Messages in this thread | | | Date | Tue, 15 Feb 2005 12:54:09 -0600 | From | Ray Bryant <> | Subject | Re: [RFC 2.6.11-rc2-mm2 7/7] mm: manual page migration -- sys_page_migrate |
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Dave Hansen wrote: > On Tue, 2005-02-15 at 04:50 -0600, Robin Holt wrote: > >>What is the fundamental opposition to an array from from-to node mappings? >>They are not that difficult to follow. They make the expensive traversal >>of ptes the single pass operation. The time to scan the list of from nodes >>to locate the node this page belongs to is relatively quick when compared >>to the time to scan ptes and will result in probably no cache trashing >>like the long traversal of all ptes in the system required for multiple >>system calls. I can not see the node array as anything but the right way >>when compared to multiple system calls. What am I missing? > > > I don't really have any fundamental opposition. I'm just trying to make > sure that there's not a simpler (better) way of doing it. You've > obviously thought about it a lot more than I have, and I'm trying to > understand your process. > > As far as the execution speed with a simpler system call. Yes, it will > likely be slower. However, I'm not sure that the increase in scan time > is all that significant compared to the migration code (it's pretty > slow). > > -- Dave > > I'm worried about doing all of those find_get_page() things over and over when the mapped file we are migrating is large. I suppose one can argue that that is never going to be the case (e. g. no one in their right mind would migrate a job with a 300 GB mapped file). So we are back to the overlapping set of nodes issue. Let me look into this some more.
-- ----------------------------------------------- Ray Bryant 512-453-9679 (work) 512-507-7807 (cell) raybry@sgi.com raybry@austin.rr.com The box said: "Requires Windows 98 or better", so I installed Linux. ----------------------------------------------- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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