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  1. 21 6月, 2012 1 次提交
  3. 18 6月, 2012 3 次提交
  5. 07 6月, 2012 1 次提交
  7. 04 6月, 2012 1 次提交
  9. 03 6月, 2012 1 次提交
    • J
      dm thin: provide userspace access to pool metadata · cc8394d8
      由 Joe Thornber 提交于 
      This patch implements two new messages that can be sent to the thin
pool target allowing it to take a snapshot of the _metadata_.  This,
read-only snapshot can be accessed by userland, concurrently with the
live target.

Only one metadata snapshot can be held at a time.  The pool's status
line will give the block location for the current msnap.

Since version 0.1.5 of the userland thin provisioning tools, the
thin_dump program displays the msnap as follows:

    thin_dump -m <msnap root> <metadata dev>

Available here: https://github.com/jthornber/thin-provisioning-tools

Now that userland can access the metadata we can do various things
that have traditionally been kernel side tasks:

     i) Incremental backups.

     By using metadata snapshots we can work out what blocks have
     changed over time.  Combined with data snapshots we can ensure
     the data doesn't change while we back it up.

     A short proof of concept script can be found here:

     https://github.com/jthornber/thinp-test-suite/blob/master/incremental_backup_example.rb

     ii) Migration of thin devices from one pool to another.

     iii) Merging snapshots back into an external origin.

     iv) Asyncronous replication.
Signed-off-by: NJoe Thornber <ejt@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      cc8394d8
  11. 02 6月, 2012 2 次提交
    • M
      x86, efi: Add EFI boot stub documentation · 0c759662
      由 Matt Fleming 提交于 
      Since we can't expect every user to read the EFI boot stub code it
seems prudent to have a couple of paragraphs explaining what it is and
how it works.

The "initrd=" option in particular is tricky because it only
understands absolute EFI-style paths (backslashes as directory
separators), and until now this hasn't been documented anywhere. This
has tripped up a couple of users.

Cc: Matthew Garrett <mjg@redhat.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/1331907517-3985-4-git-send-email-matt@console-pimps.orgSigned-off-by: NH. Peter Anvin <hpa@zytor.com>
      0c759662
    • J
      fs: introduce inode operation ->update_time · c3b2da31
      由 Josef Bacik 提交于 
      Btrfs has to make sure we have space to allocate new blocks in order to modify
the inode, so updating time can fail.  We've gotten around this by having our
own file_update_time but this is kind of a pain, and Christoph has indicated he
would like to make xfs do something different with atime updates.  So introduce
->update_time, where we will deal with i_version an a/m/c time updates and
indicate which changes need to be made.  The normal version just does what it
has always done, updates the time and marks the inode dirty, and then
filesystems can choose to do something different.

I've gone through all of the users of file_update_time and made them check for
errors with the exception of the fault code since it's complicated and I wasn't
quite sure what to do there, also Jan is going to be pushing the file time
updates into page_mkwrite for those who have it so that should satisfy btrfs and
make it not a big deal to check the file_update_time() return code in the
generic fault path. Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
      c3b2da31
  13. 01 6月, 2012 5 次提交
  15. 31 5月, 2012 1 次提交
  17. 30 5月, 2012 18 次提交
  19. 25 5月, 2012 7 次提交
    • S
      doc: ext3: update documentation with barrier=1 default · 21848d08
      由 Stefan Hajnoczi 提交于 
      Commit 00eacd66 ("ext3: make ext3 mount default to barrier=1") changed
the default barrier mount option for ext3.  The documentation needs to
be updated, so this patch does that.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Acked-by: NRob Landley <rob@landley.net>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
      21848d08
    • M
      Documentation/initrd.txt: Change the location of util-linux · 76dab97c
      由 Marcos Paulo de Souza 提交于 
      The address of util-linux seems deprecated. The new util-linux location is
in the kernel.org. So, change this for the correct address.
Signed-off-by: NMarcos Paulo de Souza <marcos.souza.org@gmail.com>
Acked-by: NRob Landley <rob@landley.net>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
      76dab97c
    • M
      Documentation/SubmittingPatches: suggested the use of scripts/get_maintainer.pl · e52d2e1f
      由 Michel Machado 提交于 
      Had I found a reference to scripts/get_maintainer.pl when I first read
Documentation/SubmittingPatches, it would've saved me some time.
Signed-off-by: NMichel Machado <michel@digirati.com.br>
Acked-by: NRob Landley <rob@landley.net>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
      e52d2e1f
    • S
      Documentation/kernel-parameters: remove autotest and mcatest · 9b170dbd
      由 Sebastian Andrzej Siewior 提交于 
      It has no more users, the last one is gone in "[PATCH] ia64: Kconfig
cleanup" aka ("6fd79ab50b").
mcatest is gone in commit "[PATCH] ia64: SGI SN update"
("c6bacd5010ec").

Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NSebastian Andrzej Siewior <sebastian@breakpoint.cc>
Acked-by: NRob Landley <rob@landley.net>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
      9b170dbd
    • D
      dma-buf: add initial vmap documentation · b25b086d
      由 Dave Airlie 提交于 
      Signed-off-by: NDave Airlie <airlied@redhat.com>
Signed-off-by: NSumit Semwal <sumit.semwal@linaro.org>
      b25b086d
    • D
      dma-buf: mmap support · 4c78513e
      由 Daniel Vetter 提交于 
      Compared to Rob Clark's RFC I've ditched the prepare/finish hooks
and corresponding ioctls on the dma_buf file. The major reason for
that is that many people seem to be under the impression that this is
also for synchronization with outstanding asynchronous processsing.
I'm pretty massively opposed to this because:

- It boils down reinventing a new rather general-purpose userspace
  synchronization interface. If we look at things like futexes, this
  is hard to get right.
- Furthermore a lot of kernel code has to interact with this
  synchronization primitive. This smells a look like the dri1 hw_lock,
  a horror show I prefer not to reinvent.
- Even more fun is that multiple different subsystems would interact
  here, so we have plenty of opportunities to create funny deadlock
  scenarios.

I think synchronization is a wholesale different problem from data
sharing and should be tackled as an orthogonal problem.

Now we could demand that prepare/finish may only ensure cache
coherency (as Rob intended), but that runs up into the next problem:
We not only need mmap support to facilitate sw-only processing nodes
in a pipeline (without jumping through hoops by importing the dma_buf
into some sw-access only importer), which allows for a nicer
ION->dma-buf upgrade path for existing Android userspace. We also need
mmap support for existing importing subsystems to support existing
userspace libraries. And a loot of these subsystems are expected to
export coherent userspace mappings.

So prepare/finish can only ever be optional and the exporter /needs/
to support coherent mappings. Given that mmap access is always
somewhat fallback-y in nature I've decided to drop this optimization,
instead of just making it optional. If we demonstrate a clear need for
this, supported by benchmark results, we can always add it in again
later as an optional extension.

Other differences compared to Rob's RFC is the above mentioned support
for mapping a dma-buf through facilities provided by the importer.
Which results in mmap support no longer being optional.

Note that this dma-buf mmap patch does _not_ support every possible
insanity an existing subsystem could pull of with mmap: Because it
does not allow to intercept pagefaults and shoot down ptes importing
subsystems can't add some magic of their own at these points (e.g. to
automatically synchronize with outstanding rendering or set up some
special resources). I've done a cursory read through a few mmap
implementions of various subsytems and I'm hopeful that we can avoid
this (and the complexity it'd bring with it).

Additonally I've extended the documentation a bit to explain the hows
and whys of this mmap extension.

In case we ever want to add support for explicitly cache maneged
userspace mmap with a prepare/finish ioctl pair, we could specify that
userspace needs to mmap a different part of the dma_buf, e.g. the
range starting at dma_buf->size up to dma_buf->size*2. This works
because the size of a dma_buf is invariant over it's lifetime. The
exporter would obviously need to fall back to coherent mappings for
both ranges if a legacy clients maps the coherent range and the
architecture cannot suppor conflicting caching policies. Also, this
would obviously be optional and userspace needs to be able to fall
back to coherent mappings.

v2:
- Spelling fixes from Rob Clark.
- Compile fix for !DMA_BUF from Rob Clark.
- Extend commit message to explain how explicitly cache managed mmap
  support could be added later.
- Extend the documentation with implementations notes for exporters
  that need to manually fake coherency.

v3:
- dma_buf pointer initialization goof-up noticed by Rebecca Schultz
  Zavin.

Cc: Rob Clark <rob.clark@linaro.org>
Cc: Rebecca Schultz Zavin <rebecca@android.com>
Acked-by: NRob Clark <rob.clark@linaro.org>
Signed-Off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NSumit Semwal <sumit.semwal@linaro.org>
      4c78513e
    • M
      tick: Add tick skew boot option · 5307c955
      由 Mike Galbraith 提交于 
      Let the user decide whether power consumption or jitter is the
more important consideration for their machines.

Quoting removal commit af5ab277:

"Historically, Linux has tried to make the regular timer tick on the
 various CPUs not happen at the same time, to avoid contention on
 xtime_lock.
    
 Nowadays, with the tickless kernel, this contention no longer happens
 since time keeping and updating are done differently. In addition,
 this skew is actually hurting power consumption in a measurable way on
 many-core systems."

Problems:

- Contrary to the above, systems do encounter contention on both
  xtime_lock and RCU structure locks when the tick is synchronized.
  
- Moderate sized RT systems suffer intolerable jitter due to the tick
  being synchronized.

- SGI reports the same for their large systems.

- Fully utilized systems reap no power saving benefit from skew removal,
  but do suffer from resulting induced lock contention.

- 0209f649 rcu: limit rcu_node leaf-level fanout
  This patch was born to combat lock contention which testing showed
  to have been _induced by_ skew removal.  Skew the tick, contention
  disappeared virtually completely.
Signed-off-by: NMike Galbraith <mgalbraith@suse.de>
Link: http://lkml.kernel.org/r/1336472458.21924.78.camel@marge.simpson.netSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
      5307c955