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* Merge branch 'writeback-for-linus' of ↵Linus Torvalds2011-11-0715-225/+806
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux * 'writeback-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux: writeback: Add a 'reason' to wb_writeback_work writeback: send work item to queue_io, move_expired_inodes writeback: trace event balance_dirty_pages writeback: trace event bdi_dirty_ratelimit writeback: fix ppc compile warnings on do_div(long long, unsigned long) writeback: per-bdi background threshold writeback: dirty position control - bdi reserve area writeback: control dirty pause time writeback: limit max dirty pause time writeback: IO-less balance_dirty_pages() writeback: per task dirty rate limit writeback: stabilize bdi->dirty_ratelimit writeback: dirty rate control writeback: add bg_threshold parameter to __bdi_update_bandwidth() writeback: dirty position control writeback: account per-bdi accumulated dirtied pages
| * writeback: Add a 'reason' to wb_writeback_workCurt Wohlgemuth2011-10-3013-34/+88
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This creates a new 'reason' field in a wb_writeback_work structure, which unambiguously identifies who initiates writeback activity. A 'wb_reason' enumeration has been added to writeback.h, to enumerate the possible reasons. The 'writeback_work_class' and tracepoint event class and 'writeback_queue_io' tracepoints are updated to include the symbolic 'reason' in all trace events. And the 'writeback_inodes_sbXXX' family of routines has had a wb_stats parameter added to them, so callers can specify why writeback is being started. Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Curt Wohlgemuth <curtw@google.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
| * writeback: send work item to queue_io, move_expired_inodesCurt Wohlgemuth2011-10-302-10/+11
| | | | | | | | | | | | | | | | | | | | | | Instead of sending ->older_than_this to queue_io() and move_expired_inodes(), send the entire wb_writeback_work structure. There are other fields of a work item that are useful in these routines and in tracepoints. Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Curt Wohlgemuth <curtw@google.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
| * writeback: trace event balance_dirty_pagesWu Fengguang2011-10-302-0/+95
| | | | | | | | | | | | | | Useful for analyzing the dynamics of the throttling algorithms and debugging user reported problems. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
| * writeback: trace event bdi_dirty_ratelimitWu Fengguang2011-10-302-0/+47
| | | | | | | | | | | | It helps understand how various throttle bandwidths are updated. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
| * writeback: fix ppc compile warnings on do_div(long long, unsigned long)Wu Fengguang2011-10-111-8/+7Star
| | | | | | | | | | | | | | | | | | | | | | | | | | Fix powerpc compile warnings mm/page-writeback.c: In function 'bdi_position_ratio': mm/page-writeback.c:622:3: warning: comparison of distinct pointer types lacks a cast [enabled by default] page-writeback.c:635:4: warning: comparison of distinct pointer types lacks a cast [enabled by default] Also fix gcc "uninitialized var" warnings. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
| * writeback: per-bdi background thresholdWu Fengguang2011-10-031-5/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | One thing puzzled me is that in JBOD case, the per-disk writeout performance is smaller than the corresponding single-disk case even when they have comparable bdi_thresh. Tracing shows find that in single disk case, bdi_writeback is always kept high while in JBOD case, it could drop low from time to time and correspondingly bdi_reclaimable could sometimes rush high. The fix is to watch bdi_reclaimable and kick background writeback as soon as it goes high. This resembles the global background threshold but in per-bdi manner. The trick is, as long as bdi_reclaimable does not go high, bdi_writeback naturally won't go low because bdi_reclaimable+bdi_writeback ~= bdi_thresh. With less fluctuated writeback pages, JBOD performance is observed to increase noticeably in various cases. vmstat:nr_written values before/after patch: 3.1.0-rc4-wo-underrun+ 3.1.0-rc4-bgthresh3+ ------------------------ ------------------------ 125596480 +25.9% 158179363 JBOD-10HDD-16G/ext4-100dd-1M-24p-16384M-20:10-X 61790815 +110.4% 130032231 JBOD-10HDD-16G/ext4-10dd-1M-24p-16384M-20:10-X 58853546 -0.1% 58823828 JBOD-10HDD-16G/ext4-1dd-1M-24p-16384M-20:10-X 110159811 +24.7% 137355377 JBOD-10HDD-16G/xfs-100dd-1M-24p-16384M-20:10-X 69544762 +10.8% 77080047 JBOD-10HDD-16G/xfs-10dd-1M-24p-16384M-20:10-X 50644862 +0.5% 50890006 JBOD-10HDD-16G/xfs-1dd-1M-24p-16384M-20:10-X 42677090 +28.0% 54643527 JBOD-10HDD-thresh=100M/ext4-100dd-1M-24p-16384M-100M:10-X 47491324 +13.3% 53785605 JBOD-10HDD-thresh=100M/ext4-10dd-1M-24p-16384M-100M:10-X 52548986 +0.9% 53001031 JBOD-10HDD-thresh=100M/ext4-1dd-1M-24p-16384M-100M:10-X 26783091 +36.8% 36650248 JBOD-10HDD-thresh=100M/xfs-100dd-1M-24p-16384M-100M:10-X 35526347 +14.0% 40492312 JBOD-10HDD-thresh=100M/xfs-10dd-1M-24p-16384M-100M:10-X 44670723 -1.1% 44177606 JBOD-10HDD-thresh=100M/xfs-1dd-1M-24p-16384M-100M:10-X 127996037 +22.4% 156719990 JBOD-10HDD-thresh=2G/ext4-100dd-1M-24p-16384M-2048M:10-X 57518856 +3.8% 59677625 JBOD-10HDD-thresh=2G/ext4-10dd-1M-24p-16384M-2048M:10-X 51919909 +12.2% 58269894 JBOD-10HDD-thresh=2G/ext4-1dd-1M-24p-16384M-2048M:10-X 86410514 +79.0% 154660433 JBOD-10HDD-thresh=2G/xfs-100dd-1M-24p-16384M-2048M:10-X 40132519 +38.6% 55617893 JBOD-10HDD-thresh=2G/xfs-10dd-1M-24p-16384M-2048M:10-X 48423248 +7.5% 52042927 JBOD-10HDD-thresh=2G/xfs-1dd-1M-24p-16384M-2048M:10-X 206041046 +44.1% 296846536 JBOD-10HDD-thresh=4G/xfs-100dd-1M-24p-16384M-4096M:10-X 72312903 -19.4% 58272885 JBOD-10HDD-thresh=4G/xfs-10dd-1M-24p-16384M-4096M:10-X 50635672 -0.5% 50384787 JBOD-10HDD-thresh=4G/xfs-1dd-1M-24p-16384M-4096M:10-X 68308534 +115.7% 147324758 JBOD-10HDD-thresh=800M/ext4-100dd-1M-24p-16384M-800M:10-X 57882933 +14.5% 66269621 JBOD-10HDD-thresh=800M/ext4-10dd-1M-24p-16384M-800M:10-X 52183472 +12.8% 58855181 JBOD-10HDD-thresh=800M/ext4-1dd-1M-24p-16384M-800M:10-X 53788956 +94.2% 104460352 JBOD-10HDD-thresh=800M/xfs-100dd-1M-24p-16384M-800M:10-X 44493342 +35.5% 60298210 JBOD-10HDD-thresh=800M/xfs-10dd-1M-24p-16384M-800M:10-X 42641209 +18.9% 50681038 JBOD-10HDD-thresh=800M/xfs-1dd-1M-24p-16384M-800M:10-X Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
| * writeback: dirty position control - bdi reserve areaWu Fengguang2011-10-031-0/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Keep a minimal pool of dirty pages for each bdi, so that the disk IO queues won't underrun. Also gently increase a small bdi_thresh to avoid it stuck in 0 for some light dirtied bdi. It's particularly useful for JBOD and small memory system. It may result in (pos_ratio > 1) at the setpoint and push the dirty pages high. This is more or less intended because the bdi is in the danger of IO queue underflow. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
| * writeback: control dirty pause timeWu Fengguang2011-10-031-1/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The dirty pause time shall ultimately be controlled by adjusting nr_dirtied_pause, since there is relationship pause = pages_dirtied / task_ratelimit Assuming pages_dirtied ~= nr_dirtied_pause task_ratelimit ~= dirty_ratelimit We get nr_dirtied_pause ~= dirty_ratelimit * desired_pause Here dirty_ratelimit is preferred over task_ratelimit because it's more stable. It's also important to limit possible large transitional errors: - bw is changing quickly - pages_dirtied << nr_dirtied_pause on entering dirty exceeded area - pages_dirtied >> nr_dirtied_pause on btrfs (to be improved by a separate fix, but still expect non-trivial errors) So we end up using the above formula inside clamp_val(). The best test case for this code is to run 100 "dd bs=4M" tasks on btrfs and check its pause time distribution. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
| * writeback: limit max dirty pause timeWu Fengguang2011-10-031-2/+42
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Apply two policies to scale down the max pause time for 1) small number of concurrent dirtiers 2) small memory system (comparing to storage bandwidth) MAX_PAUSE=200ms may only be suitable for high end servers with lots of concurrent dirtiers, where the large pause time can reduce much overheads. Otherwise, smaller pause time is desirable whenever possible, so as to get good responsiveness and smooth user experiences. It's actually required for good disk utilization in the case when all the dirty pages can be synced to disk within MAX_PAUSE=200ms. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
| * writeback: IO-less balance_dirty_pages()Wu Fengguang2011-10-032-129/+56Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As proposed by Chris, Dave and Jan, don't start foreground writeback IO inside balance_dirty_pages(). Instead, simply let it idle sleep for some time to throttle the dirtying task. In the mean while, kick off the per-bdi flusher thread to do background writeback IO. RATIONALS ========= - disk seeks on concurrent writeback of multiple inodes (Dave Chinner) If every thread doing writes and being throttled start foreground writeback, it leads to N IO submitters from at least N different inodes at the same time, end up with N different sets of IO being issued with potentially zero locality to each other, resulting in much lower elevator sort/merge efficiency and hence we seek the disk all over the place to service the different sets of IO. OTOH, if there is only one submission thread, it doesn't jump between inodes in the same way when congestion clears - it keeps writing to the same inode, resulting in large related chunks of sequential IOs being issued to the disk. This is more efficient than the above foreground writeback because the elevator works better and the disk seeks less. - lock contention and cache bouncing on concurrent IO submitters (Dave Chinner) With this patchset, the fs_mark benchmark on a 12-drive software RAID0 goes from CPU bound to IO bound, freeing "3-4 CPUs worth of spinlock contention". * "CPU usage has dropped by ~55%", "it certainly appears that most of the CPU time saving comes from the removal of contention on the inode_wb_list_lock" (IMHO at least 10% comes from the reduction of cacheline bouncing, because the new code is able to call much less frequently into balance_dirty_pages() and hence access the global page states) * the user space "App overhead" is reduced by 20%, by avoiding the cacheline pollution by the complex writeback code path * "for a ~5% throughput reduction", "the number of write IOs have dropped by ~25%", and the elapsed time reduced from 41:42.17 to 40:53.23. * On a simple test of 100 dd, it reduces the CPU %system time from 30% to 3%, and improves IO throughput from 38MB/s to 42MB/s. - IO size too small for fast arrays and too large for slow USB sticks The write_chunk used by current balance_dirty_pages() cannot be directly set to some large value (eg. 128MB) for better IO efficiency. Because it could lead to more than 1 second user perceivable stalls. Even the current 4MB write size may be too large for slow USB sticks. The fact that balance_dirty_pages() starts IO on itself couples the IO size to wait time, which makes it hard to do suitable IO size while keeping the wait time under control. Now it's possible to increase writeback chunk size proportional to the disk bandwidth. In a simple test of 50 dd's on XFS, 1-HDD, 3GB ram, the larger writeback size dramatically reduces the seek count to 1/10 (far beyond my expectation) and improves the write throughput by 24%. - long block time in balance_dirty_pages() hurts desktop responsiveness Many of us may have the experience: it often takes a couple of seconds or even long time to stop a heavy writing dd/cp/tar command with Ctrl-C or "kill -9". - IO pipeline broken by bumpy write() progress There are a broad class of "loop {read(buf); write(buf);}" applications whose read() pipeline will be under-utilized or even come to a stop if the write()s have long latencies _or_ don't progress in a constant rate. The current threshold based throttling inherently transfers the large low level IO completion fluctuations to bumpy application write()s, and further deteriorates with increasing number of dirtiers and/or bdi's. For example, when doing 50 dd's + 1 remote rsync to an XFS partition, the rsync progresses very bumpy in legacy kernel, and throughput is improved by 67% by this patchset. (plus the larger write chunk size, it will be 93% speedup). The new rate based throttling can support 1000+ dd's with excellent smoothness, low latency and low overheads. For the above reasons, it's much better to do IO-less and low latency pauses in balance_dirty_pages(). Jan Kara, Dave Chinner and me explored the scheme to let balance_dirty_pages() wait for enough writeback IO completions to safeguard the dirty limit. However it's found to have two problems: - in large NUMA systems, the per-cpu counters may have big accounting errors, leading to big throttle wait time and jitters. - NFS may kill large amount of unstable pages with one single COMMIT. Because NFS server serves COMMIT with expensive fsync() IOs, it is desirable to delay and reduce the number of COMMITs. So it's not likely to optimize away such kind of bursty IO completions, and the resulted large (and tiny) stall times in IO completion based throttling. So here is a pause time oriented approach, which tries to control the pause time in each balance_dirty_pages() invocations, by controlling the number of pages dirtied before calling balance_dirty_pages(), for smooth and efficient dirty throttling: - avoid useless (eg. zero pause time) balance_dirty_pages() calls - avoid too small pause time (less than 4ms, which burns CPU power) - avoid too large pause time (more than 200ms, which hurts responsiveness) - avoid big fluctuations of pause times It can control pause times at will. The default policy (in a followup patch) will be to do ~10ms pauses in 1-dd case, and increase to ~100ms in 1000-dd case. BEHAVIOR CHANGE =============== (1) dirty threshold Users will notice that the applications will get throttled once crossing the global (background + dirty)/2=15% threshold, and then balanced around 17.5%. Before patch, the behavior is to just throttle it at 20% dirtyable memory in 1-dd case. Since the task will be soft throttled earlier than before, it may be perceived by end users as performance "slow down" if his application happens to dirty more than 15% dirtyable memory. (2) smoothness/responsiveness Users will notice a more responsive system during heavy writeback. "killall dd" will take effect instantly. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
| * writeback: per task dirty rate limitWu Fengguang2011-10-033-39/+60
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add two fields to task_struct. 1) account dirtied pages in the individual tasks, for accuracy 2) per-task balance_dirty_pages() call intervals, for flexibility The balance_dirty_pages() call interval (ie. nr_dirtied_pause) will scale near-sqrt to the safety gap between dirty pages and threshold. The main problem of per-task nr_dirtied is, if 1k+ tasks start dirtying pages at exactly the same time, each task will be assigned a large initial nr_dirtied_pause, so that the dirty threshold will be exceeded long before each task reached its nr_dirtied_pause and hence call balance_dirty_pages(). The solution is to watch for the number of pages dirtied on each CPU in between the calls into balance_dirty_pages(). If it exceeds ratelimit_pages (3% dirty threshold), force call balance_dirty_pages() for a chance to set bdi->dirty_exceeded. In normal situations, this safeguarding condition is not expected to trigger at all. On the sqrt in dirty_poll_interval(): It will serve as an initial guess when dirty pages are still in the freerun area. When dirty pages are floating inside the dirty control scope [freerun, limit], a followup patch will use some refined dirty poll interval to get the desired pause time. thresh-dirty (MB) sqrt 1 16 2 22 4 32 8 45 16 64 32 90 64 128 128 181 256 256 512 362 1024 512 The above table means, given 1MB (or 1GB) gap and the dd tasks polling balance_dirty_pages() on every 16 (or 512) pages, the dirty limit won't be exceeded as long as there are less than 16 (or 512) concurrent dd's. So sqrt naturally leads to less overheads and more safe concurrent tasks for large memory servers, which have large (thresh-freerun) gaps. peter: keep the per-CPU ratelimit for safeguarding the 1k+ tasks case CC: Peter Zijlstra <a.p.zijlstra@chello.nl> Reviewed-by: Andrea Righi <andrea@betterlinux.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
| * writeback: stabilize bdi->dirty_ratelimitWu Fengguang2011-10-033-1/+74
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are some imperfections in balanced_dirty_ratelimit. 1) large fluctuations The dirty_rate used for computing balanced_dirty_ratelimit is merely averaged in the past 200ms (very small comparing to the 3s estimation period for write_bw), which makes rather dispersed distribution of balanced_dirty_ratelimit. It's pretty hard to average out the singular points by increasing the estimation period. Considering that the averaging technique will introduce very undesirable time lags, I give it up totally. (btw, the 3s write_bw averaging time lag is much more acceptable because its impact is one-way and therefore won't lead to oscillations.) The more practical way is filtering -- most singular balanced_dirty_ratelimit points can be filtered out by remembering some prev_balanced_rate and prev_prev_balanced_rate. However the more reliable way is to guard balanced_dirty_ratelimit with task_ratelimit. 2) due to truncates and fs redirties, the (write_bw <=> dirty_rate) match could become unbalanced, which may lead to large systematical errors in balanced_dirty_ratelimit. The truncates, due to its possibly bumpy nature, can hardly be compensated smoothly. So let's face it. When some over-estimated balanced_dirty_ratelimit brings dirty_ratelimit high, dirty pages will go higher than the setpoint. task_ratelimit will in turn become lower than dirty_ratelimit. So if we consider both balanced_dirty_ratelimit and task_ratelimit and update dirty_ratelimit only when they are on the same side of dirty_ratelimit, the systematical errors in balanced_dirty_ratelimit won't be able to bring dirty_ratelimit far away. The balanced_dirty_ratelimit estimation may also be inaccurate near @limit or @freerun, however is less an issue. 3) since we ultimately want to - keep the fluctuations of task ratelimit as small as possible - keep the dirty pages around the setpoint as long time as possible the update policy used for (2) also serves the above goals nicely: if for some reason the dirty pages are high (task_ratelimit < dirty_ratelimit), and dirty_ratelimit is low (dirty_ratelimit < balanced_dirty_ratelimit), there is no point to bring up dirty_ratelimit in a hurry only to hurt both the above two goals. So, we make use of task_ratelimit to limit the update of dirty_ratelimit in two ways: 1) avoid changing dirty rate when it's against the position control target (the adjusted rate will slow down the progress of dirty pages going back to setpoint). 2) limit the step size. task_ratelimit is changing values step by step, leaving a consistent trace comparing to the randomly jumping balanced_dirty_ratelimit. task_ratelimit also has the nice smaller errors in stable state and typically larger errors when there are big errors in rate. So it's a pretty good limiting factor for the step size of dirty_ratelimit. Note that bdi->dirty_ratelimit is always tracking balanced_dirty_ratelimit. task_ratelimit is merely used as a limiting factor. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
| * writeback: dirty rate controlWu Fengguang2011-10-033-2/+89
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It's all about bdi->dirty_ratelimit, which aims to be (write_bw / N) when there are N dd tasks. On write() syscall, use bdi->dirty_ratelimit ============================================ balance_dirty_pages(pages_dirtied) { task_ratelimit = bdi->dirty_ratelimit * bdi_position_ratio(); pause = pages_dirtied / task_ratelimit; sleep(pause); } On every 200ms, update bdi->dirty_ratelimit =========================================== bdi_update_dirty_ratelimit() { task_ratelimit = bdi->dirty_ratelimit * bdi_position_ratio(); balanced_dirty_ratelimit = task_ratelimit * write_bw / dirty_rate; bdi->dirty_ratelimit = balanced_dirty_ratelimit } Estimation of balanced bdi->dirty_ratelimit =========================================== balanced task_ratelimit ----------------------- balance_dirty_pages() needs to throttle tasks dirtying pages such that the total amount of dirty pages stays below the specified dirty limit in order to avoid memory deadlocks. Furthermore we desire fairness in that tasks get throttled proportionally to the amount of pages they dirty. IOW we want to throttle tasks such that we match the dirty rate to the writeout bandwidth, this yields a stable amount of dirty pages: dirty_rate == write_bw (1) The fairness requirement gives us: task_ratelimit = balanced_dirty_ratelimit == write_bw / N (2) where N is the number of dd tasks. We don't know N beforehand, but still can estimate balanced_dirty_ratelimit within 200ms. Start by throttling each dd task at rate task_ratelimit = task_ratelimit_0 (3) (any non-zero initial value is OK) After 200ms, we measured dirty_rate = # of pages dirtied by all dd's / 200ms write_bw = # of pages written to the disk / 200ms For the aggressive dd dirtiers, the equality holds dirty_rate == N * task_rate == N * task_ratelimit_0 (4) Or task_ratelimit_0 == dirty_rate / N (5) Now we conclude that the balanced task ratelimit can be estimated by write_bw balanced_dirty_ratelimit = task_ratelimit_0 * ---------- (6) dirty_rate Because with (4) and (5) we can get the desired equality (1): write_bw balanced_dirty_ratelimit == (dirty_rate / N) * ---------- dirty_rate == write_bw / N Then using the balanced task ratelimit we can compute task pause times like: task_pause = task->nr_dirtied / task_ratelimit task_ratelimit with position control ------------------------------------ However, while the above gives us means of matching the dirty rate to the writeout bandwidth, it at best provides us with a stable dirty page count (assuming a static system). In order to control the dirty page count such that it is high enough to provide performance, but does not exceed the specified limit we need another control. The dirty position control works by extending (2) to task_ratelimit = balanced_dirty_ratelimit * pos_ratio (7) where pos_ratio is a negative feedback function that subjects to 1) f(setpoint) = 1.0 2) df/dx < 0 That is, if the dirty pages are ABOVE the setpoint, we throttle each task a bit more HEAVY than balanced_dirty_ratelimit, so that the dirty pages are created less fast than they are cleaned, thus DROP to the setpoints (and the reverse). Based on (7) and the assumption that both dirty_ratelimit and pos_ratio remains CONSTANT for the past 200ms, we get task_ratelimit_0 = balanced_dirty_ratelimit * pos_ratio (8) Putting (8) into (6), we get the formula used in bdi_update_dirty_ratelimit(): write_bw balanced_dirty_ratelimit *= pos_ratio * ---------- (9) dirty_rate Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
| * writeback: add bg_threshold parameter to __bdi_update_bandwidth()Wu Fengguang2011-10-033-5/+9
| | | | | | | | | | | | No behavior change. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
| * writeback: dirty position controlWu Fengguang2011-10-031-1/+190
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | bdi_position_ratio() provides a scale factor to bdi->dirty_ratelimit, so that the resulted task rate limit can drive the dirty pages back to the global/bdi setpoints. Old scheme is, | free run area | throttle area ----------------------------------------+----------------------------> thresh^ dirty pages New scheme is, ^ task rate limit | | * | * | * |[free run] * [smooth throttled] | * | * | * ..bdi->dirty_ratelimit..........* | . * | . * | . * | . * | . * +-------------------------------.-----------------------*------------> setpoint^ limit^ dirty pages The slope of the bdi control line should be 1) large enough to pull the dirty pages to setpoint reasonably fast 2) small enough to avoid big fluctuations in the resulted pos_ratio and hence task ratelimit Since the fluctuation range of the bdi dirty pages is typically observed to be within 1-second worth of data, the bdi control line's slope is selected to be a linear function of bdi write bandwidth, so that it can adapt to slow/fast storage devices well. Assume the bdi control line pos_ratio = 1.0 + k * (dirty - bdi_setpoint) where k is the negative slope. If targeting for 12.5% fluctuation range in pos_ratio when dirty pages are fluctuating in range [bdi_setpoint - write_bw/2, bdi_setpoint + write_bw/2], we get slope k = - 1 / (8 * write_bw) Let pos_ratio(x_intercept) = 0, we get the parameter used in code: x_intercept = bdi_setpoint + 8 * write_bw The global/bdi slopes are nicely complementing each other when the system has only one major bdi (indicated by bdi_thresh ~= thresh): 1) slope of global control line => scaling to the control scope size 2) slope of main bdi control line => scaling to the writeout bandwidth so that - in memory tight systems, (1) becomes strong enough to squeeze dirty pages inside the control scope - in large memory systems where the "gravity" of (1) for pulling the dirty pages to setpoint is too weak, (2) can back (1) up and drive dirty pages to bdi_setpoint ~= setpoint reasonably fast. Unfortunately in JBOD setups, the fluctuation range of bdi threshold is related to memory size due to the interferences between disks. In this case, the bdi slope will be weighted sum of write_bw and bdi_thresh. Given equations span = x_intercept - bdi_setpoint k = df/dx = - 1 / span and the extremum values span = bdi_thresh dx = bdi_thresh we get df = - dx / span = - 1.0 That means, when bdi_dirty deviates bdi_thresh up, pos_ratio and hence task ratelimit will fluctuate by -100%. peter: use 3rd order polynomial for the global control line CC: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
| * writeback: account per-bdi accumulated dirtied pagesWu Fengguang2011-10-033-0/+4
| | | | | | | | | | | | | | | | | | | | Introduce the BDI_DIRTIED counter. It will be used for estimating the bdi's dirty bandwidth. CC: Jan Kara <jack@suse.cz> CC: Michael Rubin <mrubin@google.com> CC: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
* | Merge branch 'for-next' of ↵Linus Torvalds2011-11-0718-475/+629
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending * 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: target: use ->exectute_task for all CDB emulation target: remove SCF_EMULATE_CDB_ASYNC target: refactor transport_emulate_control_cdb target: pass the se_task to the CDB emulation callback target: split core_scsi3_emulate_pr target: split core_scsi2_emulate_crh target: Add generic active I/O shutdown logic target: add back error handling in transport_complete_task target/pscsi: blk_make_request() returns an ERR_PTR() target: Remove core TRANSPORT_FREE_CMD_INTR usage target: Make TFO->check_stop_free return free status iscsi-target: Fix non-immediate TMR handling iscsi-target: Add missing CMDSN_LOWER_THAN_EXP check in iscsit_handle_scsi_cmd target: Avoid double list_del for aborted se_tmr_req target: Minor cleanups to core_tmr_drain_tmr_list target: Fix wrong se_tmr being added to drain_tmr_list target: Fix incorrect se_cmd assignment in core_tmr_drain_tmr_list target: Check -ENOMEM to signal QUEUE_FULL from fabric callbacks tcm_loop: Add explict read buffer memset for SCF_SCSI_CONTROL_SG_IO_CDB target: Fix compile warning w/ missing module.h include
| * | target: use ->exectute_task for all CDB emulationChristoph Hellwig2011-11-043-140/+97Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of calling into transport_emulate_control_cdb from __transport_execute_tasks for some CDBs always set up ->exectute_tasks in the command sequence and use it uniformly. (nab: Add default passthrough break for SERVICE_ACTION_IN) Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
| * | target: remove SCF_EMULATE_CDB_ASYNCChristoph Hellwig2011-11-046-100/+142
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All ->execute_task instances now need to complete the I/O explicitly, which can either happen synchronously or asynchronously. Note that a lot of the CDB emulations appear to return success even if some lowlevel operations failed. Given that this is an existing issue this patch doesn't change that fact. (nab: Adding missing switch breaks in PR-IN + PR_OUT) Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
| * | target: refactor transport_emulate_control_cdbChristoph Hellwig2011-11-041-46/+59
| | | | | | | | | | | | | | | | | | | | | | | | Encapsulate each CDB emulation into a function of its own, to prepare setting ->exectute_task to these routines. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
| * | target: pass the se_task to the CDB emulation callbackChristoph Hellwig2011-11-048-55/+42Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We want to be able to handle all CDBs through it and remove hacks like always using the first task in a CDB in target_report_luns. Also rename the callback to ->execute_task to better describe its use. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
| * | target: split core_scsi3_emulate_prChristoph Hellwig2011-11-043-32/+45
| | | | | | | | | | | | | | | | | | | | | | | | Split core_scsi2_emulate_crh into one routine each for the PERSISTENT_RESERVE_IN and PERSISTENT_RESERVE_OUT side. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
| * | target: split core_scsi2_emulate_crhChristoph Hellwig2011-11-043-106/+102Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | Split core_scsi2_emulate_crh into one routine each for the reserve and release side. The common code now is in a helper called by both routines. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
| * | target: Add generic active I/O shutdown logicNicholas Bellinger2011-11-044-6/+145
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds the initial pieces of generic active I/O shutdown logic. This is intended to be a 'opt-in' feature for fabric modules that includes the following functions to provide a mechinism for fabric modules to track se_cmd via se_session->sess_cmd_list: *) target_get_sess_cmd() - Add se_cmd to sess->sess_cmd_list, called from fabric module incoming I/O path. *) target_put_sess_cmd() - Check for completion or drop se_cmd from ->sess_cmd_list *) target_splice_sess_cmd_list() - Splice active I/O list from ->sess_cmd_list to ->sess_wait_list, can called with HW fabric lock held. *) target_wait_for_sess_cmds() - Walk ->sess_wait_list waiting on individual ->cmd_wait_comp. Optional transport_wait_for_tasks() call. target_splice_sess_cmd_list() is allowed to be called under HW fabric lock, and performs the splice into se_sess->sess_wait_list and set se_cmd->cmd_wait_set. Then target_wait_for_sess_cmds() walks the list waiting for individual target_put_sess_cmd() fabric callbacks to complete. It also adds TFO->check_release_cmd() to split the completion and memory release calls, where a fabric module uses target_put_sess_cmd() to check for I/O completion during session shutdown. This is currently pushed out into fabric modules as current fabric code may sleep here waiting for TFO->check_stop_free() to complete in main response path, and because target_wait_for_sess_cmds() calling TFO->release_cmd() to free fabric descriptor memory directly. Cc: Christoph Hellwig <hch@lst.de> Cc: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
| * | target: add back error handling in transport_complete_taskChristoph Hellwig2011-11-021-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The commit target: use a workqueue for I/O completions accidentally removed setting t_tasks_failed in transport_complete_task. Add it back in a slightly cleaner way; now it is set for every failed task instead of special casing the last one completing by using the success argument directly for it. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
| * | target/pscsi: blk_make_request() returns an ERR_PTR()Dan Carpenter2011-11-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | The check is wrong here because blk_make_request() returns an ERR_PTR() and it doesn't return NULL. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
| * | target: Remove core TRANSPORT_FREE_CMD_INTR usageNicholas Bellinger2011-11-024-22/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch drops TRANSPORT_FREE_CMD_INTR usage from target core, which includes the removal of transport_generic_free_cmd_intr() symbol, TRANSPORT_FREE_CMD_INTR usage in transport_processing_thread(), and special case LUN_RESET handling to skip TRANSPORT_FREE_CMD_INTR processing in core_tmr_drain_cmd_list(). We now expect that fabric modules will use an internal workqueue to provide process context when releasing se_cmd descriptor resources via transport_generic_free_cmd(). Reported-by: Christoph Hellwig <hch@lst.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Roland Dreier <roland@purestorage.com> Cc: Madhuranath Iyengar <mni@risingtidesystems.com> Signed-off-by: Nicholas Bellinger <nab@risingtidesystems.com>
| * | target: Make TFO->check_stop_free return free statusNicholas Bellinger2011-11-025-8/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch converts target_core_fabric_ops->check_stop_free() usage in transport_cmd_check_stop() and associated fabric module usage to return '1' when the passed se_cmd has been released directly within ->check_stop_free(), or return '0' when the passed se_cmd has not been released. This addresses an issue where transport_cmd_finish_abort() -> transport_cmd_check_stop_to_fabric() was leaking descriptors during LUN_RESET for modules using ->check_stop_free(), but not directly releasing se_cmd in all cases. Cc: stable@kernel.org Signed-off-by: Nicholas Bellinger <nab@risingtidesystems.com>
| * | iscsi-target: Fix non-immediate TMR handlingNicholas Bellinger2011-11-021-4/+3Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch addresses two issues with non immediate TMR handling in iscsit_handle_task_mgt_cmd(). The first involves breakage due to v3.1-rc conversion of iscsit_sequence_cmd(), which upon good status would hit the iscsit_add_reject_from_cmd() block of code. This patch adds an explict check for CMDSN_ERROR_CANNOT_RECOVER. The second adds a check to return when non immediate TMR operation is detected after iscsit_ack_from_expstatsn(), as iscsit_sequence_cmd() -> iscsit_execute_cmd() will have called transport_generic_handle_tmr() for the non immediate TMR case already. Cc: Andy Grover <agrover@redhat.com> Cc: stable@kernel.org Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
| * | iscsi-target: Add missing CMDSN_LOWER_THAN_EXP check in iscsit_handle_scsi_cmdNicholas Bellinger2011-11-021-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds a missing CMDSN_LOWER_THAN_EXP return check for iscsit_sequence_cmd() in iscsit_handle_scsi_cmd() that was incorrectly dropped during the v3.1-rc cleanups to use iscsit_sequence_cmd(). Cc: Andy Grover <agrover@redhat.com> Cc: stable@kernel.org Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
| * | target: Avoid double list_del for aborted se_tmr_reqJoern Engel2011-11-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After the list_del() in core_tmr_drain_tmr_list(), core_tmr_release_req() would list_del() the same object again. Call graph: core_tmr_drain_tmr_list transport_cmd_finish_abort_tmr transport_generic_remove transport_free_se_cmd core_tmr_release_req So use list_del_init(), as list_del() of an initialized list_head is safe and essentially a nop. In the CONFIG_DEBUG_LIST case, list_del() actually poisons the list_head, but that is fine as we free the object directly afterwards. Signed-off-by: Joern Engel <joern@logfs.org> Cc: stable@kernel.org Signed-off-by: Nicholas Bellinger <nab@risingtidesystems.com>
| * | target: Minor cleanups to core_tmr_drain_tmr_listJoern Engel2011-10-271-7/+6Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds a handful minor cleanups to core_tmr_drain_tmr_list() that remove an unnecessary NULL check, use list_for_each_entry_safe() instead of list_entry(), and makes the drain_tmr_list walk use *tmr_p instead of directly referencing the passed *tmr function parameter. Signed-off-by: Joern Engel <joern@logfs.org> Cc: Joern Engel <joern@logfs.org> Reviewed-by: Roland Dreier <roland@purestorage.com> Cc: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
| * | target: Fix wrong se_tmr being added to drain_tmr_listJoern Engel2011-10-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes another bug from LUN_RESET re-org fallout in core_tmr_drain_tmr_list() that was adding the wrong se_tmr_req into the local drain_tmr_list to be walked + released. Signed-off-by: Joern Engel <joern@logfs.org> Cc: Joern Engel <joern@logfs.org> Reviewed-by: Roland Dreier <roland@purestorage.com> Cc: Roland Dreier <roland@purestorage.com> Cc: stable@kernel.org Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
| * | target: Fix incorrect se_cmd assignment in core_tmr_drain_tmr_listJoern Engel2011-10-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes a bug in core_tmr_drain_tmr_list() where drain_tmr_list was using the wrong se_tmr_req for cmd assignment due to a typo during the LUN_RESET re-org. This was resulting in general protection faults while using the leftover bogus *tmr_p pointer from list_for_each_entry_safe(). Signed-off-by: Joern Engel <joern@logfs.org> Cc: Joern Engel <joern@logfs.org> Cc: stable@kernel.org Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
| * | target: Check -ENOMEM to signal QUEUE_FULL from fabric callbacksNicholas Bellinger2011-10-271-16/+15Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch changes target core to also check for -ENOMEM from fabric callbacks to signal QUEUE_FULL status, instead of just -EAGAIN in order to catch a larger set of fabric failure cases that want to trigger QUEUE_FULL logic. This includes the callbacks for ->write_pending(), ->queue_data_in() and ->queue_status(). It also makes transport_generic_write_pending() return zero upon QUEUE_FULL, and removes two unnecessary -EAGAIN checks to catch write pending QUEUE_FULL cases from transport_generic_new_cmd() failures in transport_handle_cdb_direct() and transport_processing_thread():TRANSPORT_NEW_CMD_MAP state. Reported-by: Bart Van Assche <bvanassche@acm.org> Cc: Bart Van Assche <bvanassche@acm.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
| * | tcm_loop: Add explict read buffer memset for SCF_SCSI_CONTROL_SG_IO_CDBNicholas Bellinger2011-10-261-0/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch addresses an issue with buggy userspace code sending I/O via scsi-generic that does not explictly clear their associated read buffers. It adds an explict memset of the first SGL entry within tcm_loop_new_cmd_map() for SCF_SCSI_CONTROL_SG_IO_CDB payloads that are currently guaranteed to be a single SGL by target-core code. This issue is a side effect of the v3.1-rc1 merge to remove the extra memcpy between certain control CDB types using a contigious + cleared buffer in target-core, and performing a memcpy into the SGL list within tcm_loop. It was originally mainfesting itself by udev + scsi_id + scsi-generic not properly setting up the expected /dev/disk/by-id/ symlinks because the INQUIRY payload was containing extra bogus data preventing the proper NAA IEEE WWN from being parsed by userspace. Cc: Christoph Hellwig <hch@lst.de> Cc: Andy Grover <agrover@redhat.com> Cc: stable@kernel.org Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
| * | target: Fix compile warning w/ missing module.h includeNicholas Bellinger2011-10-261-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes the following compile warning in target_core_cdb.c in recent linux-next code due to the new use of EXPORT_SYMBOL() for target_get_task_cdb(). drivers/target/target_core_cdb.c:1316: warning: data definition has no type or storage class drivers/target/target_core_cdb.c:1316: warning: type defaults to ‘int’ in declaration of ‘EXPORT_SYMBOL’ drivers/target/target_core_cdb.c:1316: warning: parameter names (without types) in function declaration Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
* | | Merge branch 'trivial' of ↵Linus Torvalds2011-11-0721-198/+1Star
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild * 'trivial' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: scsi: drop unused Kconfig symbol pci: drop unused Kconfig symbol stmmac: drop unused Kconfig symbol x86: drop unused Kconfig symbol powerpc: drop unused Kconfig symbols powerpc: 40x: drop unused Kconfig symbol mips: drop unused Kconfig symbols openrisc: drop unused Kconfig symbols arm: at91: drop unused Kconfig symbol samples: drop unused Kconfig symbol m32r: drop unused Kconfig symbol score: drop unused Kconfig symbols sh: drop unused Kconfig symbol um: drop unused Kconfig symbol sparc: drop unused Kconfig symbol alpha: drop unused Kconfig symbol Fix up trivial conflict in drivers/net/ethernet/stmicro/stmmac/Kconfig as per Michal: the STMMAC_DUAL_MAC config variable is still unused and should be deleted.
| * | | scsi: drop unused Kconfig symbolPaul Bolle2011-10-311-14/+0Star
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Michal Marek <mmarek@suse.cz>
| * | | pci: drop unused Kconfig symbolPaul Bolle2011-10-311-11/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There's no other Kconfig symbol that depends on XEN_PCIDEV_FE_DEBUG. Neither is there anything that uses CONFIG_XEN_PCIDEV_FE_DEBUG. Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
| * | | stmmac: drop unused Kconfig symbolPaul Bolle2011-10-311-9/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Acked-by: Giuseppe Cavallaro <peppe.cavallaro@st.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
| * | | x86: drop unused Kconfig symbolPaul Bolle2011-10-311-3/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
| * | | powerpc: drop unused Kconfig symbolsPaul Bolle2011-10-315-48/+0Star
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Michal Marek <mmarek@suse.cz>
| * | | powerpc: 40x: drop unused Kconfig symbolPaul Bolle2011-10-311-5/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Acked-by: Josh Boyer <jwboyer@gmail.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
| * | | mips: drop unused Kconfig symbolsPaul Bolle2011-10-313-44/+0Star
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Michal Marek <mmarek@suse.cz>
| * | | openrisc: drop unused Kconfig symbolsPaul Bolle2011-10-311-12/+0Star
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Michal Marek <mmarek@suse.cz>
| * | | arm: at91: drop unused Kconfig symbolPaul Bolle2011-10-311-6/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
| * | | samples: drop unused Kconfig symbolPaul Bolle2011-10-311-6/+0Star
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Michal Marek <mmarek@suse.cz>
| * | | m32r: drop unused Kconfig symbolPaul Bolle2011-10-311-7/+0Star
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Michal Marek <mmarek@suse.cz>