Re: [PATCH 1/6] tracing, page-allocator: Add trace events for pageallocation and page freeing

[Ingo Molnar]

* Mel Gorman <mel@xxxxxxxxx> wrote:

> +TRACE_EVENT(mm_pagevec_free,

> +	TP_fast_assign(
> +		__entry->page		= page;
> +		__entry->order		= order;
> +		__entry->cold		= cold;
> +	),

> -	while (--i >= 0)
> +	while (--i >= 0) {
> +		trace_mm_pagevec_free(pvec->pages[i], 0, pvec->cold);
>  		free_hot_cold_page(pvec->pages[i], pvec->cold);
> +	}

Pagevec freeing has order 0 implicit, so you can further optimize 
this by leaving out the 'order' field and using this format string:

+	TP_printk("page=%p pfn=%lu order=0 cold=%d",
+                       __entry->page,
+                       page_to_pfn(__entry->page),
+                       __entry->cold)

the trace record becomes smaller by 4 bytes and the tracepoint 
fastpath becomes shorter as well.

	Ingo
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