Remove zonelist cache and high-order watermark checking v4
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b4 am [email protected]Versions newest first
- v1 Latest10 patches 36 repliesIn review
Changelog since V3 from the cover letter
o Rebase to 4.3-rc1
o Consistent style for __GFP_WAIT (joonsoo)
o Restored cpuset static checking behaviour (vbabka)
o Fix cpusets check in allocator fastpath (vbabka)
o Applied acks
Patches in v1 No applies recorded yet
| # | Subject and files | Size | Replies | Applied |
|---|---|---|---|---|
| 1/10 | mm, page_alloc: Remove unnecessary parameter from zone_watermark_ok_safeinclude/ mm/ mm/ | +6 | 1 reply | |
| 2/10 | mm, page_alloc: Remove unnecessary recalculations for dirty zone balancingmm/ mm/ | +8 | 1 reply | |
| 3/10 | mm, page_alloc: Remove unnecessary taking of a seqlock when cpusets are disabledinclude/ | +6 | 3 replies | |
| 4/10 | mm, page_alloc: Use masks and shifts when converting GFP flags to migrate typesinclude/ include/ | +8 | 3 replies | |
| 5/10 | mm, page_alloc: Distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapdDocumentation/ arch/ arch/ +63 more | +212 | 9 replies | |
| 6/10 | mm, page_alloc: Rename __GFP_WAIT to __GFP_RECLAIMblock/ block/ drivers/ +33 more | +63 | 7 replies | |
| 7/10 | mm, page_alloc: Delete the zonelist_cacheinclude/ mm/ | +0 | 1 reply | |
| 8/10 | mm, page_alloc: Remove MIGRATE_RESERVEinclude/ mm/ mm/ +1 more | +11 | 0 replies | |
| 9/10 | mm, page_alloc: Reserve pageblocks for high-order atomic allocations on demandinclude/ mm/ mm/ | +122 | 5 replies | |
| 10/10 | mm, page_alloc: Only enforce watermarks for order-0 allocationsmm/ | +37 | 7 replies |
Reviews trailers per patch
All 10 patches have a Reviewed-by or Acked-by.
| Patch | David Rientjes | Vlastimil Babka | Michal Hocko | Christoph Lameter | Johannes Weiner |
|---|---|---|---|---|---|
| 1/10 | A-b | A-b | A-b | R-b | A-b |
| 2/10 | A-b | A-b | A-b | A-b | |
| 3/10 | A-b | A-b | A-b | A-b | A-b |
| 4/10 | A-b | ||||
| 5/10 | A-b | A-b | A-b | ||
| 6/10 | A-b | A-b A-b | A-b A-b | A-b | |
| 7/10 | A-b | A-b | A-b | A-b | A-b |
| 8/10 | A-b | ||||
| 9/10 | A-b | A-b | A-b | ||
| 10/10 | A-b | A-b | 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 5 reviewers.
Cover letter [PATCH 00/10] Remove zonelist cache and high-order watermark checking v4
Changelog since V3
o Rebase to 4.3-rc1
o Consistent style for __GFP_WAIT (joonsoo)
o Restored cpuset static checking behaviour (vbabka)
o Fix cpusets check in allocator fastpath (vbabka)
o Applied acks
Changelog since V2
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 V1
o Improve cpusets checks as suggested (rientjes)
o Add various acks and reviewed-bys
o Rebase to 4.2-rc6
Changelog since RFC
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 | 6 +- 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/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/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/staging/rdma/hfi1/init.c | 2 +- drivers/staging/rdma/ipath/ipath_file_ops.c | 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/ext4/super.c | 2 +- fs/fscache/cookie.c | 2 +- fs/fscache/page.c | 6 +- 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 | 6 + 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/cgroup.c | 2 +- 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 | 599 +++++++-------------- mm/slab.c | 18 +- mm/slub.c | 10 +- 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/rds/ib_recv.c | 4 +- net/rxrpc/ar-connection.c | 2 +- net/sctp/associola.c | 2 +- security/integrity/ima/ima_crypto.c | 2 +- 101 files changed, 466 insertions(+), 705 deletions(-)
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