The waitqueue which is used in struct futex_q is a leftover from the
futexfd implementation. There is no need to use a waitqueue at all, as
the waiting task is the only user of it. The waitqueue just adds
additional locking and a loop in the wake up path which both can be
avoided.
We have already a task reference in struct futex_q which is used for
PI futexes. Use it for normal futexes as well and just wake up the
task directly.
The logic of signalling the futex wakeup via setting q->lock_ptr to
NULL is kept with the difference that we set it NULL before doing the
wakeup. This opens an exit race window vs. a non futex wake up of the
to be woken up task, which we prevent with get_task_struct /
put_task_struct on the waiter.
[ Impact: simplification ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The new requeue PI futex op codes were modeled after the existing
FUTEX_REQUEUE and FUTEX_CMP_REQUEUE calls. I was unaware at the time
that FUTEX_REQUEUE was only around for compatibility reasons and
shouldn't be used in new code. Ulrich Drepper elaborates on this in his
Futexes are Tricky paper: http://people.redhat.com/drepper/futex.pdf.
The deprecated call doesn't catch changes to the futex corresponding to
the destination futex which can lead to deadlock.
Therefor, I feel it best to remove FUTEX_REQUEUE_PI and leave only
FUTEX_CMP_REQUEUE_PI as there are not yet any existing users of the API.
This patch does change the OP code value of FUTEX_CMP_REQUEUE_PI to 12
from 13. Since my test case is the only known user of this API, I felt
this was the right thing to do, rather than leave a hole in the
enumeration.
I chose to continue using the _CMP_ modifier in the OP code to make it
explicit to the user that the test is being done.
Builds, boots, and ran several hundred iterations requeue_pi.c.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
LKML-Reference: <49ED580E.1050502@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
If the get_futex_key() call were to fail, the existing code would
try and put_futex_key() prior to returning. This patch makes sure
we only put_futex_key() if get_futex_key() succeeded.
Reported-by: Clark Williams <williams@redhat.com>
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
LKML-Reference: <20090410165005.14342.16973.stgit@Aeon>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Impact: build fix
Today's linux-next build (sparc64 defconfig) failed like this:
arch/sparc/kernel/built-in.o: In function `trap_init':
(.init.text+0x4): undefined reference to `thread_info_offsets_are_bolixed_dave'
Caused by commit 52400ba946 ("futex: add
requeue_pi functionality") (from the tip-core tree) which changed the
size of struct restart_block.
Shift TI_KUNA_REGS and TI_KUNA_INSN up by 8 bytes to make space for the
larger restart block.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: "David S. Miller" <davem@davemloft.net>
Cc: Darren Hart <dvhltc@us.ibm.com>
LKML-Reference: <20090409151722.c8eabb56.sfr@canb.auug.org.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Thomas's testing caught a problem when the requeue target futex is
unowned and multiple tasks are requeued to it. This patch ensures
the FUTEX_WAITERS bit gets set if futex_requeue() will requeue one
or more tasks in addition to the one acquiring the lock.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
PI Futexes and their underlying rt_mutex cannot be left ownerless if
there are pending waiters as this will break the PI boosting logic, so
the standard requeue commands aren't sufficient. The new commands
properly manage pi futex ownership by ensuring a futex with waiters
has an owner at all times. This will allow glibc to properly handle
pi mutexes with pthread_condvars.
The approach taken here is to create two new futex op codes:
FUTEX_WAIT_REQUEUE_PI:
Tasks will use this op code to wait on a futex (such as a non-pi waitqueue)
and wake after they have been requeued to a pi futex. Prior to returning to
userspace, they will acquire this pi futex (and the underlying rt_mutex).
futex_wait_requeue_pi() is the result of a high speed collision between
futex_wait() and futex_lock_pi() (with the first part of futex_lock_pi() being
done by futex_proxy_trylock_atomic() on behalf of the top_waiter).
FUTEX_REQUEUE_PI (and FUTEX_CMP_REQUEUE_PI):
This call must be used to wake tasks waiting with FUTEX_WAIT_REQUEUE_PI,
regardless of how many tasks the caller intends to wake or requeue.
pthread_cond_broadcast() should call this with nr_wake=1 and
nr_requeue=INT_MAX. pthread_cond_signal() should call this with nr_wake=1 and
nr_requeue=0. The reason being we need both callers to get the benefit of the
futex_proxy_trylock_atomic() routine. futex_requeue() also enqueues the
top_waiter on the rt_mutex via rt_mutex_start_proxy_lock().
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Refactor the code to validate the expected futex value in order to
reuse it with the requeue_pi code.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
futex_requeue() is getting a bit long-winded, and will be getting more
so after the requeue_pi patch. Factor out the actual requeueing into a
nicely contained inline function to reduce function length and improve
legibility.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Currently restart is only used if there is a timeout. The requeue_pi
functionality requires restarting to futex_lock_pi() on signal after
wakeup in futex_wait_requeue_pi() regardless of if there was a timeout
or not. Using 0 for the timeout value is confusing as that could
indicate an expired timer. The flag makes this explicit. While the
check is not technically needed in futex_wait_restart(), doing so
makes the code consistent with and will avoid confusion should the
need arise to restart wait without a timeout.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This patch is a prerequisite for futex requeue_pi. It basically splits
rt_mutex_slowlock() right down the middle, just before the first call
to schedule(). It further adds helper functions which make use of the
split and provide the rt-mutex preliminaries for futex requeue_pi.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Refactor the post lock acquisition logic from futex_lock_pi(). This
code will be reused in futex_wait_requeue_pi().
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Refactor the atomic portion of futex_lock_pi() into futex_lock_pi_atomic().
This logic will be needed by requeue_pi, so modularize it to reduce
code duplication. The only significant change is passing of the task
to try and take the lock for. This simplifies the -EDEADLK test as if
the lock is owned by task t, it's a deadlock, regardless of if we are
doing requeue pi or not. This patch updates the corresponding comment
accordingly.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Improve legibility by wrapping finding the top waiter in a function.
This will be used by the follow-on patches for enabling requeue pi.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Refactor futex_wait() in preparation for futex_wait_requeue_pi(). In
order to reuse a good chunk of the futex_wait() code for the upcoming
futex_wait_requeue_pi() function, this patch breaks out the
queue-to-wakeup section of futex_wait() into futex_wait_queue_me().
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* 'stacktrace-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
symbols, stacktrace: look up init symbols after module symbols
* 'rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
rcu: rcu_barrier VS cpu_hotplug: Ensure callbacks in dead cpu are migrated to online cpu
* 'ipi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
s390: remove arch specific smp_send_stop()
panic: clean up kernel/panic.c
panic, smp: provide smp_send_stop() wrapper on UP too
panic: decrease oops_in_progress only after having done the panic
generic-ipi: eliminate WARN_ON()s during oops/panic
generic-ipi: cleanups
generic-ipi: remove CSD_FLAG_WAIT
generic-ipi: remove kmalloc()
generic IPI: simplify barriers and locking
* 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
locking: rename trace_softirq_[enter|exit] => lockdep_softirq_[enter|exit]
lockdep: remove duplicate CONFIG_DEBUG_LOCKDEP definitions
lockdep: require framepointers for x86
lockdep: remove extra "irq" string
lockdep: fix incorrect state name
Bring the devices.txt back into some relationship with reality. Update the
documentation a bit.
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid:
HID: remove compat stuff
HID: constify arrays of struct apple_key_translation
HID: add support for Kye/Genius Ergo 525V
HID: Support Apple mini aluminum keyboard
HID: support for Kensington slimblade device
HID: DragonRise game controller force feedback driver
HID: add support for another version of 0e8f:0003 device in hid-pl
HID: fix race between usb_register_dev() and hiddev_open()
HID: bring back possibility to specify vid/pid ignore on module load
HID: make HID_DEBUG defaults consistent
HID: autosuspend -- fix lockup of hid on reset
HID: hid_reset_resume() needs to be defined only when CONFIG_PM is set
HID: fix USB HID devices after STD with autosuspend
HID: do not try to compile PM code with CONFIG_PM unset
HID: autosuspend support for USB HID
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (28 commits)
trivial: Update my email address
trivial: NULL noise: drivers/mtd/tests/mtd_*test.c
trivial: NULL noise: drivers/media/dvb/frontends/drx397xD_fw.h
trivial: Fix misspelling of "Celsius".
trivial: remove unused variable 'path' in alloc_file()
trivial: fix a pdlfush -> pdflush typo in comment
trivial: jbd header comment typo fix for JBD_PARANOID_IOFAIL
trivial: wusb: Storage class should be before const qualifier
trivial: drivers/char/bsr.c: Storage class should be before const qualifier
trivial: h8300: Storage class should be before const qualifier
trivial: fix where cgroup documentation is not correctly referred to
trivial: Give the right path in Documentation example
trivial: MTD: remove EOL from MODULE_DESCRIPTION
trivial: Fix typo in bio_split()'s documentation
trivial: PWM: fix of #endif comment
trivial: fix typos/grammar errors in Kconfig texts
trivial: Fix misspelling of firmware
trivial: cgroups: documentation typo and spelling corrections
trivial: Update contact info for Jochen Hein
trivial: fix typo "resgister" -> "register"
...
* git://git.kernel.org/pub/scm/linux/kernel/git/czankel/xtensa-2.6: (21 commits)
xtensa: we don't need to include asm/io.h
xtensa: only build platform or variant if they contain a Makefile
xtensa: make startup code discardable
xtensa: ccount clocksource
xtensa: remove platform rtc hooks
xtensa: use generic sched_clock()
xtensa: platform: s6105
xtensa: let platform override KERNELOFFSET
xtensa: s6000 variant
xtensa: s6000 variant core definitions
xtensa: variant irq set callbacks
xtensa: variant-specific code
xtensa: nommu support
xtensa: add flat support
xtensa: enforce slab alignment to maximum register width
xtensa: cope with ram beginning at higher addresses
xtensa: don't make bootmem bitmap larger than required
xtensa: fix init_bootmem_node() argument order
xtensa: use correct stack pointer for stack traces
xtensa: beat Kconfig into shape
...
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
Btrfs: BUG to BUG_ON changes
Btrfs: remove dead code
Btrfs: remove dead code
Btrfs: fix typos in comments
Btrfs: remove unused ftrace include
Btrfs: fix __ucmpdi2 compile bug on 32 bit builds
Btrfs: free inode struct when btrfs_new_inode fails
Btrfs: fix race in worker_loop
Btrfs: add flushoncommit mount option
Btrfs: notreelog mount option
Btrfs: introduce btrfs_show_options
Btrfs: rework allocation clustering
Btrfs: Optimize locking in btrfs_next_leaf()
Btrfs: break up btrfs_search_slot into smaller pieces
Btrfs: kill the pinned_mutex
Btrfs: kill the block group alloc mutex
Btrfs: clean up find_free_extent
Btrfs: free space cache cleanups
Btrfs: unplug in the async bio submission threads
Btrfs: keep processing bios for a given bdev if our proc is batching
pci mmap code was doing memtype reserve for a while now. Recently we
added memtype tracking in remap_pfn_range, and pci code indirectly calls
remap_pfn_range. So, we don't need seperate tracking in pci code
anymore. Which means a patch that removes ~50 lines of code :-).
Also, recently we found out that the pci tracking is not working as we expect
it to work in some cases. Specifically, userlevel X mmap of pci, with some
recent version of X, is having a problem with vm_page_prot getting reset.
The pci tracking uses vm_page_prot to pass on the protection type from parent
to child during fork.
a) Parent does a pci mmap
b) We look at PAT and get either UC_MINUS or WC mapping for parent
c) Store that mapping type in vma vm_page_prot for future use
d) This thread does a fork
e) Fork results in mmap_ops ->open for the child process
f) We get the vm_page_prot from vma and reserve that type for the child process
But, between c) and e) above, the vma vm_page_prot is getting reset to zero.
This results in PAT reserve failing at the time of fork as in here.
http://marc.info/?l=linux-kernel&m=123858163103240&w=2
This cleanup makes the above problem go away as we do not depend on
vm_page_prot in our PAT code anymore.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mfasheh/ocfs2: (32 commits)
ocfs2: recover orphans in offline slots during recovery and mount
ocfs2: Pagecache usage optimization on ocfs2
ocfs2: fix rare stale inode errors when exporting via nfs
ocfs2/dlm: Tweak mle_state output
ocfs2/dlm: Do not purge lockres that is being migrated dlm_purge_lockres()
ocfs2/dlm: Remove struct dlm_lock_name in struct dlm_master_list_entry
ocfs2/dlm: Show the number of lockres/mles in dlm_state
ocfs2/dlm: dlm_set_lockres_owner() and dlm_change_lockres_owner() inlined
ocfs2/dlm: Improve lockres counts
ocfs2/dlm: Track number of mles
ocfs2/dlm: Indent dlm_cleanup_master_list()
ocfs2/dlm: Activate dlm->master_hash for master list entries
ocfs2/dlm: Create and destroy the dlm->master_hash
ocfs2/dlm: Refactor dlm_clean_master_list()
ocfs2/dlm: Clean up struct dlm_lock_name
ocfs2/dlm: Encapsulate adding and removing of mle from dlm->master_list
ocfs2: Optimize inode group allocation by recording last used group.
ocfs2: Allocate inode groups from global_bitmap.
ocfs2: Optimize inode allocation by remembering last group
ocfs2: fix leaf start calculation in ocfs2_dx_dir_rebalance()
...
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx:
dma: Add SoF and EoF debugging to ipu_idmac.c, minor cleanup
dw_dmac: add cyclic API to DW DMA driver
dmaengine: Add privatecnt to revert DMA_PRIVATE property
dmatest: add dma interrupts and callbacks
dmatest: add xor test
dmaengine: allow dma support for async_tx to be toggled
async_tx: provide __async_inline for HAS_DMA=n archs
dmaengine: kill some unused headers
dmaengine: initialize tx_list in dma_async_tx_descriptor_init
dma: i.MX31 IPU DMA robustness improvements
dma: improve section assignment in i.MX31 IPU DMA driver
dma: ipu_idmac driver cosmetic clean-up
dmaengine: fail device registration if channel registration fails
During recovery, a node recovers orphans in it's slot and the dead node(s). But
if the dead nodes were holding orphans in offline slots, they will be left
unrecovered.
If the dead node is the last one to die and is holding orphans in other slots
and is the first one to mount, then it only recovers it's own slot, which
leaves orphans in offline slots.
This patch queues complete_recovery to clean orphans for all offline slots
during mount and node recovery.
Signed-off-by: Srinivas Eeda <srinivas.eeda@oracle.com>
Acked-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
A page can have multiple buffers and even if a page is not uptodate, some buffers
can be uptodate on pagesize != blocksize environment.
This aops checks that all buffers which correspond to a part of a file
that we want to read are uptodate. If so, we do not have to issue actual
read IO to HDD even if a page is not uptodate because the portion we
want to read are uptodate.
"block_is_partially_uptodate" function is already used by ext2/3/4.
With the following patch random read/write mixed workloads or random read after
random write workloads can be optimized and we can get performance improvement.
Signed-off-by: Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
For nfs exporting, ocfs2_get_dentry() returns the dentry for fh.
ocfs2_get_dentry() may read from disk when the inode is not in memory,
without any cross cluster lock. this leads to the file system loading a
stale inode.
This patch fixes above problem.
Solution is that in case of inode is not in memory, we get the cluster
lock(PR) of alloc inode where the inode in question is allocated from (this
causes node on which deletion is done sync the alloc inode) before reading
out the inode itsself. then we check the bitmap in the group (the inode in
question allcated from) to see if the bit is clear. if it's clear then it's
stale. if the bit is set, we then check generation as the existing code
does.
We have to read out the inode in question from disk first to know its alloc
slot and allot bit. And if its not stale we read it out using ocfs2_iget().
The second read should then be from cache.
And also we have to add a per superblock nfs_sync_lock to cover the lock for
alloc inode and that for inode in question. this is because ocfs2_get_dentry()
and ocfs2_delete_inode() lock on them in reverse order. nfs_sync_lock is locked
in EX mode in ocfs2_get_dentry() and in PR mode in ocfs2_delete_inode(). so
that mutliple ocfs2_delete_inode() can run concurrently in normal case.
[mfasheh@suse.com: build warning fixes and comment cleanups]
Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Acked-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
The debugfs file, mle_state, now prints the number of largest number of mles
in one hash link.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
This patch attempts to fix a fine race between purging and migration.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
This patch removes struct dlm_lock_name and adds the entries directly
to struct dlm_master_list_entry. Under the new scheme, both mles that
are backed by a lockres or not, will have the name populated in mle->mname.
This allows us to get rid of code that was figuring out the location of
the mle name.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
This patch shows the number of lockres' and mles in the debugfs file, dlm_state.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
This patch inlines dlm_set_lockres_owner() and dlm_change_lockres_owner().
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
This patch replaces the lockres counts that tracked the number number of
locally and remotely mastered lockres' with a current and total count. The
total count is the number of lockres' that have been created since the dlm
domain was created.
The number of locally and remotely mastered counts can be computed using
the locking_state output.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
The lifetime of a mle is limited to the duration of the lockres mastery
process. While typically this lifetime is fairly short, we have noticed
the number of mles explode under certain circumstances. This patch tracks
the number of each different types of mles and should help us determine
how best to speed up the mastery process.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
The previous patch explicitly did not indent dlm_cleanup_master_list()
so as to make the patch readable. This patch properly indents the
function.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
With this patch, the mles are stored in a hash and not a simple list.
This should improve the mle lookup time when the number of outstanding
masteries is large.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
This patch adds code to create and destroy the dlm->master_hash.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
This patch refactors dlm_clean_master_list() so as to make it
easier to convert the mle list to a hash.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
For master mle, the name it stored in the attached lockres in struct qstr.
For block and migration mle, the name is stored inline in struct dlm_lock_name.
This patch attempts to make struct dlm_lock_name look like a struct qstr. While
we could use struct qstr, we don't because we want to avoid having to malloc
and free the lockname string as the mle's lifetime is fairly short.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
This patch encapsulates adding and removing of the mle from the
dlm->master_list. This patch is part of the series of patches that
converts the mle list to a mle hash.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
In ocfs2, the block group search looks for the "emptiest" group
to allocate from. So if the allocator has many equally(or almost
equally) empty groups, new block group will tend to get spread
out amongst them.
So we add osb_inode_alloc_group in ocfs2_super to record the last
used inode allocation group.
For more details, please see
http://oss.oracle.com/osswiki/OCFS2/DesignDocs/InodeAllocationStrategy.
I have done some basic test and the results are a ten times improvement on
some cold-cache stat workloads.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Inode groups used to be allocated from local alloc file,
but since we want all inodes to be contiguous enough, we
will try to allocate them directly from global_bitmap.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
In ocfs2, the inode block search looks for the "emptiest" inode
group to allocate from. So if an inode alloc file has many equally
(or almost equally) empty groups, new inodes will tend to get
spread out amongst them, which in turn can put them all over the
disk. This is undesirable because directory operations on conceptually
"nearby" inodes force a large number of seeks.
So we add ip_last_used_group in core directory inodes which records
the last used allocation group. Another field named ip_last_used_slot
is also added in case inode stealing happens. When claiming new inode,
we passed in directory's inode so that the allocation can use this
information.
For more details, please see
http://oss.oracle.com/osswiki/OCFS2/DesignDocs/InodeAllocationStrategy.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
