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From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: yalin wang <yalin.wang2010@gmail.com>,
	akpm@linux-foundation.org, kirill.shutemov@linux.intel.com,
	jmarchan@redhat.com, mgorman@techsingularity.net,
	ebru.akagunduz@gmail.com, willy@linux.intel.com,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH V2] mm: fix kernel crash in khugepaged thread
Date: Thu, 5 Nov 2015 10:50:33 +0200	[thread overview]
Message-ID: <20151105085033.GB7614@node.shutemov.name> (raw)
In-Reply-To: <563B0F72.5030908@suse.cz>

On Thu, Nov 05, 2015 at 09:12:34AM +0100, Vlastimil Babka wrote:
> On 10/29/2015 01:35 AM, Kirill A. Shutemov wrote:
> >> @@ -2605,9 +2603,9 @@ out_unmap:
> >>  		/* collapse_huge_page will return with the mmap_sem released */
> >>  		collapse_huge_page(mm, address, hpage, vma, node);
> >>  	}
> >> -out:
> >> -	trace_mm_khugepaged_scan_pmd(mm, page_to_pfn(page), writable, referenced,
> >> -				     none_or_zero, result, unmapped);
> >> +	trace_mm_khugepaged_scan_pmd(mm, pte_present(pteval) ?
> >> +			pte_pfn(pteval) : -1, writable, referenced,
> >> +			none_or_zero, result, unmapped);
> > 
> > maybe passing down pte instead of pfn?
> 
> Maybe just pass the page, and have tracepoint's fast assign check for !NULL and
> do page_to_pfn itself? That way the complexity and overhead is only in the
> tracepoint and when enabled.

Agreed.

-- 
 Kirill A. Shutemov

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  reply	other threads:[~2015-11-05  8:50 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-26 10:39 [PATCH V2] mm: fix kernel crash in khugepaged thread yalin wang
2015-10-29  0:35 ` Kirill A. Shutemov
2015-11-05  8:12   ` Vlastimil Babka
2015-11-05  8:50     ` Kirill A. Shutemov [this message]
2015-11-12  7:15       ` yalin wang

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