Commit c1561cf4 authored by Tim Shimmin's avatar Tim Shimmin
Browse files

Merge branch 'master' of... 

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into for-linus
parents 053c59a0 bbf25010

Documentation/devices.txt

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@@ -94,6 +94,8 @@ Your cooperation is appreciated. 
		  9 = /dev/urandom	Faster, less secure random number gen.

		 10 = /dev/aio		Asynchronous I/O notification interface

		 11 = /dev/kmsg		Writes to this come out as printk's

		 12 = /dev/oldmem	Used by crashdump kernels to access

					the memory of the kernel that crashed.



  1 block	RAM disk

		  0 = /dev/ram0		First RAM disk

Documentation/lockstat.txt

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Original line number Diff line number Diff line 


LOCK STATISTICS



- WHAT



As the name suggests, it provides statistics on locks.



- WHY



Because things like lock contention can severely impact performance.



- HOW



Lockdep already has hooks in the lock functions and maps lock instances to

lock classes. We build on that. The graph below shows the relation between

the lock functions and the various hooks therein.



        __acquire

            |

           lock _____

            |        \

            |    __contended

            |         |

            |       <wait>

            | _______/

            |/

            |

       __acquired

            |

            .

          <hold>

            .

            |

       __release

            |

         unlock



lock, unlock	- the regular lock functions

__*		- the hooks

<> 		- states



With these hooks we provide the following statistics:



 con-bounces       - number of lock contention that involved x-cpu data

 contentions       - number of lock acquisitions that had to wait

 wait time min     - shortest (non-0) time we ever had to wait for a lock

           max     - longest time we ever had to wait for a lock

           total   - total time we spend waiting on this lock

 acq-bounces       - number of lock acquisitions that involved x-cpu data

 acquisitions      - number of times we took the lock

 hold time min     - shortest (non-0) time we ever held the lock

           max     - longest time we ever held the lock

           total   - total time this lock was held



From these number various other statistics can be derived, such as:



 hold time average = hold time total / acquisitions



These numbers are gathered per lock class, per read/write state (when

applicable).



It also tracks 4 contention points per class. A contention point is a call site

that had to wait on lock acquisition.



 - USAGE



Look at the current lock statistics:



( line numbers not part of actual output, done for clarity in the explanation

  below )



# less /proc/lock_stat



01 lock_stat version 0.2

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

07               &inode->i_data.tree_lock-R:             0              0           0.00           0.00           0.00          23302         231198           0.25           8.45       98023.38

08               --------------------------

09                 &inode->i_data.tree_lock              0          [<ffffffff8027c08f>] add_to_page_cache+0x5f/0x190

10

11 ...............................................................................................................................................................................................

12

13                              dcache_lock:          1037           1161           0.38          45.32         774.51           6611         243371           0.15         306.48       77387.24

14                              -----------

15                              dcache_lock            180          [<ffffffff802c0d7e>] sys_getcwd+0x11e/0x230

16                              dcache_lock            165          [<ffffffff802c002a>] d_alloc+0x15a/0x210

17                              dcache_lock             33          [<ffffffff8035818d>] _atomic_dec_and_lock+0x4d/0x70

18                              dcache_lock              1          [<ffffffff802beef8>] shrink_dcache_parent+0x18/0x130



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

statistics. These statistics come in two parts; the actual stats separated by a

short separator (line 08, 14) from the contention points.



The first lock (05-10) 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.





View the top contending locks:



# grep : /proc/lock_stat | head

              &inode->i_data.tree_lock-W:            15          21657           0.18     1093295.30 11547131054.85             58          10415           0.16          87.51        6387.60

              &inode->i_data.tree_lock-R:             0              0           0.00           0.00           0.00          23302         231198           0.25           8.45       98023.38

                             dcache_lock:          1037           1161           0.38          45.32         774.51           6611         243371           0.15         306.48       77387.24

                         &inode->i_mutex:           161            286 18446744073709       62882.54     1244614.55           3653          20598 18446744073709       62318.60     1693822.74

                         &zone->lru_lock:            94             94           0.53           7.33          92.10           4366          32690           0.29          59.81       16350.06

              &inode->i_data.i_mmap_lock:            79             79           0.40           3.77          53.03          11779          87755           0.28         116.93       29898.44

                        &q->__queue_lock:            48             50           0.52          31.62          86.31            774          13131           0.17         113.08       12277.52

                        &rq->rq_lock_key:            43             47           0.74          68.50         170.63           3706          33929           0.22         107.99       17460.62

                      &rq->rq_lock_key#2:            39             46           0.75           6.68          49.03           2979          32292           0.17         125.17       17137.63

                         tasklist_lock-W:            15             15           1.45          10.87          32.70           1201           7390           0.58          62.55       13648.47



Clear the statistics:



# echo 0 > /proc/lock_stat

Documentation/sysrq.txt

+1 −1
Original line number Diff line number Diff line
@@ -43,7 +43,7 @@ On x86 - You press the key combo 'ALT-SysRq-<command key>'. Note - Some 
           keyboards may not have a key labeled 'SysRq'. The 'SysRq' key is

           also known as the 'Print Screen' key. Also some keyboards cannot

	   handle so many keys being pressed at the same time, so you might

	   have better luck with "press Alt", "press SysRq", "release Alt",

	   have better luck with "press Alt", "press SysRq", "release SysRq",

	   "press <command key>", release everything.



On SPARC - You press 'ALT-STOP-<command key>', I believe.

Makefile

+1 −1
Original line number Diff line number Diff line 
VERSION = 2

PATCHLEVEL = 6

SUBLEVEL = 23

EXTRAVERSION =-rc8

EXTRAVERSION =

NAME = Arr Matey! A Hairy Bilge Rat!



# *DOCUMENTATION*

arch/arm/kernel/bios32.c

+2 −2
Original line number Diff line number Diff line
@@ -338,7 +338,7 @@ pbus_assign_bus_resources(struct pci_bus *bus, struct pci_sys_data *root) 
 * pcibios_fixup_bus - Called after each bus is probed,

 * but before its children are examined.

 */

void __devinit pcibios_fixup_bus(struct pci_bus *bus)

void pcibios_fixup_bus(struct pci_bus *bus)

{

	struct pci_sys_data *root = bus->sysdata;

	struct pci_dev *dev;
@@ -419,7 +419,7 @@ void __devinit pcibios_fixup_bus(struct pci_bus *bus) 
/*

 * Convert from Linux-centric to bus-centric addresses for bridge devices.

 */

void __devinit

void

pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region,

			 struct resource *res)

{