Slab lacks any memory hotplug support for nodes that are hotplugged
without cpus being hotplugged. This is possible at least on x86
CONFIG_MEMORY_HOTPLUG_SPARSE kernels where SRAT entries are marked
ACPI_SRAT_MEM_HOT_PLUGGABLE and the regions of RAM represent a seperate
node. It can also be done manually by writing the start address to
/sys/devices/system/memory/probe for kernels that have
CONFIG_ARCH_MEMORY_PROBE set, which is how this patch was tested, and
then onlining the new memory region.
When a node is hotadded, a nodelist for that node is allocated and
initialized for each slab cache. If this isn't completed due to a lack
of memory, the hotadd is aborted: we have a reasonable expectation that
kmalloc_node(nid) will work for all caches if nid is online and memory is
available.
Since nodelists must be allocated and initialized prior to the new node's
memory actually being online, the struct kmem_list3 is allocated off-node
due to kmalloc_node()'s fallback.
When an entire node would be offlined, its nodelists are subsequently
drained. If slab objects still exist and cannot be freed, the offline is
aborted. It is possible that objects will be allocated between this
drain and page isolation, so it's still possible that the offline will
still fail, however.
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
This patch allow to inject faults only for specific slabs.
In order to preserve default behavior cache filter is off by
default (all caches are faulty).
One may define specific set of slabs like this:
# mark skbuff_head_cache as faulty
echo 1 > /sys/kernel/slab/skbuff_head_cache/failslab
# Turn on cache filter (off by default)
echo 1 > /sys/kernel/debug/failslab/cache-filter
# Turn on fault injection
echo 1 > /sys/kernel/debug/failslab/times
echo 1 > /sys/kernel/debug/failslab/probability
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
When factoring common code into transfer_objects in commit 3ded175 ("slab: add
transfer_objects() function"), the 'touched' logic got a bit broken. When
refilling from the shared array (taking objects from the shared array), we are
making use of the shared array so it should be marked as touched.
Subsequently pulling an element from the cpu array and allocating it should
also touch the cpu array, but that is taken care of after the alloc_done label.
(So yes, the cpu array was getting touched = 1 twice).
So revert this logic to how it worked in earlier kernels.
This also affects the behaviour in __drain_alien_cache, which would previously
'touch' the shared array and now does not. I think it is more logical not to
touch there, because we are pushing objects into the shared array rather than
pulling them off. So there is no good reason to postpone reaping them -- if the
shared array is getting utilized, then it will get 'touched' in the alloc path
(where this patch now restores the touch).
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Commit ce79ddc8e2 ("SLAB: Fix lockdep annotations
for CPU hotplug") broke init_node_lock_keys() off-slab logic which causes
lockdep false positives.
Fix that up by reverting the logic back to original while keeping CPU hotplug
fixes intact.
Reported-and-tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reported-and-tested-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
* 'cpumask-cleanups' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
cpumask: rename tsk_cpumask to tsk_cpus_allowed
cpumask: don't recommend set_cpus_allowed hack in Documentation/cpu-hotplug.txt
cpumask: avoid dereferencing struct cpumask
cpumask: convert drivers/idle/i7300_idle.c to cpumask_var_t
cpumask: use modern cpumask style in drivers/scsi/fcoe/fcoe.c
cpumask: avoid deprecated function in mm/slab.c
cpumask: use cpu_online in kernel/perf_event.c
* 'kmemleak' of git://linux-arm.org/linux-2.6:
kmemleak: fix kconfig for crc32 build error
kmemleak: Reduce the false positives by checking for modified objects
kmemleak: Show the age of an unreferenced object
kmemleak: Release the object lock before calling put_object()
kmemleak: Scan the _ftrace_events section in modules
kmemleak: Simplify the kmemleak_scan_area() function prototype
kmemleak: Do not use off-slab management with SLAB_NOLEAKTRACE
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf sched: Fix build failure on sparc
perf bench: Add "all" pseudo subsystem and "all" pseudo suite
perf tools: Introduce perf_session class
perf symbols: Ditch dso->find_symbol
perf symbols: Allow lookups by symbol name too
perf symbols: Add missing "Variables" entry to map_type__name
perf symbols: Add support for 'variable' symtabs
perf symbols: Introduce ELF counterparts to symbol_type__is_a
perf symbols: Introduce symbol_type__is_a
perf symbols: Rename kthreads to kmaps, using another abstraction for it
perf tools: Allow building for ARM
hw-breakpoints: Handle bad modify_user_hw_breakpoint off-case return value
perf tools: Allow cross compiling
tracing, slab: Fix no callsite ifndef CONFIG_KMEMTRACE
tracing, slab: Define kmem_cache_alloc_notrace ifdef CONFIG_TRACING
Trivial conflict due to different fixes to modify_user_hw_breakpoint()
in include/linux/hw_breakpoint.h
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (34 commits)
m68k: rename global variable vmalloc_end to m68k_vmalloc_end
percpu: add missing per_cpu_ptr_to_phys() definition for UP
percpu: Fix kdump failure if booted with percpu_alloc=page
percpu: make misc percpu symbols unique
percpu: make percpu symbols in ia64 unique
percpu: make percpu symbols in powerpc unique
percpu: make percpu symbols in x86 unique
percpu: make percpu symbols in xen unique
percpu: make percpu symbols in cpufreq unique
percpu: make percpu symbols in oprofile unique
percpu: make percpu symbols in tracer unique
percpu: make percpu symbols under kernel/ and mm/ unique
percpu: remove some sparse warnings
percpu: make alloc_percpu() handle array types
vmalloc: fix use of non-existent percpu variable in put_cpu_var()
this_cpu: Use this_cpu_xx in trace_functions_graph.c
this_cpu: Use this_cpu_xx for ftrace
this_cpu: Use this_cpu_xx in nmi handling
this_cpu: Use this_cpu operations in RCU
this_cpu: Use this_cpu ops for VM statistics
...
Fix up trivial (famous last words) global per-cpu naming conflicts in
arch/x86/kvm/svm.c
mm/slab.c
When the gotten object is NULL (probably due to ENOMEM), kmemleak_erase() is
unnecessary here, It just sets NULL to where already is NULL. Add a condition.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: J. R. Okajima <hooanon05@yahoo.co.jp>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Branch profiling on my nehalem machine showed 99% incorrect branch hints:
28459 7678524 99 __cache_alloc_node slab.c 3551
Discussion on lkml [1] led to the solution to remove this hint.
[1] http://patchwork.kernel.org/patch/63517/
Signed-off-by: Tim Blechmann <tim@klingt.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
As reported by Paul McKenney:
I am seeing some lockdep complaints in rcutorture runs that include
frequent CPU-hotplug operations. The tests are otherwise successful.
My first thought was to send a patch that gave each array_cache
structure's ->lock field its own struct lock_class_key, but you already
have a init_lock_keys() that seems to be intended to deal with this.
------------------------------------------------------------------------
=============================================
[ INFO: possible recursive locking detected ]
2.6.32-rc4-autokern1 #1
---------------------------------------------
syslogd/2908 is trying to acquire lock:
(&nc->lock){..-...}, at: [<c0000000001407f4>] .kmem_cache_free+0x118/0x2d4
but task is already holding lock:
(&nc->lock){..-...}, at: [<c0000000001411bc>] .kfree+0x1f0/0x324
other info that might help us debug this:
3 locks held by syslogd/2908:
#0: (&u->readlock){+.+.+.}, at: [<c0000000004556f8>] .unix_dgram_recvmsg+0x70/0x338
#1: (&nc->lock){..-...}, at: [<c0000000001411bc>] .kfree+0x1f0/0x324
#2: (&parent->list_lock){-.-...}, at: [<c000000000140f64>] .__drain_alien_cache+0x50/0xb8
stack backtrace:
Call Trace:
[c0000000e8ccafc0] [c0000000000101e4] .show_stack+0x70/0x184 (unreliable)
[c0000000e8ccb070] [c0000000000afebc] .validate_chain+0x6ec/0xf58
[c0000000e8ccb180] [c0000000000b0ff0] .__lock_acquire+0x8c8/0x974
[c0000000e8ccb280] [c0000000000b2290] .lock_acquire+0x140/0x18c
[c0000000e8ccb350] [c000000000468df0] ._spin_lock+0x48/0x70
[c0000000e8ccb3e0] [c0000000001407f4] .kmem_cache_free+0x118/0x2d4
[c0000000e8ccb4a0] [c000000000140b90] .free_block+0x130/0x1a8
[c0000000e8ccb540] [c000000000140f94] .__drain_alien_cache+0x80/0xb8
[c0000000e8ccb5e0] [c0000000001411e0] .kfree+0x214/0x324
[c0000000e8ccb6a0] [c0000000003ca860] .skb_release_data+0xe8/0x104
[c0000000e8ccb730] [c0000000003ca2ec] .__kfree_skb+0x20/0xd4
[c0000000e8ccb7b0] [c0000000003cf2c8] .skb_free_datagram+0x1c/0x5c
[c0000000e8ccb830] [c00000000045597c] .unix_dgram_recvmsg+0x2f4/0x338
[c0000000e8ccb920] [c0000000003c0f14] .sock_recvmsg+0xf4/0x13c
[c0000000e8ccbb30] [c0000000003c28ec] .SyS_recvfrom+0xb4/0x130
[c0000000e8ccbcb0] [c0000000003bfb78] .sys_recv+0x18/0x2c
[c0000000e8ccbd20] [c0000000003ed388] .compat_sys_recv+0x14/0x28
[c0000000e8ccbd90] [c0000000003ee1bc] .compat_sys_socketcall+0x178/0x220
[c0000000e8ccbe30] [c0000000000085d4] syscall_exit+0x0/0x40
This patch fixes the issue by setting up lockdep annotations during CPU
hotplug.
Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
This patch updates percpu related symbols under kernel/ and mm/ such
that percpu symbols are unique and don't clash with local symbols.
This serves two purposes of decreasing the possibility of global
percpu symbol collision and allowing dropping per_cpu__ prefix from
percpu symbols.
* kernel/lockdep.c: s/lock_stats/cpu_lock_stats/
* kernel/sched.c: s/init_rq_rt/init_rt_rq_var/ (any better idea?)
s/sched_group_cpus/sched_groups/
* kernel/softirq.c: s/ksoftirqd/run_ksoftirqd/a
* kernel/softlockup.c: s/(*)_timestamp/softlockup_\1_ts/
s/watchdog_task/softlockup_watchdog/
s/timestamp/ts/ for local variables
* kernel/time/timer_stats: s/lookup_lock/tstats_lookup_lock/
* mm/slab.c: s/reap_work/slab_reap_work/
s/reap_node/slab_reap_node/
* mm/vmstat.c: local variable changed to avoid collision with vmstat_work
Partly based on Rusty Russell's "alloc_percpu: rename percpu vars
which cause name clashes" patch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: (slab/vmstat) Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
With the slab allocator, if off-slab management is enabled for the
kmem_caches used by kmemleak, it leads to recursive calls into
kmemleak_alloc(). Off-slab management can be triggered by other config
options increasing the slab size, e.g. DEBUG_PAGEALLOC.
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Pekka Enberg
David Rientjes
Joe Perches
Dmitry Monakhov
Nick Piggin
Haicheng Li
Linus Torvalds
Rusty Russell
Li Zefan
J. R. Okajima
Tim Blechmann
Tejun Heo
Catalin Marinas
Jan Beulich