On 06.11.2018 11:43, Arun KS wrote:
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/
Could you point what exactly are you fixing with this set?
from v2:
> totalram_pages, zone->managed_pages and totalhigh_pages updates
> are protected by managed_page_count_lock, but readers never care
> about it. Convert these variables to atomic to avoid readers
> potentially seeing a store tear.
This?
Aligned unsigned long almost always stored at once.
To make it completely correct you could replace
a += b;
with
WRITE_ONCE(a, a + b);
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):
mm: Fix multiple evaluvations of totalram_pages and managed_pages
mm: Convert zone->managed_pages to atomic variable
mm: convert totalram_pages and totalhigh_pages variables to atomic
mm: Remove managed_page_count spinlock
arch/csky/mm/init.c | 4 +-
arch/powerpc/platforms/pseries/cmm.c | 10 ++--
arch/s390/mm/init.c | 2 +-
arch/um/kernel/mem.c | 3 +-
arch/x86/kernel/cpu/microcode/core.c | 5 +-
drivers/char/agp/backend.c | 4 +-
drivers/gpu/drm/amd/amdkfd/kfd_crat.c | 2 +-
drivers/gpu/drm/i915/i915_gem.c | 2 +-
drivers/gpu/drm/i915/selftests/i915_gem_gtt.c | 4 +-
drivers/hv/hv_balloon.c | 19 +++----
drivers/md/dm-bufio.c | 2 +-
drivers/md/dm-crypt.c | 2 +-
drivers/md/dm-integrity.c | 2 +-
drivers/md/dm-stats.c | 2 +-
drivers/media/platform/mtk-vpu/mtk_vpu.c | 2 +-
drivers/misc/vmw_balloon.c | 2 +-
drivers/parisc/ccio-dma.c | 4 +-
drivers/parisc/sba_iommu.c | 4 +-
drivers/staging/android/ion/ion_system_heap.c | 2 +-
drivers/xen/xen-selfballoon.c | 6 +--
fs/ceph/super.h | 2 +-
fs/file_table.c | 7 +--
fs/fuse/inode.c | 2 +-
fs/nfs/write.c | 2 +-
fs/nfsd/nfscache.c | 2 +-
fs/ntfs/malloc.h | 2 +-
fs/proc/base.c | 2 +-
include/linux/highmem.h | 28 ++++++++++-
include/linux/mm.h | 27 +++++++++-
include/linux/mmzone.h | 15 +++---
include/linux/swap.h | 1 -
kernel/fork.c | 5 +-
kernel/kexec_core.c | 5 +-
kernel/power/snapshot.c | 2 +-
lib/show_mem.c | 2 +-
mm/highmem.c | 4 +-
mm/huge_memory.c | 2 +-
mm/kasan/quarantine.c | 2 +-
mm/memblock.c | 6 +--
mm/memory_hotplug.c | 4 +-
mm/mm_init.c | 2 +-
mm/oom_kill.c | 2 +-
mm/page_alloc.c | 71 +++++++++++++--------------
mm/shmem.c | 7 +--
mm/slab.c | 2 +-
mm/swap.c | 2 +-
mm/util.c | 2 +-
mm/vmalloc.c | 4 +-
mm/vmstat.c | 4 +-
mm/workingset.c | 2 +-
mm/zswap.c | 4 +-
net/dccp/proto.c | 7 +--
net/decnet/dn_route.c | 2 +-
net/ipv4/tcp_metrics.c | 2 +-
net/netfilter/nf_conntrack_core.c | 7 +--
net/netfilter/xt_hashlimit.c | 5 +-
net/sctp/protocol.c | 7 +--
security/integrity/ima/ima_kexec.c | 2 +-
58 files changed, 195 insertions(+), 144 deletions(-)
