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From: Karmarkar Suyash <skarmarkar@sonusnet.com>
To: "dev@dpdk.org" <dev@dpdk.org>
Thread-Topic: DDPK use of MAP_FIXED in mmap
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Date: Mon, 8 Dec 2014 19:02:38 +0000
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Subject: [dpdk-dev] DDPK use of MAP_FIXED in mmap
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Hello,

In DPDK when we use mmap why are we passing the MAP_FIXED flag when Linux m=
an page itself says that the option is discouraged? Any specific reason for=
 passing the MAP_FIXED flag?


http://linux.die.net/man/2/mmap

MAP_FIXED
Don't interpret addr as a hint: place the mapping at exactly that address. =
addr must be a multiple of the page size. If the memory region specified by=
 addr and len overlaps pages of any existing mapping(s), then the overlappe=
d part of the existing mapping(s) will be discarded. If the specified addre=
ss cannot be used, mmap() will fail. Because requiring a fixed address for =
a mapping is less portable, the use of this option is discouraged.


Regards
Suyash Karmarkar