- 03 Nov, 2009 1 commit
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Jens Axboe authored
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- 02 Nov, 2009 2 commits
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Alberto Bertogli authored
So remove both the comment and the inline requirement, going back to the inline hint. Signed-off-by:
Alberto Bertogli <albertito@blitiri.com.ar> Signed-off-by:
Jens Axboe <jens.axboe@oracle.com>
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Corrado Zoccolo authored
Eliminate redundant checks. Signed-off-by:
Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by:
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- 29 Oct, 2009 2 commits
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Christoph Hellwig authored
Currently there is no barrier support in the block device code. That means we cannot guarantee any sort of data integerity when using the block device node with dis kwrite caches enabled. Using the raw block device node is a typical use case for virtualization (and I assume databases, too). This patch changes block_fsync to issue a cache flush and thus make fsync on block device nodes actually useful. Note that in mainline we would also need to add such code to the ->aio_write method for O_SYNC handling, but assuming that Jan's patch series for the O_SYNC rewrite goes in it will also call into ->fsync for 2.6.32. Signed-off-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
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Jens Axboe authored
There's nothing block related about them, the backing device is used by things like NFS etc as well. This gets rid of the need to protect such calls by CONFIG_BLOCK. Signed-off-by:
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- 28 Oct, 2009 9 commits
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Jens Axboe authored
Signed-off-by: -
Jeff Moyer authored
Hi, Some workloads issue batches of small I/O, and the performance is poor due to the call to blk_run_address_space for every single iocb. Nathan Roberts pointed this out, and suggested that by deferring this call until all I/Os in the iocb array are submitted to the block layer, we can realize some impressive performance gains (up to 30% for sequential 4k reads in batches of 16). Signed-off-by:
Jeff Moyer <jmoyer@redhat.com> Signed-off-by:
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Jeff Moyer authored
Hi, The WRITE_ODIRECT flag is only used in one place, and that code path happens to also call blk_run_address_space. The introduction of this flag, then, could result in the device being unplugged twice for every I/O. Further, with the batching changes in the next patch, we don't want an O_DIRECT write to imply a queue unplug. Signed-off-by:
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Jens Axboe authored
Line breaks and bad brace placement. Signed-off-by: -
Corrado Zoccolo authored
Currently no-idle queues in cfq are not serviced fairly: even if they can only dispatch a small number of requests at a time, they have to compete with idling queues to be serviced, experiencing large latencies. We should notice, instead, that no-idle queues are the ones that would benefit most from having low latency, in fact they are any of: * processes with large think times (e.g. interactive ones like file managers) * seeky (e.g. programs faulting in their code at startup) * or marked as no-idle from upper levels, to improve latencies of those requests. This patch improves the fairness and latency for those queues, by: * separating sync idle, sync no-idle and async queues in separate service_trees, for each priority * service all no-idle queues together * and idling when the last no-idle queue has been serviced, to anticipate for more no-idle work * the timeslices allotted for idle and no-idle service_trees are computed proportionally to the number of processes in each set. Servicing all no-idle queues together should have a performance boost for NCQ-capable drives, without compromising fairness. Signed-off-by:
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Corrado Zoccolo authored
cfq can disable idling for queues in various circumstances. When workloads of different priorities are competing, if the higher priority queue has idling disabled, lower priority queues may steal its disk share. For example, in a scenario with an RT process performing seeky reads vs a BE process performing sequential reads, on an NCQ enabled hardware, with low_latency unset, the RT process will dispatch only the few pending requests every full slice of service for the BE process. The patch solves this issue by always performing idle on the last queue at a given priority class > idle. If the same process, or one that can pre-empt it (so at the same priority or higher), submits a new request within the idle window, the lower priority queue won't dispatch, saving the disk bandwidth for higher priority ones. Note: this doesn't touch the non_rotational + NCQ case (no hardware to test if this is a benefit in that case). Signed-off-by:
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Corrado Zoccolo authored
We use different service trees for different priority classes. This allows a simplification in the service tree insertion code, that no longer has to consider priority while walking the tree. Signed-off-by:
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Corrado Zoccolo authored
We embed a pointer to the service tree in each queue, to handle multiple service trees easily. Service trees are enriched with a counter. cfq_add_rq_rb is invoked after putting the rq in the fifo, to ensure that all fields in rq are properly initialized. Signed-off-by:
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Corrado Zoccolo authored
When the number of processes performing I/O concurrently increases, a fixed time slice per process will cause large latencies. This patch, if low_latency mode is enabled, will scale the time slice assigned to each process according to a 300ms target latency. In order to keep fairness among processes: * The number of active processes is computed using a special form of running average, that quickly follows sudden increases (to keep latency low), and decrease slowly (to have fairness in spite of rapid decreases of this value). To safeguard sequential bandwidth, we impose a minimum time slice (computed using 2*cfq_slice_idle as base, adjusted according to priority and async-ness). Signed-off-by:
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- 27 Oct, 2009 1 commit
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Shaohua Li authored
If active queue hasn't enough requests and idle window opens, cfq will not dispatch sufficient requests to hardware. In such situation, current code will zero hw_tag. But this is because cfq doesn't dispatch enough requests instead of hardware queue doesn't work. Don't zero hw_tag in such case. Signed-off-by:
Shaohua Li <shaohua.li@intel.com> Signed-off-by:
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- 26 Oct, 2009 4 commits
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Jeff Moyer authored
cfq_queues are merged if they are issuing requests within the mean seek distance of one another. This patch detects when the coopearting stops and breaks the queues back up. Signed-off-by:
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Jeff Moyer authored
The flag used to indicate that a cfqq was allowed to jump ahead in the scheduling order due to submitting a request close to the queue that just executed. Since closely cooperating queues are now merged, the flag holds little meaning. Change it to indicate that multiple queues were merged. This will later be used to allow the breaking up of merged queues when they are no longer cooperating. Signed-off-by:
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Jeff Moyer authored
When cooperating cfq_queues are detected currently, they are allowed to skip ahead in the scheduling order. It is much more efficient to automatically share the cfq_queue data structure between cooperating processes. Performance of the read-test2 benchmark (which is written to emulate the dump(8) utility) went from 12MB/s to 90MB/s on my SATA disk. NFS servers with multiple nfsd threads also saw performance increases. Signed-off-by:
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Jeff Moyer authored
async cfq_queue's are already shared between processes within the same priority, and forthcoming patches will change the mapping of cic to sync cfq_queue from 1:1 to 1:N. So, calculate the seekiness of a process based on the cfq_queue instead of the cfq_io_context. Signed-off-by:
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- 13 Oct, 2009 3 commits
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Jens Axboe authored
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Stephen M. Cameron authored
Add cciss_allow_hpsa module parameter. This parameter causes the cciss driver to ignore any Smart Array devices known to be supported by the hpsa driver. Signed-off-by:
Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by:
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Stephen M. Cameron authored
Fix multiple calls to pci_release_regions. If cciss_pci_init fails, it already does any necessary call to pci_release_regions, so this does not need to be done again in cciss_init_one in that case. Signed-off-by:
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- 12 Oct, 2009 1 commit
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Randy Dunlap authored
Fix kernel-doc notation in blk-settings.c::blk_queue_max_discard_sectors(). Signed-off-by:
Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by:
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- 09 Oct, 2009 3 commits
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Wu Fengguang authored
The space is not script friendly, kill it. Signed-off-by:
Wu Fengguang <fengguang.wu@intel.com> Signed-off-by:
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Wu Fengguang authored
It makes sense to do IOWAIT when someone is blocked due to IO throttle, as suggested by Kame and Peter. There is an old comment for not doing IOWAIT on throttle, however it has been mismatching the code for a long time. If we stop accounting IOWAIT for 2.6.32, it could be an undesirable behavior change. So restore the io_schedule. CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> CC: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by:
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KOSAKI Motohiro authored
elv_iosched_store() ignore the return value of strstrip(). It makes small inconsistent behavior. This patch fixes it. <before> ==================================== # cd /sys/block/{blockdev}/queue case1: # echo "anticipatory" > scheduler # cat scheduler noop [anticipatory] deadline cfq case2: # echo "anticipatory " > scheduler # cat scheduler noop [anticipatory] deadline cfq case3: # echo " anticipatory" > scheduler bash: echo: write error: Invalid argument <after> ==================================== # cd /sys/block/{blockdev}/queue case1: # echo "anticipatory" > scheduler # cat scheduler noop [anticipatory] deadline cfq case2: # echo "anticipatory " > scheduler # cat scheduler noop [anticipatory] deadline cfq case3: # echo " anticipatory" > scheduler noop [anticipatory] deadline cfq Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by:KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by:
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- 08 Oct, 2009 1 commit
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Corrado Zoccolo authored
If the average think time is larger than the remaining time slice for any given queue, don't allow it to idle. A succesful idle also means that we need to dispatch and complete a request, so if we don't even have time left for the idle process, we would overrun the slice in any case. Signed-off-by:
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- 07 Oct, 2009 3 commits
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Jens Axboe authored
Saves 16 bytes of text, woohoo. But the more important point is that it makes the code more readable when returning bool for 0/1 cases. Signed-off-by: -
Corrado Zoccolo authored
CFQ enables idle only for processes that think less than the allowed idle time. Since idle time is lower for seeky queues, we should use the correct value in the comparison. Signed-off-by:
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Randy Dunlap authored
drbd_int.h uses __ratelimit(), so it needs to #include ratelimit.h: drivers/block/drbd/drbd_int.h:1765: error: implicit declaration of function '__ratelimit' Signed-off-by:
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- 06 Oct, 2009 5 commits
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Jens Axboe authored
We should subtract the slice residual from the rb tree key, since a negative residual count indicates that the cfqq overran its slice the last time. Hence we want to add the overrun time, to position it a bit further away in the service tree. Reported-by:
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Jens Axboe authored
Makes the whole thing easier to read, cfq_dispatch_requests() was a bit messy before. Signed-off-by: -
Jens Axboe authored
Makes it easier to read than the 0. Signed-off-by: -
Nikanth Karthikesan authored
Commit a9327cac added seperate read and write statistics of in_flight requests. And exported the number of read and write requests in progress seperately through sysfs. But Corrado Zoccolo <czoccolo@gmail.com> reported getting strange output from "iostat -kx 2". Global values for service time and utilization were garbage. For interval values, utilization was always 100%, and service time is higher than normal. So this was reverted by commit 0f78ab98 The problem was in part_round_stats_single(), I missed the following: if (now == part->stamp) return; - if (part->in_flight) { + if (part_in_flight(part)) { __part_stat_add(cpu, part, time_in_queue, part_in_flight(part) * (now - part->stamp)); __part_stat_add(cpu, part, io_ticks, (now - part->stamp)); With this chunk included, the reported regression gets fixed. Signed-off-by:
Nikanth Karthikesan <knikanth@suse.de> -- Signed-off-by:
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Philipp Reisner authored
Now we have the capabilities of the sending process available, use them to enforce CAP_SYS_ADMIN. Signed-off-by:
Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by:
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- 05 Oct, 2009 5 commits
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Jens Axboe authored
It was briefly introduced to allow CFQ to to delayed scheduling, but we ended up removing that feature again. So lets kill the function and export, and just switch CFQ back to the normal work schedule since it is now passing in a '0' delay from all call sites. Signed-off-by: -
Corrado Zoccolo authored
The RR service tree is indexed by a key that is relative to current jiffies. This can cause problems on jiffies wraparound. The patch fixes it using time_before comparison, and changing the add_front path to use a relative number, too. Signed-off-by:
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Jens Axboe authored
cfq uses rq->start_time as the fifo indicator, but that field may get modified prior to cfq doing it's fifo list adjustment when a request gets merged with another request. This can cause the fifo list to become unordered. Reported-by:
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Jens Axboe authored
Signed-off-by: -
Jens Axboe authored
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