diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/00-INDEX | 2 | ||||
| -rw-r--r-- | Documentation/DocBook/kernel-locking.tmpl | 2 | ||||
| -rw-r--r-- | Documentation/locking/lockdep-design.txt (renamed from Documentation/lockdep-design.txt) | 0 | ||||
| -rw-r--r-- | Documentation/locking/lockstat.txt (renamed from Documentation/lockstat.txt) | 2 | ||||
| -rw-r--r-- | Documentation/locking/mutex-design.txt (renamed from Documentation/mutex-design.txt) | 0 | ||||
| -rw-r--r-- | Documentation/locking/rt-mutex-design.txt (renamed from Documentation/rt-mutex-design.txt) | 0 | ||||
| -rw-r--r-- | Documentation/locking/rt-mutex.txt (renamed from Documentation/rt-mutex.txt) | 0 | ||||
| -rw-r--r-- | Documentation/locking/spinlocks.txt (renamed from Documentation/spinlocks.txt) | 14 | ||||
| -rw-r--r-- | Documentation/locking/ww-mutex-design.txt (renamed from Documentation/ww-mutex-design.txt) | 0 |
9 files changed, 11 insertions, 9 deletions
diff --git a/Documentation/00-INDEX b/Documentation/00-INDEX index 27e67a98b7be..1750fcef1ab4 100644 --- a/Documentation/00-INDEX +++ b/Documentation/00-INDEX @@ -287,6 +287,8 @@ local_ops.txt - semantics and behavior of local atomic operations. lockdep-design.txt - documentation on the runtime locking correctness validator. +locking/ + - directory with info about kernel locking primitives lockstat.txt - info on collecting statistics on locks (and contention). lockup-watchdogs.txt diff --git a/Documentation/DocBook/kernel-locking.tmpl b/Documentation/DocBook/kernel-locking.tmpl index e584ee12a1e7..7c9cc4846cb6 100644 --- a/Documentation/DocBook/kernel-locking.tmpl +++ b/Documentation/DocBook/kernel-locking.tmpl @@ -1972,7 +1972,7 @@ machines due to caching. <itemizedlist> <listitem> <para> - <filename>Documentation/spinlocks.txt</filename>: + <filename>Documentation/locking/spinlocks.txt</filename>: Linus Torvalds' spinlocking tutorial in the kernel sources. </para> </listitem> diff --git a/Documentation/lockdep-design.txt b/Documentation/locking/lockdep-design.txt index 5dbc99c04f6e..5dbc99c04f6e 100644 --- a/Documentation/lockdep-design.txt +++ b/Documentation/locking/lockdep-design.txt diff --git a/Documentation/lockstat.txt b/Documentation/locking/lockstat.txt index 72d010689751..7428773a1e69 100644 --- a/Documentation/lockstat.txt +++ b/Documentation/locking/lockstat.txt @@ -12,7 +12,7 @@ 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 (see Documentation/lockdep-design.txt). +lock classes. We build on that (see Documentation/lokcing/lockdep-design.txt). The graph below shows the relation between the lock functions and the various hooks therein. diff --git a/Documentation/mutex-design.txt b/Documentation/locking/mutex-design.txt index ee231ed09ec6..ee231ed09ec6 100644 --- a/Documentation/mutex-design.txt +++ b/Documentation/locking/mutex-design.txt diff --git a/Documentation/rt-mutex-design.txt b/Documentation/locking/rt-mutex-design.txt index 8666070d3189..8666070d3189 100644 --- a/Documentation/rt-mutex-design.txt +++ b/Documentation/locking/rt-mutex-design.txt diff --git a/Documentation/rt-mutex.txt b/Documentation/locking/rt-mutex.txt index 243393d882ee..243393d882ee 100644 --- a/Documentation/rt-mutex.txt +++ b/Documentation/locking/rt-mutex.txt diff --git a/Documentation/spinlocks.txt b/Documentation/locking/spinlocks.txt index 97eaf5727178..ff35e40bdf5b 100644 --- a/Documentation/spinlocks.txt +++ b/Documentation/locking/spinlocks.txt @@ -105,9 +105,9 @@ never used in interrupt handlers, you can use the non-irq versions: spin_unlock(&lock); (and the equivalent read-write versions too, of course). The spinlock will -guarantee the same kind of exclusive access, and it will be much faster. +guarantee the same kind of exclusive access, and it will be much faster. This is useful if you know that the data in question is only ever -manipulated from a "process context", ie no interrupts involved. +manipulated from a "process context", ie no interrupts involved. The reasons you mustn't use these versions if you have interrupts that play with the spinlock is that you can get deadlocks: @@ -122,21 +122,21 @@ the other interrupt happens on another CPU, but it is _not_ ok if the interrupt happens on the same CPU that already holds the lock, because the lock will obviously never be released (because the interrupt is waiting for the lock, and the lock-holder is interrupted by the interrupt and will -not continue until the interrupt has been processed). +not continue until the interrupt has been processed). (This is also the reason why the irq-versions of the spinlocks only need to disable the _local_ interrupts - it's ok to use spinlocks in interrupts on other CPU's, because an interrupt on another CPU doesn't interrupt the CPU that holds the lock, so the lock-holder can continue and eventually -releases the lock). +releases the lock). Note that you can be clever with read-write locks and interrupts. For example, if you know that the interrupt only ever gets a read-lock, then you can use a non-irq version of read locks everywhere - because they -don't block on each other (and thus there is no dead-lock wrt interrupts. -But when you do the write-lock, you have to use the irq-safe version. +don't block on each other (and thus there is no dead-lock wrt interrupts. +But when you do the write-lock, you have to use the irq-safe version. -For an example of being clever with rw-locks, see the "waitqueue_lock" +For an example of being clever with rw-locks, see the "waitqueue_lock" handling in kernel/sched/core.c - nothing ever _changes_ a wait-queue from within an interrupt, they only read the queue in order to know whom to wake up. So read-locks are safe (which is good: they are very common diff --git a/Documentation/ww-mutex-design.txt b/Documentation/locking/ww-mutex-design.txt index 8a112dc304c3..8a112dc304c3 100644 --- a/Documentation/ww-mutex-design.txt +++ b/Documentation/locking/ww-mutex-design.txt |