Merge branch 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (63 commits) stacktrace: provide save_stack_trace_tsk() weak alias rcu: provide RCU options on non-preempt architectures too printk: fix discarding message when recursion_bug futex: clean up futex_(un)lock_pi fault handling "Tree RCU": scalable classic RCU implementation futex: rename field in futex_q to clarify single waiter semantics x86/swiotlb: add default swiotlb_arch_range_needs_mapping x86/swiotlb: add default phys<->bus conversion x86: unify pci iommu setup and allow swiotlb to compile for 32 bit x86: add swiotlb allocation functions swiotlb: consolidate swiotlb info message printing swiotlb: support bouncing of HighMem pages swiotlb: factor out copy to/from device swiotlb: add arch hook to force mapping swiotlb: allow architectures to override phys<->bus<->phys conversions swiotlb: add comment where we handle the overflow of a dma mask on 32 bit rcu: fix rcutorture behavior during reboot resources: skip sanity check of busy resources swiotlb: move some definitions to header swiotlb: allow architectures to override swiotlb pool allocation ... Fix up trivial conflicts in arch/x86/kernel/Makefile arch/x86/mm/init_32.c include/linux/hardirq.h as per Ingo's suggestions.
2026-05-01 15:00:59 -07:00 · 2008-12-30 16:10:19 -08:00
parent eca1bf5b4f 6638101c11
commit 5f34fe1cfc
61 changed files with 3424 additions and 487 deletions
@@ -16,6 +16,8 @@ RTFP.txt
 	- List of RCU papers (bibliography) going back to 1980.
 torture.txt
 	- RCU Torture Test Operation (CONFIG_RCU_TORTURE_TEST)
 trace.txt
 	- CONFIG_RCU_TRACE debugfs files and formats
 UP.txt
 	- RCU on Uniprocessor Systems
 whatisRCU.txt
@@ -0,0 +1,413 @@
 CONFIG_RCU_TRACE debugfs Files and Formats
 The rcupreempt and rcutree implementations of RCU provide debugfs trace
 output that summarizes counters and state.  This information is useful for
 debugging RCU itself, and can sometimes also help to debug abuses of RCU.
 Note that the rcuclassic implementation of RCU does not provide debugfs
 trace output.
 The following sections describe the debugfs files and formats for
 preemptable RCU (rcupreempt) and hierarchical RCU (rcutree).
 Preemptable RCU debugfs Files and Formats
 This implementation of RCU provides three debugfs files under the
 top-level directory RCU: rcu/rcuctrs (which displays the per-CPU
 counters used by preemptable RCU) rcu/rcugp (which displays grace-period
 counters), and rcu/rcustats (which internal counters for debugging RCU).
 The output of "cat rcu/rcuctrs" looks as follows:
 CPU last cur F M
  0    5  -5 0 0
  1   -1   0 0 0
  2    0   1 0 0
  3    0   1 0 0
  4    0   1 0 0
  5    0   1 0 0
  6    0   2 0 0
  7    0  -1 0 0
  8    0   1 0 0
 ggp = 26226, state = waitzero
 The per-CPU fields are as follows:
 o	"CPU" gives the CPU number.  Offline CPUs are not displayed.
 o	"last" gives the value of the counter that is being decremented
 	for the current grace period phase.  In the example above,
 	the counters sum to 4, indicating that there are still four
 	RCU read-side critical sections still running that started
 	before the last counter flip.
 o	"cur" gives the value of the counter that is currently being
 	both incremented (by rcu_read_lock()) and decremented (by
 	rcu_read_unlock()).  In the example above, the counters sum to
 	1, indicating that there is only one RCU read-side critical section
 	still running that started after the last counter flip.
 o	"F" indicates whether RCU is waiting for this CPU to acknowledge
 	a counter flip.  In the above example, RCU is not waiting on any,
 	which is consistent with the state being "waitzero" rather than
 	"waitack".
 o	"M" indicates whether RCU is waiting for this CPU to execute a
 	memory barrier.  In the above example, RCU is not waiting on any,
 	which is consistent with the state being "waitzero" rather than
 	"waitmb".
 o	"ggp" is the global grace-period counter.
 o	"state" is the RCU state, which can be one of the following:
 	o	"idle": there is no grace period in progress.
 	o	"waitack": RCU just incremented the global grace-period
 		counter, which has the effect of reversing the roles of
 		the "last" and "cur" counters above, and is waiting for
 		all the CPUs to acknowledge the flip.  Once the flip has
 		been acknowledged, CPUs will no longer be incrementing
 		what are now the "last" counters, so that their sum will
 		decrease monotonically down to zero.
 	o	"waitzero": RCU is waiting for the sum of the "last" counters
 		to decrease to zero.
 	o	"waitmb": RCU is waiting for each CPU to execute a memory
 		barrier, which ensures that instructions from a given CPU's
 		last RCU read-side critical section cannot be reordered
 		with instructions following the memory-barrier instruction.
 The output of "cat rcu/rcugp" looks as follows:
 oldggp=48870  newggp=48873
 Note that reading from this file provokes a synchronize_rcu().  The
 "oldggp" value is that of "ggp" from rcu/rcuctrs above, taken before
 executing the synchronize_rcu(), and the "newggp" value is also the
 "ggp" value, but taken after the synchronize_rcu() command returns.
 The output of "cat rcu/rcugp" looks as follows:
 na=1337955 nl=40 wa=1337915 wl=44 da=1337871 dl=0 dr=1337871 di=1337871
 1=50989 e1=6138 i1=49722 ie1=82 g1=49640 a1=315203 ae1=265563 a2=49640
 z1=1401244 ze1=1351605 z2=49639 m1=5661253 me1=5611614 m2=49639
 These are counters tracking internal preemptable-RCU events, however,
 some of them may be useful for debugging algorithms using RCU.  In
 particular, the "nl", "wl", and "dl" values track the number of RCU
 callbacks in various states.  The fields are as follows:
 o	"na" is the total number of RCU callbacks that have been enqueued
 	since boot.
 o	"nl" is the number of RCU callbacks waiting for the previous
 	grace period to end so that they can start waiting on the next
 	grace period.
 o	"wa" is the total number of RCU callbacks that have started waiting
 	for a grace period since boot.  "na" should be roughly equal to
 	"nl" plus "wa".
 o	"wl" is the number of RCU callbacks currently waiting for their
 	grace period to end.
 o	"da" is the total number of RCU callbacks whose grace periods
 	have completed since boot.  "wa" should be roughly equal to
 	"wl" plus "da".
 o	"dr" is the total number of RCU callbacks that have been removed
 	from the list of callbacks ready to invoke.  "dr" should be roughly
 	equal to "da".
 o	"di" is the total number of RCU callbacks that have been invoked
 	since boot.  "di" should be roughly equal to "da", though some
 	early versions of preemptable RCU had a bug so that only the
 	last CPU's count of invocations was displayed, rather than the
 	sum of all CPU's counts.
 o	"1" is the number of calls to rcu_try_flip().  This should be
 	roughly equal to the sum of "e1", "i1", "a1", "z1", and "m1"
 	described below.  In other words, the number of times that
 	the state machine is visited should be equal to the sum of the
 	number of times that each state is visited plus the number of
 	times that the state-machine lock acquisition failed.
 o	"e1" is the number of times that rcu_try_flip() was unable to
 	acquire the fliplock.
 o	"i1" is the number of calls to rcu_try_flip_idle().
 o	"ie1" is the number of times rcu_try_flip_idle() exited early
 	due to the calling CPU having no work for RCU.
 o	"g1" is the number of times that rcu_try_flip_idle() decided
 	to start a new grace period.  "i1" should be roughly equal to
 	"ie1" plus "g1".
 o	"a1" is the number of calls to rcu_try_flip_waitack().
 o	"ae1" is the number of times that rcu_try_flip_waitack() found
 	that at least one CPU had not yet acknowledge the new grace period
 	(AKA "counter flip").
 o	"a2" is the number of time rcu_try_flip_waitack() found that
 	all CPUs had acknowledged.  "a1" should be roughly equal to
 	"ae1" plus "a2".  (This particular output was collected on
 	a 128-CPU machine, hence the smaller-than-usual fraction of
 	calls to rcu_try_flip_waitack() finding all CPUs having already
 	acknowledged.)
 o	"z1" is the number of calls to rcu_try_flip_waitzero().
 o	"ze1" is the number of times that rcu_try_flip_waitzero() found
 	that not all of the old RCU read-side critical sections had
 	completed.
 o	"z2" is the number of times that rcu_try_flip_waitzero() finds
 	the sum of the counters equal to zero, in other words, that
 	all of the old RCU read-side critical sections had completed.
 	The value of "z1" should be roughly equal to "ze1" plus
 	"z2".
 o	"m1" is the number of calls to rcu_try_flip_waitmb().
 o	"me1" is the number of times that rcu_try_flip_waitmb() finds
 	that at least one CPU has not yet executed a memory barrier.
 o	"m2" is the number of times that rcu_try_flip_waitmb() finds that
 	all CPUs have executed a memory barrier.
 Hierarchical RCU debugfs Files and Formats
 This implementation of RCU provides three debugfs files under the
 top-level directory RCU: rcu/rcudata (which displays fields in struct
 rcu_data), rcu/rcugp (which displays grace-period counters), and
 rcu/rcuhier (which displays the struct rcu_node hierarchy).
 The output of "cat rcu/rcudata" looks as follows:
 rcu:
  0 c=4011 g=4012 pq=1 pqc=4011 qp=0 rpfq=1 rp=3c2a dt=23301/73 dn=2 df=1882 of=0 ri=2126 ql=2 b=10
  1 c=4011 g=4012 pq=1 pqc=4011 qp=0 rpfq=3 rp=39a6 dt=78073/1 dn=2 df=1402 of=0 ri=1875 ql=46 b=10
  2 c=4010 g=4010 pq=1 pqc=4010 qp=0 rpfq=-5 rp=1d12 dt=16646/0 dn=2 df=3140 of=0 ri=2080 ql=0 b=10
  3 c=4012 g=4013 pq=1 pqc=4012 qp=1 rpfq=3 rp=2b50 dt=21159/1 dn=2 df=2230 of=0 ri=1923 ql=72 b=10
  4 c=4012 g=4013 pq=1 pqc=4012 qp=1 rpfq=3 rp=1644 dt=5783/1 dn=2 df=3348 of=0 ri=2805 ql=7 b=10
  5 c=4012 g=4013 pq=0 pqc=4011 qp=1 rpfq=3 rp=1aac dt=5879/1 dn=2 df=3140 of=0 ri=2066 ql=10 b=10
  6 c=4012 g=4013 pq=1 pqc=4012 qp=1 rpfq=3 rp=ed8 dt=5847/1 dn=2 df=3797 of=0 ri=1266 ql=10 b=10
  7 c=4012 g=4013 pq=1 pqc=4012 qp=1 rpfq=3 rp=1fa2 dt=6199/1 dn=2 df=2795 of=0 ri=2162 ql=28 b=10
 rcu_bh:
  0 c=-268 g=-268 pq=1 pqc=-268 qp=0 rpfq=-145 rp=21d6 dt=23301/73 dn=2 df=0 of=0 ri=0 ql=0 b=10
  1 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-170 rp=20ce dt=78073/1 dn=2 df=26 of=0 ri=5 ql=0 b=10
  2 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-83 rp=fbd dt=16646/0 dn=2 df=28 of=0 ri=4 ql=0 b=10
  3 c=-268 g=-268 pq=1 pqc=-268 qp=0 rpfq=-105 rp=178c dt=21159/1 dn=2 df=28 of=0 ri=2 ql=0 b=10
  4 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-30 rp=b54 dt=5783/1 dn=2 df=32 of=0 ri=0 ql=0 b=10
  5 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-29 rp=df5 dt=5879/1 dn=2 df=30 of=0 ri=3 ql=0 b=10
  6 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-28 rp=788 dt=5847/1 dn=2 df=32 of=0 ri=0 ql=0 b=10
  7 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-53 rp=1098 dt=6199/1 dn=2 df=30 of=0 ri=3 ql=0 b=10
 The first section lists the rcu_data structures for rcu, the second for
 rcu_bh.  Each section has one line per CPU, or eight for this 8-CPU system.
 The fields are as follows:
 o	The number at the beginning of each line is the CPU number.
 	CPUs numbers followed by an exclamation mark are offline,
 	but have been online at least once since boot.	There will be
 	no output for CPUs that have never been online, which can be
 	a good thing in the surprisingly common case where NR_CPUS is
 	substantially larger than the number of actual CPUs.
 o	"c" is the count of grace periods that this CPU believes have
 	completed.  CPUs in dynticks idle mode may lag quite a ways
 	behind, for example, CPU 4 under "rcu" above, which has slept
 	through the past 25 RCU grace periods.	It is not unusual to
 	see CPUs lagging by thousands of grace periods.
 o	"g" is the count of grace periods that this CPU believes have
 	started.  Again, CPUs in dynticks idle mode may lag behind.
 	If the "c" and "g" values are equal, this CPU has already
 	reported a quiescent state for the last RCU grace period that
 	it is aware of, otherwise, the CPU believes that it owes RCU a
 	quiescent state.
 o	"pq" indicates that this CPU has passed through a quiescent state
 	for the current grace period.  It is possible for "pq" to be
 	"1" and "c" different than "g", which indicates that although
 	the CPU has passed through a quiescent state, either (1) this
 	CPU has not yet reported that fact, (2) some other CPU has not
 	yet reported for this grace period, or (3) both.
 o	"pqc" indicates which grace period the last-observed quiescent
 	state for this CPU corresponds to.  This is important for handling
 	the race between CPU 0 reporting an extended dynticks-idle
 	quiescent state for CPU 1 and CPU 1 suddenly waking up and
 	reporting its own quiescent state.  If CPU 1 was the last CPU
 	for the current grace period, then the CPU that loses this race
 	will attempt to incorrectly mark CPU 1 as having checked in for
 	the next grace period!
 o	"qp" indicates that RCU still expects a quiescent state from
 	this CPU.
 o	"rpfq" is the number of rcu_pending() calls on this CPU required
 	to induce this CPU to invoke force_quiescent_state().
 o	"rp" is low-order four hex digits of the count of how many times
 	rcu_pending() has been invoked on this CPU.
 o	"dt" is the current value of the dyntick counter that is incremented
 	when entering or leaving dynticks idle state, either by the
 	scheduler or by irq.  The number after the "/" is the interrupt
 	nesting depth when in dyntick-idle state, or one greater than
 	the interrupt-nesting depth otherwise.
 	This field is displayed only for CONFIG_NO_HZ kernels.
 o	"dn" is the current value of the dyntick counter that is incremented
 	when entering or leaving dynticks idle state via NMI.  If both
 	the "dt" and "dn" values are even, then this CPU is in dynticks
 	idle mode and may be ignored by RCU.  If either of these two
 	counters is odd, then RCU must be alert to the possibility of
 	an RCU read-side critical section running on this CPU.
 	This field is displayed only for CONFIG_NO_HZ kernels.
 o	"df" is the number of times that some other CPU has forced a
 	quiescent state on behalf of this CPU due to this CPU being in
 	dynticks-idle state.
 	This field is displayed only for CONFIG_NO_HZ kernels.
 o	"of" is the number of times that some other CPU has forced a
 	quiescent state on behalf of this CPU due to this CPU being
 	offline.  In a perfect world, this might neve happen, but it
 	turns out that offlining and onlining a CPU can take several grace
 	periods, and so there is likely to be an extended period of time
 	when RCU believes that the CPU is online when it really is not.
 	Please note that erring in the other direction (RCU believing a
 	CPU is offline when it is really alive and kicking) is a fatal
 	error, so it makes sense to err conservatively.
 o	"ri" is the number of times that RCU has seen fit to send a
 	reschedule IPI to this CPU in order to get it to report a
 	quiescent state.
 o	"ql" is the number of RCU callbacks currently residing on
 	this CPU.  This is the total number of callbacks, regardless
 	of what state they are in (new, waiting for grace period to
 	start, waiting for grace period to end, ready to invoke).
 o	"b" is the batch limit for this CPU.  If more than this number
 	of RCU callbacks is ready to invoke, then the remainder will
 	be deferred.
 The output of "cat rcu/rcugp" looks as follows:
 rcu: completed=33062  gpnum=33063
 rcu_bh: completed=464  gpnum=464
 Again, this output is for both "rcu" and "rcu_bh".  The fields are
 taken from the rcu_state structure, and are as follows:
 o	"completed" is the number of grace periods that have completed.
 	It is comparable to the "c" field from rcu/rcudata in that a
 	CPU whose "c" field matches the value of "completed" is aware
 	that the corresponding RCU grace period has completed.
 o	"gpnum" is the number of grace periods that have started.  It is
 	comparable to the "g" field from rcu/rcudata in that a CPU
 	whose "g" field matches the value of "gpnum" is aware that the
 	corresponding RCU grace period has started.
 	If these two fields are equal (as they are for "rcu_bh" above),
 	then there is no grace period in progress, in other words, RCU
 	is idle.  On the other hand, if the two fields differ (as they
 	do for "rcu" above), then an RCU grace period is in progress.
 The output of "cat rcu/rcuhier" looks as follows, with very long lines:
 c=6902 g=6903 s=2 jfq=3 j=72c7 nfqs=13142/nfqsng=0(13142) fqlh=6
 1/1 0:127 ^0    
 3/3 0:35 ^0    0/0 36:71 ^1    0/0 72:107 ^2    0/0 108:127 ^3    
 3/3f 0:5 ^0    2/3 6:11 ^1    0/0 12:17 ^2    0/0 18:23 ^3    0/0 24:29 ^4    0/0 30:35 ^5    0/0 36:41 ^0    0/0 42:47 ^1    0/0 48:53 ^2    0/0 54:59 ^3    0/0 60:65 ^4    0/0 66:71 ^5    0/0 72:77 ^0    0/0 78:83 ^1    0/0 84:89 ^2    0/0 90:95 ^3    0/0 96:101 ^4    0/0 102:107 ^5    0/0 108:113 ^0    0/0 114:119 ^1    0/0 120:125 ^2    0/0 126:127 ^3    
 rcu_bh:
 c=-226 g=-226 s=1 jfq=-5701 j=72c7 nfqs=88/nfqsng=0(88) fqlh=0
 0/1 0:127 ^0    
 0/3 0:35 ^0    0/0 36:71 ^1    0/0 72:107 ^2    0/0 108:127 ^3    
 0/3f 0:5 ^0    0/3 6:11 ^1    0/0 12:17 ^2    0/0 18:23 ^3    0/0 24:29 ^4    0/0 30:35 ^5    0/0 36:41 ^0    0/0 42:47 ^1    0/0 48:53 ^2    0/0 54:59 ^3    0/0 60:65 ^4    0/0 66:71 ^5    0/0 72:77 ^0    0/0 78:83 ^1    0/0 84:89 ^2    0/0 90:95 ^3    0/0 96:101 ^4    0/0 102:107 ^5    0/0 108:113 ^0    0/0 114:119 ^1    0/0 120:125 ^2    0/0 126:127 ^3
 This is once again split into "rcu" and "rcu_bh" portions.  The fields are
 as follows:
 o	"c" is exactly the same as "completed" under rcu/rcugp.
 o	"g" is exactly the same as "gpnum" under rcu/rcugp.
 o	"s" is the "signaled" state that drives force_quiescent_state()'s
 	state machine.
 o	"jfq" is the number of jiffies remaining for this grace period
 	before force_quiescent_state() is invoked to help push things
 	along.  Note that CPUs in dyntick-idle mode thoughout the grace
 	period will not report on their own, but rather must be check by
 	some other CPU via force_quiescent_state().
 o	"j" is the low-order four hex digits of the jiffies counter.
 	Yes, Paul did run into a number of problems that turned out to
 	be due to the jiffies counter no longer counting.  Why do you ask?
 o	"nfqs" is the number of calls to force_quiescent_state() since
 	boot.
 o	"nfqsng" is the number of useless calls to force_quiescent_state(),
 	where there wasn't actually a grace period active.  This can
 	happen due to races.  The number in parentheses is the difference
 	between "nfqs" and "nfqsng", or the number of times that
 	force_quiescent_state() actually did some real work.
 o	"fqlh" is the number of calls to force_quiescent_state() that
 	exited immediately (without even being counted in nfqs above)
 	due to contention on ->fqslock.
 o	Each element of the form "1/1 0:127 ^0" represents one struct
 	rcu_node.  Each line represents one level of the hierarchy, from
 	root to leaves.  It is best to think of the rcu_data structures
 	as forming yet another level after the leaves.  Note that there
 	might be either one, two, or three levels of rcu_node structures,
 	depending on the relationship between CONFIG_RCU_FANOUT and
 	CONFIG_NR_CPUS.
 	o	The numbers separated by the "/" are the qsmask followed
 		by the qsmaskinit.  The qsmask will have one bit
 		set for each entity in the next lower level that
 		has not yet checked in for the current grace period.
 		The qsmaskinit will have one bit for each entity that is
 		currently expected to check in during each grace period.
 		The value of qsmaskinit is assigned to that of qsmask
 		at the beginning of each grace period.
 		For example, for "rcu", the qsmask of the first entry
 		of the lowest level is 0x14, meaning that we are still
 		waiting for CPUs 2 and 4 to check in for the current
 		grace period.
 	o	The numbers separated by the ":" are the range of CPUs
 		served by this struct rcu_node.  This can be helpful
 		in working out how the hierarchy is wired together.
 		For example, the first entry at the lowest level shows
 		"0:5", indicating that it covers CPUs 0 through 5.
 	o	The number after the "^" indicates the bit in the
 		next higher level rcu_node structure that this
 		rcu_node structure corresponds to.
 		For example, the first entry at the lowest level shows
 		"^0", indicating that it corresponds to bit zero in
 		the first entry at the middle level.
@@ -71,35 +71,50 @@ Look at the current lock statistics:
 # less /proc/lock_stat
-01 lock_stat version 0.2
+01 lock_stat version 0.3
 02 -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 03                               class name    con-bounces    contentions   waittime-min   waittime-max waittime-total    acq-bounces   acquisitions   holdtime-min   holdtime-max holdtime-total
 04 -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 05
-06               &inode->i_data.tree_lock-W:            15          21657           0.18     1093295.30 11547131054.85             58          10415           0.16          87.51        6387.60
+06                          &mm->mmap_sem-W:           233            538 18446744073708       22924.27      607243.51           1342          45806           1.71        8595.89     1180582.34
-07               &inode->i_data.tree_lock-R:             0              0           0.00           0.00           0.00          23302         231198           0.25           8.45       98023.38
+07                          &mm->mmap_sem-R:           205            587 18446744073708       28403.36      731975.00           1940         412426           0.58      187825.45     6307502.88
-08               --------------------------
+08                          ---------------
-09                 &inode->i_data.tree_lock              0          [<ffffffff8027c08f>] add_to_page_cache+0x5f/0x190
+09                            &mm->mmap_sem            487          [<ffffffff8053491f>] do_page_fault+0x466/0x928
-10
+10                            &mm->mmap_sem            179          [<ffffffff802a6200>] sys_mprotect+0xcd/0x21d
-11 ...............................................................................................................................................................................................
+11                            &mm->mmap_sem            279          [<ffffffff80210a57>] sys_mmap+0x75/0xce
-12
+12                            &mm->mmap_sem             76          [<ffffffff802a490b>] sys_munmap+0x32/0x59
-13                              dcache_lock:          1037           1161           0.38          45.32         774.51           6611         243371           0.15         306.48       77387.24
+13                          ---------------
-14                              -----------
+14                            &mm->mmap_sem            270          [<ffffffff80210a57>] sys_mmap+0x75/0xce
-15                              dcache_lock            180          [<ffffffff802c0d7e>] sys_getcwd+0x11e/0x230
+15                            &mm->mmap_sem            431          [<ffffffff8053491f>] do_page_fault+0x466/0x928
-16                              dcache_lock            165          [<ffffffff802c002a>] d_alloc+0x15a/0x210
+16                            &mm->mmap_sem            138          [<ffffffff802a490b>] sys_munmap+0x32/0x59
-17                              dcache_lock             33          [<ffffffff8035818d>] _atomic_dec_and_lock+0x4d/0x70
+17                            &mm->mmap_sem            145          [<ffffffff802a6200>] sys_mprotect+0xcd/0x21d
-18                              dcache_lock              1          [<ffffffff802beef8>] shrink_dcache_parent+0x18/0x130
+18
 19 ...............................................................................................................................................................................................
 20
 21                              dcache_lock:           621            623           0.52         118.26        1053.02           6745          91930           0.29         316.29      118423.41
 22                              -----------
 23                              dcache_lock            179          [<ffffffff80378274>] _atomic_dec_and_lock+0x34/0x54
 24                              dcache_lock            113          [<ffffffff802cc17b>] d_alloc+0x19a/0x1eb
 25                              dcache_lock             99          [<ffffffff802ca0dc>] d_rehash+0x1b/0x44
 26                              dcache_lock            104          [<ffffffff802cbca0>] d_instantiate+0x36/0x8a
 27                              -----------
 28                              dcache_lock            192          [<ffffffff80378274>] _atomic_dec_and_lock+0x34/0x54
 29                              dcache_lock             98          [<ffffffff802ca0dc>] d_rehash+0x1b/0x44
 30                              dcache_lock             72          [<ffffffff802cc17b>] d_alloc+0x19a/0x1eb
 31                              dcache_lock            112          [<ffffffff802cbca0>] d_instantiate+0x36/0x8a
 This excerpt shows the first two lock class statistics. Line 01 shows the
 output version - each time the format changes this will be updated. Line 02-04
-show the header with column descriptions. Lines 05-10 and 13-18 show the actual
+show the header with column descriptions. Lines 05-18 and 20-31 show the actual
 statistics. These statistics come in two parts; the actual stats separated by a
-short separator (line 08, 14) from the contention points.
+short separator (line 08, 13) from the contention points.
-The first lock (05-10) is a read/write lock, and shows two lines above the
+The first lock (05-18) is a read/write lock, and shows two lines above the
 short separator. The contention points don't match the column descriptors,
-they have two: contentions and [<IP>] symbol.
+they have two: contentions and [<IP>] symbol. The second set of contention
 points are the points we're contending with.
 The integer part of the time values is in us.
 View the top contending locks:
@@ -208,6 +208,7 @@ void pSeries_log_error(char *buf, unsigned int err_type, int fatal)
 		break;
 	case ERR_TYPE_KERNEL_PANIC:
 	default:
 		WARN_ON_ONCE(!irqs_disabled()); /* @@@ DEBUG @@@ */
 		spin_unlock_irqrestore(&rtasd_log_lock, s);
 		return;
 	}
@@ -227,6 +228,7 @@ void pSeries_log_error(char *buf, unsigned int err_type, int fatal)
 	/* Check to see if we need to or have stopped logging */
 	if (fatal || !logging_enabled) {
 		logging_enabled = 0;
 		WARN_ON_ONCE(!irqs_disabled()); /* @@@ DEBUG @@@ */
 		spin_unlock_irqrestore(&rtasd_log_lock, s);
 		return;
 	}
@@ -249,11 +251,13 @@ void pSeries_log_error(char *buf, unsigned int err_type, int fatal)
 		else
 			rtas_log_start += 1;
 		WARN_ON_ONCE(!irqs_disabled()); /* @@@ DEBUG @@@ */
 		spin_unlock_irqrestore(&rtasd_log_lock, s);
 		wake_up_interruptible(&rtas_log_wait);
 		break;
 	case ERR_TYPE_KERNEL_PANIC:
 	default:
 		WARN_ON_ONCE(!irqs_disabled()); /* @@@ DEBUG @@@ */
 		spin_unlock_irqrestore(&rtasd_log_lock, s);
 		return;
 	}
@@ -11,21 +11,21 @@ extern int get_signals(void);
 extern void block_signals(void);
 extern void unblock_signals(void);
-#define local_save_flags(flags) do { typecheck(unsigned long, flags); \
+#define raw_local_save_flags(flags) do { typecheck(unsigned long, flags); \
 				     (flags) = get_signals(); } while(0)
-#define local_irq_restore(flags) do { typecheck(unsigned long, flags); \
+#define raw_local_irq_restore(flags) do { typecheck(unsigned long, flags); \
 				      set_signals(flags); } while(0)
-#define local_irq_save(flags) do { local_save_flags(flags); \
+#define raw_local_irq_save(flags) do { raw_local_save_flags(flags); \
-                                   local_irq_disable(); } while(0)
+                                   raw_local_irq_disable(); } while(0)
-#define local_irq_enable() unblock_signals()
+#define raw_local_irq_enable() unblock_signals()
-#define local_irq_disable() block_signals()
+#define raw_local_irq_disable() block_signals()
 #define irqs_disabled()                 \
 ({                                      \
        unsigned long flags;            \
-        local_save_flags(flags);        \
+        raw_local_save_flags(flags);        \
        (flags == 0);                   \
 })
@@ -65,7 +65,7 @@ static inline struct dma_mapping_ops *get_dma_ops(struct device *dev)
 		return dma_ops;
 	else
 		return dev->archdata.dma_ops;
-#endif /* _ASM_X86_DMA_MAPPING_H */
+#endif
 }
 /* Make sure we keep the same behaviour */
@@ -7,8 +7,6 @@ extern struct dma_mapping_ops nommu_dma_ops;
 extern int force_iommu, no_iommu;
 extern int iommu_detected;
 extern unsigned long iommu_nr_pages(unsigned long addr, unsigned long len);
 /* 10 seconds */
 #define DMAR_OPERATION_TIMEOUT ((cycles_t) tsc_khz*10*1000)
@@ -84,6 +84,8 @@ static inline void pci_dma_burst_advice(struct pci_dev *pdev,
 static inline void early_quirks(void) { }
 #endif
 extern void pci_iommu_alloc(void);
 #endif  /* __KERNEL__ */
 #ifdef CONFIG_X86_32
@@ -23,7 +23,6 @@ extern int (*pci_config_write)(int seg, int bus, int dev, int fn,
 			       int reg, int len, u32 value);
 extern void dma32_reserve_bootmem(void);
 extern void pci_iommu_alloc(void);
 /* The PCI address space does equal the physical memory
 * address space.  The networking and block device layers use
@@ -157,6 +157,7 @@ extern int __get_user_bad(void);
 	int __ret_gu;							\
 	unsigned long __val_gu;						\
 	__chk_user_ptr(ptr);						\
 	might_fault();							\
 	switch (sizeof(*(ptr))) {					\
 	case 1:								\
 		__get_user_x(1, __ret_gu, __val_gu, ptr);		\
@@ -241,6 +242,7 @@ extern void __put_user_8(void);
 	int __ret_pu;						\
 	__typeof__(*(ptr)) __pu_val;				\
 	__chk_user_ptr(ptr);					\
 	might_fault();						\
 	__pu_val = x;						\
 	switch (sizeof(*(ptr))) {				\
 	case 1:							\
@@ -82,8 +82,8 @@ __copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)
 static __always_inline unsigned long __must_check
 __copy_to_user(void __user *to, const void *from, unsigned long n)
 {
-       might_sleep();
+	might_fault();
-       return __copy_to_user_inatomic(to, from, n);
+	return __copy_to_user_inatomic(to, from, n);
 }
 static __always_inline unsigned long
@@ -137,7 +137,7 @@ __copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
 static __always_inline unsigned long
 __copy_from_user(void *to, const void __user *from, unsigned long n)
 {
-	might_sleep();
+	might_fault();
 	if (__builtin_constant_p(n)) {
 		unsigned long ret;
@@ -159,7 +159,7 @@ __copy_from_user(void *to, const void __user *from, unsigned long n)
 static __always_inline unsigned long __copy_from_user_nocache(void *to,
 				const void __user *from, unsigned long n)
 {
-	might_sleep();
+	might_fault();
 	if (__builtin_constant_p(n)) {
 		unsigned long ret;
@@ -29,6 +29,8 @@ static __always_inline __must_check
 int __copy_from_user(void *dst, const void __user *src, unsigned size)
 {
 	int ret = 0;
 	might_fault();
 	if (!__builtin_constant_p(size))
 		return copy_user_generic(dst, (__force void *)src, size);
 	switch (size) {
@@ -71,6 +73,8 @@ static __always_inline __must_check
 int __copy_to_user(void __user *dst, const void *src, unsigned size)
 {
 	int ret = 0;
 	might_fault();
 	if (!__builtin_constant_p(size))
 		return copy_user_generic((__force void *)dst, src, size);
 	switch (size) {
@@ -113,6 +117,8 @@ static __always_inline __must_check
 int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
 {
 	int ret = 0;
 	might_fault();
 	if (!__builtin_constant_p(size))
 		return copy_user_generic((__force void *)dst,
 					 (__force void *)src, size);
@@ -109,6 +109,8 @@ obj-$(CONFIG_MICROCODE)			+= microcode.o
 obj-$(CONFIG_X86_CHECK_BIOS_CORRUPTION) += check.o
 obj-$(CONFIG_SWIOTLB)			+= pci-swiotlb_64.o # NB rename without _64
 ###
 # 64 bit specific files
 ifeq ($(CONFIG_X86_64),y)
@@ -122,7 +124,6 @@ ifeq ($(CONFIG_X86_64),y)
        obj-$(CONFIG_GART_IOMMU)	+= pci-gart_64.o aperture_64.o
        obj-$(CONFIG_CALGARY_IOMMU)	+= pci-calgary_64.o tce_64.o
        obj-$(CONFIG_AMD_IOMMU)		+= amd_iommu_init.o amd_iommu.o
        obj-$(CONFIG_SWIOTLB)		+= pci-swiotlb_64.o
        obj-$(CONFIG_PCI_MMCONFIG)	+= mmconf-fam10h_64.o
 endif
@@ -101,11 +101,15 @@ static void __init dma32_free_bootmem(void)
 	dma32_bootmem_ptr = NULL;
 	dma32_bootmem_size = 0;
 }
 #endif
 void __init pci_iommu_alloc(void)
 {
 #ifdef CONFIG_X86_64
 	/* free the range so iommu could get some range less than 4G */
 	dma32_free_bootmem();
 #endif
 	/*
 	 * The order of these functions is important for
 	 * fall-back/fail-over reasons
@@ -121,15 +125,6 @@ void __init pci_iommu_alloc(void)
 	pci_swiotlb_init();
 }
 unsigned long iommu_nr_pages(unsigned long addr, unsigned long len)
 {
 	unsigned long size = roundup((addr & ~PAGE_MASK) + len, PAGE_SIZE);
 	return size >> PAGE_SHIFT;
 }
 EXPORT_SYMBOL(iommu_nr_pages);
 #endif
 void *dma_generic_alloc_coherent(struct device *dev, size_t size,
 				 dma_addr_t *dma_addr, gfp_t flag)
 {
@@ -3,6 +3,8 @@
 #include <linux/pci.h>
 #include <linux/cache.h>
 #include <linux/module.h>
 #include <linux/swiotlb.h>
 #include <linux/bootmem.h>
 #include <linux/dma-mapping.h>
 #include <asm/iommu.h>
@@ -11,6 +13,31 @@
 int swiotlb __read_mostly;
 void *swiotlb_alloc_boot(size_t size, unsigned long nslabs)
 {
 	return alloc_bootmem_low_pages(size);
 }
 void *swiotlb_alloc(unsigned order, unsigned long nslabs)
 {
 	return (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN, order);
 }
 dma_addr_t swiotlb_phys_to_bus(phys_addr_t paddr)
 {
 	return paddr;
 }
 phys_addr_t swiotlb_bus_to_phys(dma_addr_t baddr)
 {
 	return baddr;
 }
 int __weak swiotlb_arch_range_needs_mapping(void *ptr, size_t size)
 {
 	return 0;
 }
 static dma_addr_t
 swiotlb_map_single_phys(struct device *hwdev, phys_addr_t paddr, size_t size,
 			int direction)
@@ -50,8 +77,10 @@ struct dma_mapping_ops swiotlb_dma_ops = {
 void __init pci_swiotlb_init(void)
 {
 	/* don't initialize swiotlb if iommu=off (no_iommu=1) */
 #ifdef CONFIG_X86_64
 	if (!iommu_detected && !no_iommu && max_pfn > MAX_DMA32_PFN)
 	       swiotlb = 1;
 #endif
 	if (swiotlb_force)
 		swiotlb = 1;
 	if (swiotlb) {
@@ -39,7 +39,7 @@ static inline int __movsl_is_ok(unsigned long a1, unsigned long a2, unsigned lon
 #define __do_strncpy_from_user(dst, src, count, res)			   \
 do {									   \
 	int __d0, __d1, __d2;						   \
-	might_sleep();							   \
+	might_fault();							   \
 	__asm__ __volatile__(						   \
 		"	testl %1,%1\n"					   \
 		"	jz 2f\n"					   \
@@ -126,7 +126,7 @@ EXPORT_SYMBOL(strncpy_from_user);
 #define __do_clear_user(addr,size)					\
 do {									\
 	int __d0;							\
-	might_sleep();							\
+	might_fault();							\
 	__asm__ __volatile__(						\
 		"0:	rep; stosl\n"					\
 		"	movl %2,%0\n"					\
@@ -155,7 +155,7 @@ do {									\
 unsigned long
 clear_user(void __user *to, unsigned long n)
 {
-	might_sleep();
+	might_fault();
 	if (access_ok(VERIFY_WRITE, to, n))
 		__do_clear_user(to, n);
 	return n;
@@ -197,7 +197,7 @@ long strnlen_user(const char __user *s, long n)
 	unsigned long mask = -__addr_ok(s);
 	unsigned long res, tmp;
-	might_sleep();
+	might_fault();
 	__asm__ __volatile__(
 		"	testl %0, %0\n"
@@ -15,7 +15,7 @@
 #define __do_strncpy_from_user(dst,src,count,res)			   \
 do {									   \
 	long __d0, __d1, __d2;						   \
-	might_sleep();							   \
+	might_fault();							   \
 	__asm__ __volatile__(						   \
 		"	testq %1,%1\n"					   \
 		"	jz 2f\n"					   \
@@ -64,7 +64,7 @@ EXPORT_SYMBOL(strncpy_from_user);
 unsigned long __clear_user(void __user *addr, unsigned long size)
 {
 	long __d0;
-	might_sleep();
+	might_fault();
 	/* no memory constraint because it doesn't change any memory gcc knows
 	   about */
 	asm volatile(
@@ -21,6 +21,7 @@
 #include <linux/init.h>
 #include <linux/highmem.h>
 #include <linux/pagemap.h>
 #include <linux/pci.h>
 #include <linux/pfn.h>
 #include <linux/poison.h>
 #include <linux/bootmem.h>
@@ -967,6 +968,8 @@ void __init mem_init(void)
 	int codesize, reservedpages, datasize, initsize;
 	int tmp;
 	pci_iommu_alloc();
 #ifdef CONFIG_FLATMEM
 	BUG_ON(!mem_map);
 #endif
@@ -41,15 +41,14 @@ struct bug_entry {
 #ifndef __WARN
 #ifndef __ASSEMBLY__
 extern void warn_on_slowpath(const char *file, const int line);
 extern void warn_slowpath(const char *file, const int line,
 		const char *fmt, ...) __attribute__((format(printf, 3, 4)));
 #define WANT_WARN_ON_SLOWPATH
 #endif
-#define __WARN() warn_on_slowpath(__FILE__, __LINE__)
+#define __WARN()		warn_slowpath(__FILE__, __LINE__, NULL)
-#define __WARN_printf(arg...) warn_slowpath(__FILE__, __LINE__, arg)
+#define __WARN_printf(arg...)	warn_slowpath(__FILE__, __LINE__, arg)
 #else
-#define __WARN_printf(arg...) do { printk(arg); __WARN(); } while (0)
+#define __WARN_printf(arg...)	do { printk(arg); __WARN(); } while (0)
 #endif
 #ifndef WARN_ON
@@ -2,7 +2,6 @@
 #define _LINUX_BH_H
 extern void local_bh_disable(void);
 extern void __local_bh_enable(void);
 extern void _local_bh_enable(void);
 extern void local_bh_enable(void);
 extern void local_bh_enable_ip(unsigned long ip);
--- a/Show More
+++ b/Show More