Cschalle: Add category

2011-10-28T10:32:23Z

Add category

RBot: Bot (Edward's framework)

2007-03-06T03:36:43Z

Bot (Edward's framework)

New page

Here is a table of rt-preempt sub-patches and the kernel features they introduce and affect:
{|
|- bgcolor="80c080"
| .
| align="center" | '''PATCH'''
|- bgcolor="80c080"
| Kernel item
| p-smp
| p-cleanup
| add-lnr
| add-crs
| *fix-scheduling*
| *keventd*
| idle-thread-p-fix
| remove-bkl
|-
| spinlock_t
| add break_lock
| .
| .
| .
| .
| .
| .
| .
|-
| rwlock_t
| add break_lock
| .
| .
| .
| .
| .
| .
| .
|-
| _raw_read_trylock()
| create
| .
| .
| .
| .
| .
| .
| .
|-
| generic_raw_read_trylock()
| create
| .
| .
| .
| .
| .
| .
| .
|-
| cond_resched_lock()
| check for break_lock
| .
| .
| .
| add calls to
| .
| .
| .
|-
| <spinlock routines>() (read_lock(), spin_lock_irqsave(), spin_lock_irq(), spin_lock_bh(), read_lock_irqsave(), read_lock_irq(), read_lock_bh(), write_lock_irqsave(), write_lock_irq(), write_lock_bh())
| enabled irqs, check for lock break requests
| .
| .
| .
| change some *_lock() to *_lock_irq()s
| .
| .
| .
|-
| need_lockbreak()
| .
| create
| .
| .
| .
| .
| .
| .
|-
| cond_resched()
| .
| fix
| .
| .
| add calls to
| .
| .
| .
|-
| lock_need_resched()
| .
| .
| create
| .
| add calls to
| .
| .
| .
|-
| lock/unlock_kernel()
| .
| .
| .
| .
| add calls to
| .
| .
| .
|-
| cond_resched_softirq()
| .
| .
| .
| .
| add calls to
| .
| .
| .
|-
| filemap_sync()
| .
| .
| .
| .
| create replacement with cond_resched()
| .
| .
| .
|-
| __filemap_sync()
| .
| .
| .
| .
| create?
| .
| .
| .
|-
| unmap_vmas()
| .
| .
| .
| .
| change ZAP_BLOCK_SIZE
| .
| .
| .
|-
| helper_init()
| .
| .
| .
| .
| .
| create
| .
| .
|-
| rest_init()
| .
| .
| .
| .
| .
| .
| enable_preemption
| .
|-
| start_kernel()
| .
| .
| .
| .
| .
| .
| disable preemption
| .
|-
| PREEMPT_BKL
| .
| .
| .
| .
| .
| .
| .
| create
|-
| _smp_processor_id()
| .
| .
| .
| .
| .
| .
| .
| create
|-
| current_cpu_data
| .
| .
| .
| .
| .
| .
| .
| replace with cpu_data[]
|-
| in_atomic()
| .
| .
| .
| .
| .
| .
| .
| alters
|-
| nmi_enter/exit(), irq_enter()
| .
| .
| .
| .
| .
| .
| .
| alter to use add/sub_preempt_count()
|-
| add/sub_preempt_count()
| .
| .
| .
| .
| .
| .
| .
| create
|-
| <u>ARRAY(0x1016aca4)</u>release_kernel_lock()
| .
| .
| .
| .
| .
| .
| .
| create
|-
| lock/unlock_kernel()
| .
| .
| .
| .
| .
| .
| .
| create sem version
|-
| DEBUG_PREEMPT
| .
| .
| .
| .
| .
| .
| .
| create
|-
| smp_processor_id()
| .
| .
| .
| .
| .
| .
| .
| add debug version
|-
| might_sleep()
| .
| .
| .
| .
| .
| .
| .
| .
| created in rtp3
|}

== Sub-patch summaries ==
* preempt-smp - spin irq-nicely and request cross-CPU lock-breaks if needed.
*** add break_lock field to spinlock_t and rwlock_t, and add _raw_read_trylock() function
*** generic_raw_read_trylock() needs to an ARCH-optimized version
* preempt-cleanup - fixes some issues with cond_resched, and adds need_lockbreak()
* add-lock_need_resched - self-explanatory
* sched-add-cond_resched_softirq - allows some softirqs-disabled codepaths to preempt
* *fix-scheduling*, break-latency* - add cond_resched() to lots of places
*** add lock_kernel and unlock_kernel in a few places
*** adjust some routines to allow rescheduling better (dependent on PREEMPT and SMP)
* fix-keventd-execution-dependency - schedule work differently during kevent initialization
* idle-thread-preemption-fix - disable preemption during bootup (until idle thread is running)
* remove-the-bkl-by-turning-it-into-a-sempahore - self-explanatory
*** adds _smp_processor_id() to help debug incorrect usage of this routine
*** adds add/sub_preempt_count, with debug aids to detect underflows
*** adds DEBUG_PREEMPT to enable both of the above
*** replace current_cpu_data with cpu_data[_smp_processor_id()]
*** add PREEMPT_BKL, and change routines lock/unlock_kernel to use a semaphore

== Terminology ==
* voluntary preempt = add preemption points to PREEMPT kernels (mostly via added calls to cond_resched())
* might_sleep =
* latency timing = system for keeping track of preemption request vs. actual preemption occurence
** this is used to emit warnings when a user-defined threshold is exceeded, and is useful for debugging the preemption features of this patchset
* latency trace = system for logging preemption-related events

← Older revision		Revision as of 10:32, 28 October 2011
Line 323:		Line 323:
	** this is used to emit warnings when a user-defined threshold is exceeded, and is useful for debugging the preemption features of this patchset		** this is used to emit warnings when a user-defined threshold is exceeded, and is useful for debugging the preemption features of this patchset
	* latency trace = system for logging preemption-related events		* latency trace = system for logging preemption-related events
		+
		+	[[Category:Kernel]]

Rt Preempt Subpatch Table - Revision history

Cschalle: Add category

RBot: Bot (Edward's framework)