On Sat, Feb 12, 2005 at 10:29:14PM +0100, Andi Kleen wrote: > On Sat, Feb 12, 2005 at 01:54:26PM -0200, Marcelo Tosatti wrote: > > On Sat, Feb 12, 2005 at 12:17:25PM +0100, Andi Kleen wrote: > > > Ray Bryant <[EMAIL PROTECTED]> writes: > > > > set of pages associated with a particular process need to be moved. > > > > The kernel interface that we are proposing is the following: > > > > > > > > page_migrate(pid, va_start, va_end, count, old_nodes, new_nodes); > > > > > > [Only commenting on the interface, haven't read your patches at all] > > > > > > This is basically mbind() with MPOL_F_STRICT, except that it has a pid > > > argument. I assume that's for the benefit of your batch scheduler. > > > > As far as I understand mbind() is used to set policies to given memory > > regions, not move memory regions? > > There is a MPOL_F_STRICT flag. Currently it fails when the memory > is not on the right node(s) and the flag is set, but it could as well move. > > In fact Steve Longerbeam already did a patch to move in this case, > but it hasn't been merged yet for some reasons. > > > > > mmap in parallel. The only way I can think of to do this would be to > > > check for changes in maps after a full move and loop, but then you risk > > > livelock. > > > > True. > > > > There is no problem, however, if all threads beloging to the process are > > stopped, > > as Ray mentions. > > > > So, there wont be memory mapping changes happening at the same time. > > Ok. But it's still quite ugly to read /proc/*/maps for this. > > > > > > And you cannot also just specify va_start=0, va_end=~0UL because that > > > would make the node arrays grow infinitely. > > > > > > Also is there a good use case why the batch scheduler should only > > > move individual areas in a process around, not the full process? > > > > Quoting him: > > > > "In addition to its use by batch schedulers, we also envision that > > this facility could be used by a program to re-arrange the allocation > > of its own pages on various nodes of the NUMA system, most likely > > to optimize performance of the application during different phases > > of its computation." > > > > Seems doable. > > That is what mbind() already supports, just someone needs to hook up > the page moving code with MPOL_F_STRICT.
But how do you use mbind() to change the memory placement for an anonymous private mapping used by a vendor provided executable with mbind()? Robin - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
