Remove zonelist cache and high-order watermark checking v3
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b4 am [email protected]Versions newest first
- v1 Latest12 patches 42 repliesIn review
Changelog since V3 from the cover letter
o Covered cases where __GFP_KSWAPD_RECLAIM is needed (vbabka)
o Cleaned up trailing references to zlc (vbabka)
o Fixed a subtle problem with GFP_TRANSHUGE checks (vbabka)
o Split out an unrelated change to its own patch (vbabka)
o Reordered series to put GFP flag modifications at start (mhocko)
o Added a number of clarifications on reclaim modifications (mhocko)
o Only check cpusets when one exists that can limit memory (rientjes)
o Applied acks
Patches in v1 No applies recorded yet
Reviews trailers per patch
10 of 12 patches have a Reviewed-by or Acked-by.
| Patch | David Rientjes | Michal Hocko | Vlastimil Babka | Christoph Lameter |
|---|---|---|---|---|
| 1/12 | A-b | A-b | A-b | R-b |
| 2/12 | A-b | A-b | A-b | |
| 3/12 | A-b | A-b | A-b | A-b |
| 4/12 | ||||
| 5/12 | ||||
| 6/12 | A-b | |||
| 7/12 | A-b | A-b | ||
| 8/12 | A-b | A-b | ||
| 9/12 | A-b | A-b | A-b | A-b |
| 10/12 | A-b | |||
| 11/12 | A-b | A-b | ||
| 12/12 | A-b |
Trailers given in replies are filled; those carried in the patches from earlier versions are outlined with dashes. Scroll the table sideways for all 4 reviewers.
Cover letter [PATCH 00/12] Remove zonelist cache and high-order watermark checking v3
Changelog since V3
o Covered cases where __GFP_KSWAPD_RECLAIM is needed (vbabka)
o Cleaned up trailing references to zlc (vbabka)
o Fixed a subtle problem with GFP_TRANSHUGE checks (vbabka)
o Split out an unrelated change to its own patch (vbabka)
o Reordered series to put GFP flag modifications at start (mhocko)
o Added a number of clarifications on reclaim modifications (mhocko)
o Only check cpusets when one exists that can limit memory (rientjes)
o Applied acks
Changelog since V2
o Improve cpusets checks as suggested (rientjes)
o Add various acks and reviewed-bys
o Rebase to 4.2-rc6
Changelog since V1
o Rebase to 4.2-rc5
o Distinguish between high priority callers and callers that avoid sleep
o Remove jump label related damage patches
Overall, the intent of this series is to remove the zonelist cache which was introduced to avoid high overhead in the page allocator. Once this is done, it is necessary to reduce the cost of watermark checks.
The series starts with minor micro-optimisations.
Next it notes that GFP flags that affect watermark checks are bused. __GFP_WAIT historically identified callers that could not sleep and could access reserves. This was later abused to identify callers that simply prefer to avoid sleeping and have other options. A patch distinguishes between atomic callers, high-priority callers and those that simply wish to avoid sleep.
The zonelist cache has been around for a long time but it is of dubious merit with a lot of complexity and some issues that are explained. The most important issue is that a failed THP allocation can cause a zone to be treated as "full". This potentially causes unnecessary stalls, reclaim activity or remote fallbacks. The issues could be fixed but it's not worth it. The series places a small number of other micro-optimisations on top before examining GFP flags watermarks.
High-order watermarks enforcement can cause high-order allocations to fail even though pages are free. The watermark checks both protect high-order atomic allocations and make kswapd aware of high-order pages but there is a much better way that can be handled using migrate types. This series uses page grouping by mobility to reserve pageblocks for high-order allocations with the size of the reservation depending on demand. kswapd awareness is maintained by examining the free lists. By patch 12 in this series, there are no high-order watermark checks while preserving the properties that motivated the introduction of the watermark checks.
Documentation/vm/balance | 14 +- arch/arm/mm/dma-mapping.c | 4 +- arch/arm/xen/mm.c | 2 +- arch/arm64/mm/dma-mapping.c | 4 +- arch/x86/kernel/pci-dma.c | 2 +- block/bio.c | 26 +- block/blk-core.c | 16 +- block/blk-ioc.c | 2 +- block/blk-mq-tag.c | 2 +- block/blk-mq.c | 8 +- block/cfq-iosched.c | 4 +- block/scsi_ioctl.c | 6 +- drivers/block/drbd/drbd_bitmap.c | 2 +- drivers/block/drbd/drbd_receiver.c | 3 +- drivers/block/mtip32xx/mtip32xx.c | 2 +- drivers/block/nvme-core.c | 4 +- drivers/block/osdblk.c | 2 +- drivers/block/paride/pd.c | 2 +- drivers/block/pktcdvd.c | 4 +- drivers/connector/connector.c | 3 +- drivers/firewire/core-cdev.c | 2 +- drivers/gpu/drm/i915/i915_gem.c | 4 +- drivers/ide/ide-atapi.c | 2 +- drivers/ide/ide-cd.c | 2 +- drivers/ide/ide-cd_ioctl.c | 2 +- drivers/ide/ide-devsets.c | 2 +- drivers/ide/ide-disk.c | 2 +- drivers/ide/ide-ioctls.c | 4 +- drivers/ide/ide-park.c | 2 +- drivers/ide/ide-pm.c | 4 +- drivers/ide/ide-tape.c | 4 +- drivers/ide/ide-taskfile.c | 4 +- drivers/infiniband/core/sa_query.c | 2 +- drivers/infiniband/hw/ipath/ipath_file_ops.c | 2 +- drivers/infiniband/hw/qib/qib_init.c | 2 +- drivers/iommu/amd_iommu.c | 2 +- drivers/iommu/intel-iommu.c | 2 +- drivers/md/dm-crypt.c | 6 +- drivers/md/dm-kcopyd.c | 2 +- drivers/media/pci/solo6x10/solo6x10-v4l2-enc.c | 2 +- drivers/media/pci/solo6x10/solo6x10-v4l2.c | 2 +- drivers/media/pci/tw68/tw68-video.c | 2 +- drivers/misc/vmw_balloon.c | 2 +- drivers/mtd/mtdcore.c | 3 +- drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 2 +- drivers/scsi/scsi_error.c | 2 +- drivers/scsi/scsi_lib.c | 4 +- drivers/staging/android/ion/ion_system_heap.c | 2 +- .../lustre/include/linux/libcfs/libcfs_private.h | 2 +- drivers/usb/host/u132-hcd.c | 2 +- drivers/video/fbdev/vermilion/vermilion.c | 2 +- fs/btrfs/disk-io.c | 2 +- fs/btrfs/extent_io.c | 14 +- fs/btrfs/volumes.c | 4 +- fs/cachefiles/internal.h | 2 +- fs/direct-io.c | 2 +- fs/ext3/super.c | 2 +- fs/ext4/super.c | 2 +- fs/fscache/cookie.c | 2 +- fs/fscache/page.c | 6 +- fs/jbd/transaction.c | 4 +- fs/jbd2/transaction.c | 4 +- fs/nfs/file.c | 6 +- fs/nilfs2/mdt.h | 2 +- fs/xfs/xfs_qm.c | 2 +- include/linux/cpuset.h | 18 +- include/linux/gfp.h | 70 ++- include/linux/mmzone.h | 88 +--- include/linux/skbuff.h | 6 +- include/net/sock.h | 2 +- include/trace/events/gfpflags.h | 5 +- kernel/audit.c | 6 +- kernel/locking/lockdep.c | 2 +- kernel/power/snapshot.c | 2 +- kernel/power/swap.c | 14 +- kernel/smp.c | 2 +- lib/idr.c | 4 +- lib/percpu_ida.c | 2 +- lib/radix-tree.c | 10 +- mm/backing-dev.c | 2 +- mm/dmapool.c | 2 +- mm/failslab.c | 8 +- mm/filemap.c | 2 +- mm/huge_memory.c | 4 +- mm/internal.h | 1 + mm/memcontrol.c | 8 +- mm/mempool.c | 10 +- mm/migrate.c | 4 +- mm/page_alloc.c | 585 +++++++-------------- mm/slab.c | 18 +- mm/slub.c | 6 +- mm/vmalloc.c | 2 +- mm/vmscan.c | 8 +- mm/vmstat.c | 2 +- mm/zswap.c | 5 +- net/core/skbuff.c | 8 +- net/core/sock.c | 6 +- net/netlink/af_netlink.c | 2 +- net/rxrpc/ar-connection.c | 2 +- net/sctp/associola.c | 2 +- security/integrity/ima/ima_crypto.c | 2 +- 101 files changed, 455 insertions(+), 710 deletions(-)
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