1. 10 Oct, 2014 40 commits
    • Paul McQuade's avatar
      mm: ksm use pr_err instead of printk · 25acde31
      Paul McQuade authored
      WARNING: Prefer: pr_err(...  to printk(KERN_ERR ...
      
      [akpm@linux-foundation.org: remove KERN_ERR]
      Signed-off-by: default avatarPaul McQuade <paulmcquad@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      25acde31
    • Yasuaki Ishimatsu's avatar
      drivers/firmware/memmap.c: don't create memmap sysfs of same firmware_map_entry · 22880ebe
      Yasuaki Ishimatsu authored
      By the following commits, we prevented from allocating firmware_map_entry
      of same memory range:
        f0093ede: drivers/firmware/memmap.c: don't allocate firmware_map_entry
                  of same memory range
        49c8b24d: drivers/firmware/memmap.c: pass the correct argument to
                  firmware_map_find_entry_bootmem()
      
      But it's not enough. When PNP0C80 device is added by acpi_scan_init(),
      memmap sysfses of same firmware_map_entry are created twice as follows:
      
        # cat /sys/firmware/memmap/*/start
        0x40000000000
        0x60000000000
        0x4a837000
        0x4a83a000
        0x4a8b5000
        ...
        0x40000000000
        0x60000000000
        ...
      
      The flows of the issues are as follows:
      
        1. e820_reserve_resources() allocates firmware_map_entrys of all
           memory ranges defined in e820. And, these firmware_map_entrys
           are linked with map_entries list.
      
           map_entries -> entry 1 -> ... -> entry N
      
        2. When PNP0C80 device is limited by mem= boot option, acpi_scan_init()
           added the memory device. In this case, firmware_map_add_hotplug()
           allocates firmware_map_entry and creates memmap sysfs.
      
           map_entries -> entry 1 -> ... -> entry N -> entry N+1
                                                       |
                                                       memmap 1
      
        3. firmware_memmap_init() creates memmap sysfses of firmware_map_entrys
           linked with map_entries.
      
           map_entries -> entry 1 -> ... -> entry N -> entry N+1
                           |                 |             |
                           memmap 2          memmap N+1    memmap 1
                                                           memmap N+2
      
      So while hot removing the PNP0C80 device, kernel panic occurs as follows:
      
           BUG: unable to handle kernel paging request at 00000001003e000b
            IP: sysfs_open_file+0x46/0x2b0
            PGD 203a89fe067 PUD 0
            Oops: 0000 [#1] SMP
            ...
            Call Trace:
              do_dentry_open+0x1ef/0x2a0
              finish_open+0x31/0x40
              do_last+0x57c/0x1220
              path_openat+0xc2/0x4c0
              do_filp_open+0x4b/0xb0
              do_sys_open+0xf3/0x1f0
              SyS_open+0x1e/0x20
              system_call_fastpath+0x16/0x1b
      
      The patch adds a check of confirming whether memmap sysfs of
      firmware_map_entry has been created, and does not create memmap
      sysfs of same firmware_map_entry.
      Signed-off-by: default avatarYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
      Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
      Cc: Toshi Kani <toshi.kani@hp.com>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      22880ebe
    • Paul McQuade's avatar
      mm/bootmem.c: use include/linux/ headers · d85fbee8
      Paul McQuade authored
      Replace asm. headers with linux/headers:
      
      <linux/bug.h>
      <linux/io.h>
      Signed-off-by: default avatarPaul McQuade <paulmcquad@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d85fbee8
    • Paul McQuade's avatar
    • Paul McQuade's avatar
      mm/mremap.c: use linux headers · 2581d202
      Paul McQuade authored
      "WARNING: Use #include <linux/uaccess.h> instead of <asm/uaccess.h>"
      Signed-off-by: default avatarPaul McQuade <paulmcquad@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2581d202
    • Vladimir Davydov's avatar
      memcg: zap memcg_can_account_kmem · cf2b8fbf
      Vladimir Davydov authored
      memcg_can_account_kmem() returns true iff
      
          !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) &&
                                         memcg_kmem_is_active(memcg);
      
      To begin with the !mem_cgroup_is_root(memcg) check is useless, because one
      can't enable kmem accounting for the root cgroup (mem_cgroup_write()
      returns EINVAL on an attempt to set the limit on the root cgroup).
      
      Furthermore, the !mem_cgroup_disabled() check also seems to be redundant.
      The point is memcg_can_account_kmem() is called from three places:
      mem_cgroup_salbinfo_read(), __memcg_kmem_get_cache(), and
      __memcg_kmem_newpage_charge().  The latter two functions are only invoked
      if memcg_kmem_enabled() returns true, which implies that the memory cgroup
      subsystem is enabled.  And mem_cgroup_slabinfo_read() shows the output of
      memory.kmem.slabinfo, which won't exist if the memory cgroup is completely
      disabled.
      
      So let's substitute all the calls to memcg_can_account_kmem() with plain
      memcg_kmem_is_active(), and kill the former.
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      cf2b8fbf
    • Johannes Weiner's avatar
      mm: memcontrol: fix transparent huge page allocations under pressure · b70a2a21
      Johannes Weiner authored
      In a memcg with even just moderate cache pressure, success rates for
      transparent huge page allocations drop to zero, wasting a lot of effort
      that the allocator puts into assembling these pages.
      
      The reason for this is that the memcg reclaim code was never designed for
      higher-order charges.  It reclaims in small batches until there is room
      for at least one page.  Huge page charges only succeed when these batches
      add up over a series of huge faults, which is unlikely under any
      significant load involving order-0 allocations in the group.
      
      Remove that loop on the memcg side in favor of passing the actual reclaim
      goal to direct reclaim, which is already set up and optimized to meet
      higher-order goals efficiently.
      
      This brings memcg's THP policy in line with the system policy: if the
      allocator painstakingly assembles a hugepage, memcg will at least make an
      honest effort to charge it.  As a result, transparent hugepage allocation
      rates amid cache activity are drastically improved:
      
                                            vanilla                 patched
      pgalloc                 4717530.80 (  +0.00%)   4451376.40 (  -5.64%)
      pgfault                  491370.60 (  +0.00%)    225477.40 ( -54.11%)
      pgmajfault                    2.00 (  +0.00%)         1.80 (  -6.67%)
      thp_fault_alloc               0.00 (  +0.00%)       531.60 (+100.00%)
      thp_fault_fallback          749.00 (  +0.00%)       217.40 ( -70.88%)
      
      [ Note: this may in turn increase memory consumption from internal
        fragmentation, which is an inherent risk of transparent hugepages.
        Some setups may have to adjust the memcg limits accordingly to
        accomodate this - or, if the machine is already packed to capacity,
        disable the transparent huge page feature. ]
      Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Reviewed-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Dave Hansen <dave@sr71.net>
      Cc: Greg Thelen <gthelen@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b70a2a21
    • Johannes Weiner's avatar
      mm: memcontrol: simplify detecting when the memory+swap limit is hit · 3fbe7244
      Johannes Weiner authored
      When attempting to charge pages, we first charge the memory counter and
      then the memory+swap counter.  If one of the counters is at its limit, we
      enter reclaim, but if it's the memory+swap counter, reclaim shouldn't swap
      because that wouldn't change the situation.  However, if the counters have
      the same limits, we never get to the memory+swap limit.  To know whether
      reclaim should swap or not, there is a state flag that indicates whether
      the limits are equal and whether hitting the memory limit implies hitting
      the memory+swap limit.
      
      Just try the memory+swap counter first.
      Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Reviewed-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
      Cc: Dave Hansen <dave@sr71.net>
      Cc: Greg Thelen <gthelen@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3fbe7244
    • Michal Hocko's avatar
      mm: memcontrol: do not kill uncharge batching in free_pages_and_swap_cache · aabfb572
      Michal Hocko authored
      free_pages_and_swap_cache limits release_pages to PAGEVEC_SIZE chunks.
      This is not a big deal for the normal release path but it completely kills
      memcg uncharge batching which reduces res_counter spin_lock contention.
      Dave has noticed this with his page fault scalability test case on a large
      machine when the lock was basically dominating on all CPUs:
      
          80.18%    80.18%  [kernel]               [k] _raw_spin_lock
                        |
                        --- _raw_spin_lock
                           |
                           |--66.59%-- res_counter_uncharge_until
                           |          res_counter_uncharge
                           |          uncharge_batch
                           |          uncharge_list
                           |          mem_cgroup_uncharge_list
                           |          release_pages
                           |          free_pages_and_swap_cache
                           |          tlb_flush_mmu_free
                           |          |
                           |          |--90.12%-- unmap_single_vma
                           |          |          unmap_vmas
                           |          |          unmap_region
                           |          |          do_munmap
                           |          |          vm_munmap
                           |          |          sys_munmap
                           |          |          system_call_fastpath
                           |          |          __GI___munmap
                           |          |
                           |           --9.88%-- tlb_flush_mmu
                           |                     tlb_finish_mmu
                           |                     unmap_region
                           |                     do_munmap
                           |                     vm_munmap
                           |                     sys_munmap
                           |                     system_call_fastpath
                           |                     __GI___munmap
      
      In his case the load was running in the root memcg and that part has been
      handled by reverting 05b84301 ("mm: memcontrol: use root_mem_cgroup
      res_counter") because this is a clear regression, but the problem remains
      inside dedicated memcgs.
      
      There is no reason to limit release_pages to PAGEVEC_SIZE batches other
      than lru_lock held times.  This logic, however, can be moved inside the
      function.  mem_cgroup_uncharge_list and free_hot_cold_page_list do not
      hold any lock for the whole pages_to_free list so it is safe to call them
      in a single run.
      
      The release_pages() code was previously breaking the lru_lock each
      PAGEVEC_SIZE pages (ie, 14 pages).  However this code has no usage of
      pagevecs so switch to breaking the lock at least every SWAP_CLUSTER_MAX
      (32) pages.  This means that the lock acquisition frequency is
      approximately halved and the max hold times are approximately doubled.
      
      The now unneeded batching is removed from free_pages_and_swap_cache().
      
      Also update the grossly out-of-date release_pages documentation.
      Signed-off-by: default avatarMichal Hocko <mhocko@suse.cz>
      Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Reported-by: default avatarDave Hansen <dave@sr71.net>
      Cc: Vladimir Davydov <vdavydov@parallels.com>
      Cc: Greg Thelen <gthelen@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      aabfb572
    • Sebastian Andrzej Siewior's avatar
      mm: dmapool: add/remove sysfs file outside of the pool lock lock · 01c2965f
      Sebastian Andrzej Siewior authored
      cat /sys/.../pools followed by removal the device leads to:
      
      |======================================================
      |[ INFO: possible circular locking dependency detected ]
      |3.17.0-rc4+ #1498 Not tainted
      |-------------------------------------------------------
      |rmmod/2505 is trying to acquire lock:
      | (s_active#28){++++.+}, at: [<c017f754>] kernfs_remove_by_name_ns+0x3c/0x88
      |
      |but task is already holding lock:
      | (pools_lock){+.+.+.}, at: [<c011494c>] dma_pool_destroy+0x18/0x17c
      |
      |which lock already depends on the new lock.
      |the existing dependency chain (in reverse order) is:
      |
      |-> #1 (pools_lock){+.+.+.}:
      |   [<c0114ae8>] show_pools+0x30/0xf8
      |   [<c0313210>] dev_attr_show+0x1c/0x48
      |   [<c0180e84>] sysfs_kf_seq_show+0x88/0x10c
      |   [<c017f960>] kernfs_seq_show+0x24/0x28
      |   [<c013efc4>] seq_read+0x1b8/0x480
      |   [<c011e820>] vfs_read+0x8c/0x148
      |   [<c011ea10>] SyS_read+0x40/0x8c
      |   [<c000e960>] ret_fast_syscall+0x0/0x48
      |
      |-> #0 (s_active#28){++++.+}:
      |   [<c017e9ac>] __kernfs_remove+0x258/0x2ec
      |   [<c017f754>] kernfs_remove_by_name_ns+0x3c/0x88
      |   [<c0114a7c>] dma_pool_destroy+0x148/0x17c
      |   [<c03ad288>] hcd_buffer_destroy+0x20/0x34
      |   [<c03a4780>] usb_remove_hcd+0x110/0x1a4
      
      The problem is the lock order of pools_lock and kernfs_mutex in
      dma_pool_destroy() vs show_pools() call path.
      
      This patch breaks out the creation of the sysfs file outside of the
      pools_lock mutex.  The newly added pools_reg_lock ensures that there is no
      race of create vs destroy code path in terms whether or not the sysfs file
      has to be deleted (and was it deleted before we try to create a new one)
      and what to do if device_create_file() failed.
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      01c2965f
    • Vladimir Davydov's avatar
      memcg: move memcg_update_cache_size() to slab_common.c · 6f817f4c
      Vladimir Davydov authored
      `While growing per memcg caches arrays, we jump between memcontrol.c and
      slab_common.c in a weird way:
      
        memcg_alloc_cache_id - memcontrol.c
          memcg_update_all_caches - slab_common.c
            memcg_update_cache_size - memcontrol.c
      
      There's absolutely no reason why memcg_update_cache_size can't live on the
      slab's side though.  So let's move it there and settle it comfortably amid
      per-memcg cache allocation functions.
      
      Besides, this patch cleans this function up a bit, removing all the
      useless comments from it, and renames it to memcg_update_cache_params to
      conform to memcg_alloc/free_cache_params, which we already have in
      slab_common.c.
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Glauber Costa <glommer@gmail.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6f817f4c
    • Vladimir Davydov's avatar
      memcg: don't call memcg_update_all_caches if new cache id fits · f3bb3043
      Vladimir Davydov authored
      memcg_update_all_caches grows arrays of per-memcg caches, so we only need
      to call it when memcg_limited_groups_array_size is increased.  However,
      currently we invoke it each time a new kmem-active memory cgroup is
      created.  Then it just iterates over all slab_caches and does nothing
      (memcg_update_cache_size returns immediately).
      
      This patch fixes this insanity.  In the meantime it moves the code dealing
      with id allocations to separate functions, memcg_alloc_cache_id and
      memcg_free_cache_id.
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Glauber Costa <glommer@gmail.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f3bb3043
    • Vladimir Davydov's avatar
      memcg: move memcg_{alloc,free}_cache_params to slab_common.c · 33a690c4
      Vladimir Davydov authored
      The only reason why they live in memcontrol.c is that we get/put css
      reference to the owner memory cgroup in them.  However, we can do that in
      memcg_{un,}register_cache.  OTOH, there are several reasons to move them
      to slab_common.c.
      
      First, I think that the less public interface functions we have in
      memcontrol.h the better.  Since the functions I move don't depend on
      memcontrol, I think it's worth making them private to slab, especially
      taking into account that the arrays are defined on the slab's side too.
      
      Second, the way how per-memcg arrays are updated looks rather awkward: it
      proceeds from memcontrol.c (__memcg_activate_kmem) to slab_common.c
      (memcg_update_all_caches) and back to memcontrol.c again
      (memcg_update_array_size).  In the following patches I move the function
      relocating the arrays (memcg_update_array_size) to slab_common.c and
      therefore get rid this circular call path.  I think we should have the
      cache allocation stuff in the same place where we have relocation, because
      it's easier to follow the code then.  So I move arrays alloc/free
      functions to slab_common.c too.
      
      The third point isn't obvious.  I'm going to make the list_lru structure
      per-memcg to allow targeted kmem reclaim.  That means we will have
      per-memcg arrays in list_lrus too.  It turns out that it's much easier to
      update these arrays in list_lru.c rather than in memcontrol.c, because all
      the stuff we need is defined there.  This patch makes memcg caches arrays
      allocation path conform that of the upcoming list_lru.
      
      So let's move these functions to slab_common.c and make them static.
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Glauber Costa <glommer@gmail.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      33a690c4
    • Andrew Morton's avatar
      mm/debug.c: use pr_emerg() · 7a82ca0d
      Andrew Morton authored
      - s/KERN_ALERT/pr_emerg/: we're going BUG so let's maximize the changes
        of getting the message out.
      
      - convert debug.c to pr_foo()
      
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7a82ca0d
    • Sasha Levin's avatar
      mm: use VM_BUG_ON_MM where possible · 96dad67f
      Sasha Levin authored
      Dump the contents of the relevant struct_mm when we hit the bug condition.
      Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      96dad67f
    • Sasha Levin's avatar
      mm: introduce VM_BUG_ON_MM · 31c9afa6
      Sasha Levin authored
      Very similar to VM_BUG_ON_PAGE and VM_BUG_ON_VMA, dump struct_mm when the
      bug is hit.
      
      [akpm@linux-foundation.org: coding-style fixes]
      [mhocko@suse.cz: fix build]
      [mhocko@suse.cz: fix build some more]
      [akpm@linux-foundation.org: do strange things to avoid doing strange things for the comma separators]
      Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Cc: Dave Jones <davej@redhat.com>
      Signed-off-by: default avatarMichal Hocko <mhocko@suse.cz>
      Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      31c9afa6
    • Sasha Levin's avatar
      mm: move debug code out of page_alloc.c · 82742a3a
      Sasha Levin authored
      dump_page() and dump_vma() are not specific to page_alloc.c, move them out
      so page_alloc.c won't turn into the unofficial debug repository.
      Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      82742a3a
    • Peter Feiner's avatar
      mm: softdirty: unmapped addresses between VMAs are clean · 81d0fa62
      Peter Feiner authored
      If a /proc/pid/pagemap read spans a [VMA, an unmapped region, then a
      VM_SOFTDIRTY VMA], the virtual pages in the unmapped region are reported
      as softdirty.  Here's a program to demonstrate the bug:
      
      int main() {
      	const uint64_t PAGEMAP_SOFTDIRTY = 1ul << 55;
      	uint64_t pme[3];
      	int fd = open("/proc/self/pagemap", O_RDONLY);;
      	char *m = mmap(NULL, 3 * getpagesize(), PROT_READ,
      	               MAP_ANONYMOUS | MAP_SHARED, -1, 0);
      	munmap(m + getpagesize(), getpagesize());
      	pread(fd, pme, 24, (unsigned long) m / getpagesize() * 8);
      	assert(pme[0] & PAGEMAP_SOFTDIRTY);    /* passes */
      	assert(!(pme[1] & PAGEMAP_SOFTDIRTY)); /* fails */
      	assert(pme[2] & PAGEMAP_SOFTDIRTY);    /* passes */
      	return 0;
      }
      
      (Note that all pages in new VMAs are softdirty until cleared).
      
      Tested:
      	Used the program given above. I'm going to include this code in
      	a selftest in the future.
      
      [n-horiguchi@ah.jp.nec.com: prevent pagemap_pte_range() from overrunning]
      Signed-off-by: default avatarPeter Feiner <pfeiner@google.com>
      Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
      Cc: Cyrill Gorcunov <gorcunov@openvz.org>
      Cc: Pavel Emelyanov <xemul@parallels.com>
      Cc: Jamie Liu <jamieliu@google.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Signed-off-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      81d0fa62
    • Mel Gorman's avatar
      mm: page_alloc: default node-ordering on 64-bit NUMA, zone-ordering on 32-bit · 3193913c
      Mel Gorman authored
      Zones are allocated by the page allocator in either node or zone order.
      Node ordering is preferred in terms of locality and is applied
      automatically in one of three cases:
      
        1. If a node has only low memory
      
        2. If DMA/DMA32 is a high percentage of memory
      
        3. If low memory on a single node is greater than 70% of the node size
      
      Otherwise zone ordering is used to preserve low memory for devices that
      require it.  Unfortunately a consequence of this is that applications
      running on a machine with balanced NUMA nodes will experience different
      performance characteristics depending on which node they happen to start
      from.
      
      The point of zone ordering is to protect lower zones for devices that
      require DMA/DMA32 memory.  When NUMA was first introduced, this was
      critical as 32-bit NUMA machines existed and exhausting low memory
      triggered OOMs easily as so many allocations required low memory.  On
      64-bit machines the primary concern is devices that are 32-bit only which
      is less severe than the low memory exhaustion problem on 32-bit NUMA.  It
      seems there are really few devices that depends on it.
      
      AGP -- I assume this is getting more rare but even then I think the allocations
      	happen early in boot time where lowmem pressure is less of a problem
      
      DRM -- If the device is 32-bit only then there may be low pressure. I didn't
      	evaluate these in detail but it looks like some of these are mobile
      	graphics card. Not many NUMA laptops out there. DRM folk should know
      	better though.
      
      Some TV cards -- Much demand for 32-bit capable TV cards on NUMA machines?
      
      B43 wireless card -- again not really a NUMA thing.
      
      I cannot find a good reason to incur a performance penalty on all 64-bit NUMA
      machines in case someone throws a brain damanged TV or graphics card in there.
      This patch defaults to node-ordering on 64-bit NUMA machines. I was tempted
      to make it default everywhere but I understand that some embedded arches may
      be using 32-bit NUMA where I cannot predict the consequences.
      
      The performance impact depends on the workload and the characteristics of the
      machine and the machine I tested on had a large Normal zone on node 0 so the
      impact is within the noise for the majority of tests. The allocation stats
      show more allocation requests were from DMA32 and local node. Running SpecJBB
      with multiple JVMs and automatic NUMA balancing disabled the results were
      
      specjbb
                           3.17.0-rc2            3.17.0-rc2
                              vanilla        nodeorder-v1r1
      Min    1      29534.00 (  0.00%)     30020.00 (  1.65%)
      Min    10    115717.00 (  0.00%)    134038.00 ( 15.83%)
      Min    19    109718.00 (  0.00%)    114186.00 (  4.07%)
      Min    28    104459.00 (  0.00%)    103639.00 ( -0.78%)
      Min    37     98245.00 (  0.00%)    103756.00 (  5.61%)
      Min    46     97198.00 (  0.00%)     96197.00 ( -1.03%)
      Mean   1      30953.25 (  0.00%)     31917.75 (  3.12%)
      Mean   10    124432.50 (  0.00%)    140904.00 ( 13.24%)
      Mean   19    116033.50 (  0.00%)    119294.75 (  2.81%)
      Mean   28    108365.25 (  0.00%)    106879.50 ( -1.37%)
      Mean   37    102984.75 (  0.00%)    106924.25 (  3.83%)
      Mean   46    100783.25 (  0.00%)    105368.50 (  4.55%)
      Stddev 1       1260.38 (  0.00%)      1109.66 ( 11.96%)
      Stddev 10      7434.03 (  0.00%)      5171.91 ( 30.43%)
      Stddev 19      8453.84 (  0.00%)      5309.59 ( 37.19%)
      Stddev 28      4184.55 (  0.00%)      2906.63 ( 30.54%)
      Stddev 37      5409.49 (  0.00%)      3192.12 ( 40.99%)
      Stddev 46      4521.95 (  0.00%)      7392.52 (-63.48%)
      Max    1      32738.00 (  0.00%)     32719.00 ( -0.06%)
      Max    10    136039.00 (  0.00%)    148614.00 (  9.24%)
      Max    19    130566.00 (  0.00%)    127418.00 ( -2.41%)
      Max    28    115404.00 (  0.00%)    111254.00 ( -3.60%)
      Max    37    112118.00 (  0.00%)    111732.00 ( -0.34%)
      Max    46    108541.00 (  0.00%)    116849.00 (  7.65%)
      TPut   1     123813.00 (  0.00%)    127671.00 (  3.12%)
      TPut   10    497730.00 (  0.00%)    563616.00 ( 13.24%)
      TPut   19    464134.00 (  0.00%)    477179.00 (  2.81%)
      TPut   28    433461.00 (  0.00%)    427518.00 ( -1.37%)
      TPut   37    411939.00 (  0.00%)    427697.00 (  3.83%)
      TPut   46    403133.00 (  0.00%)    421474.00 (  4.55%)
      
                                  3.17.0-rc2  3.17.0-rc2
                                     vanillanodeorder-v1r1
      DMA allocs                           0           0
      DMA32 allocs                        57     1491992
      Normal allocs                 32543566    30026383
      Movable allocs                       0           0
      Direct pages scanned                 0           0
      Kswapd pages scanned                 0           0
      Kswapd pages reclaimed               0           0
      Direct pages reclaimed               0           0
      Kswapd efficiency                 100%        100%
      Kswapd velocity                  0.000       0.000
      Direct efficiency                 100%        100%
      Direct velocity                  0.000       0.000
      Percentage direct scans             0%          0%
      Zone normal velocity             0.000       0.000
      Zone dma32 velocity              0.000       0.000
      Zone dma velocity                0.000       0.000
      THP fault alloc                  55164       52987
      THP collapse alloc                 139         147
      THP splits                          26          21
      NUMA alloc hit                 4169066     4250692
      NUMA alloc miss                      0           0
      
      Note that there were more DMA32 allocations with the patch applied.  In this
      particular case there was no difference in numa_hit and numa_miss. The
      expectation is that DMA32 was being used at the low watermark instead of
      falling into the slow path. kswapd was not woken but it's not worken for
      THP allocations.
      
      On 32-bit, this patch defaults to zone-ordering as low memory depletion
      can be a serious problem on 32-bit large memory machines. If the default
      ordering was node then processes on node 0 will deplete the Normal zone
      due to normal activity.  The problem is worse if CONFIG_HIGHPTE is not
      set. If combined with large amounts of dirty/writeback pages in Normal
      zone then there is also a high risk of OOM. The heuristics are removed
      as it's not clear they were ever important on 32-bit. They were only
      relevant for setting node-ordering on 64-bit.
      Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Fengguang Wu <fengguang.wu@intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3193913c
    • Mel Gorman's avatar
      mm: page_alloc: Make paranoid check in move_freepages a VM_BUG_ON · 97ee4ba7
      Mel Gorman authored
      Since 2.6.24 there has been a paranoid check in move_freepages that looks
      up the zone of two pages.  This is a very slow path and the only time I've
      seen this bug trigger recently is when memory initialisation was broken
      during patch development.  Despite the fact it's a slow path, this patch
      converts the check to a VM_BUG_ON anyway as it has served its purpose by
      now.
      Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
      Acked-by: default avatarDavid Rientjes <rientjes@google.com>
      Acked-by: default avatarRik van Riel <riel@redhat.com>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      97ee4ba7
    • Xue jiufei's avatar
      ocfs2: fix a deadlock while o2net_wq doing direct memory reclaim · b246d3d1
      Xue jiufei authored
      Fix a deadlock problem caused by direct memory reclaim in o2net_wq.  The
      situation is as follows:
      
      1) Receive a connect message from another node, node queues a
         work_struct o2net_listen_work.
      
      2) o2net_wq processes this work and call the following functions:
      
      o2net_wq
      -> o2net_accept_one
        -> sock_create_lite
          -> sock_alloc()
            -> kmem_cache_alloc with GFP_KERNEL
              -> ____cache_alloc_node
                ->__alloc_pages_nodemask
                  -> do_try_to_free_pages
                    -> shrink_slab
                      -> evict
                        -> ocfs2_evict_inode
                          -> ocfs2_drop_lock
                            -> dlmunlock
                              -> o2net_send_message_vec
      
         then o2net_wq wait for the unlock reply from master.
      
      3) tcp layer received the reply, call o2net_data_ready() and queue
         sc_rx_work, waiting o2net_wq to process this work.
      
      4) o2net_wq is a single thread workqueue, it process the work one by
         one.  Right now it is still doing o2net_listen_work and cannot handle
         sc_rx_work.  so we deadlock.
      
      Junxiao Bi's patch "mm: clear __GFP_FS when PF_MEMALLOC_NOIO is set"
      (http://ozlabs.org/~akpm/mmots/broken-out/mm-clear-__gfp_fs-when-pf_memalloc_noio-is-set.patch)
      clears __GFP_FS in memalloc_noio_flags() besides __GFP_IO.  We use
      memalloc_noio_save() to set process flag PF_MEMALLOC_NOIO so that all
      allocations done by this process are done as if GFP_NOIO was specified.
      We are not reentering filesystem while doing memory reclaim.
      Signed-off-by: default avatarjoyce.xue <xuejiufei@huawei.com>
      Cc: Junxiao Bi <junxiao.bi@oracle.com>
      Cc: Joel Becker <jlbec@evilplan.org>
      Cc: Mark Fasheh <mfasheh@suse.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b246d3d1
    • Junxiao Bi's avatar
      mm: clear __GFP_FS when PF_MEMALLOC_NOIO is set · 934f3072
      Junxiao Bi authored
      commit 21caf2fc ("mm: teach mm by current context info to not do I/O
      during memory allocation") introduces PF_MEMALLOC_NOIO flag to avoid doing
      I/O inside memory allocation, __GFP_IO is cleared when this flag is set,
      but __GFP_FS implies __GFP_IO, it should also be cleared.  Or it may still
      run into I/O, like in superblock shrinker.  And this will make the kernel
      run into the deadlock case described in that commit.
      
      See Dave Chinner's comment about io in superblock shrinker:
      
      Filesystem shrinkers do indeed perform IO from the superblock shrinker and
      have for years.  Even clean inodes can require IO before they can be freed
      - e.g.  on an orphan list, need truncation of post-eof blocks, need to
      wait for ordered operations to complete before it can be freed, etc.
      
      IOWs, Ext4, btrfs and XFS all can issue and/or block on arbitrary amounts
      of IO in the superblock shrinker context.  XFS, in particular, has been
      doing transactions and IO from the VFS inode cache shrinker since it was
      first introduced....
      
      Fix this by clearing __GFP_FS in memalloc_noio_flags(), this function has
      masked all the gfp_mask that will be passed into fs for the processes
      setting PF_MEMALLOC_NOIO in the direct reclaim path.
      
      v1 thread at: https://lkml.org/lkml/2014/9/3/32Signed-off-by: default avatarJunxiao Bi <junxiao.bi@oracle.com>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: joyce.xue <xuejiufei@huawei.com>
      Cc: Ming Lei <ming.lei@canonical.com>
      Cc: Trond Myklebust <trond.myklebust@primarydata.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      934f3072
    • Xiubo Li's avatar
      mm/compaction.c: fix warning of 'flags' may be used uninitialized · b8b2d825
      Xiubo Li authored
      C      mm/compaction.o
      mm/compaction.c: In function isolate_freepages_block:
      mm/compaction.c:364:37: warning: flags may be used uninitialized in this function [-Wmaybe-uninitialized]
             && compact_unlock_should_abort(&cc->zone->lock, flags,
                                           ^
      Signed-off-by: default avatarXiubo Li <Li.Xiubo@freescale.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b8b2d825
    • Andrew Morton's avatar
      mm/mmap.c: clean up CONFIG_DEBUG_VM_RB checks · ff26f70f
      Andrew Morton authored
      - be consistent in printing the test which failed
      
      - one message was actually wrong (a<b != b>a)
      
      - don't print second bogus warning if browse_rb() failed
      
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ff26f70f
    • Johannes Weiner's avatar
      mm: clean up zone flags · 57054651
      Johannes Weiner authored
      Page reclaim tests zone_is_reclaim_dirty(), but the site that actually
      sets this state does zone_set_flag(zone, ZONE_TAIL_LRU_DIRTY), sending the
      reader through layers indirection just to track down a simple bit.
      
      Remove all zone flag wrappers and just use bitops against zone->flags
      directly.  It's just as readable and the lines are barely any longer.
      
      Also rename ZONE_TAIL_LRU_DIRTY to ZONE_DIRTY to match ZONE_WRITEBACK, and
      remove the zone_flags_t typedef.
      Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Acked-by: default avatarDavid Rientjes <rientjes@google.com>
      Acked-by: default avatarMel Gorman <mgorman@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      57054651
    • Mark Rustad's avatar
      mm/page-writeback.c: use min3/max3 macros to avoid shadow warnings · 7c809968
      Mark Rustad authored
      Nested calls to min/max functions result in shadow warnings in W=2 builds.
       Avoid the warning by using the min3 and max3 macros to get the min/max of
      3 values instead of nested calls.
      Signed-off-by: default avatarMark Rustad <mark.d.rustad@intel.com>
      Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7c809968
    • Weijie Yang's avatar
      mm: page_alloc: avoid wakeup kswapd on the unintended node · 7ade3c99
      Weijie Yang authored
      When entering the page_alloc slowpath, we wakeup kswapd on every pgdat
      according to the zonelist and high_zoneidx.  However, this doesn't take
      nodemask into account, and could prematurely wakeup kswapd on some
      unintended nodes.
      
      This patch uses for_each_zone_zonelist_nodemask() instead of
      for_each_zone_zonelist() in wake_all_kswapds() to avoid the above
      situation.
      Signed-off-by: default avatarWeijie Yang <weijie.yang@samsung.com>
      Acked-by: default avatarMel Gorman <mgorman@suse.de>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7ade3c99
    • Sasha Levin's avatar
      mm: convert a few VM_BUG_ON callers to VM_BUG_ON_VMA · 81d1b09c
      Sasha Levin authored
      Trivially convert a few VM_BUG_ON calls to VM_BUG_ON_VMA to extract
      more information when they trigger.
      
      [akpm@linux-foundation.org: coding-style fixes]
      Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Reviewed-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Michel Lespinasse <walken@google.com>
      Cc: Minchan Kim <minchan@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      81d1b09c
    • Sasha Levin's avatar
      mm: introduce VM_BUG_ON_VMA · fa3759cc
      Sasha Levin authored
      Very similar to VM_BUG_ON_PAGE but dumps VMA information instead.
      Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Reviewed-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Michel Lespinasse <walken@google.com>
      Cc: Minchan Kim <minchan@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      fa3759cc
    • Sasha Levin's avatar
      mm: introduce dump_vma · 0bf55139
      Sasha Levin authored
      Introduce a helper to dump information about a VMA, this also makes
      dump_page_flags more generic and re-uses that so the output looks very
      similar to dump_page:
      
      [   61.903437] vma ffff88070f88be00 start 00007fff25970000 end 00007fff25992000
      [   61.903437] next ffff88070facd600 prev ffff88070face400 mm ffff88070fade000
      [   61.903437] prot 8000000000000025 anon_vma ffff88070fa1e200 vm_ops           (null)
      [   61.903437] pgoff 7ffffffdd file           (null) private_data           (null)
      [   61.909129] flags: 0x100173(read|write|mayread|maywrite|mayexec|growsdown|account)
      
      [akpm@linux-foundation.org: make dump_vma() require CONFIG_DEBUG_VM]
      [swarren@nvidia.com: fix dump_vma() compilation]
      Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Reviewed-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Michel Lespinasse <walken@google.com>
      Cc: Minchan Kim <minchan@kernel.org>
      Signed-off-by: default avatarStephen Warren <swarren@nvidia.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0bf55139
    • Rob Jones's avatar
      mm/slab.c: use __seq_open_private() instead of seq_open() · b208ce32
      Rob Jones authored
      Using __seq_open_private() removes boilerplate code from slabstats_open()
      
      The resultant code is shorter and easier to follow.
      
      This patch does not change any functionality.
      Signed-off-by: default avatarRob Jones <rob.jones@codethink.co.uk>
      Acked-by: default avatarChristoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b208ce32
    • Rob Jones's avatar
      mm/vmalloc.c: use seq_open_private() instead of seq_open() · 703394c1
      Rob Jones authored
      Using seq_open_private() removes boilerplate code from vmalloc_open().
      
      The resultant code is shorter and easier to follow.
      
      However, please note that seq_open_private() call kzalloc() rather than
      kmalloc() which may affect timing due to the memory initialisation
      overhead.
      Signed-off-by: default avatarRob Jones <rob.jones@codethink.co.uk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      703394c1
    • Andrew Morton's avatar
      include/linux/migrate.h: remove migrate_page #define · 1c93923c
      Andrew Morton authored
      This is designed to avoid a few ifdefs in .c files but it's obnoxious
      because it can cause unsuspecting "migrate_page" symbols to get turned into
      "NULL".
      
      Just nuke it and use the ifdefs.
      
      Cc: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
      Cc: Rafael Aquini <aquini@redhat.com>
      Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      1c93923c
    • Oleg Nesterov's avatar
      mempolicy: unexport get_vma_policy() and remove its "task" arg · dd6eecb9
      Oleg Nesterov authored
      - get_vma_policy(task) is not safe if task != current, remove this
        argument.
      
      - get_vma_policy() no longer has callers outside of mempolicy.c,
        make it static.
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: Cyrill Gorcunov <gorcunov@openvz.org>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      dd6eecb9
    • Oleg Nesterov's avatar
      mempolicy: kill do_set_mempolicy()->down_write(&mm->mmap_sem) · 2c7c3a7d
      Oleg Nesterov authored
      Remove down_write(&mm->mmap_sem) in do_set_mempolicy(). This logic
      was never correct and it is no longer needed, see the previous patch.
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: Cyrill Gorcunov <gorcunov@openvz.org>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2c7c3a7d
    • Oleg Nesterov's avatar
      mempolicy: fix show_numa_map() vs exec() + do_set_mempolicy() race · 498f2371
      Oleg Nesterov authored
      9e781440 "hold task->mempolicy while numa_maps scans." fixed the
      race with the exiting task but this is not enough.
      
      The current code assumes that get_vma_policy(task) should either see
      task->mempolicy == NULL or it should be equal to ->task_mempolicy saved
      by hold_task_mempolicy(), so we can never race with __mpol_put(). But
      this can only work if we can't race with do_set_mempolicy(), and thus
      we can't race with another do_set_mempolicy() or do_exit() after that.
      
      However, do_set_mempolicy()->down_write(mmap_sem) can not prevent this
      race. This task can exec, change it's ->mm, and call do_set_mempolicy()
      after that; in this case they take 2 different locks.
      
      Change hold_task_mempolicy() to use get_task_policy(), it never returns
      NULL, and change show_numa_map() to use __get_vma_policy() or fall back
      to proc_priv->task_mempolicy.
      
      Note: this is the minimal fix, we will cleanup this code later. I think
      hold_task_mempolicy() and release_task_mempolicy() should die, we can
      move this logic into show_numa_map(). Or we can move get_task_policy()
      outside of ->mmap_sem and !CONFIG_NUMA code at least.
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: Cyrill Gorcunov <gorcunov@openvz.org>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      498f2371
    • Oleg Nesterov's avatar
      mempolicy: introduce __get_vma_policy(), export get_task_policy() · 74d2c3a0
      Oleg Nesterov authored
      Extract the code which looks for vma's policy from get_vma_policy()
      into the new helper, __get_vma_policy(). Export get_task_policy().
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: Cyrill Gorcunov <gorcunov@openvz.org>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      74d2c3a0
    • Oleg Nesterov's avatar
      mempolicy: remove the "task" arg of vma_policy_mof() and simplify it · 6b6482bb
      Oleg Nesterov authored
      1. vma_policy_mof(task) is simply not safe unless task == current,
         it can race with do_exit()->mpol_put(). Remove this arg and update
         its single caller.
      
      2. vma can not be NULL, remove this check and simplify the code.
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: Cyrill Gorcunov <gorcunov@openvz.org>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6b6482bb
    • Oleg Nesterov's avatar
      mempolicy: sanitize the usage of get_task_policy() · 8d90274b
      Oleg Nesterov authored
      Cleanup + preparation. Every user of get_task_policy() calls it
      unconditionally, even if it is not going to use the result.
      
      get_task_policy() is cheap but still this does not look clean, plus
      the code looks simpler if get_task_policy() is called only when this
      is really needed.
      
      Note: I hope this is correct, but it is not clear why vma_policy_mof()
      doesn't fall back to get_task_policy() if ->get_policy() returns NULL.
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: Cyrill Gorcunov <gorcunov@openvz.org>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8d90274b
    • Oleg Nesterov's avatar
      mempolicy: change get_task_policy() to return default_policy rather than NULL · f15ca78e
      Oleg Nesterov authored
      Every caller of get_task_policy() falls back to default_policy if it
      returns NULL. Change get_task_policy() to do this.
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: Cyrill Gorcunov <gorcunov@openvz.org>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f15ca78e