Re: [PATCH v1 0/4]mm: convert totalram_pages, totalhigh_pages and managed pages to atomic

[Arun KS]

On 2018-11-06 14:07, Konstantin Khlebnikov wrote:
> On 06.11.2018 11:30, Arun KS wrote:
> > On 2018-11-06 13:47, Konstantin Khlebnikov wrote:
> > > On 06.11.2018 8:38, Arun KS wrote:
> > > > Any comments?
> > >
> > > Looks good.
> > > Except unclear motivation behind this change.
> > > This should be in comment of one of patch.
> >
> > totalram_pages, zone->managed_pages and totalhigh_pages are sometimes 
> > modified outside managed_page_count_lock. Hence convert these variable 
> > to atomic to avoid readers potentially seeing a store tear.
>
> So, this is just theoretical issue or splat from sanitizer.
> After boot memory online\offline are strictly serialized by 
> rw-semaphore.

Few instances which can race with hot add. Please see below,
https://patchwork.kernel.org/patch/10627521/

Regards,
Arun

> > Will update the comment.
> >
> > Regards,
> > Arun
> >
> > > Reviewed-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
> > >
> > > > Regards,
> > > > Arun
> > > >
> > > > On 2018-10-26 16:30, Arun KS wrote:
> > > > > This series convert totalram_pages, totalhigh_pages and
> > > > > zone->managed_pages to atomic variables.
> > > > >
> > > > > The patch was comiple tested on x86(x86_64_defconfig & 
> > > > > i386_defconfig)
> > > > > on tip of linux-mmotm. And memory hotplug tested on arm64, but on 
> > > > > an
> > > > > older version of kernel.
> > > > >
> > > > > Arun KS (4):
> > > > > Â mm: Fix multiple evaluvations of totalram_pages and managed_pages
> > > > > Â mm: Convert zone->managed_pages to atomic variable
> > > > > Â mm: convert totalram_pages and totalhigh_pages variables to 
> > > > > atomic
> > > > > Â mm: Remove managed_page_count spinlock
> > > > >
> > > > > Âarch/csky/mm/init.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 4 +-
> > > > > Âarch/powerpc/platforms/pseries/cmm.cÂÂÂÂÂÂÂÂÂ | 10 ++--
> > > > > Âarch/s390/mm/init.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âarch/um/kernel/mem.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 3 +-
> > > > > Âarch/x86/kernel/cpu/microcode/core.cÂÂÂÂÂÂÂÂÂ |Â 5 +-
> > > > > Âdrivers/char/agp/backend.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 4 +-
> > > > > Âdrivers/gpu/drm/amd/amdkfd/kfd_crat.cÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âdrivers/gpu/drm/i915/i915_gem.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âdrivers/gpu/drm/i915/selftests/i915_gem_gtt.c |Â 4 +-
> > > > > Âdrivers/hv/hv_balloon.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | 19 +++----
> > > > > Âdrivers/md/dm-bufio.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âdrivers/md/dm-crypt.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âdrivers/md/dm-integrity.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âdrivers/md/dm-stats.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âdrivers/media/platform/mtk-vpu/mtk_vpu.cÂÂÂÂÂ |Â 2 +-
> > > > > Âdrivers/misc/vmw_balloon.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âdrivers/parisc/ccio-dma.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 4 +-
> > > > > Âdrivers/parisc/sba_iommu.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 4 +-
> > > > > Âdrivers/staging/android/ion/ion_system_heap.c |Â 2 +-
> > > > > Âdrivers/xen/xen-selfballoon.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 6 +--
> > > > > Âfs/ceph/super.hÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âfs/file_table.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 7 +--
> > > > > Âfs/fuse/inode.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âfs/nfs/write.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âfs/nfsd/nfscache.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âfs/ntfs/malloc.hÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âfs/proc/base.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âinclude/linux/highmem.hÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | 28 ++++++++++-
> > > > > Âinclude/linux/mm.hÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | 27 +++++++++-
> > > > > Âinclude/linux/mmzone.hÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | 15 +++---
> > > > > Âinclude/linux/swap.hÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 1 -
> > > > > Âkernel/fork.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 5 +-
> > > > > Âkernel/kexec_core.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 5 +-
> > > > > Âkernel/power/snapshot.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âlib/show_mem.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âmm/highmem.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 4 +-
> > > > > Âmm/huge_memory.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âmm/kasan/quarantine.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âmm/memblock.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 6 +--
> > > > > Âmm/memory_hotplug.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 4 +-
> > > > > Âmm/mm_init.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âmm/oom_kill.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âmm/page_alloc.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | 71 
> > > > > +++++++++++++--------------
> > > > > Âmm/shmem.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 7 +--
> > > > > Âmm/slab.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âmm/swap.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âmm/util.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âmm/vmalloc.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 4 +-
> > > > > Âmm/vmstat.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 4 +-
> > > > > Âmm/workingset.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Âmm/zswap.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 4 +-
> > > > > Ânet/dccp/proto.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 7 +--
> > > > > Ânet/decnet/dn_route.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Ânet/ipv4/tcp_metrics.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Ânet/netfilter/nf_conntrack_core.cÂÂÂÂÂÂÂÂÂÂÂÂ |Â 7 +--
> > > > > Ânet/netfilter/xt_hashlimit.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 5 +-
> > > > > Ânet/sctp/protocol.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 7 +--
> > > > > Âsecurity/integrity/ima/ima_kexec.cÂÂÂÂÂÂÂÂÂÂÂ |Â 2 +-
> > > > > Â58 files changed, 195 insertions(+), 144 deletions(-)