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  1. 17 4月, 2009 1 次提交
    • M
      Driver Core: early platform driver · 13977091
      由 Magnus Damm 提交于 
      V3 of the early platform driver implementation.

Platform drivers are great for embedded platforms because we can separate
driver configuration from the actual driver.  So base addresses,
interrupts and other configuration can be kept with the processor or board
code, and the platform driver can be reused by many different platforms.

For early devices we have nothing today.  For instance, to configure early
timers and early serial ports we cannot use platform devices.  This
because the setup order during boot.  Timers are needed before the
platform driver core code is available.  The same goes for early printk
support.  Early in this case means before initcalls.

These early drivers today have their configuration either hard coded or
they receive it using some special configuration method.  This is working
quite well, but if we want to support both regular kernel modules and
early devices then we need to have two ways of configuring the same
driver.  A single way would be better.

The early platform driver patch is basically a set of functions that allow
drivers to register themselves and architecture code to locate them and
probe.  Registration happens through early_param().  The time for the
probe is decided by the architecture code.

See Documentation/driver-model/platform.txt for more details.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NMagnus Damm <damm@igel.co.jp>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Tejun Heo <htejun@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      13977091
  3. 01 4月, 2009 1 次提交
  5. 30 3月, 2009 2 次提交
  7. 26 3月, 2009 1 次提交
    • L
      init,cpuset: fix initialize order · 759ee091
      由 Lai Jiangshan 提交于 
      Impact: cpuset_wq should be initialized after init_workqueues()

When I read /debugfs/tracing/trace_stat/workqueues,
I got this:

 # CPU  INSERTED  EXECUTED   NAME
 # |      |         |          |

   0      0          0       cpuset
   0    285        285       events/0
   0      2          2       work_on_cpu/0
   0   1115       1115       khelper
   0    325        325       kblockd/0
   0      0          0       kacpid
   0      0          0       kacpi_notify
   0      0          0       ata/0
   0      0          0       ata_aux
   0      0          0       ksuspend_usbd
   0      0          0       aio/0
   0      0          0       nfsiod
   0      0          0       kpsmoused
   0      0          0       kstriped
   0      0          0       kondemand/0
   0      1          1       hid_compat
   0      0          0       rpciod/0

   1     64         64       events/1
   1      2          2       work_on_cpu/1
   1      5          5       kblockd/1
   1      0          0       ata/1
   1      0          0       aio/1
   1      0          0       kondemand/1
   1      0          0       rpciod/1

I found "cpuset" is at the earliest.

I found a create_singlethread_workqueue() is earlier than
init_workqueues():

kernel_init()
->cpuset_init_smp()
  ->create_singlethread_workqueue()
->do_basic_setup()
  ->init_workqueues()

I think it's better that create_singlethread_workqueue() is called
after workqueue subsystem has been initialized.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: NSteven Rostedt <srostedt@redhat.com>
Acked-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Menage <menage@google.com>
Cc: miaoxie <miaox@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <49C9F416.1050707@cn.fujitsu.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      759ee091
  9. 26 2月, 2009 1 次提交
    • P
      rcu: Teach RCU that idle task is not quiscent state at boot · a6826048
      由 Paul E. McKenney 提交于 
      This patch fixes a bug located by Vegard Nossum with the aid of
kmemcheck, updated based on review comments from Nick Piggin,
Ingo Molnar, and Andrew Morton.  And cleans up the variable-name
and function-name language.  ;-)

The boot CPU runs in the context of its idle thread during boot-up.
During this time, idle_cpu(0) will always return nonzero, which will
fool Classic and Hierarchical RCU into deciding that a large chunk of
the boot-up sequence is a big long quiescent state.  This in turn causes
RCU to prematurely end grace periods during this time.

This patch changes the rcutree.c and rcuclassic.c rcu_check_callbacks()
function to ignore the idle task as a quiescent state until the
system has started up the scheduler in rest_init(), introducing a
new non-API function rcu_idle_now_means_idle() to inform RCU of this
transition.  RCU maintains an internal rcu_idle_cpu_truthful variable
to track this state, which is then used by rcu_check_callback() to
determine if it should believe idle_cpu().

Because this patch has the effect of disallowing RCU grace periods
during long stretches of the boot-up sequence, this patch also introduces
Josh Triplett's UP-only optimization that makes synchronize_rcu() be a
no-op if num_online_cpus() returns 1.  This allows boot-time code that
calls synchronize_rcu() to proceed normally.  Note, however, that RCU
callbacks registered by call_rcu() will likely queue up until later in
the boot sequence.  Although rcuclassic and rcutree can also use this
same optimization after boot completes, rcupreempt must restrict its
use of this optimization to the portion of the boot sequence before the
scheduler starts up, given that an rcupreempt RCU read-side critical
section may be preeempted.

In addition, this patch takes Nick Piggin's suggestion to make the
system_state global variable be __read_mostly.

Changes since v4:

o	Changes the name of the introduced function and variable to
	be less emotional.  ;-)

Changes since v3:

o	WARN_ON(nr_context_switches() > 0) to verify that RCU
	switches out of boot-time mode before the first context
	switch, as suggested by Nick Piggin.

Changes since v2:

o	Created rcu_blocking_is_gp() internal-to-RCU API that
	determines whether a call to synchronize_rcu() is itself
	a grace period.

o	The definition of rcu_blocking_is_gp() for rcuclassic and
	rcutree checks to see if but a single CPU is online.

o	The definition of rcu_blocking_is_gp() for rcupreempt
	checks to see both if but a single CPU is online and if
	the system is still in early boot.

	This allows rcupreempt to again work correctly if running
	on a single CPU after booting is complete.

o	Added check to rcupreempt's synchronize_sched() for there
	being but one online CPU.

Tested all three variants both SMP and !SMP, booted fine, passed a short
rcutorture test on both x86 and Power.
Located-by: NVegard Nossum <vegard.nossum@gmail.com>
Tested-by: NVegard Nossum <vegard.nossum@gmail.com>
Tested-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      a6826048
  11. 06 2月, 2009 1 次提交
  13. 08 1月, 2009 1 次提交
    • A
      async: Asynchronous function calls to speed up kernel boot · 22a9d645
      由 Arjan van de Ven 提交于 
      Right now, most of the kernel boot is strictly synchronous, such that
various hardware delays are done sequentially.

In order to make the kernel boot faster, this patch introduces
infrastructure to allow doing some of the initialization steps
asynchronously, which will hide significant portions of the hardware delays
in practice.

In order to not change device order and other similar observables, this
patch does NOT do full parallel initialization.

Rather, it operates more in the way an out of order CPU does; the work may
be done out of order and asynchronous, but the observable effects
(instruction retiring for the CPU) are still done in the original sequence.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
      22a9d645
  15. 07 1月, 2009 3 次提交
  17. 06 1月, 2009 1 次提交
  19. 03 1月, 2009 1 次提交
  21. 01 1月, 2009 2 次提交
  23. 30 12月, 2008 1 次提交
    • F
      tracing/kmemtrace: normalize the raw tracer event to the unified tracing API · 36994e58
      由 Frederic Weisbecker 提交于 
      Impact: new tracer plugin

This patch adapts kmemtrace raw events tracing to the unified tracing API.

To enable and use this tracer, just do the following:

 echo kmemtrace > /debugfs/tracing/current_tracer
 cat /debugfs/tracing/trace

You will have the following output:

 # tracer: kmemtrace
 #
 #
 # ALLOC  TYPE  REQ   GIVEN  FLAGS           POINTER         NODE    CALLER
 # FREE   |      |     |       |              |   |            |        |
 # |

type_id 1 call_site 18446744071565527833 ptr 18446612134395152256
type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1
type_id 1 call_site 18446744071565585534 ptr 18446612134405955584
type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1
type_id 0 call_site 18446744071565636711 ptr 18446612134345164672 bytes_req 240 bytes_alloc 240 gfp_flags 208 node -1
type_id 1 call_site 18446744071565585534 ptr 18446612134405955584
type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1
type_id 0 call_site 18446744071565636711 ptr 18446612134345164912 bytes_req 240 bytes_alloc 240 gfp_flags 208 node -1
type_id 1 call_site 18446744071565585534 ptr 18446612134405955584
type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1
type_id 0 call_site 18446744071565636711 ptr 18446612134345165152 bytes_req 240 bytes_alloc 240 gfp_flags 208 node -1
type_id 0 call_site 18446744071566144042 ptr 18446612134346191680 bytes_req 1304 bytes_alloc 1312 gfp_flags 208 node -1
type_id 1 call_site 18446744071565585534 ptr 18446612134405955584
type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1
type_id 1 call_site 18446744071565585534 ptr 18446612134405955584

That was to stay backward compatible with the format output produced in
inux/tracepoint.h.

This is the default ouput, but note that I tried something else.

If you change an option:

echo kmem_minimalistic > /debugfs/trace_options

and then cat /debugfs/trace, you will have the following output:

 # tracer: kmemtrace
 #
 #
 # ALLOC  TYPE  REQ   GIVEN  FLAGS           POINTER         NODE    CALLER
 # FREE   |      |     |       |              |   |            |        |
 # |

   -      C                            0xffff88007c088780          file_free_rcu
   +      K   4096   4096   000000d0   0xffff88007cad6000     -1   getname
   -      C                            0xffff88007cad6000          putname
   +      K   4096   4096   000000d0   0xffff88007cad6000     -1   getname
   +      K    240    240   000000d0   0xffff8800790dc780     -1   d_alloc
   -      C                            0xffff88007cad6000          putname
   +      K   4096   4096   000000d0   0xffff88007cad6000     -1   getname
   +      K    240    240   000000d0   0xffff8800790dc870     -1   d_alloc
   -      C                            0xffff88007cad6000          putname
   +      K   4096   4096   000000d0   0xffff88007cad6000     -1   getname
   +      K    240    240   000000d0   0xffff8800790dc960     -1   d_alloc
   +      K   1304   1312   000000d0   0xffff8800791d7340     -1   reiserfs_alloc_inode
   -      C                            0xffff88007cad6000          putname
   +      K   4096   4096   000000d0   0xffff88007cad6000     -1   getname
   -      C                            0xffff88007cad6000          putname
   +      K    992   1000   000000d0   0xffff880079045b58     -1   alloc_inode
   +      K    768   1024   000080d0   0xffff88007c096400     -1   alloc_pipe_info
   +      K    240    240   000000d0   0xffff8800790dca50     -1   d_alloc
   +      K    272    320   000080d0   0xffff88007c088780     -1   get_empty_filp
   +      K    272    320   000080d0   0xffff88007c088000     -1   get_empty_filp

Yeah I shall confess kmem_minimalistic should be: kmem_alternative.

Whatever, I find it more readable but this a personal opinion of course.
We can drop it if you want.

On the ALLOC/FREE column, + means an allocation and - a free.

On the type column, you have K = kmalloc, C = cache, P = page

I would like the flags to be GFP_* strings but that would not be easy to not
break the column with strings....

About the node...it seems to always be -1. I don't know why but that shouldn't
be difficult to find.

I moved linux/tracepoint.h to trace/tracepoint.h as well. I think that would
be more easy to find the tracer headers if they are all in their common
directory.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      36994e58
  25. 29 12月, 2008 2 次提交
  27. 27 12月, 2008 1 次提交
  29. 08 12月, 2008 1 次提交
    • Y
      sparse irq_desc[] array: core kernel and x86 changes · 0b8f1efa
      由 Yinghai Lu 提交于 
      Impact: new feature

Problem on distro kernels: irq_desc[NR_IRQS] takes megabytes of RAM with
NR_CPUS set to large values. The goal is to be able to scale up to much
larger NR_IRQS value without impacting the (important) common case.

To solve this, we generalize irq_desc[NR_IRQS] to an (optional) array of
irq_desc pointers.

When CONFIG_SPARSE_IRQ=y is used, we use kzalloc_node to get irq_desc,
this also makes the IRQ descriptors NUMA-local (to the site that calls
request_irq()).

This gets rid of the irq_cfg[] static array on x86 as well: irq_cfg now
uses desc->chip_data for x86 to store irq_cfg.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      0b8f1efa
  31. 23 11月, 2008 1 次提交
  33. 14 11月, 2008 1 次提交
    • D
      CRED: Inaugurate COW credentials · d84f4f99
      由 David Howells 提交于 
      Inaugurate copy-on-write credentials management.  This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.

A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().

With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:

	struct cred *new = prepare_creds();
	int ret = blah(new);
	if (ret < 0) {
		abort_creds(new);
		return ret;
	}
	return commit_creds(new);

There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.

To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const.  The purpose of this is compile-time
discouragement of altering credentials through those pointers.  Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:

  (1) Its reference count may incremented and decremented.

  (2) The keyrings to which it points may be modified, but not replaced.

The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).

This patch and the preceding patches have been tested with the LTP SELinux
testsuite.

This patch makes several logical sets of alteration:

 (1) execve().

     This now prepares and commits credentials in various places in the
     security code rather than altering the current creds directly.

 (2) Temporary credential overrides.

     do_coredump() and sys_faccessat() now prepare their own credentials and
     temporarily override the ones currently on the acting thread, whilst
     preventing interference from other threads by holding cred_replace_mutex
     on the thread being dumped.

     This will be replaced in a future patch by something that hands down the
     credentials directly to the functions being called, rather than altering
     the task's objective credentials.

 (3) LSM interface.

     A number of functions have been changed, added or removed:

     (*) security_capset_check(), ->capset_check()
     (*) security_capset_set(), ->capset_set()

     	 Removed in favour of security_capset().

     (*) security_capset(), ->capset()

     	 New.  This is passed a pointer to the new creds, a pointer to the old
     	 creds and the proposed capability sets.  It should fill in the new
     	 creds or return an error.  All pointers, barring the pointer to the
     	 new creds, are now const.

     (*) security_bprm_apply_creds(), ->bprm_apply_creds()

     	 Changed; now returns a value, which will cause the process to be
     	 killed if it's an error.

     (*) security_task_alloc(), ->task_alloc_security()

     	 Removed in favour of security_prepare_creds().

     (*) security_cred_free(), ->cred_free()

     	 New.  Free security data attached to cred->security.

     (*) security_prepare_creds(), ->cred_prepare()

     	 New. Duplicate any security data attached to cred->security.

     (*) security_commit_creds(), ->cred_commit()

     	 New. Apply any security effects for the upcoming installation of new
     	 security by commit_creds().

     (*) security_task_post_setuid(), ->task_post_setuid()

     	 Removed in favour of security_task_fix_setuid().

     (*) security_task_fix_setuid(), ->task_fix_setuid()

     	 Fix up the proposed new credentials for setuid().  This is used by
     	 cap_set_fix_setuid() to implicitly adjust capabilities in line with
     	 setuid() changes.  Changes are made to the new credentials, rather
     	 than the task itself as in security_task_post_setuid().

     (*) security_task_reparent_to_init(), ->task_reparent_to_init()

     	 Removed.  Instead the task being reparented to init is referred
     	 directly to init's credentials.

	 NOTE!  This results in the loss of some state: SELinux's osid no
	 longer records the sid of the thread that forked it.

     (*) security_key_alloc(), ->key_alloc()
     (*) security_key_permission(), ->key_permission()

     	 Changed.  These now take cred pointers rather than task pointers to
     	 refer to the security context.

 (4) sys_capset().

     This has been simplified and uses less locking.  The LSM functions it
     calls have been merged.

 (5) reparent_to_kthreadd().

     This gives the current thread the same credentials as init by simply using
     commit_thread() to point that way.

 (6) __sigqueue_alloc() and switch_uid()

     __sigqueue_alloc() can't stop the target task from changing its creds
     beneath it, so this function gets a reference to the currently applicable
     user_struct which it then passes into the sigqueue struct it returns if
     successful.

     switch_uid() is now called from commit_creds(), and possibly should be
     folded into that.  commit_creds() should take care of protecting
     __sigqueue_alloc().

 (7) [sg]et[ug]id() and co and [sg]et_current_groups.

     The set functions now all use prepare_creds(), commit_creds() and
     abort_creds() to build and check a new set of credentials before applying
     it.

     security_task_set[ug]id() is called inside the prepared section.  This
     guarantees that nothing else will affect the creds until we've finished.

     The calling of set_dumpable() has been moved into commit_creds().

     Much of the functionality of set_user() has been moved into
     commit_creds().

     The get functions all simply access the data directly.

 (8) security_task_prctl() and cap_task_prctl().

     security_task_prctl() has been modified to return -ENOSYS if it doesn't
     want to handle a function, or otherwise return the return value directly
     rather than through an argument.

     Additionally, cap_task_prctl() now prepares a new set of credentials, even
     if it doesn't end up using it.

 (9) Keyrings.

     A number of changes have been made to the keyrings code:

     (a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
     	 all been dropped and built in to the credentials functions directly.
     	 They may want separating out again later.

     (b) key_alloc() and search_process_keyrings() now take a cred pointer
     	 rather than a task pointer to specify the security context.

     (c) copy_creds() gives a new thread within the same thread group a new
     	 thread keyring if its parent had one, otherwise it discards the thread
     	 keyring.

     (d) The authorisation key now points directly to the credentials to extend
     	 the search into rather pointing to the task that carries them.

     (e) Installing thread, process or session keyrings causes a new set of
     	 credentials to be created, even though it's not strictly necessary for
     	 process or session keyrings (they're shared).

(10) Usermode helper.

     The usermode helper code now carries a cred struct pointer in its
     subprocess_info struct instead of a new session keyring pointer.  This set
     of credentials is derived from init_cred and installed on the new process
     after it has been cloned.

     call_usermodehelper_setup() allocates the new credentials and
     call_usermodehelper_freeinfo() discards them if they haven't been used.  A
     special cred function (prepare_usermodeinfo_creds()) is provided
     specifically for call_usermodehelper_setup() to call.

     call_usermodehelper_setkeys() adjusts the credentials to sport the
     supplied keyring as the new session keyring.

(11) SELinux.

     SELinux has a number of changes, in addition to those to support the LSM
     interface changes mentioned above:

     (a) selinux_setprocattr() no longer does its check for whether the
     	 current ptracer can access processes with the new SID inside the lock
     	 that covers getting the ptracer's SID.  Whilst this lock ensures that
     	 the check is done with the ptracer pinned, the result is only valid
     	 until the lock is released, so there's no point doing it inside the
     	 lock.

(12) is_single_threaded().

     This function has been extracted from selinux_setprocattr() and put into
     a file of its own in the lib/ directory as join_session_keyring() now
     wants to use it too.

     The code in SELinux just checked to see whether a task shared mm_structs
     with other tasks (CLONE_VM), but that isn't good enough.  We really want
     to know if they're part of the same thread group (CLONE_THREAD).

(13) nfsd.

     The NFS server daemon now has to use the COW credentials to set the
     credentials it is going to use.  It really needs to pass the credentials
     down to the functions it calls, but it can't do that until other patches
     in this series have been applied.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NJames Morris <jmorris@namei.org>
Signed-off-by: NJames Morris <jmorris@namei.org>
      d84f4f99
  35. 12 11月, 2008 2 次提交
    • F
      tracing/fastboot: Use the ring-buffer timestamp for initcall entries · 74239072
      由 Frederic Weisbecker 提交于 
      Impact: Split the boot tracer entries in two parts: call and return

Now that we are using the sched tracer from the boot tracer, we want
to use the same timestamp than the ring-buffer to have consistent time
captures between sched events and initcall events.

So we get rid of the old time capture by the boot tracer and split the
initcall events in two parts: call and return. This way we have the
ring buffer timestamp of both.

An example trace:

[   27.904149584] calling  net_ns_init+0x0/0x1c0 @ 1
[   27.904429624] initcall net_ns_init+0x0/0x1c0 returned 0 after 0 msecs
[   27.904575926] calling  reboot_init+0x0/0x20 @ 1
[   27.904655399] initcall reboot_init+0x0/0x20 returned 0 after 0 msecs
[   27.904800228] calling  sysctl_init+0x0/0x30 @ 1
[   27.905142914] initcall sysctl_init+0x0/0x30 returned 0 after 0 msecs
[   27.905287211] calling  ksysfs_init+0x0/0xb0 @ 1
 ##### CPU 0 buffer started ####
            init-1     [000]    27.905395:      1:120:R   + [001]    11:115:S
 ##### CPU 1 buffer started ####
          <idle>-0     [001]    27.905425:      0:140:R ==> [001]    11:115:R
            init-1     [000]    27.905426:      1:120:D ==> [000]     0:140:R
          <idle>-0     [000]    27.905431:      0:140:R   + [000]     4:115:S
          <idle>-0     [000]    27.905451:      0:140:R ==> [000]     4:115:R
     ksoftirqd/0-4     [000]    27.905456:      4:115:S ==> [000]     0:140:R
           udevd-11    [001]    27.905458:     11:115:R   + [001]    14:115:R
          <idle>-0     [000]    27.905459:      0:140:R   + [000]     4:115:S
          <idle>-0     [000]    27.905462:      0:140:R ==> [000]     4:115:R
           udevd-11    [001]    27.905462:     11:115:R ==> [001]    14:115:R
     ksoftirqd/0-4     [000]    27.905467:      4:115:S ==> [000]     0:140:R
          <idle>-0     [000]    27.905470:      0:140:R   + [000]     4:115:S
          <idle>-0     [000]    27.905473:      0:140:R ==> [000]     4:115:R
     ksoftirqd/0-4     [000]    27.905476:      4:115:S ==> [000]     0:140:R
          <idle>-0     [000]    27.905479:      0:140:R   + [000]     4:115:S
          <idle>-0     [000]    27.905482:      0:140:R ==> [000]     4:115:R
     ksoftirqd/0-4     [000]    27.905486:      4:115:S ==> [000]     0:140:R
           udevd-14    [001]    27.905499:     14:120:X ==> [001]    11:115:R
           udevd-11    [001]    27.905506:     11:115:R   + [000]     1:120:D
          <idle>-0     [000]    27.905515:      0:140:R ==> [000]     1:120:R
           udevd-11    [001]    27.905517:     11:115:S ==> [001]     0:140:R
[   27.905557107] initcall ksysfs_init+0x0/0xb0 returned 0 after 3906 msecs
[   27.905705736] calling  init_jiffies_clocksource+0x0/0x10 @ 1
[   27.905779239] initcall init_jiffies_clocksource+0x0/0x10 returned 0 after 0 msecs
[   27.906769814] calling  pm_init+0x0/0x30 @ 1
[   27.906853627] initcall pm_init+0x0/0x30 returned 0 after 0 msecs
[   27.906997803] calling  pm_disk_init+0x0/0x20 @ 1
[   27.907076946] initcall pm_disk_init+0x0/0x20 returned 0 after 0 msecs
[   27.907222556] calling  swsusp_header_init+0x0/0x30 @ 1
[   27.907294325] initcall swsusp_header_init+0x0/0x30 returned 0 after 0 msecs
[   27.907439620] calling  stop_machine_init+0x0/0x50 @ 1
            init-1     [000]    27.907485:      1:120:R   + [000]     2:115:S
            init-1     [000]    27.907490:      1:120:D ==> [000]     2:115:R
        kthreadd-2     [000]    27.907507:      2:115:R   + [001]    15:115:R
          <idle>-0     [001]    27.907517:      0:140:R ==> [001]    15:115:R
        kthreadd-2     [000]    27.907517:      2:115:D ==> [000]     0:140:R
          <idle>-0     [000]    27.907521:      0:140:R   + [000]     4:115:S
          <idle>-0     [000]    27.907524:      0:140:R ==> [000]     4:115:R
           udevd-15    [001]    27.907527:     15:115:D   + [000]     2:115:D
     ksoftirqd/0-4     [000]    27.907537:      4:115:S ==> [000]     2:115:R
           udevd-15    [001]    27.907537:     15:115:D ==> [001]     0:140:R
        kthreadd-2     [000]    27.907546:      2:115:R   + [000]     1:120:D
        kthreadd-2     [000]    27.907550:      2:115:S ==> [000]     1:120:R
            init-1     [000]    27.907584:      1:120:R   + [000]    15:  0:D
            init-1     [000]    27.907589:      1:120:R   + [000]     2:115:S
            init-1     [000]    27.907593:      1:120:D ==> [000]    15:  0:R
           udevd-15    [000]    27.907601:     15:  0:S ==> [000]     2:115:R
 ##### CPU 0 buffer started ####
        kthreadd-2     [000]    27.907616:      2:115:R   + [001]    16:115:R
 ##### CPU 1 buffer started ####
          <idle>-0     [001]    27.907620:      0:140:R ==> [001]    16:115:R
        kthreadd-2     [000]    27.907621:      2:115:D ==> [000]     0:140:R
           udevd-16    [001]    27.907625:     16:115:D   + [000]     2:115:D
          <idle>-0     [000]    27.907628:      0:140:R   + [000]     4:115:S
           udevd-16    [001]    27.907629:     16:115:D ==> [001]     0:140:R
          <idle>-0     [000]    27.907631:      0:140:R ==> [000]     4:115:R
     ksoftirqd/0-4     [000]    27.907636:      4:115:S ==> [000]     2:115:R
        kthreadd-2     [000]    27.907644:      2:115:R   + [000]     1:120:D
        kthreadd-2     [000]    27.907647:      2:115:S ==> [000]     1:120:R
            init-1     [000]    27.907657:      1:120:R   + [001]    16:  0:D
          <idle>-0     [001]    27.907666:      0:140:R ==> [001]    16:  0:R
[   27.907703862] initcall stop_machine_init+0x0/0x50 returned 0 after 0 msecs
[   27.907850704] calling  filelock_init+0x0/0x30 @ 1
[   27.907926573] initcall filelock_init+0x0/0x30 returned 0 after 0 msecs
[   27.908071327] calling  init_script_binfmt+0x0/0x10 @ 1
[   27.908165195] initcall init_script_binfmt+0x0/0x10 returned 0 after 0 msecs
[   27.908309461] calling  init_elf_binfmt+0x0/0x10 @ 1
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      74239072
    • F
      tracing/fastboot: move boot tracer structs and funcs into their own header. · 3f5ec136
      由 Frederic Weisbecker 提交于 
      Impact: Cleanups on the boot tracer and ftrace

This patch bring some cleanups about the boot tracer headers. The
functions and structures of this tracer have nothing related to ftrace
and should have so their own header file.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      3f5ec136
  37. 05 11月, 2008 1 次提交
    • F
      tracing/fastboot: Enable boot tracing only during initcalls · 71566a0d
      由 Frederic Weisbecker 提交于 
      Impact: modify boot tracer

We used to disable the initcall tracing at a specified time (IE: end
of builtin initcalls). But we don't need it anymore. It will be
stopped when initcalls are finished.

However we want two things:

_Start this tracing only after pre-smp initcalls are finished.

_Since we are planning to trace sched_switches at the same time, we
want to enable them only during the initcall execution.

For this purpose, this patch introduce two functions to enable/disable
the sched_switch tracing during boot.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      71566a0d
  39. 26 10月, 2008 1 次提交
    • L
      Revert "Call init_workqueues before pre smp initcalls." · 4403b406
      由 Linus Torvalds 提交于 
      This reverts commit a802dd0e by moving
the call to init_workqueues() back where it belongs - after SMP has been
initialized.

It also moves stop_machine_init() - which needs workqueues - to a later
phase using a core_initcall() instead of early_initcall().  That should
satisfy all ordering requirements, and was apparently the reason why
init_workqueues() was moved to be too early.

Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4403b406
  41. 23 10月, 2008 2 次提交
  43. 22 10月, 2008 2 次提交
  45. 20 10月, 2008 1 次提交
    • N
      mm: rewrite vmap layer · db64fe02
      由 Nick Piggin 提交于 
      Rewrite the vmap allocator to use rbtrees and lazy tlb flushing, and
provide a fast, scalable percpu frontend for small vmaps (requires a
slightly different API, though).

The biggest problem with vmap is actually vunmap.  Presently this requires
a global kernel TLB flush, which on most architectures is a broadcast IPI
to all CPUs to flush the cache.  This is all done under a global lock.  As
the number of CPUs increases, so will the number of vunmaps a scaled
workload will want to perform, and so will the cost of a global TLB flush.
 This gives terrible quadratic scalability characteristics.

Another problem is that the entire vmap subsystem works under a single
lock.  It is a rwlock, but it is actually taken for write in all the fast
paths, and the read locking would likely never be run concurrently anyway,
so it's just pointless.

This is a rewrite of vmap subsystem to solve those problems.  The existing
vmalloc API is implemented on top of the rewritten subsystem.

The TLB flushing problem is solved by using lazy TLB unmapping.  vmap
addresses do not have to be flushed immediately when they are vunmapped,
because the kernel will not reuse them again (would be a use-after-free)
until they are reallocated.  So the addresses aren't allocated again until
a subsequent TLB flush.  A single TLB flush then can flush multiple
vunmaps from each CPU.

XEN and PAT and such do not like deferred TLB flushing because they can't
always handle multiple aliasing virtual addresses to a physical address.
They now call vm_unmap_aliases() in order to flush any deferred mappings.
That call is very expensive (well, actually not a lot more expensive than
a single vunmap under the old scheme), however it should be OK if not
called too often.

The virtual memory extent information is stored in an rbtree rather than a
linked list to improve the algorithmic scalability.

There is a per-CPU allocator for small vmaps, which amortizes or avoids
global locking.

To use the per-CPU interface, the vm_map_ram / vm_unmap_ram interfaces
must be used in place of vmap and vunmap.  Vmalloc does not use these
interfaces at the moment, so it will not be quite so scalable (although it
will use lazy TLB flushing).

As a quick test of performance, I ran a test that loops in the kernel,
linearly mapping then touching then unmapping 4 pages.  Different numbers
of tests were run in parallel on an 4 core, 2 socket opteron.  Results are
in nanoseconds per map+touch+unmap.

threads           vanilla         vmap rewrite
1                 14700           2900
2                 33600           3000
4                 49500           2800
8                 70631           2900

So with a 8 cores, the rewritten version is already 25x faster.

In a slightly more realistic test (although with an older and less
scalable version of the patch), I ripped the not-very-good vunmap batching
code out of XFS, and implemented the large buffer mapping with vm_map_ram
and vm_unmap_ram...  along with a couple of other tricks, I was able to
speed up a large directory workload by 20x on a 64 CPU system.  I believe
vmap/vunmap is actually sped up a lot more than 20x on such a system, but
I'm running into other locks now.  vmap is pretty well blown off the
profiles.

Before:
1352059 total                                      0.1401
798784 _write_lock                              8320.6667 <- vmlist_lock
529313 default_idle                             1181.5022
 15242 smp_call_function                         15.8771  <- vmap tlb flushing
  2472 __get_vm_area_node                         1.9312  <- vmap
  1762 remove_vm_area                             4.5885  <- vunmap
   316 map_vm_area                                0.2297  <- vmap
   312 kfree                                      0.1950
   300 _spin_lock                                 3.1250
   252 sn_send_IPI_phys                           0.4375  <- tlb flushing
   238 vmap                                       0.8264  <- vmap
   216 find_lock_page                             0.5192
   196 find_next_bit                              0.3603
   136 sn2_send_IPI                               0.2024
   130 pio_phys_write_mmr                         2.0312
   118 unmap_kernel_range                         0.1229

After:
 78406 total                                      0.0081
 40053 default_idle                              89.4040
 33576 ia64_spinlock_contention                 349.7500
  1650 _spin_lock                                17.1875
   319 __reg_op                                   0.5538
   281 _atomic_dec_and_lock                       1.0977
   153 mutex_unlock                               1.5938
   123 iget_locked                                0.1671
   117 xfs_dir_lookup                             0.1662
   117 dput                                       0.1406
   114 xfs_iget_core                              0.0268
    92 xfs_da_hashname                            0.1917
    75 d_alloc                                    0.0670
    68 vmap_page_range                            0.0462 <- vmap
    58 kmem_cache_alloc                           0.0604
    57 memset                                     0.0540
    52 rb_next                                    0.1625
    50 __copy_user                                0.0208
    49 bitmap_find_free_region                    0.2188 <- vmap
    46 ia64_sn_udelay                             0.1106
    45 find_inode_fast                            0.1406
    42 memcmp                                     0.2188
    42 finish_task_switch                         0.1094
    42 __d_lookup                                 0.0410
    40 radix_tree_lookup_slot                     0.1250
    37 _spin_unlock_irqrestore                    0.3854
    36 xfs_bmapi                                  0.0050
    36 kmem_cache_free                            0.0256
    35 xfs_vn_getattr                             0.0322
    34 radix_tree_lookup                          0.1062
    33 __link_path_walk                           0.0035
    31 xfs_da_do_buf                              0.0091
    30 _xfs_buf_find                              0.0204
    28 find_get_page                              0.0875
    27 xfs_iread                                  0.0241
    27 __strncpy_from_user                        0.2812
    26 _xfs_buf_initialize                        0.0406
    24 _xfs_buf_lookup_pages                      0.0179
    24 vunmap_page_range                          0.0250 <- vunmap
    23 find_lock_page                             0.0799
    22 vm_map_ram                                 0.0087 <- vmap
    20 kfree                                      0.0125
    19 put_page                                   0.0330
    18 __kmalloc                                  0.0176
    17 xfs_da_node_lookup_int                     0.0086
    17 _read_lock                                 0.0885
    17 page_waitqueue                             0.0664

vmap has gone from being the top 5 on the profiles and flushing the crap
out of all TLBs, to using less than 1% of kernel time.

[akpm@linux-foundation.org: cleanups, section fix]
[akpm@linux-foundation.org: fix build on alpha]
Signed-off-by: NNick Piggin <npiggin@suse.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      db64fe02
  47. 16 10月, 2008 6 次提交
  49. 14 10月, 2008 3 次提交