On 04/14/2015 12:14 AM, Arnaldo Carvalho de Melo wrote: > From: Namhyung Kim <[email protected]> > > The struct page is opaque for userspace tools, so it'd be better to save > pfn in order to identify page frames. > > The textual output of $debugfs/tracing/trace file remains unchanged and > only raw (binary) data format is changed - but thanks to libtraceevent, > userspace tools which deal with the raw data (like perf and trace-cmd) > can parse the format easily.
Hmm it seems trace-cmd doesn't work that well, at least on current x86_64 kernel where I noticed it: trace-cmd-22020 [003] 105219.542610: mm_page_alloc: [FAILED TO PARSE] pfn=0x165cb4 order=0 gfp_flags=29491274 migratetype=1 I'm quite sure it's due to the "page=%p" part, which uses pfn_to_page(). The events/kmem/mm_page_alloc/format file contains this for page: REC->pfn != -1UL ? (((struct page *)vmemmap_base) + (REC->pfn)) : ((void *)0) I think userspace can't know vmmemap_base nor the implied sizeof(struct page) for pointer arithmetic? On older 4.4-based kernel: REC->pfn != -1UL ? (((struct page *)(0xffffea0000000000UL)) + (REC->pfn)) : ((void *)0) This also fails to parse, so it must be the struct page part? I think the problem is, even if ve solve this with some more preprocessor trickery to make the format file contain only constant numbers, pfn_to_page() on e.g. sparse memory model without vmmemap is more complicated than simple arithmetic, and can't be exported in the format file. I'm afraid that to support userspace parsing of the trace data, we will have to store both struct page and pfn... or perhaps give up on reporting the struct page pointer completely. Thoughts? > So impact on the userspace will also be > minimal. > > Signed-off-by: Namhyung Kim <[email protected]> > Based-on-patch-by: Joonsoo Kim <[email protected]> > Acked-by: Ingo Molnar <[email protected]> > Acked-by: Steven Rostedt <[email protected]> > Cc: David Ahern <[email protected]> > Cc: Jiri Olsa <[email protected]> > Cc: Minchan Kim <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: [email protected] > Link: > http://lkml.kernel.org/r/[email protected] > Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> > --- > include/trace/events/filemap.h | 8 ++++---- > include/trace/events/kmem.h | 42 > +++++++++++++++++++++--------------------- > include/trace/events/vmscan.h | 8 ++++---- > 3 files changed, 29 insertions(+), 29 deletions(-) > > diff --git a/include/trace/events/filemap.h b/include/trace/events/filemap.h > index 0421f49a20f7..42febb6bc1d5 100644 > --- a/include/trace/events/filemap.h > +++ b/include/trace/events/filemap.h > @@ -18,14 +18,14 @@ DECLARE_EVENT_CLASS(mm_filemap_op_page_cache, > TP_ARGS(page), > > TP_STRUCT__entry( > - __field(struct page *, page) > + __field(unsigned long, pfn) > __field(unsigned long, i_ino) > __field(unsigned long, index) > __field(dev_t, s_dev) > ), > > TP_fast_assign( > - __entry->page = page; > + __entry->pfn = page_to_pfn(page); > __entry->i_ino = page->mapping->host->i_ino; > __entry->index = page->index; > if (page->mapping->host->i_sb) > @@ -37,8 +37,8 @@ DECLARE_EVENT_CLASS(mm_filemap_op_page_cache, > TP_printk("dev %d:%d ino %lx page=%p pfn=%lu ofs=%lu", > MAJOR(__entry->s_dev), MINOR(__entry->s_dev), > __entry->i_ino, > - __entry->page, > - page_to_pfn(__entry->page), > + pfn_to_page(__entry->pfn), > + __entry->pfn, > __entry->index << PAGE_SHIFT) > ); > > diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h > index 4ad10baecd4d..81ea59812117 100644 > --- a/include/trace/events/kmem.h > +++ b/include/trace/events/kmem.h > @@ -154,18 +154,18 @@ TRACE_EVENT(mm_page_free, > TP_ARGS(page, order), > > TP_STRUCT__entry( > - __field( struct page *, page ) > + __field( unsigned long, pfn ) > __field( unsigned int, order ) > ), > > TP_fast_assign( > - __entry->page = page; > + __entry->pfn = page_to_pfn(page); > __entry->order = order; > ), > > TP_printk("page=%p pfn=%lu order=%d", > - __entry->page, > - page_to_pfn(__entry->page), > + pfn_to_page(__entry->pfn), > + __entry->pfn, > __entry->order) > ); > > @@ -176,18 +176,18 @@ TRACE_EVENT(mm_page_free_batched, > TP_ARGS(page, cold), > > TP_STRUCT__entry( > - __field( struct page *, page ) > + __field( unsigned long, pfn ) > __field( int, cold ) > ), > > TP_fast_assign( > - __entry->page = page; > + __entry->pfn = page_to_pfn(page); > __entry->cold = cold; > ), > > TP_printk("page=%p pfn=%lu order=0 cold=%d", > - __entry->page, > - page_to_pfn(__entry->page), > + pfn_to_page(__entry->pfn), > + __entry->pfn, > __entry->cold) > ); > > @@ -199,22 +199,22 @@ TRACE_EVENT(mm_page_alloc, > TP_ARGS(page, order, gfp_flags, migratetype), > > TP_STRUCT__entry( > - __field( struct page *, page ) > + __field( unsigned long, pfn ) > __field( unsigned int, order ) > __field( gfp_t, gfp_flags ) > __field( int, migratetype ) > ), > > TP_fast_assign( > - __entry->page = page; > + __entry->pfn = page ? page_to_pfn(page) : -1UL; > __entry->order = order; > __entry->gfp_flags = gfp_flags; > __entry->migratetype = migratetype; > ), > > TP_printk("page=%p pfn=%lu order=%d migratetype=%d gfp_flags=%s", > - __entry->page, > - __entry->page ? page_to_pfn(__entry->page) : 0, > + __entry->pfn != -1UL ? pfn_to_page(__entry->pfn) : NULL, > + __entry->pfn != -1UL ? __entry->pfn : 0, > __entry->order, > __entry->migratetype, > show_gfp_flags(__entry->gfp_flags)) > @@ -227,20 +227,20 @@ DECLARE_EVENT_CLASS(mm_page, > TP_ARGS(page, order, migratetype), > > TP_STRUCT__entry( > - __field( struct page *, page ) > + __field( unsigned long, pfn ) > __field( unsigned int, order ) > __field( int, migratetype ) > ), > > TP_fast_assign( > - __entry->page = page; > + __entry->pfn = page ? page_to_pfn(page) : -1UL; > __entry->order = order; > __entry->migratetype = migratetype; > ), > > TP_printk("page=%p pfn=%lu order=%u migratetype=%d percpu_refill=%d", > - __entry->page, > - __entry->page ? page_to_pfn(__entry->page) : 0, > + __entry->pfn != -1UL ? pfn_to_page(__entry->pfn) : NULL, > + __entry->pfn != -1UL ? __entry->pfn : 0, > __entry->order, > __entry->migratetype, > __entry->order == 0) > @@ -260,7 +260,7 @@ DEFINE_EVENT_PRINT(mm_page, mm_page_pcpu_drain, > TP_ARGS(page, order, migratetype), > > TP_printk("page=%p pfn=%lu order=%d migratetype=%d", > - __entry->page, page_to_pfn(__entry->page), > + pfn_to_page(__entry->pfn), __entry->pfn, > __entry->order, __entry->migratetype) > ); > > @@ -275,7 +275,7 @@ TRACE_EVENT(mm_page_alloc_extfrag, > alloc_migratetype, fallback_migratetype), > > TP_STRUCT__entry( > - __field( struct page *, page ) > + __field( unsigned long, pfn ) > __field( int, alloc_order ) > __field( int, fallback_order ) > __field( int, alloc_migratetype ) > @@ -284,7 +284,7 @@ TRACE_EVENT(mm_page_alloc_extfrag, > ), > > TP_fast_assign( > - __entry->page = page; > + __entry->pfn = page_to_pfn(page); > __entry->alloc_order = alloc_order; > __entry->fallback_order = fallback_order; > __entry->alloc_migratetype = alloc_migratetype; > @@ -294,8 +294,8 @@ TRACE_EVENT(mm_page_alloc_extfrag, > ), > > TP_printk("page=%p pfn=%lu alloc_order=%d fallback_order=%d > pageblock_order=%d alloc_migratetype=%d fallback_migratetype=%d > fragmenting=%d change_ownership=%d", > - __entry->page, > - page_to_pfn(__entry->page), > + pfn_to_page(__entry->pfn), > + __entry->pfn, > __entry->alloc_order, > __entry->fallback_order, > pageblock_order, > diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h > index 69590b6ffc09..f66476b96264 100644 > --- a/include/trace/events/vmscan.h > +++ b/include/trace/events/vmscan.h > @@ -336,18 +336,18 @@ TRACE_EVENT(mm_vmscan_writepage, > TP_ARGS(page, reclaim_flags), > > TP_STRUCT__entry( > - __field(struct page *, page) > + __field(unsigned long, pfn) > __field(int, reclaim_flags) > ), > > TP_fast_assign( > - __entry->page = page; > + __entry->pfn = page_to_pfn(page); > __entry->reclaim_flags = reclaim_flags; > ), > > TP_printk("page=%p pfn=%lu flags=%s", > - __entry->page, > - page_to_pfn(__entry->page), > + pfn_to_page(__entry->pfn), > + __entry->pfn, > show_reclaim_flags(__entry->reclaim_flags)) > ); > >
