1. 14 4月, 2016 6 次提交
  2. 13 4月, 2016 2 次提交
    • J
      arm64: cpuidle: make arm_cpuidle_suspend() a bit more efficient · b5fda7ed
      Jisheng Zhang 提交于
      Currently, we check two pointers: cpu_ops and cpu_suspend on every idle
      state entry. These pointers check can be avoided:
      
      If cpu_ops has not been registered, arm_cpuidle_init() will return
      -EOPNOTSUPP, so arm_cpuidle_suspend() will never have chance to
      run. In other word, the cpu_ops check can be avoid.
      
      Similarly, the cpu_suspend check could be avoided in this hot path by
      moving it into arm_cpuidle_init().
      
      I measured the 4096 * time from arm_cpuidle_suspend entry point to the
      cpu_psci_cpu_suspend entry point. HW platform is Marvell BG4CT STB
      board.
      
      1. only one shell, no other process, hot-unplug secondary cpus, execute
      the following cmd
      
      while true
      do
      	sleep 0.2
      done
      
      before the patch: 1581220ns
      
      after the patch: 1579630ns
      
      reduced by 0.1%
      
      2. only one shell, no other process, hot-unplug secondary cpus, execute
      the following cmd
      
      while true
      do
      	md5sum /tmp/testfile
      	sleep 0.2
      done
      
      NOTE: the testfile size should be larger than L1+L2 cache size
      
      before the patch: 1961960ns
      after the patch: 1912500ns
      
      reduced by 2.5%
      
      So the more complex the system load, the bigger the improvement.
      Signed-off-by: NJisheng Zhang <jszhang@marvell.com>
      Acked-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
      Signed-off-by: NWill Deacon <will.deacon@arm.com>
      b5fda7ed
    • K
      arm64: cpufeature: append additional id_aa64mmfr2 fields to cpufeature · 7d7b4ae4
      Kefeng Wang 提交于
      There are some new cpu features which can be identified by id_aa64mmfr2,
      this patch appends all fields of it.
      Signed-off-by: NKefeng Wang <wangkefeng.wang@huawei.com>
      Signed-off-by: NWill Deacon <will.deacon@arm.com>
      7d7b4ae4
  3. 09 4月, 2016 5 次提交
  4. 08 4月, 2016 3 次提交
  5. 07 4月, 2016 1 次提交
  6. 05 4月, 2016 4 次提交
    • L
      kvm: x86: make lapic hrtimer pinned · 61abdbe0
      Luiz Capitulino 提交于
      When a vCPU runs on a nohz_full core, the hrtimer used by
      the lapic emulation code can be migrated to another core.
      When this happens, it's possible to observe milisecond
      latency when delivering timer IRQs to KVM guests.
      
      The huge latency is mainly due to the fact that
      apic_timer_fn() expects to run during a kvm exit. It
      sets KVM_REQ_PENDING_TIMER and let it be handled on kvm
      entry. However, if the timer fires on a different core,
      we have to wait until the next kvm exit for the guest
      to see KVM_REQ_PENDING_TIMER set.
      
      This problem became visible after commit 9642d18e. This
      commit changed the timer migration code to always attempt
      to migrate timers away from nohz_full cores. While it's
      discussable if this is correct/desirable (I don't think
      it is), it's clear that the lapic emulation code has
      a requirement on firing the hrtimer in the same core
      where it was started. This is achieved by making the
      hrtimer pinned.
      
      Lastly, note that KVM has code to migrate timers when a
      vCPU is scheduled to run in different core. However, this
      forced migration may fail. When this happens, we can have
      the same problem. If we want 100% correctness, we'll have
      to modify apic_timer_fn() to cause a kvm exit when it runs
      on a different core than the vCPU. Not sure if this is
      possible.
      
      Here's a reproducer for the issue being fixed:
      
       1. Set all cores but core0 to be nohz_full cores
       2. Start a guest with a single vCPU
       3. Trace apic_timer_fn() and kvm_inject_apic_timer_irqs()
      
      You'll see that apic_timer_fn() will run in core0 while
      kvm_inject_apic_timer_irqs() runs in a different core. If
      you get both on core0, try running a program that takes 100%
      of the CPU and pin it to core0 to force the vCPU out.
      Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
      Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      61abdbe0
    • C
      s390/mm/kvm: fix mis-merge in gmap handling · 9c650d09
      Christian Borntraeger 提交于
      commit 1e133ab2 ("s390/mm: split arch/s390/mm/pgtable.c") dropped
      some changes from commit a3a92c31 ("KVM: s390: fix mismatch
      between user and in-kernel guest limit") - this breaks KVM for some
      memory sizes (kvm-s390: failed to commit memory region) like
      exactly 2GB.
      
      Cc: Dominik Dingel <dingel@linux.vnet.ibm.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
      Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
      Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      9c650d09
    • K
      mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usage · ea1754a0
      Kirill A. Shutemov 提交于
      Mostly direct substitution with occasional adjustment or removing
      outdated comments.
      Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Acked-by: NMichal Hocko <mhocko@suse.com>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      ea1754a0
    • K
      mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros · 09cbfeaf
      Kirill A. Shutemov 提交于
      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: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Acked-by: NMichal Hocko <mhocko@suse.com>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      09cbfeaf
  7. 04 4月, 2016 2 次提交
  8. 03 4月, 2016 13 次提交
  9. 02 4月, 2016 3 次提交
  10. 01 4月, 2016 1 次提交