Messages in this thread | | | Date | Tue, 14 Oct 2008 22:53:34 +0200 | From | Brice Goglin <> | Subject | Re: [PATCH 0/5] mm: rework sys_move_pages() to avoid vmalloc and reduce the overhead |
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By the way, this patchset replaces mm-use-a-radix-tree-to-make-do_move_pages-complexity-linear-checkpatch-fixes (currently in -mm).
Brice
Brice Goglin wrote: > Hello, > > Here's the first patchset reworking sys_move_pages() as discussed earlier. > It removes the possibly large vmalloc by using multiple chunks when migrating > large buffers. It also dramatically increases the throughput for large buffers > since the lookup in new_page_node() is now limited to a single chunk, causing > the quadratic complexity to have a much slower impact. There is no need to use > any radix-tree-like structure to improve this lookup. > > sys_move_pages() duration on a 4-quadcore-opteron 2347HE (1.9Gz), migrating > between nodes #2 and #3: > length move_pages (us) move_pages+patch (us) > 4kB 126 98 > 40kB 198 168 > 400kB 963 937 > 4MB 12503 11930 > 40MB 246867 11848 > > Patches #1 and #4 are the important ones: > 1) stop returning -ENOENT from sys_move_pages() if nothing got migrated > 2) don't vmalloc a huge page_to_node array for do_pages_stat() > 3) extract do_pages_move() out of sys_move_pages() > 4) rework do_pages_move() to work on page_sized chunks > 5) move_pages: no need to set pp->page to ZERO_PAGE(0) by default > > thanks, > Brice > > > >
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