hg: hsx/hotspot-gc/hotspot: 2 new changesets

Jason Schroeder shrode at subnature.com
Sat Aug 6 14:46:07 PDT 2011


Why is the MADV_DONTNEED usage being removed?  My reading
of the kernel sources for swapping indicates the change could/would
cause a needless page write.

On Sat, Aug 6, 2011 at 3:32 PM, Igor Veresov <igor.veresov at oracle.com> wrote:
> Yes, but not only that. It basically discards the page, to quote from the
> man page: "Subsequent accesses of pages in this range will succeed, but will
> result either in re-loading of the memory contents from the underlying
> mapped file (see mmap()) or zero-fill-on-demand pages for mappings without
> an underlying file."
>
> igor
>
> On 8/6/11 9:24 AM, Jason Schroeder wrote:
>>
>> I thought the benefit of MADV_DONTNEED was to stop Linux from
>> writing dirty pages to disk.
>>
>> On Sat, Aug 6, 2011 at 6:00 AM,<igor.veresov at oracle.com>  wrote:
>>>
>>> Changeset: a20e6e447d3d
>>> Author:    iveresov
>>> Date:      2011-08-05 16:44 -0700
>>> URL:
>>> http://hg.openjdk.java.net/hsx/hotspot-gc/hotspot/rev/a20e6e447d3d
>>>
>>> 7060842: UseNUMA crash with UseHugreTLBFS running SPECjvm2008
>>> Summary: Use mmap() instead of madvise(MADV_DONTNEED) to uncommit pages
>>> Reviewed-by: ysr
>>>
>>> ! src/os/linux/vm/os_linux.cpp
>>>
>
>


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