From 2a1dcb1f796ad37028df37d96fc7c5b6b1705a43 Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Sun, 7 Jun 2015 11:37:03 -0700 Subject: x86/mpx: Trace the attempts to find bounds tables There are two different events being traced here. They are doing similar things so share a trace "EVENT_CLASS" and are presented together. 1. Trace when MPX is zapping pages "mpx_unmap_zap": When MPX can not free an entire bounds table, it will instead try to zap unused parts of a bounds table to free the backing memory. This decreases RSS (resident set size) without decreasing the virtual space allocated for bounds tables. 2. Trace attempts to find bounds tables "mpx_unmap_search": This event traces any time we go looking to unmap a bounds table for a given virtual address range. This is useful to ensure that the kernel actually "tried" to free a bounds table versus times it succeeded in finding one. It might try and fail if it realized that a table was shared with an adjacent VMA which is not being unmapped. Signed-off-by: Dave Hansen Reviewed-by: Thomas Gleixner Cc: Andrew Morton Cc: Dave Hansen Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20150607183703.B9D2468B@viggo.jf.intel.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/trace/mpx.h | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/trace/mpx.h b/arch/x86/include/asm/trace/mpx.h index 5c3af06a2ae1..c13c6fa3fa92 100644 --- a/arch/x86/include/asm/trace/mpx.h +++ b/arch/x86/include/asm/trace/mpx.h @@ -63,6 +63,38 @@ TRACE_EVENT(bounds_exception_mpx, __entry->bndstatus) ); +DECLARE_EVENT_CLASS(mpx_range_trace, + + TP_PROTO(unsigned long start, + unsigned long end), + TP_ARGS(start, end), + + TP_STRUCT__entry( + __field(unsigned long, start) + __field(unsigned long, end) + ), + + TP_fast_assign( + __entry->start = start; + __entry->end = end; + ), + + TP_printk("[0x%p:0x%p]", + (void *)__entry->start, + (void *)__entry->end + ) +); + +DEFINE_EVENT(mpx_range_trace, mpx_unmap_zap, + TP_PROTO(unsigned long start, unsigned long end), + TP_ARGS(start, end) +); + +DEFINE_EVENT(mpx_range_trace, mpx_unmap_search, + TP_PROTO(unsigned long start, unsigned long end), + TP_ARGS(start, end) +); + #else /* -- cgit v1.2.3