Messages in this thread | | | From | Andy Whitcroft <> | Subject | [PATCH 0/3] Lumpy Reclaim V6 | Date | Fri, 20 Apr 2007 16:03:03 +0100 |
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Following this email are three patches to the lumpy reclaim algorithm. These apply on top of the lumpy patches in 2.6.21-rc6-mm1 (lumpy V5); making lumpy V6. The first enables kswapd to apply reclaim at the order of the allocations which trigger background reclaim. The second increases pressure on the area at the end of the inactive list. The last introduces a new symbolic constant representing the boundary between easily reclaimed areas and those where extra pressure is applicable. Andrew, please consider for -mm.
Comparitive testing between lumpy-V5 and lumpy-V6 shows a considerable improvement when under extreme load. lumpy-V5 relies on the pages in an area being rotated onto the inactive list together and remaining inactive long enough to be reclaimed from that list. Under high load a significant portion of the pages return to active or are referenced before this can occur. Lumpy-V6 targets all LRU pages in the area greatly increasing the chance of reclaiming it completely.
kswapd-use-reclaim-order-in-background-reclaim: When an allocator has to dip below the low water mark for a zone, kswapd is awoken to start background reclaim. Make kswapd use the highest order of these allocations to define the order at which it reclaims.
lumpy-increase-pressure-at-the-end-of-the-inactive-list: when reclaiming at higher order target all pages in the contigious area for reclaim, including active and recently referenced pages. This increases the chances of that area becoming free.
introduce-HIGH_ORDER-delineating-easily-reclaimable-orders: The memory allocator treats lower and higher order allocations slightly differently. Lumpy reclaim also changes behaviour at this same boundary. Pull out the magic numbers and replace them with a symbolic constant.
Against: 2.6.21-rc6-mm1
-apw
Changes in lumpy V5:
Andy Whitcroft: lumpy: back out removal of active check in isolate_lru_pages lumpy: only count taken pages as scanned
Changes in lumpy V4:
Andy Whitcroft: lumpy: isolate_lru_pages wants to specifically take active or inactive pages lumpy: ensure that we compare PageActive and active safely lumpy: update commentry on subtle comparisons and rounding assumptions lumpy: only check for valid pages when holes are present
Changes in lumpy V3:
Adrian Bunk: lumpy-reclaim-cleanup
Andrew Morton: lumpy-reclaim-v2-page_to_pfn-fix lumpy-reclaim-v2-tidy
Andy Whitcroft: lumpy: ensure we respect zone boundaries lumpy: take the other active/inactive pages in the area - 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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