On Wed, Dec 19, 2018 at 05:10:18PM +0800, Yi Zhang wrote: > > > + > > > + - 'sync' option of memory-backend-file is not 'off', and > > > + > > > + - 'share' option of memory-backend-file is 'on'. > > > + > > > + - 'pmem' option of memory-backend-file is 'on' > > > + > > > > Wait isn't this what pmem was supposed to do? > > Doesn't it mean "persistent memory"? > pmem is a option for memory-backend-file, user should know the backend > is in host persistent memory, with this flags on, while there is a host crash > or a power failures. > > [1] Qemu will take necessary operations to guarantee the persistence. > https://patchwork.ozlabs.org/cover/944749/ > > [2] Host kernel also take opretions to consistent filesystem metadata. > Add MAP_SYNC flags.
OK so I'm a user. Can you educate me please? When should MAP_SYNC not be set? Are there any disadvantages (e.g. performance?)? -- MST
