17 Oct, 2007
40 commits
-
Control the trigger limit for softlockup warnings. This is useful for
debugging softlockups, by lowering the softlockup_thresh to identify
possible softlockups earlier.This patch:
1. Adds a sysctl softlockup_thresh with valid values of 1-60s
(Higher value to disable false positives)
2. Changes the softlockup printk to print the cpu softlockup time[akpm@linux-foundation.org: Fix various warnings and add definition of "two"]
Signed-off-by: Ravikiran Thirumalai
Signed-off-by: Shai Fultheim
Acked-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
kernel/softirq.c grew a few style uncleanlinesses in the past few
months, clean that up. No functional changes:text data bss dec hex filename
1126 76 4 1206 4b6 softlockup.o.before
1129 76 4 1209 4b9 softlockup.o.after( the 3 bytes .text increase is due to the "" appended to one of
the printk messages. )Signed-off-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Improve the debuggability of kernel lockups by enhancing the debug
output of the softlockup detector: print the task that causes the lockup
and try to print a more intelligent backtrace.The old format was:
BUG: soft lockup detected on CPU#1!
[] show_trace_log_lvl+0x19/0x2e
[] show_trace+0x12/0x14
[] dump_stack+0x14/0x16
[] softlockup_tick+0xbe/0xd0
[] run_local_timers+0x12/0x14
[] update_process_times+0x3e/0x63
[] tick_sched_timer+0x7c/0xc0
[] hrtimer_interrupt+0x135/0x1ba
[] smp_apic_timer_interrupt+0x6e/0x80
[] apic_timer_interrupt+0x33/0x38
[] syscall_call+0x7/0xb
=======================The new format is:
BUG: soft lockup detected on CPU#1! [prctl:2363]
Pid: 2363, comm: prctl
EIP: 0060:[] CPU: 1
EIP is at sys_prctl+0x24/0x18c
EFLAGS: 00000213 Not tainted (2.6.22-cfs-v20 #26)
EAX: 00000001 EBX: 000003e7 ECX: 00000001 EDX: f6df0000
ESI: 000003e7 EDI: 000003e7 EBP: f6df0fb0 DS: 007b ES: 007b FS: 00d8
CR0: 8005003b CR2: 4d8c3340 CR3: 3731d000 CR4: 000006d0
[] show_trace_log_lvl+0x19/0x2e
[] show_trace+0x12/0x14
[] show_regs+0x1ab/0x1b3
[] softlockup_tick+0xef/0x108
[] run_local_timers+0x12/0x14
[] update_process_times+0x3e/0x63
[] tick_sched_timer+0x7c/0xc0
[] hrtimer_interrupt+0x135/0x1ba
[] smp_apic_timer_interrupt+0x6e/0x80
[] apic_timer_interrupt+0x33/0x38
[] syscall_call+0x7/0xb
=======================Note that in the old format we only knew that some system call locked
up, we didnt know _which_. With the new format we know that it's at a
specific place in sys_prctl(). [which was where i created an artificial
kernel lockup to test the new format.]This is also useful if the lockup happens in user-space - the user-space
EIP (and other registers) will be printed too. (such a lockup would
either suggest that the task was running at SCHED_FIFO:99 and looping
for more than 10 seconds, or that the softlockup detector has a
false-positive.)The task name is printed too first, just in case we dont manage to print
a useful backtrace.[satyam@infradead.org: fix warning]
Signed-off-by: Ingo Molnar
Signed-off-by: Satyam Sharma
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The softlockup detector would like to use get_irq_regs(), so generalize the
availability on every Linux architecture.(It is fine for an architecture to always return NULL to get_irq_regs(),
which it does by default.)Signed-off-by: Ingo Molnar
Cc: Ian Molton
Cc: Kumar Gala
Cc: Paul Mackerras
Cc: Benjamin Herrenschmidt
Cc: Mikael Starvik
Cc: Miles Bader
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
this Xen related commit:
commit 966812dc98e6a7fcdf759cbfa0efab77500a8868
Author: Jeremy Fitzhardinge
Date: Tue May 8 00:28:02 2007 -0700Ignore stolen time in the softlockup watchdog
broke the softlockup watchdog to never report any lockups. (!)
print_timestamp defaults to 0, this makes the following condition
always true:if (print_timestamp < (touch_timestamp + 1) ||
and we'll in essence never report soft lockups.
apparently the functionality of the soft lockup watchdog was never
actually tested with that patch applied ...Signed-off-by: Ingo Molnar
Cc: Jeremy Fitzhardinge
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
sched_clock() is not a reliable time-source, use cpu_clock() instead.
Signed-off-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Remove the rmb() from mce_log(), since the immunized version of
rcu_dereference() makes it unnecessary.Signed-off-by: Paul E. McKenney
Cc: Ingo Molnar
Cc: Andi Kleen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Turns out that compiler writers are a bit more aggressive about optimizing
than one might expect. This patch prevents a number of such optimizations
from messing up rcu_deference(). This is not merely a theoretical problem, as
evidenced by the rmb() in mce_log().Signed-off-by: Paul E. McKenney
Cc: Ingo Molnar
Acked-by: Josh Triplett
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
list_del() hardly can fail, so checking for return value is pointless
(and current code always return 0).Nobody really cared that return value anyway.
Signed-off-by: Alexey Dobriyan
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Switch single-linked binfmt formats list to usual list_head's. This leads
to one-liners in register_binfmt() and unregister_binfmt(). The downside
is one pointer more in struct linux_binfmt. This is not a problem, since
the set of registered binfmts on typical box is very small -- (ELF +
something distro enabled for you).Test-booted, played with executable .txt files, modprobe/rmmod binfmt_misc.
Signed-off-by: Alexey Dobriyan
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
- remove the following no longer used functions:
- bitmap.c: reiserfs_claim_blocks_to_be_allocated()
- bitmap.c: reiserfs_release_claimed_blocks()
- bitmap.c: reiserfs_can_fit_pages()- make the following functions static:
- inode.c: restart_transaction()
- journal.c: reiserfs_async_progress_wait()Signed-off-by: Adrian Bunk
Acked-by: Vladimir V. Saveliev
Cc: Nick Piggin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This is a writeback-internal marker but we're propagating it all the way back
to userspace!.Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
zone->lock is quite an "inner" lock and mostly constrained to page alloc as
well, so like slab locks, it probably isn't something that is critically
important to document here. However unlike slab locks, zone lock could be
used more widely in future, and page_alloc.c might possibly have more
business to do tricky things with pagecache than does slab. So... I don't
think it hurts to document it.Signed-off-by: Nick Piggin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Introduces new zone flag interface for testing and setting flags:
int zone_test_and_set_flag(struct zone *zone, zone_flags_t flag)
Instead of setting and clearing ZONE_RECLAIM_LOCKED each time shrink_zone() is
called, this flag is test and set before starting zone reclaim. Zone reclaim
starts in __alloc_pages() when a zone's watermark fails and the system is in
zone_reclaim_mode. If it's already in reclaim, there's no need to start again
so it is simply considered full for that allocation attempt.There is a change of behavior with regard to concurrent zone shrinking. It is
now possible for try_to_free_pages() or kswapd to already be shrinking a
particular zone when __alloc_pages() starts zone reclaim. In this case, it is
possible for two concurrent threads to invoke shrink_zone() for a single zone.This change forbids a zone to be in zone reclaim twice, which was always the
behavior, but allows for concurrent try_to_free_pages() or kswapd shrinking
when starting zone reclaim.Cc: Andrea Arcangeli
Cc: Christoph Lameter
Signed-off-by: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
There's no reason to sleep in try_set_zone_oom() or clear_zonelist_oom() if
the lock can't be acquired; it will be available soon enough once the zonelist
scanning is done. All other threads waiting for the OOM killer are also
contingent on the exiting task being able to acquire the lock in
clear_zonelist_oom() so it doesn't make sense to put it to sleep.Cc: Andrea Arcangeli
Cc: Christoph Lameter
Signed-off-by: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Preprocess include/linux/oom.h before exporting it to userspace.
Cc: Andrea Arcangeli
Cc: Christoph Lameter
Cc: Alexey Dobriyan
Signed-off-by: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
It's not necessary to include all of linux/sched.h in linux/oom.h. Instead,
simply include prototypes for the relevant structs and include linux/types.h
for gfp_t.Cc: Andrea Arcangeli
Cc: Christoph Lameter
Acked-by: Alexey Dobriyan
Signed-off-by: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Since no task descriptor's 'cpuset' field is dereferenced in the execution of
the OOM killer anymore, it is no longer necessary to take callback_mutex.[akpm@linux-foundation.org: restore cpuset_lock for other patches]
Cc: Andrea Arcangeli
Acked-by: Christoph Lameter
Signed-off-by: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Instead of testing for overlap in the memory nodes of the the nearest
exclusive ancestor of both current and the candidate task, it is better to
simply test for intersection between the task's mems_allowed in their task
descriptors. This does not require taking callback_mutex since it is only
used as a hint in the badness scoring.Tasks that do not have an intersection in their mems_allowed with the current
task are not explicitly restricted from being OOM killed because it is quite
possible that the candidate task has allocated memory there before and has
since changed its mems_allowed.Cc: Andrea Arcangeli
Acked-by: Christoph Lameter
Signed-off-by: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Suppresses the extraneous stack and memory dump when a parallel OOM killing
has been found. There's no need to fill the ring buffer with this information
if its already been printed and the condition that triggered the previous OOM
killer has not yet been alleviated.Cc: Andrea Arcangeli
Acked-by: Christoph Lameter
Signed-off-by: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Adds a new sysctl, 'oom_kill_allocating_task', which will automatically kill
the OOM-triggering task instead of scanning through the tasklist to find a
memory-hogging target. This is helpful for systems with an insanely large
number of tasks where scanning the tasklist significantly degrades
performance.Cc: Andrea Arcangeli
Acked-by: Christoph Lameter
Signed-off-by: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
A final allocation attempt with a very high watermark needs to be attempted
before invoking out_of_memory(). OOM killer serialization needs to occur
before this final attempt, otherwise tasks attempting to OOM-lock all zones in
its zonelist may spin and acquire the lock unnecessarily after the OOM
condition has already been alleviated.If the final allocation does succeed, the zonelist is simply OOM-unlocked and
__alloc_pages() returns the page. Otherwise, the OOM killer is invoked.If the task cannot acquire OOM-locks on all zones in its zonelist, it is put
to sleep and the allocation is retried when it gets rescheduled. One of its
zones is already marked as being in the OOM killer so it'll hopefully be
getting some free memory soon, at least enough to satisfy a high watermark
allocation attempt. This prevents needlessly killing a task when the OOM
condition would have already been alleviated if it had simply been given
enough time.Cc: Andrea Arcangeli
Acked-by: Christoph Lameter
Signed-off-by: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
OOM killer synchronization should be done with zone granularity so that memory
policy and cpuset allocations may have their corresponding zones locked and
allow parallel kills for other OOM conditions that may exist elsewhere in the
system. DMA allocations can be targeted at the zone level, which would not be
possible if locking was done in nodes or globally.Synchronization shall be done with a variation of "trylocks." The goal is to
put the current task to sleep and restart the failed allocation attempt later
if the trylock fails. Otherwise, the OOM killer is invoked.Each zone in the zonelist that __alloc_pages() was called with is checked for
the newly-introduced ZONE_OOM_LOCKED flag. If any zone has this flag present,
the "trylock" to serialize the OOM killer fails and returns zero. Otherwise,
all the zones have ZONE_OOM_LOCKED set and the try_set_zone_oom() function
returns non-zero.Cc: Andrea Arcangeli
Cc: Christoph Lameter
Signed-off-by: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Convert the int all_unreclaimable member of struct zone to unsigned long
flags. This can now be used to specify several different zone flags such as
all_unreclaimable and reclaim_in_progress, which can now be removed and
converted to a per-zone flag.Flags are set and cleared as follows:
zone_set_flag(struct zone *zone, zone_flags_t flag)
zone_clear_flag(struct zone *zone, zone_flags_t flag)Defines the first zone flags, ZONE_ALL_UNRECLAIMABLE and ZONE_RECLAIM_LOCKED,
which have the same semantics as the old zone->all_unreclaimable and
zone->reclaim_in_progress, respectively. Also converts all current users that
set or clear either flag to use the new interface.Helper functions are defined to test the flags:
int zone_is_all_unreclaimable(const struct zone *zone)
int zone_is_reclaim_locked(const struct zone *zone)All flag operators are of the atomic variety because there are currently
readers that are implemented that do not take zone->lock.[akpm@linux-foundation.org: add needed include]
Cc: Andrea Arcangeli
Acked-by: Christoph Lameter
Signed-off-by: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The OOM killer's CONSTRAINT definitions are really more appropriate in an
enum, so define them in include/linux/oom.h.Cc: Andrea Arcangeli
Acked-by: Christoph Lameter
Signed-off-by: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Move the OOM killer's extern function prototypes to include/linux/oom.h and
include it where necessary.[clg@fr.ibm.com: build fix]
Cc: Andrea Arcangeli
Acked-by: Christoph Lameter
Signed-off-by: David Rientjes
Signed-off-by: Cedric Le Goater
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Slab constructors currently have a flags parameter that is never used. And
the order of the arguments is opposite to other slab functions. The object
pointer is placed before the kmem_cache pointer.Convert
ctor(void *object, struct kmem_cache *s, unsigned long flags)
to
ctor(struct kmem_cache *s, void *object)
throughout the kernel
[akpm@linux-foundation.org: coupla fixes]
Signed-off-by: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Move irq handling out of new slab into __slab_alloc. That is useful for
Mathieu's cmpxchg_local patchset and also allows us to remove the crude
local_irq_off in early_kmem_cache_alloc().Signed-off-by: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Based on ideas of Andrew:
http://marc.info/?l=linux-kernel&m=102912915020543&w=2Scale the bdi dirty limit inversly with the tasks dirty rate.
This makes heavy writers have a lower dirty limit than the occasional writer.Andrea proposed something similar:
http://lwn.net/Articles/152277/The main disadvantage to his patch is that he uses an unrelated quantity to
measure time, which leaves him with a workload dependant tunable. Other than
that the two approaches appear quite similar.[akpm@linux-foundation.org: fix warning]
Signed-off-by: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Scale writeback cache per backing device, proportional to its writeout speed.
By decoupling the BDI dirty thresholds a number of problems we currently have
will go away, namely:- mutual interference starvation (for any number of BDIs);
- deadlocks with stacked BDIs (loop, FUSE and local NFS mounts).It might be that all dirty pages are for a single BDI while other BDIs are
idling. By giving each BDI a 'fair' share of the dirty limit, each one can have
dirty pages outstanding and make progress.A global threshold also creates a deadlock for stacked BDIs; when A writes to
B, and A generates enough dirty pages to get throttled, B will never start
writeback until the dirty pages go away. Again, by giving each BDI its own
'independent' dirty limit, this problem is avoided.So the problem is to determine how to distribute the total dirty limit across
the BDIs fairly and efficiently. A DBI that has a large dirty limit but does
not have any dirty pages outstanding is a waste.What is done is to keep a floating proportion between the DBIs based on
writeback completions. This way faster/more active devices get a larger share
than slower/idle devices.[akpm@linux-foundation.org: fix warnings]
[hugh@veritas.com: Fix occasional hang when a task couldn't get out of balance_dirty_pages]
Signed-off-by: Peter Zijlstra
Signed-off-by: Hugh Dickins
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Given a set of objects, floating proportions aims to efficiently give the
proportional 'activity' of a single item as compared to the whole set. Where
'activity' is a measure of a temporal property of the items.It is efficient in that it need not inspect any other items of the set
in order to provide the answer. It is not even needed to know how many
other items there are.It has one parameter, and that is the period of 'time' over which the
'activity' is measured.Signed-off-by: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Count per BDI writeback pages.
Signed-off-by: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Count per BDI reclaimable pages; nr_reclaimable = nr_dirty + nr_unstable.
Signed-off-by: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Provide scalable per backing_dev_info statistics counters.
Signed-off-by: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
provide BDI constructor/destructor hooks
[akpm@linux-foundation.org: compile fix]
Signed-off-by: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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 -
alloc_percpu can fail, propagate that error.
Signed-off-by: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Provide an accurate version of percpu_counter_read.
Signed-off-by: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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 -
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
