|From:||Johannes Weiner <email@example.com>|
|Subject:||[patch 0/5] refault distance-based file cache sizing|
|Date:||Tue, 1 May 2012 10:41:48 +0200|
|Cc:||Rik van Riel <firstname.lastname@example.org>, Andrea Arcangeli <email@example.com>, Peter Zijlstra <firstname.lastname@example.org>, Mel Gorman <email@example.com>, Andrew Morton <firstname.lastname@example.org>, Minchan Kim <email@example.com>, Hugh Dickins <firstname.lastname@example.org>, KOSAKI Motohiro <email@example.com>, firstname.lastname@example.org, email@example.com|
Hi, our file data caching implementation is done by having an inactive list of pages that have yet to prove worth keeping around and an active list of pages that already did. The question is how to balance those two lists against each other. On one hand, the space for inactive pages needs to be big enough so that they have the necessary time in memory to gather the references required for an activation. On the other hand, we want an active list big enough to hold all data that is frequently used, if possible, to protect it from streams of less frequently used/once used pages. Our current balancing ("active can't grow larger than inactive") does not really work too well. We have people complaining that the working set is not well protected from used-once file cache, and other people complaining that we don't adapt to changes in the workingset and protect stale pages in other cases. This series stores file cache eviction information in the vacated page cache radix tree slots and uses it on refault to see if the pages currently on the active list need to have their status challenged. A fully activated file set that occupies 85% of memory is successfully detected as stale when another file set of equal size is accessed for a few times (4-5). The old kernel would never adapt to the second one. If the new set is bigger than memory, the old set is left untouched, where the old kernel would shrink the old set to half of memory and leave it at that. Tested on a multi-zone single-node machine. More testing is obviously required, but I first wanted some opinions at this point. Is there fundamental disagreement with the concept? With the implementation? Memcg hard limit reclaim is not converted (anymore, ripped it out to focus on the global case first) and it still does the 50/50 balancing between lists, but this will be re-added in the next version. Patches are based on 3.3. fs/btrfs/compression.c | 10 +- fs/btrfs/extent_io.c | 3 +- fs/cachefiles/rdwr.c | 26 +++-- fs/ceph/xattr.c | 2 +- fs/inode.c | 7 +- fs/logfs/readwrite.c | 9 +- fs/nilfs2/inode.c | 6 +- fs/ntfs/file.c | 11 ++- fs/splice.c | 10 +- include/linux/mm.h | 8 ++ include/linux/mmzone.h | 7 ++ include/linux/pagemap.h | 54 ++++++++--- include/linux/pagevec.h | 3 + include/linux/radix-tree.h | 4 - include/linux/sched.h | 1 + include/linux/shmem_fs.h | 1 + include/linux/swap.h | 7 ++ lib/radix-tree.c | 75 --------------- mm/Makefile | 1 + mm/filemap.c | 222 ++++++++++++++++++++++++++++++++++---------- mm/memcontrol.c | 3 + mm/mincore.c | 20 +++- mm/page_alloc.c | 7 ++ mm/readahead.c | 51 +++++++++- mm/shmem.c | 89 +++--------------- mm/swap.c | 23 +++++ mm/truncate.c | 73 +++++++++++--- mm/vmscan.c | 80 +++++++++------- mm/vmstat.c | 4 + mm/workingset.c | 174 ++++++++++++++++++++++++++++++++++ net/ceph/messenger.c | 2 +- net/ceph/pagelist.c | 4 +- net/ceph/pagevec.c | 2 +- 33 files changed, 682 insertions(+), 317 deletions(-) Thanks, Johannes -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to firstname.lastname@example.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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