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Date: Thu, 05 Mar 2015 17:33:23 +0300
From: Stefan Strogin <s.strogin@partner.samsung.com>
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To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Michal Nazarewicz <mina86@mina86.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Dmitry Safonov <d.safonov@partner.samsung.com>,
        Pintu Kumar <pintu.k@samsung.com>,
        Weijie Yang <weijie.yang@samsung.com>,
        Laura Abbott <lauraa@codeaurora.org>,
        SeongJae Park <sj38.park@gmail.com>, Hui Zhu <zhuhui@xiaomi.com>,
        Minchan Kim <minchan@kernel.org>, Dyasly Sergey <s.dyasly@samsung.com>,
        Vyacheslav Tyrtov <v.tyrtov@samsung.com>,
        Aleksei Mateosian <a.mateosian@samsung.com>, gregory.0xf0@gmail.com,
        sasha.levin@oracle.com, gioh.kim@lge.com, pavel@ucw.cz,
        stefan.strogin@gmail.com
Subject: Re: [PATCH v3 1/4] mm: cma: add trace events to debug
 physically-contiguous memory allocations
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Hi Aneesh,

On 03/03/15 12:13, Aneesh Kumar K.V wrote:
> 
> Are we interested only in successful allocation and release ? Should we also
> have the trace point carry information regarding failure ?
> 
> -aneesh
> 

I think we actually can be interested in tracing allocation failures
too. Thanks for the remark.

Should it be smth like that?
@@ -408,6 +410,8 @@ struct page *cma_alloc(struct cma *cma, int count,
unsigned int align)
 		start = bitmap_no + mask + 1;
 	}

+	trace_cma_alloc(cma, page, count);
+
 	pr_debug("%s(): returned %p\n", __func__, page);
 	return page;
 }

and in include/trace/events/cma.h:
+TRACE_EVENT(cma_alloc,
<...>
+	TP_fast_assign(
+		__entry->page = page;
+		__entry->count = count;
+	),
+
+	TP_printk("page=%p pfn=%lu count=%lu\n",
+		  __entry->page,
+		  __entry->page ? page_to_pfn(__entry->page) : 0,
+		  __entry->count)