So after not getting too much positive feedback on my last attempt at trying to use a non-shrinker method for managing & purging volatile ranges, I decided I'd go ahead and try to implement something along Minchan's ERECLAIM LRU list idea.
Again this patchset has two parts: The first 3 patches add generic volatile range management code, as well as tmpfs support for FALLOC_FL_MARK_VOLATILE, which uses a shrinker to purge ranges, and converts ashmem to use FALLOC_FL_MARK_VOLATILE, almost reducing the driver in half. Since Kosaki-san objected to using the shrinker, as its not numa aware, and is only called after we shrink normal lru lists. The second half of this patch set provides a different method that is not shrinker based. The last two patches introduce a new lru list, LRU_VOLATILE. When pages are marked volatile, they are moved to this lru list, which we will shrink first when trying to free up memory. The reason why I'm keeping this in two parts is that I want to be able to easily do performance comparisons between the more lightweight, but numa-unaware, shrinker method vs the more correct, but slower (due to the page-by-page management) method of handling it deeper in the VM. I know the way this is currently implemented is really bad for performance, since we add/remove pages to the LRU_VOLATILE list page by page instead of batching. So I know this needs more work, but I wanted to get just some initial reactions to this approach versus the earlier ones. Also, I know this isn't exactly the same as the ERECLAIM lru list that Minchan suggested, since that might also contain inactive clean file pages as well, but I wanted to stick to just volatile pages for now as I learn more about how the core vm works. I'll be fine to rename LRU_VOLATILE later if its appropriate. What's new in this iteration: * Dropped the writepage style purging instead for the LRU_VOLATILE CC: Andrew Morton <[email protected]> CC: Android Kernel Team <[email protected]> CC: Robert Love <[email protected]> CC: Mel Gorman <[email protected]> CC: Hugh Dickins <[email protected]> CC: Dave Hansen <[email protected]> CC: Rik van Riel <[email protected]> CC: Dmitry Adamushko <[email protected]> CC: Dave Chinner <[email protected]> CC: Neil Brown <[email protected]> CC: Andrea Righi <[email protected]> CC: Aneesh Kumar K.V <[email protected]> CC: Mike Hommey <[email protected]> CC: Jan Kara <[email protected]> CC: KOSAKI Motohiro <[email protected]> CC: Michel Lespinasse <[email protected]> CC: Minchan Kim <[email protected]> CC: [email protected] <[email protected]> John Stultz (5): [RFC] Add volatile range management code [RFC] tmpfs: Add FALLOC_FL_MARK_VOLATILE/UNMARK_VOLATILE handlers [RFC] ashmem: Convert ashmem to use volatile ranges [RFC][HACK] Add LRU_VOLATILE support to the VM [RFC][HACK] Switch volatile/shmem over to LRU_VOLATILE drivers/staging/android/ashmem.c | 331 +-------------------------- fs/open.c | 3 +- include/linux/falloc.h | 7 +- include/linux/fs.h | 1 + include/linux/mm_inline.h | 2 + include/linux/mmzone.h | 1 + include/linux/page-flags.h | 3 + include/linux/swap.h | 3 + include/linux/volatile.h | 39 ++++ mm/Makefile | 2 +- mm/memcontrol.c | 1 + mm/page_alloc.c | 1 + mm/shmem.c | 118 ++++++++++ mm/swap.c | 71 ++++++ mm/vmscan.c | 76 ++++++- mm/volatile.c | 459 ++++++++++++++++++++++++++++++++++++++ 16 files changed, 788 insertions(+), 330 deletions(-) create mode 100644 include/linux/volatile.h create mode 100644 mm/volatile.c -- 1.7.9.5 -- 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/
