Steven Rostedt 61e9dea20e tracing/filter: Use a tree instead of stack for filter_match_preds() ... Currently the filter_match_preds() requires a stack to push and pop the preds to determine if the filter matches the record or not. This has two drawbacks: 1) It requires a stack to store state information. As this is done in fast paths we can't allocate the storage for this stack, and we can't use a global as it must be re-entrant. The stack is stored on the kernel stack and this greatly limits how many preds we may allow. 2) All conditions are calculated even when a short circuit exists. a || b will always calculate a and b even though a was determined to be true. Using a tree we can walk a constant structure that will save the state as we go. The algorithm is simply: pred = root; do { switch (move) { case MOVE_DOWN: if (OR or AND) { pred = left; continue; } if (pred == root) break; match = pred->fn(); pred = pred->parent; move = left child ? MOVE_UP_FROM_LEFT : MOVE_UP_FROM_RIGHT; continue; case MOVE_UP_FROM_LEFT: /* Only OR or AND can be a parent */ if (match && OR || !match && AND) { /* short circuit */ if (pred == root) break; pred = pred->parent; move = left child ? MOVE_UP_FROM_LEFT : MOVE_UP_FROM_RIGHT; continue; } pred = pred->right; move = MOVE_DOWN; continue; case MOVE_UP_FROM_RIGHT: if (pred == root) break; pred = pred->parent; move = left child ? MOVE_UP_FROM_LEFT : MOVE_UP_FROM_RIGHT; continue; } done = 1; } while (!done); This way there's no strict limit to how many preds we allow and it also will short circuit the logical operations when possible. Cc: Tom Zanussi <tzanussi@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>		2011-02-07 20:56:19 -05:00
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blktrace.c	block: ensure that completion error gets properly traced	2011-01-10 09:06:44 +01:00
ftrace.c
Kconfig	perf: Clean up power events by introducing new, more generic ones	2011-01-04 08:16:54 +01:00
Makefile	tracing: Fix TRACE_EVENT power tracepoint creation	2011-01-07 23:26:29 -05:00
power-traces.c	perf: Clean up power events by introducing new, more generic ones	2011-01-04 08:16:54 +01:00
ring_buffer.c	ring_buffer: Off-by-one and duplicate events in ring_buffer_read_page	2010-12-23 12:09:30 -05:00
ring_buffer_benchmark.c
trace.c	tracing: Fix preempt count leak	2011-01-07 23:20:02 -05:00
trace.h	tracing/filter: Use a tree instead of stack for filter_match_preds()	2011-02-07 20:56:19 -05:00
trace_branch.c
trace_clock.c
trace_entries.h
trace_event_perf.c
trace_events.c	tracing: Replace trace_event struct array with pointer array	2011-02-02 21:37:13 -05:00
trace_events_filter.c	tracing/filter: Use a tree instead of stack for filter_match_preds()	2011-02-07 20:56:19 -05:00
trace_export.c	tracing: Replace trace_event struct array with pointer array	2011-02-02 21:37:13 -05:00
trace_functions.c
trace_functions_graph.c
trace_irqsoff.c	lockdep: Move early boot local IRQ enable/disable status to init/main.c	2011-01-20 13:32:33 +01:00
trace_kdb.c
trace_kprobe.c
trace_mmiotrace.c
trace_nop.c
trace_output.c
trace_output.h
trace_printk.c
trace_sched_switch.c
trace_sched_wakeup.c
trace_selftest.c	sched: Constify function scope static struct sched_param usage	2011-01-07 15:55:45 +01:00
trace_selftest_dynamic.c
trace_stack.c
trace_stat.c
trace_stat.h
trace_syscalls.c	tracing: Replace syscall_meta_data struct array with pointer array	2011-02-03 09:29:06 -05:00
trace_workqueue.c