_finished. We should continue compacting in that case because
    the request came from userspace and there is no particular order to
    compact for. Similar check has been added by 82478fb7 (mm: compaction:
    prevent division-by-zero during user-requested compaction) for
    compaction_suitable.

    The check is, however, done after zone_watermark_ok which uses order as a
    right hand argument for shifts. Not only watermark check is pointless if
    we can break out without it but it also uses 1 << -1 which is not well
    defined (at least from C standard). Let's move the -1 check above
    zone_watermark_ok.

    [minchan.kim@gmail.com> - caught compaction_suitable]
    Signed-off-by: Michal Hocko
    Cc: Mel Gorman
    Reviewed-by: Minchan Kim
    Reviewed-by: KAMEZAWA Hiroyuki
    Acked-by: Mel Gorman
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Michal Hocko
     
  • Running a ktest.pl test, I hit the following bug on x86_32:

    ------------[ cut here ]------------
    WARNING: at arch/x86/mm/highmem_32.c:81 __kunmap_atomic+0x64/0xc1()
    Hardware name:
    Modules linked in:
    Pid: 93, comm: sh Not tainted 2.6.39-test+ #1
    Call Trace:
    [] warn_slowpath_common+0x7c/0x91
    [] ? __kunmap_atomic+0x64/0xc1
    [] ? __kunmap_atomic+0x64/0xc1^M
    [] warn_slowpath_null+0x22/0x24
    [] __kunmap_atomic+0x64/0xc1
    [] unmap_vmas+0x43a/0x4e0
    [] exit_mmap+0x91/0xd2
    [] mmput+0x43/0xad
    [] exit_mm+0x111/0x119
    [] do_exit+0x1ff/0x5fa
    [] ? set_current_blocked+0x3c/0x40
    [] ? sigprocmask+0x7e/0x8e
    [] do_group_exit+0x65/0x88
    [] sys_exit_group+0x18/0x1c
    [] sysenter_do_call+0x12/0x38
    ---[ end trace 8055f74ea3c0eb62 ]---

    Running a ktest.pl git bisect, found the culprit: commit e303297e6c3a
    ("mm: extended batches for generic mmu_gather")

    But although this was the commit triggering the bug, it was not the one
    originally responsible for the bug. That was commit d16dfc550f53 ("mm:
    mmu_gather rework").

    The code in zap_pte_range() has something that looks like the following:

    pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
    do {
    [...]
    } while (pte++, addr += PAGE_SIZE, addr != end);
    pte_unmap_unlock(pte - 1, ptl);

    The pte starts off pointing at the first element in the page table
    directory that was returned by the pte_offset_map_lock(). When it's done
    with the page, pte will be pointing to anything between the next entry and
    the first entry of the next page inclusive. By doing a pte - 1, this puts
    the pte back onto the original page, which is all that pte_unmap_unlock()
    needs.

    In most archs (64 bit), this is not an issue as the pte is ignored in the
    pte_unmap_unlock(). But on 32 bit archs, where things may be kmapped, it
    is essential that the pte passed to pte_unmap_unlock() resides on the same
    page that was given by pte_offest_map_lock().

    The problem came in d16dfc55 ("mm: mmu_gather rework") where it introduced
    a "break;" from the while loop. This alone did not seem to easily trigger
    the bug. But the modifications made by e303297e6 caused that "break;" to
    be hit on the first iteration, before the pte++.

    The pte not being incremented will now cause pte_unmap_unlock(pte - 1) to
    be pointing to the previous page. This will cause the wrong page to be
    unmapped, and also trigger the warning above.

    The simple solution is to just save the pointer given by
    pte_offset_map_lock() and use it in the unlock.

    Signed-off-by: Steven Rostedt
    Cc: Peter Zijlstra
    Cc: KAMEZAWA Hiroyuki
    Acked-by: Hugh Dickins
    Cc: Mel Gorman
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Steven Rostedt
     
  • Fix the wrong `if' condition for the check if the requested timer is
    available.

    The bitmap avail is used to store if a timer is used already. test_bit()
    is used to check if the requested timer is available. If a bit in the
    avail bitmap is set it means that the timer is available.

    The runtime effect would be that allocating a specific timer always fails
    (versus telling cs5535_mfgpt_alloc_timer to allocate the first available
    timer, which works).

    Signed-off-by: Christian Gmeiner
    Acked-by: Andres Salomon
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christian Gmeiner
     
  • In the case of goto err_kzalloc, we should kfree target.

    Signed-off-by: Axel Lin
    Acked-by: Pratyush Anand
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Axel Lin
     
  • Recently, Robert Mueller reported (http://lkml.org/lkml/2010/9/12/236)
    that zone_reclaim_mode doesn't work properly on his new NUMA server (Dual
    Xeon E5520 + Intel S5520UR MB). He is using Cyrus IMAPd and it's built on
    a very traditional single-process model.

    * a master process which reads config files and manages the other
    process
    * multiple imapd processes, one per connection
    * multiple pop3d processes, one per connection
    * multiple lmtpd processes, one per connection
    * periodical "cleanup" processes.

    There are thousands of independent processes. The problem is, recent
    Intel motherboard turn on zone_reclaim_mode by default and traditional
    prefork model software don't work well on it. Unfortunatelly, such models
    are still typical even in the 21st century. We can't ignore them.

    This patch raises the zone_reclaim_mode threshold to 30. 30 doesn't have
    any specific meaning. but 20 means that one-hop QPI/Hypertransport and
    such relatively cheap 2-4 socket machine are often used for traditional
    servers as above. The intention is that these machines don't use
    zone_reclaim_mode.

    Note: ia64 and Power have arch specific RECLAIM_DISTANCE definitions.
    This patch doesn't change such high-end NUMA machine behavior.

    Dave Hansen said:

    : I know specifically of pieces of x86 hardware that set the information
    : in the BIOS to '21' *specifically* so they'll get the zone_reclaim_mode
    : behavior which that implies.
    :
    : They've done performance testing and run very large and scary benchmarks
    : to make sure that they _want_ this turned on. What this means for them
    : is that they'll probably be de-optimized, at least on newer versions of
    : the kernel.
    :
    : If you want to do this for particular systems, maybe _that_'s what we
    : should do. Have a list of specific configurations that need the
    : defaults overridden either because they're buggy, or they have an
    : unusual hardware configuration not really reflected in the distance
    : table.

    And later said:

    : The original change in the hardware tables was for the benefit of a
    : benchmark. Said benchmark isn't going to get run on mainline until the
    : next batch of enterprise distros drops, at which point the hardware where
    : this was done will be irrelevant for the benchmark. I'm sure any new
    : hardware will just set this distance to another yet arbitrary value to
    : make the kernel do what it wants. :)
    :
    : Also, when the hardware got _set_ to this initially, I complained. So, I
    : guess I'm getting my way now, with this patch. I'm cool with it.

    Reported-by: Robert Mueller
    Signed-off-by: KOSAKI Motohiro
    Acked-by: Christoph Lameter
    Acked-by: David Rientjes
    Reviewed-by: KAMEZAWA Hiroyuki
    Cc: Benjamin Herrenschmidt
    Cc: "Luck, Tony"
    Acked-by: Dave Hansen
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    KOSAKI Motohiro
     
  • Warn about uses of printk_ratelimit() because it uses a global state and
    can hide subsequent useful messages.

    Signed-off-by: Joe Perches
    Cc: Andy Whitcroft
    Cc: Richard Weinberger
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Joe Perches
     
  • Fix when CONFIG_PRINTK is not enabled:

    include/linux/kmsg_dump.h:56: error: 'EINVAL' undeclared (first use in this function)
    include/linux/kmsg_dump.h:61: error: 'EINVAL' undeclared (first use in this function)

    Looks like commit 595dd3d8bf95 ("kmsg_dump: fix build for
    CONFIG_PRINTK=n") uses EINVAL without having the needed header file(s),
    but I'm sure that I build tested that patch also. oh well.

    Signed-off-by: Randy Dunlap
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Randy Dunlap
     
  • [akpm@linux-foundation.org: rework text, fit it into 80-cols]
    Signed-off-by: Ying Han
    Reviewed-by: KOSAKI Motohiro
    Acked-by: Balbir Singh
    Acked-by: KAMEZAWA Hiroyuki
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Ying Han
     
  • While testing for memcg aware swap token, I observed a swap token was
    often grabbed an intermittent running process (eg init, auditd) and they
    never release a token.

    Why?

    Some processes (eg init, auditd, audispd) wake up when a process exiting.
    And swap token can be get first page-in process when a process exiting
    makes no swap token owner. Thus such above intermittent running process
    often get a token.

    And currently, swap token priority is only decreased at page fault path.
    Then, if the process sleep immediately after to grab swap token, the swap
    token priority never be decreased. That's obviously undesirable.

    This patch implement very poor (and lightweight) priority aging. It only
    be affect to the above corner case and doesn't change swap tendency
    workload performance (eg multi process qsbench load)

    Signed-off-by: KOSAKI Motohiro
    Reviewed-by: Rik van Riel
    Reviewed-by: KAMEZAWA Hiroyuki
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    KOSAKI Motohiro
     
  • This is useful for observing swap token activity.

    example output:

    zsh-1845 [000] 598.962716: update_swap_token_priority:
    mm=ffff88015eaf7700 old_prio=1 new_prio=0
    memtoy-1830 [001] 602.033900: update_swap_token_priority:
    mm=ffff880037a45880 old_prio=947 new_prio=949
    memtoy-1830 [000] 602.041509: update_swap_token_priority:
    mm=ffff880037a45880 old_prio=949 new_prio=951
    memtoy-1830 [000] 602.051959: update_swap_token_priority:
    mm=ffff880037a45880 old_prio=951 new_prio=953
    memtoy-1830 [000] 602.052188: update_swap_token_priority:
    mm=ffff880037a45880 old_prio=953 new_prio=955
    memtoy-1830 [001] 602.427184: put_swap_token:
    token_mm=ffff880037a45880
    zsh-1789 [000] 602.427281: replace_swap_token:
    old_token_mm= (null) old_prio=0 new_token_mm=ffff88015eaf7018
    new_prio=2
    zsh-1789 [001] 602.433456: update_swap_token_priority:
    mm=ffff88015eaf7018 old_prio=2 new_prio=4
    zsh-1789 [000] 602.437613: update_swap_token_priority:
    mm=ffff88015eaf7018 old_prio=4 new_prio=6
    zsh-1789 [000] 602.443924: update_swap_token_priority:
    mm=ffff88015eaf7018 old_prio=6 new_prio=8
    zsh-1789 [000] 602.451873: update_swap_token_priority:
    mm=ffff88015eaf7018 old_prio=8 new_prio=10
    zsh-1789 [001] 602.462639: update_swap_token_priority:
    mm=ffff88015eaf7018 old_prio=10 new_prio=12

    Signed-off-by: KOSAKI Motohiro
    Acked-by: Rik van Riel
    Reviewed-by: KAMEZAWA Hiroyuki
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    KOSAKI Motohiro
     
  • Currently, memcg reclaim can disable swap token even if the swap token mm
    doesn't belong in its memory cgroup. It's slightly risky. If an admin
    creates very small mem-cgroup and silly guy runs contentious heavy memory
    pressure workload, every tasks are going to lose swap token and then
    system may become unresponsive. That's bad.

    This patch adds 'memcg' parameter into disable_swap_token(). and if the
    parameter doesn't match swap token, VM doesn't disable it.

    [akpm@linux-foundation.org: coding-style fixes]
    Signed-off-by: KOSAKI Motohiro
    Reviewed-by: KAMEZAWA Hiroyuki
    Reviewed-by: Rik van Riel
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    KOSAKI Motohiro
     
  • Cc: Michael Hennerich
    Cc: Mike Frysinger
    Cc: Matthew Garrett
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Andrew Morton
     
  • Signed-off-by: Michael Hennerich
    Signed-off-by: Mike Frysinger
    Cc: Richard Purdie
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Michael Hennerich
     
  • Commit a8bef8ff6ea1 ("mm: migration: avoid race between shift_arg_pages()
    and rmap_walk() during migration by not migrating temporary stacks")
    introduced a BUG_ON() to ensure that VM_STACK_FLAGS and
    VM_STACK_INCOMPLETE_SETUP do not overlap. The check is a compile time
    one, so BUILD_BUG_ON is more appropriate.

    Signed-off-by: Michal Hocko
    Cc: Mel Gorman
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Michal Hocko