Messages in this thread | | | Subject | Re: [RFC PATCH 1/1] mm/mremap: add MREMAP_MIRROR flag for existing mirroring functionality | From | Anshuman Khandual <> | Date | Fri, 7 Jul 2017 14:15:58 +0530 |
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On 07/06/2017 09:47 PM, Mike Kravetz wrote: > The mremap system call has the ability to 'mirror' parts of an existing > mapping. To do so, it creates a new mapping that maps the same pages as > the original mapping, just at a different virtual address. This > functionality has existed since at least the 2.6 kernel. > > This patch simply adds a new flag to mremap which will make this > functionality part of the API. It maintains backward compatibility with > the existing way of requesting mirroring (old_size == 0). > > If this new MREMAP_MIRROR flag is specified, then new_size must equal > old_size. In addition, the MREMAP_MAYMOVE flag must be specified.
Yeah it all looks good. But why is this requirement that if MREMAP_MAYMOVE is specified then old_size and new_size must be equal.
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