1. 11 Apr, 2018 1 commit
  2. 06 Apr, 2018 1 commit
  3. 13 Feb, 2018 1 commit
    • Tony Luck's avatar
      x86/mm, mm/hwpoison: Don't unconditionally unmap kernel 1:1 pages · fd0e786d
      Tony Luck authored
      In the following commit:
      
        ce0fa3e5 ("x86/mm, mm/hwpoison: Clear PRESENT bit for kernel 1:1 mappings of poison pages")
      
      ... we added code to memory_failure() to unmap the page from the
      kernel 1:1 virtual address space to avoid speculative access to the
      page logging additional errors.
      
      But memory_failure() may not always succeed in taking the page offline,
      especially if the page belongs to the kernel.  This can happen if
      there are too many corrected errors on a page and either mcelog(8)
      or drivers/ras/cec.c asks to take a page offline.
      
      Since we remove the 1:1 mapping early in memory_failure(), we can
      end up with the page unmapped, but still in use. On the next access
      the kernel crashes :-(
      
      There are also various debug paths that call memory_failure() to simulate
      occurrence of an error. Since there is no actual error in memory, we
      don't need to map out the page for those cases.
      
      Revert most of the previous attempt and keep the solution local to
      arch/x86/kernel/cpu/mcheck/mce.c. Unmap the page only when:
      
      	1) there is a real error
      	2) memory_failure() succeeds.
      
      All of this only applies to 64-bit systems. 32-bit kernel doesn't map
      all of memory into kernel space. It isn't worth adding the code to unmap
      the piece that is mapped because nobody would run a 32-bit kernel on a
      machine that has recoverable machine checks.
      Signed-off-by: 's avatarTony Luck <tony.luck@intel.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Dave <dave.hansen@intel.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Robert (Persistent Memory) <elliott@hpe.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: linux-mm@kvack.org
      Cc: stable@vger.kernel.org #v4.14
      Fixes: ce0fa3e5 ("x86/mm, mm/hwpoison: Clear PRESENT bit for kernel 1:1 mappings of poison pages")
      Signed-off-by: 's avatarIngo Molnar <mingo@kernel.org>
      fd0e786d
  4. 23 Jan, 2018 2 commits
  5. 16 Nov, 2017 1 commit
  6. 17 Aug, 2017 1 commit
    • Tony Luck's avatar
      x86/mm, mm/hwpoison: Clear PRESENT bit for kernel 1:1 mappings of poison pages · ce0fa3e5
      Tony Luck authored
      Speculative processor accesses may reference any memory that has a
      valid page table entry.  While a speculative access won't generate
      a machine check, it will log the error in a machine check bank. That
      could cause escalation of a subsequent error since the overflow bit
      will be then set in the machine check bank status register.
      
      Code has to be double-plus-tricky to avoid mentioning the 1:1 virtual
      address of the page we want to map out otherwise we may trigger the
      very problem we are trying to avoid.  We use a non-canonical address
      that passes through the usual Linux table walking code to get to the
      same "pte".
      
      Thanks to Dave Hansen for reviewing several iterations of this.
      
      Also see:
      
        http://marc.info/?l=linux-mm&m=149860136413338&w=2Signed-off-by: 's avatarTony Luck <tony.luck@intel.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Elliott, Robert (Persistent Memory) <elliott@hpe.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: linux-mm@kvack.org
      Cc: stable@vger.kernel.org
      Link: http://lkml.kernel.org/r/20170816171803.28342-1-tony.luck@intel.comSigned-off-by: 's avatarIngo Molnar <mingo@kernel.org>
      ce0fa3e5
  7. 10 Jul, 2017 9 commits
  8. 06 Jul, 2017 2 commits
  9. 16 Jun, 2017 1 commit
  10. 02 Jun, 2017 1 commit
    • Punit Agrawal's avatar
      mm/migrate: fix refcount handling when !hugepage_migration_supported() · 30809f55
      Punit Agrawal authored
      On failing to migrate a page, soft_offline_huge_page() performs the
      necessary update to the hugepage ref-count.
      
      But when !hugepage_migration_supported() , unmap_and_move_hugepage()
      also decrements the page ref-count for the hugepage.  The combined
      behaviour leaves the ref-count in an inconsistent state.
      
      This leads to soft lockups when running the overcommitted hugepage test
      from mce-tests suite.
      
        Soft offlining pfn 0x83ed600 at process virtual address 0x400000000000
        soft offline: 0x83ed600: migration failed 1, type 1fffc00000008008 (uptodate|head)
        INFO: rcu_preempt detected stalls on CPUs/tasks:
         Tasks blocked on level-0 rcu_node (CPUs 0-7): P2715
          (detected by 7, t=5254 jiffies, g=963, c=962, q=321)
          thugetlb_overco R  running task        0  2715   2685 0x00000008
          Call trace:
            dump_backtrace+0x0/0x268
            show_stack+0x24/0x30
            sched_show_task+0x134/0x180
            rcu_print_detail_task_stall_rnp+0x54/0x7c
            rcu_check_callbacks+0xa74/0xb08
            update_process_times+0x34/0x60
            tick_sched_handle.isra.7+0x38/0x70
            tick_sched_timer+0x4c/0x98
            __hrtimer_run_queues+0xc0/0x300
            hrtimer_interrupt+0xac/0x228
            arch_timer_handler_phys+0x3c/0x50
            handle_percpu_devid_irq+0x8c/0x290
            generic_handle_irq+0x34/0x50
            __handle_domain_irq+0x68/0xc0
            gic_handle_irq+0x5c/0xb0
      
      Address this by changing the putback_active_hugepage() in
      soft_offline_huge_page() to putback_movable_pages().
      
      This only triggers on systems that enable memory failure handling
      (ARCH_SUPPORTS_MEMORY_FAILURE) but not hugepage migration
      (!ARCH_ENABLE_HUGEPAGE_MIGRATION).
      
      I imagine this wasn't triggered as there aren't many systems running
      this configuration.
      
      [akpm@linux-foundation.org: remove dead comment, per Naoya]
      Link: http://lkml.kernel.org/r/20170525135146.32011-1-punit.agrawal@arm.comReported-by: 's avatarManoj Iyer <manoj.iyer@canonical.com>
      Tested-by: 's avatarManoj Iyer <manoj.iyer@canonical.com>
      Suggested-by: 's avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Signed-off-by: 's avatarPunit Agrawal <punit.agrawal@arm.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Wanpeng Li <wanpeng.li@hotmail.com>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Mel Gorman <mgorman@techsingularity.net>
      Cc: <stable@vger.kernel.org>	[3.14+]
      Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
      30809f55
  11. 12 May, 2017 1 commit
  12. 03 May, 2017 5 commits
  13. 02 Mar, 2017 2 commits
  14. 25 Feb, 2017 1 commit
  15. 25 Dec, 2016 1 commit
  16. 11 Nov, 2016 1 commit
  17. 28 Jul, 2016 2 commits
    • Naoya Horiguchi's avatar
      mm: hwpoison: remove incorrect comments · 7c7fd825
      Naoya Horiguchi authored
      dequeue_hwpoisoned_huge_page() can be called without page lock hold, so
      let's remove incorrect comment.
      
      The reason why the page lock is not really needed is that
      dequeue_hwpoisoned_huge_page() checks page_huge_active() inside
      hugetlb_lock, which allows us to avoid trying to dequeue a hugepage that
      are just allocated but not linked to active list yet, even without
      taking page lock.
      
      Link: http://lkml.kernel.org/r/20160720092901.GA15995@www9186uo.sakura.ne.jpSigned-off-by: 's avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Reported-by: 's avatarZhan Chen <zhanc1@andrew.cmu.edu>
      Acked-by: 's avatarMichal Hocko <mhocko@suse.com>
      Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
      7c7fd825
    • Mel Gorman's avatar
      mm, vmscan: move LRU lists to node · 599d0c95
      Mel Gorman authored
      This moves the LRU lists from the zone to the node and related data such
      as counters, tracing, congestion tracking and writeback tracking.
      
      Unfortunately, due to reclaim and compaction retry logic, it is
      necessary to account for the number of LRU pages on both zone and node
      logic.  Most reclaim logic is based on the node counters but the retry
      logic uses the zone counters which do not distinguish inactive and
      active sizes.  It would be possible to leave the LRU counters on a
      per-zone basis but it's a heavier calculation across multiple cache
      lines that is much more frequent than the retry checks.
      
      Other than the LRU counters, this is mostly a mechanical patch but note
      that it introduces a number of anomalies.  For example, the scans are
      per-zone but using per-node counters.  We also mark a node as congested
      when a zone is congested.  This causes weird problems that are fixed
      later but is easier to review.
      
      In the event that there is excessive overhead on 32-bit systems due to
      the nodes being on LRU then there are two potential solutions
      
      1. Long-term isolation of highmem pages when reclaim is lowmem
      
         When pages are skipped, they are immediately added back onto the LRU
         list. If lowmem reclaim persisted for long periods of time, the same
         highmem pages get continually scanned. The idea would be that lowmem
         keeps those pages on a separate list until a reclaim for highmem pages
         arrives that splices the highmem pages back onto the LRU. It potentially
         could be implemented similar to the UNEVICTABLE list.
      
         That would reduce the skip rate with the potential corner case is that
         highmem pages have to be scanned and reclaimed to free lowmem slab pages.
      
      2. Linear scan lowmem pages if the initial LRU shrink fails
      
         This will break LRU ordering but may be preferable and faster during
         memory pressure than skipping LRU pages.
      
      Link: http://lkml.kernel.org/r/1467970510-21195-4-git-send-email-mgorman@techsingularity.netSigned-off-by: 's avatarMel Gorman <mgorman@techsingularity.net>
      Acked-by: 's avatarJohannes Weiner <hannes@cmpxchg.org>
      Acked-by: 's avatarVlastimil Babka <vbabka@suse.cz>
      Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Michal Hocko <mhocko@kernel.org>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Rik van Riel <riel@surriel.com>
      Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
      599d0c95
  18. 21 May, 2016 1 commit
  19. 29 Apr, 2016 1 commit
  20. 04 Apr, 2016 1 commit
    • Kirill A. Shutemov's avatar
      mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros · 09cbfeaf
      Kirill A. Shutemov authored
      PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
      ago with promise that one day it will be possible to implement page
      cache with bigger chunks than PAGE_SIZE.
      
      This promise never materialized.  And unlikely will.
      
      We have many places where PAGE_CACHE_SIZE assumed to be equal to
      PAGE_SIZE.  And it's constant source of confusion on whether
      PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
      especially on the border between fs and mm.
      
      Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
      breakage to be doable.
      
      Let's stop pretending that pages in page cache are special.  They are
      not.
      
      The changes are pretty straight-forward:
      
       - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
      
       - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
      
       - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};
      
       - page_cache_get() -> get_page();
      
       - page_cache_release() -> put_page();
      
      This patch contains automated changes generated with coccinelle using
      script below.  For some reason, coccinelle doesn't patch header files.
      I've called spatch for them manually.
      
      The only adjustment after coccinelle is revert of changes to
      PAGE_CAHCE_ALIGN definition: we are going to drop it later.
      
      There are few places in the code where coccinelle didn't reach.  I'll
      fix them manually in a separate patch.  Comments and documentation also
      will be addressed with the separate patch.
      
      virtual patch
      
      @@
      expression E;
      @@
      - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
      + E
      
      @@
      expression E;
      @@
      - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
      + E
      
      @@
      @@
      - PAGE_CACHE_SHIFT
      + PAGE_SHIFT
      
      @@
      @@
      - PAGE_CACHE_SIZE
      + PAGE_SIZE
      
      @@
      @@
      - PAGE_CACHE_MASK
      + PAGE_MASK
      
      @@
      expression E;
      @@
      - PAGE_CACHE_ALIGN(E)
      + PAGE_ALIGN(E)
      
      @@
      expression E;
      @@
      - page_cache_get(E)
      + get_page(E)
      
      @@
      expression E;
      @@
      - page_cache_release(E)
      + put_page(E)
      Signed-off-by: 's avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Acked-by: 's avatarMichal Hocko <mhocko@suse.com>
      Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
      09cbfeaf
  21. 17 Mar, 2016 1 commit
  22. 15 Mar, 2016 1 commit
  23. 16 Jan, 2016 2 commits