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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WARNING: multiple messages have this Message-ID (diff)
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
next prev parent reply other threads:[~2015-11-05 8:50 UTC|newest]
Thread overview: 10+ 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
2015-10-26 10:39 ` yalin wang
2015-10-29 0:35 ` Kirill A. Shutemov
2015-10-29 0:35 ` Kirill A. Shutemov
2015-11-05 8:12 ` Vlastimil Babka
2015-11-05 8:12 ` Vlastimil Babka
2015-11-05 8:50 ` Kirill A. Shutemov [this message]
2015-11-05 8:50 ` Kirill A. Shutemov
2015-11-12 7:15 ` yalin wang
2015-11-12 7:15 ` yalin wang
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