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2008-07-11percpu_counter: new function percpu_counter_sum_and_setMingming Cao1-1/+6
Delayed allocation need to check free blocks at every write time. percpu_counter_read_positive() is not quit accurate. delayed allocation need a more accurate accounting, but using percpu_counter_sum_positive() is frequently is quite expensive. This patch added a new function to update center counter when sum per-cpu counter, to increase the accurate rate for next percpu_counter_read() and require less calling expensive percpu_counter_sum(). Signed-off-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2008-04-30mm: bdi: export BDI attributes in sysfsPeter Zijlstra1-0/+1
Provide a place in sysfs (/sys/class/bdi) for the backing_dev_info object. This allows us to see and set the various BDI specific variables. In particular this properly exposes the read-ahead window for all relevant users and /sys/block/<block>/queue/read_ahead_kb should be deprecated. With patient help from Kay Sievers and Greg KH [mszeredi@suse.cz] - split off NFS and FUSE changes into separate patches - document new sysfs attributes under Documentation/ABI - do bdi_class_init as a core_initcall, otherwise the "default" BDI won't be initialized - remove bdi_init_fmt macro, it's not used very much [akpm@linux-foundation.org: fix ia64 warning] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kay Sievers <kay.sievers@vrfy.org> Acked-by: Greg KH <greg@kroah.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19Add irq protection in the percpu-counters cpu-hotplug-callback pathGautham R Shenoy1-2/+3
Some of the per-cpu counters and thus their locks are accessed from IRQ contexts. This can cause a deadlock if it interrupts a cpu-offline thread which is transferring a dead-cpu's counts to the global counter. Add appropriate IRQ protection in the cpu-hotplug callback path. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17lib: percpu_counter_init_irqPeter Zijlstra1-0/+12
provide a way to tell lockdep about percpu_counters that are supposed to be used from irq safe contexts. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17lib: percpu_counter_init error handlingPeter Zijlstra1-1/+7
alloc_percpu can fail, propagate that error. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17lib: percpu_count_sum()Peter Zijlstra1-3/+3
Provide an accurate version of percpu_counter_read. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17lib: percpu_counter_sum_positivePeter Zijlstra1-2/+2
s/percpu_counter_sum/&_positive/ Because its consitent with percpu_counter_read* Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17lib: percpu_counter_setPeter Zijlstra1-0/+14
Provide a method to set a percpu counter to a specified value. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17lib: make percpu_counter_add take s64Peter Zijlstra1-2/+2
percpu_counter is a s64 counter, make _add consitent. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17lib: percpu_counter variable batchPeter Zijlstra1-3/+3
Because the current batch setup has an quadric error bound on the counter, allow for an alternative setup. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17lib: percpu_counter_addPeter Zijlstra1-2/+2
s/percpu_counter_mod/percpu_counter_add/ Because its a better name, _mod implies modulo. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16percpu_counters: use for_each_online_cpu()Andrew Morton1-1/+1
Now that we have implemented hotunplug-time counter spilling, percpu_counter_sum() only needs to look at online CPUs. Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16percpu_counters(): use cpu notifiersAndrew Morton1-0/+66
per-cpu counters presently must iterate over all possible CPUs in the exhaustive percpu_counter_sum(). But it can be much better to only iterate over the presently-online CPUs. To do this, we must arrange for an offlined CPU's count to be spilled into the counter's central count. We can do this for all percpu_counters in the machine by linking them into a single global list and walking that list at CPU_DEAD time. (I hope. Might have race windows in which the percpu_counter_sum() count is inaccurate?) Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-06-23[PATCH] percpu counter data type changes to suppport more than 2**31 ext3 ↵Mingming Cao1-5/+5
free blocks counter The percpu counter data type are changed in this set of patches to support more users like ext3 who need more than 32 bit to store the free blocks total in the filesystem. - Generic perpcu counters data type changes. The size of the global counter and local counter were explictly specified using s64 and s32. The global counter is changed from long to s64, while the local counter is changed from long to s32, so we could avoid doing 64 bit update in most cases. - Users of the percpu counters are updated to make use of the new percpu_counter_init() routine now taking an additional parameter to allow users to pass the initial value of the global counter. Signed-off-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23[PATCH] percpu_counters: create lib/percpu_counter.cRavikiran G Thirumalai1-0/+46
- Move percpu_counter routines from mm/swap.c to lib/percpu_counter.c Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>