kernel.git/lib/percpu_counter.c, branch linux-2.6.27.y

percpu: fix list_head init bug in __percpu_counter_init()

2010-12-09T21:24:15Z

commit 8474b591faf3bb0a1e08a60d21d6baac498f15e4 upstream. WARNING: at lib/list_debug.c:26 __list_add+0x3f/0x81() Hardware name: Express5800/B120a [N8400-085] list_add corruption. next->prev should be prev (ffffffff81a7ea00), but was dead000000200200. (next=ffff88080b872d58). Modules linked in: aoe ipt_MASQUERADE iptable_nat nf_nat autofs4 sunrpc bridge 8021q garp stp llc ipv6 cpufreq_ondemand acpi_cpufreq freq_table dm_round_robin dm_multipath kvm_intel kvm uinput lpfc scsi_transport_fc igb ioatdma scsi_tgt i2c_i801 i2c_core dca iTCO_wdt iTCO_vendor_support pcspkr shpchp megaraid_sas [last unloaded: aoe] Pid: 54, comm: events/3 Tainted: G W 2.6.34-vanilla1 #1 Call Trace: [] warn_slowpath_common+0x7c/0x94 [] warn_slowpath_fmt+0x41/0x43 [] __list_add+0x3f/0x81 [] __percpu_counter_init+0x59/0x6b [] bdi_init+0x118/0x17e [] blk_alloc_queue_node+0x79/0x143 [] blk_alloc_queue+0x11/0x13 [] aoeblk_gdalloc+0x8e/0x1c9 [aoe] [] aoecmd_sleepwork+0x25/0xa8 [aoe] [] worker_thread+0x1a9/0x237 [] ? aoecmd_sleepwork+0x0/0xa8 [aoe] [] ? autoremove_wake_function+0x0/0x39 [] ? worker_thread+0x0/0x237 [] kthread+0x7f/0x87 [] kernel_thread_helper+0x4/0x10 [] ? kthread+0x0/0x87 [] ? kernel_thread_helper+0x0/0x10 It's because there is no initialization code for a list_head contained in the struct backing_dev_info under CONFIG_HOTPLUG_CPU, and the bug comes up when block device drivers calling blk_alloc_queue() are used. In case of me, I got them by using aoe. Signed-off-by: Masanori Itoh Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

percpu counter: clean up percpu_counter_sum_and_set()

2010-05-26T21:27:05Z

commit 1f7c14c62ce63805f9574664a6c6de3633d4a354 upstream. percpu_counter_sum_and_set() and percpu_counter_sum() is the same except the former updates the global counter after accounting. Since we are taking the fbc->lock to calculate the precise value of the counter in percpu_counter_sum() anyway, it should simply set fbc->count too, as the percpu_counter_sum_and_set() does. This patch merges these two interfaces into one. Signed-off-by: Mingming Cao Acked-by: Peter Zijlstra Cc: Signed-off-by: Andrew Morton Signed-off-by: "Theodore Ts'o" Signed-off-by: Jayson R. King Signed-off-by: Theodore Ts'o

percpu_counter: new function percpu_counter_sum_and_set

2008-07-11T23:27:31Z

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 Signed-off-by: "Theodore Ts'o"

mm: bdi: export BDI attributes in sysfs

2008-04-30T15:29:49Z

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//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 Cc: Kay Sievers Acked-by: Greg KH Cc: Trond Myklebust Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Add irq protection in the percpu-counters cpu-hotplug-callback path

2007-10-19T18:53:44Z

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 Cc: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib: percpu_counter_init_irq

2007-10-17T15:42:44Z

provide a way to tell lockdep about percpu_counters that are supposed to be used from irq safe contexts. Signed-off-by: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib: percpu_counter_init error handling

2007-10-17T15:42:44Z

alloc_percpu can fail, propagate that error. Signed-off-by: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib: percpu_count_sum()

2007-10-17T15:42:44Z

Provide an accurate version of percpu_counter_read. Signed-off-by: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib: percpu_counter_sum_positive

2007-10-17T15:42:44Z

s/percpu_counter_sum/&_positive/ Because its consitent with percpu_counter_read* Signed-off-by: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib: percpu_counter_set

2007-10-17T15:42:44Z

Provide a method to set a percpu counter to a specified value. Signed-off-by: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds