1. 16 Sep, 2014 6 commits
  2. 15 Sep, 2014 13 commits
  3. 14 Sep, 2014 12 commits
  4. 13 Sep, 2014 8 commits
    • Linus Torvalds's avatar
      Merge branches 'locking-urgent-for-linus' and 'timers-urgent-for-linus' of... · 1536340e
      Linus Torvalds authored
      Merge branches 'locking-urgent-for-linus' and 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
      
      Pull futex and timer fixes from Thomas Gleixner:
       "A oneliner bugfix for the jinxed futex code:
      
         - Drop hash bucket lock in the error exit path.  I really could slap
           myself for intruducing that bug while fixing all the other horror
           in that code three month ago ...
      
        and the timer department is not too proud about the following fixes:
      
         - Deal with a long standing rounding bug in the timeval to jiffies
           conversion.  It's a real issue and this fix fell through the cracks
           for quite some time.
      
         - Another round of alarmtimer fixes.  Finally this code gets used
           more widely and the subtle issues hidden for quite some time are
           noticed and fixed.  Nothing really exciting, just the itty bitty
           details which bite the serious users here and there"
      
      * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        futex: Unlock hb->lock in futex_wait_requeue_pi() error path
      
      * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        alarmtimer: Lock k_itimer during timer callback
        alarmtimer: Do not signal SIGEV_NONE timers
        alarmtimer: Return relative times in timer_gettime
        jiffies: Fix timeval conversion to jiffies
      1536340e
    • Guy Martin's avatar
      parisc: Implement new LWS CAS supporting 64 bit operations. · 89206491
      Guy Martin authored
      The current LWS cas only works correctly for 32bit. The new LWS allows
      for CAS operations of variable size.
      Signed-off-by: default avatarGuy Martin <gmsoft@tuxicoman.be>
      Cc: <stable@vger.kernel.org> # 3.13+
      Signed-off-by: default avatarHelge Deller <deller@gmx.de>
      89206491
    • Linus Torvalds's avatar
      vfs: fix bad hashing of dentries · 99d263d4
      Linus Torvalds authored
      Josef Bacik found a performance regression between 3.2 and 3.10 and
      narrowed it down to commit bfcfaa77 ("vfs: use 'unsigned long'
      accesses for dcache name comparison and hashing"). He reports:
      
       "The test case is essentially
      
            for (i = 0; i < 1000000; i++)
                    mkdir("a$i");
      
        On xfs on a fio card this goes at about 20k dir/sec with 3.2, and 12k
        dir/sec with 3.10.  This is because we spend waaaaay more time in
        __d_lookup on 3.10 than in 3.2.
      
        The new hashing function for strings is suboptimal for <
        sizeof(unsigned long) string names (and hell even > sizeof(unsigned
        long) string names that I've tested).  I broke out the old hashing
        function and the new one into a userspace helper to get real numbers
        and this is what I'm getting:
      
            Old hash table had 1000000 entries, 0 dupes, 0 max dupes
            New hash table had 12628 entries, 987372 dupes, 900 max dupes
            We had 11400 buckets with a p50 of 30 dupes, p90 of 240 dupes, p99 of 567 dupes for the new hash
      
        My test does the hash, and then does the d_hash into a integer pointer
        array the same size as the dentry hash table on my system, and then
        just increments the value at the address we got to see how many
        entries we overlap with.
      
        As you can see the old hash function ended up with all 1 million
        entries in their own bucket, whereas the new one they are only
        distributed among ~12.5k buckets, which is why we're using so much
        more CPU in __d_lookup".
      
      The reason for this hash regression is two-fold:
      
       - On 64-bit architectures the down-mixing of the original 64-bit
         word-at-a-time hash into the final 32-bit hash value is very
         simplistic and suboptimal, and just adds the two 32-bit parts
         together.
      
         In particular, because there is no bit shuffling and the mixing
         boundary is also a byte boundary, similar character patterns in the
         low and high word easily end up just canceling each other out.
      
       - the old byte-at-a-time hash mixed each byte into the final hash as it
         hashed the path component name, resulting in the low bits of the hash
         generally being a good source of hash data.  That is not true for the
         word-at-a-time case, and the hash data is distributed among all the
         bits.
      
      The fix is the same in both cases: do a better job of mixing the bits up
      and using as much of the hash data as possible.  We already have the
      "hash_32|64()" functions to do that.
      Reported-by: default avatarJosef Bacik <jbacik@fb.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: Chris Mason <clm@fb.com>
      Cc: linux-fsdevel@vger.kernel.org
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      99d263d4
    • Linus Torvalds's avatar
      Make hash_64() use a 64-bit multiply when appropriate · 23d0db76
      Linus Torvalds authored
      The hash_64() function historically does the multiply by the
      GOLDEN_RATIO_PRIME_64 number with explicit shifts and adds, because
      unlike the 32-bit case, gcc seems unable to turn the constant multiply
      into the more appropriate shift and adds when required.
      
      However, that means that we generate those shifts and adds even when the
      architecture has a fast multiplier, and could just do it better in
      hardware.
      
      Use the now-cleaned-up CONFIG_ARCH_HAS_FAST_MULTIPLIER (together with
      "is it a 64-bit architecture") to decide whether to use an integer
      multiply or the explicit sequence of shift/add instructions.
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      23d0db76
    • Linus Torvalds's avatar
      Make ARCH_HAS_FAST_MULTIPLIER a real config variable · 72d93104
      Linus Torvalds authored
      It used to be an ad-hoc hack defined by the x86 version of
      <asm/bitops.h> that enabled a couple of library routines to know whether
      an integer multiply is faster than repeated shifts and additions.
      
      This just makes it use the real Kconfig system instead, and makes x86
      (which was the only architecture that did this) select the option.
      
      NOTE! Even for x86, this really is kind of wrong.  If we cared, we would
      probably not enable this for builds optimized for netburst (P4), where
      shifts-and-adds are generally faster than multiplies.  This patch does
      *not* change that kind of logic, though, it is purely a syntactic change
      with no code changes.
      
      This was triggered by the fact that we have other places that really
      want to know "do I want to expand multiples by constants by hand or
      not", particularly the hash generation code.
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      72d93104
    • Linus Torvalds's avatar
      Merge tag 'dm-3.17-fix2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm · 186cec31
      Linus Torvalds authored
      Pull device mapper fix from Mike Snitzer:
       "Fix a race in the DM cache target that caused dirty blocks to be
        marked as clean.  This could cause no writeback to occur or spurious
        dirty block counts"
      
      * tag 'dm-3.17-fix2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
        dm cache: fix race causing dirty blocks to be marked as clean
      186cec31
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.dk/linux-block · 645cc093
      Linus Torvalds authored
      Pull block fixes from Jens Axboe:
       "A small collection of fixes for the current rc series.  This contains:
      
         - Two small blk-mq patches from Rob Elliott, cleaning up error case
           at init time.
      
         - A fix from Ming Lei, fixing SG merging for blk-mq where
           QUEUE_FLAG_SG_NO_MERGE is the default.
      
         - A dev_t minor lifetime fix from Keith, fixing an issue where a
           minor might be reused before all references to it were gone.
      
         - Fix from Alan Stern where an unbalanced queue bypass caused SCSI
           some headaches when it does a series of add/del on devices without
           fully registrering the queue.
      
         - A fix from me for improving the scaling of tag depth in blk-mq if
           we are short on memory"
      
      * 'for-linus' of git://git.kernel.dk/linux-block:
        blk-mq: scale depth and rq map appropriate if low on memory
        Block: fix unbalanced bypass-disable in blk_register_queue
        block: Fix dev_t minor allocation lifetime
        blk-mq: cleanup after blk_mq_init_rq_map failures
        blk-mq: pass along blk_mq_alloc_tag_set return values
        blk-merge: fix blk_recount_segments
      645cc093
    • Linus Torvalds's avatar
      Merge tag 'stable/for-linus-3.17-b-rc4-arm-tag' of... · fc486b03
      Linus Torvalds authored
      Merge tag 'stable/for-linus-3.17-b-rc4-arm-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
      
      Pull Xen ARM bugfix from Stefano Stabellini:
       "The patches fix the "xen_add_mach_to_phys_entry: cannot add" bug that
        has been affecting xen on arm and arm64 guests since 3.16.  They
        require a few hypervisor side changes that just went in xen-unstable.
      
        A couple of days ago David sent out a pull request with a few other
        Xen fixes (it is already in master).  Sorry we didn't synchronized
        better among us"
      
      * tag 'stable/for-linus-3.17-b-rc4-arm-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
        xen/arm: remove mach_to_phys rbtree
        xen/arm: reimplement xen_dma_unmap_page & friends
        xen/arm: introduce XENFEAT_grant_map_identity
      fc486b03
  5. 12 Sep, 2014 1 commit
    • Richard Larocque's avatar
      alarmtimer: Lock k_itimer during timer callback · 474e941b
      Richard Larocque authored
      Locks the k_itimer's it_lock member when handling the alarm timer's
      expiry callback.
      
      The regular posix timers defined in posix-timers.c have this lock held
      during timout processing because their callbacks are routed through
      posix_timer_fn().  The alarm timers follow a different path, so they
      ought to grab the lock somewhere else.
      
      Cc: stable@vger.kernel.org
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Richard Cochran <richardcochran@gmail.com>
      Cc: Prarit Bhargava <prarit@redhat.com>
      Cc: Sharvil Nanavati <sharvil@google.com>
      Signed-off-by: default avatarRichard Larocque <rlarocque@google.com>
      Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
      474e941b