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  1. 04 7月, 2013 1 次提交
    • P
      mm: soft-dirty bits for user memory changes tracking · 0f8975ec
      由 Pavel Emelyanov 提交于 
      The soft-dirty is a bit on a PTE which helps to track which pages a task
writes to.  In order to do this tracking one should

  1. Clear soft-dirty bits from PTEs ("echo 4 > /proc/PID/clear_refs)
  2. Wait some time.
  3. Read soft-dirty bits (55'th in /proc/PID/pagemap2 entries)

To do this tracking, the writable bit is cleared from PTEs when the
soft-dirty bit is.  Thus, after this, when the task tries to modify a
page at some virtual address the #PF occurs and the kernel sets the
soft-dirty bit on the respective PTE.

Note, that although all the task's address space is marked as r/o after
the soft-dirty bits clear, the #PF-s that occur after that are processed
fast.  This is so, since the pages are still mapped to physical memory,
and thus all the kernel does is finds this fact out and puts back
writable, dirty and soft-dirty bits on the PTE.

Another thing to note, is that when mremap moves PTEs they are marked
with soft-dirty as well, since from the user perspective mremap modifies
the virtual memory at mremap's new address.
Signed-off-by: NPavel Emelyanov <xemul@parallels.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      0f8975ec
  3. 03 7月, 2013 1 次提交
  5. 29 6月, 2013 6 次提交
    • J
      locks: give the blocked_hash its own spinlock · 7b2296af
      由 Jeff Layton 提交于 
      There's no reason we have to protect the blocked_hash and file_lock_list
with the same spinlock. With the tests I have, breaking it in two gives
a barely measurable performance benefit, but it seems reasonable to make
this locking as granular as possible.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      7b2296af
    • J
      locks: add a new "lm_owner_key" lock operation · 3999e493
      由 Jeff Layton 提交于 
      Currently, the hashing that the locking code uses to add these values
to the blocked_hash is simply calculated using fl_owner field. That's
valid in most cases except for server-side lockd, which validates the
owner of a lock based on fl_owner and fl_pid.

In the case where you have a small number of NFS clients doing a lot
of locking between different processes, you could end up with all
the blocked requests sitting in a very small number of hash buckets.

Add a new lm_owner_key operation to the lock_manager_operations that
will generate an unsigned long to use as the key in the hashtable.
That function is only implemented for server-side lockd, and simply
XORs the fl_owner and fl_pid.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Acked-by: NJ. Bruce Fields <bfields@fieldses.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      3999e493
    • J
      locks: protect most of the file_lock handling with i_lock · 1c8c601a
      由 Jeff Layton 提交于 
      Having a global lock that protects all of this code is a clear
scalability problem. Instead of doing that, move most of the code to be
protected by the i_lock instead. The exceptions are the global lists
that the ->fl_link sits on, and the ->fl_block list.

->fl_link is what connects these structures to the
global lists, so we must ensure that we hold those locks when iterating
over or updating these lists.

Furthermore, sound deadlock detection requires that we hold the
blocked_list state steady while checking for loops. We also must ensure
that the search and update to the list are atomic.

For the checking and insertion side of the blocked_list, push the
acquisition of the global lock into __posix_lock_file and ensure that
checking and update of the  blocked_list is done without dropping the
lock in between.

On the removal side, when waking up blocked lock waiters, take the
global lock before walking the blocked list and dequeue the waiters from
the global list prior to removal from the fl_block list.

With this, deadlock detection should be race free while we minimize
excessive file_lock_lock thrashing.

Finally, in order to avoid a lock inversion problem when handling
/proc/locks output we must ensure that manipulations of the fl_block
list are also protected by the file_lock_lock.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      1c8c601a
    • L
      Don't pass inode to ->d_hash() and ->d_compare() · da53be12
      由 Linus Torvalds 提交于 
      Instances either don't look at it at all (the majority of cases) or
only want it to find the superblock (which can be had as dentry->d_sb).
A few cases that want more are actually safe with dentry->d_inode -
the only precaution needed is the check that it hadn't been replaced with
NULL by rmdir() or by overwriting rename(), which case should be simply
treated as cache miss.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      da53be12
    • A
      [readdir] ->readdir() is gone · 2233f31a
      由 Al Viro 提交于 
      everything's converted to ->iterate()
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      2233f31a
    • A
      [readdir] introduce iterate_dir() and dir_context · 5c0ba4e0
      由 Al Viro 提交于 
      iterate_dir(): new helper, replacing vfs_readdir().

struct dir_context: contains the readdir callback (and will get more stuff
in it), embedded into whatever data that callback wants to deal with;
eventually, we'll be passing it to ->readdir() replacement instead of
(data,filldir) pair.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      5c0ba4e0
  7. 28 6月, 2013 1 次提交
  9. 27 6月, 2013 1 次提交
  11. 26 6月, 2013 4 次提交
  13. 25 6月, 2013 1 次提交
  15. 24 6月, 2013 2 次提交
  17. 23 6月, 2013 2 次提交
    • D
      x86: Add NMI duration tracepoints · 0c4df02d
      由 Dave Hansen 提交于 
      This patch has been invaluable in my adventures finding
issues in the perf NMI handler.  I'm as big a fan of
printk() as anybody is, but using printk() in NMIs is
deadly when they're happening frequently.

Even hacking in trace_printk() ended up eating enough
CPU to throw off some of the measurements I was making.
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: paulus@samba.org
Cc: acme@ghostprotocols.net
Cc: Dave Hansen <dave@sr71.net>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      0c4df02d
    • D
      perf: Drop sample rate when sampling is too slow · 14c63f17
      由 Dave Hansen 提交于 
      This patch keeps track of how long perf's NMI handler is taking,
and also calculates how many samples perf can take a second.  If
the sample length times the expected max number of samples
exceeds a configurable threshold, it drops the sample rate.

This way, we don't have a runaway sampling process eating up the
CPU.

This patch can tend to drop the sample rate down to level where
perf doesn't work very well.  *BUT* the alternative is that my
system hangs because it spends all of its time handling NMIs.

I'll take a busted performance tool over an entire system that's
busted and undebuggable any day.

BTW, my suspicion is that there's still an underlying bug here.
Using the HPET instead of the TSC is definitely a contributing
factor, but I suspect there are some other things going on.
But, I can't go dig down on a bug like that with my machine
hanging all the time.
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: paulus@samba.org
Cc: acme@ghostprotocols.net
Cc: Dave Hansen <dave@sr71.net>
[ Prettified it a bit. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      14c63f17
  19. 22 6月, 2013 1 次提交
  21. 21 6月, 2013 1 次提交
  23. 20 6月, 2013 1 次提交
    • L
      clk: nomadik: implement the Nomadik clocks properly · ef6eb322
      由 Linus Walleij 提交于 
      The Nomadik clock implementation was a stub just using
fixed clocks.

This implements the clocks properly instead of relying
on them all being on at boot and leaving them all on.

The PLLs are on the top locking to the main chrystal
oscillator, then the HCLK for the peripherals are
below PLL2.

The gated clocks are implemented with zero cells and
given the clock ID as a property of each node, so every
gate need to have its own node in the device tree.
This is because the gate registers contain both HCLK
gates and PCLK gates, where the latter has HCLK as
parent. As can be seen from the register layout, this
is a complete mixup, which means all these gates need
their own node to properly model parent/child relations
for PCLKs apart from the HCLKs.

This driver also adds a helpful debugfs file to inspect
the hardware state of the clock gates.

This is the end result in <debugfs>/clk/clk_summary
after applying a proper device tree:

ulpiclk                0   0    60000000
mxtal                  3   3    19200000
   pll2                1   1    864000000
      clk48            3   3    48000000
         rngcclk       1   1    48000000
         usbmclk       0   0    48000000
         mshcclk       0   0    48000000
         mspclk3       0   0    48000000
         x3dclk        0   0    48000000
         skeclk        0   0    48000000
         owmclk        0   0    48000000
         mspclk2       0   0    48000000
         mspclk1       0   0    48000000
         uart2clk      0   0    48000000
         ipbmcclk      0   0    48000000
         ipi2cclk      0   0    48000000
         usbclk        0   0    48000000
         mspclk0       0   0    48000000
         uart1clk      1   2    48000000
         i2c1clk       0   0    48000000
         i2c0clk       0   0    48000000
         sdiclk        1   1    48000000
         uart0clk      0   0    48000000
         sspiclk       0   0    48000000
         irdaclk       0   0    48000000
      clk72            0   0    72000000
         difclk        0   0    72000000
         clcdclk       0   0    72000000
      clk216           0   0    216000000
         hsiclkrx      0   0    216000000
         clk108        0   0    108000000
            hsiclktx   0   0    108000000
            clk27      0   0    27000000
   pll1                1   1    264000000
      hclk             3   3    264000000
         hclkrng       1   1    264000000
         hclkusbm      0   0    264000000
         hclkcryp      0   0    264000000
         hclkhash      0   0    264000000
         hclk3d        0   0    264000000
         hclkhpi       0   0    264000000
         hclksva       0   0    264000000
         hclksaa       0   0    264000000
         hclkdif       0   0    264000000
         hclkusb       0   0    264000000
         hclkclcd      0   0    264000000
         hclkdma1      0   0    264000000
         hclksdram     0   0    264000000
         hclksmc       1   1    264000000
         hclkdma0      0   0    264000000
         pclk          7   9    264000000
            pclkmsp3   0   0    264000000
            pclkmshc   0   0    264000000
            pclkhsem   0   0    264000000
            pclkske    0   0    264000000
            pclkowm    0   0    264000000
            pclkmsp2   0   0    264000000
            pclkmsp1   0   0    264000000
            pclkuart2  0   0    264000000
            pclkxti    0   0    264000000
            pclkhsi    0   0    264000000
            pclkmsp0   0   0    264000000
            pclkuart1  1   1    264000000
            pclki2c1   0   0    264000000
            pclki2c0   0   0    264000000
            pclksdi    1   1    264000000
            pclkuart0  1   1    264000000
            pclkssp    0   0    264000000
            pclkirda   0   0    264000000
   timclk              1   1    2400000
Acked-by: NMike Turquette <mturquette@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
      ef6eb322
  25. 19 6月, 2013 14 次提交
  27. 18 6月, 2013 4 次提交