linux-toradex.git/Documentation/admin-guide, branch v5.17-rc4

gpio: sim: add doc file to index file

2022-01-24T08:21:28+00:00

Include the gpio-sim.rst file in the GPIO index (toc/table of contents).

Quietens this doc build warning:

Documentation/admin-guide/gpio/gpio-sim.rst: WARNING: document isn't included in any toctree

Fixes: b48f6b466e44 ("gpio: sim: new testing module")
Signed-off-by: Randy Dunlap 
Reported-by: Stephen Rothwell 
Signed-off-by: Bartosz Golaszewski

Merge branch 'akpm' (patches from Andrew)

2022-01-15T18:37:06+00:00

Merge misc updates from Andrew Morton:
 "146 patches.

  Subsystems affected by this patch series: kthread, ia64, scripts,
  ntfs, squashfs, ocfs2, vfs, and mm (slab-generic, slab, kmemleak,
  dax, kasan, debug, pagecache, gup, shmem, frontswap, memremap,
  memcg, selftests, pagemap, dma, vmalloc, memory-failure, hugetlb,
  userfaultfd, vmscan, mempolicy, oom-kill, hugetlbfs, migration, thp,
  ksm, page-poison, percpu, rmap, zswap, zram, cleanups, hmm, and
  damon)"

* emailed patches from Andrew Morton : (146 commits)
  mm/damon: hide kernel pointer from tracepoint event
  mm/damon/vaddr: hide kernel pointer from damon_va_three_regions() failure log
  mm/damon/vaddr: use pr_debug() for damon_va_three_regions() failure logging
  mm/damon/dbgfs: remove an unnecessary variable
  mm/damon: move the implementation of damon_insert_region to damon.h
  mm/damon: add access checking for hugetlb pages
  Docs/admin-guide/mm/damon/usage: update for schemes statistics
  mm/damon/dbgfs: support all DAMOS stats
  Docs/admin-guide/mm/damon/reclaim: document statistics parameters
  mm/damon/reclaim: provide reclamation statistics
  mm/damon/schemes: account how many times quota limit has exceeded
  mm/damon/schemes: account scheme actions that successfully applied
  mm/damon: remove a mistakenly added comment for a future feature
  Docs/admin-guide/mm/damon/usage: update for kdamond_pid and (mk|rm)_contexts
  Docs/admin-guide/mm/damon/usage: mention tracepoint at the beginning
  Docs/admin-guide/mm/damon/usage: remove redundant information
  Docs/admin-guide/mm/damon/usage: update for scheme quotas and watermarks
  mm/damon: convert macro functions to static inline functions
  mm/damon: modify damon_rand() macro to static inline function
  mm/damon: move damon_rand() definition into damon.h
  ...

Docs/admin-guide/mm/damon/usage: update for schemes statistics

2022-01-15T14:30:33+00:00

This updates DAMON debugfs interface for statistics of schemes
successfully applied regions and time/space quota limit exceeds counts.

Link: https://lkml.kernel.org/r/20211210150016.35349-7-sj@kernel.org
Signed-off-by: SeongJae Park 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Docs/admin-guide/mm/damon/reclaim: document statistics parameters

2022-01-15T14:30:33+00:00

This adds descriptions for the DAMON_RECLAIM statistics parameters.

Link: https://lkml.kernel.org/r/20211210150016.35349-5-sj@kernel.org
Signed-off-by: SeongJae Park 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Docs/admin-guide/mm/damon/usage: update for kdamond_pid and (mk|rm)_contexts

2022-01-15T14:30:32+00:00

The DAMON debugfs usage document is missing descriptions for
'kdamond_pid', 'mk_contexts', and 'rm_contexts' debugfs files.  This
commit adds those.

Link: https://lkml.kernel.org/r/20211209131806.19317-6-sj@kernel.org
Signed-off-by: SeongJae Park 
Cc: Jonathan Corbet 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Docs/admin-guide/mm/damon/usage: mention tracepoint at the beginning

2022-01-15T14:30:32+00:00

To get detailed monitoring results from the user space, users need to
use the damon_aggregated tracepoint.  This commit adds a brief mention
of it at the beginning of the usage document.

Link: https://lkml.kernel.org/r/20211209131806.19317-5-sj@kernel.org
Signed-off-by: SeongJae Park 
Cc: Jonathan Corbet 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Docs/admin-guide/mm/damon/usage: remove redundant information

2022-01-15T14:30:32+00:00

DAMON usage document mentions DAMON user space tool and programming
interface twice.  This commit integrates those and remove unnecessary
part.

Link: https://lkml.kernel.org/r/20211209131806.19317-4-sj@kernel.org
Signed-off-by: SeongJae Park 
Cc: Jonathan Corbet 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Docs/admin-guide/mm/damon/usage: update for scheme quotas and watermarks

2022-01-15T14:30:32+00:00

DAMOS features including time/space quota limits and watermarks are not
described in the DAMON debugfs interface document.  This commit updates
the document for the features.

Link: https://lkml.kernel.org/r/20211209131806.19317-3-sj@kernel.org
Signed-off-by: SeongJae Park 
Cc: Jonathan Corbet 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/mempolicy: add set_mempolicy_home_node syscall

2022-01-15T14:30:30+00:00

This syscall can be used to set a home node for the MPOL_BIND and
MPOL_PREFERRED_MANY memory policy.  Users should use this syscall after
setting up a memory policy for the specified range as shown below.

  mbind(p, nr_pages * page_size, MPOL_BIND, new_nodes->maskp,
        new_nodes->size + 1, 0);
  sys_set_mempolicy_home_node((unsigned long)p, nr_pages * page_size,
				home_node, 0);

The syscall allows specifying a home node/preferred node from which
kernel will fulfill memory allocation requests first.

For address range with MPOL_BIND memory policy, if nodemask specifies
more than one node, page allocations will come from the node in the
nodemask with sufficient free memory that is closest to the home
node/preferred node.

For MPOL_PREFERRED_MANY if the nodemask specifies more than one node,
page allocation will come from the node in the nodemask with sufficient
free memory that is closest to the home node/preferred node.  If there
is not enough memory in all the nodes specified in the nodemask, the
allocation will be attempted from the closest numa node to the home node
in the system.

This helps applications to hint at a memory allocation preference node
and fallback to _only_ a set of nodes if the memory is not available on
the preferred node.  Fallback allocation is attempted from the node
which is nearest to the preferred node.

This helps applications to have control on memory allocation numa nodes
and avoids default fallback to slow memory NUMA nodes.  For example a
system with NUMA nodes 1,2 and 3 with DRAM memory and 10, 11 and 12 of
slow memory

 new_nodes = numa_bitmask_alloc(nr_nodes);

 numa_bitmask_setbit(new_nodes, 1);
 numa_bitmask_setbit(new_nodes, 2);
 numa_bitmask_setbit(new_nodes, 3);

 p = mmap(NULL, nr_pages * page_size, protflag, mapflag, -1, 0);
 mbind(p, nr_pages * page_size, MPOL_BIND, new_nodes->maskp,  new_nodes->size + 1, 0);

 sys_set_mempolicy_home_node(p, nr_pages * page_size, 2, 0);

This will allocate from nodes closer to node 2 and will make sure the
kernel will only allocate from nodes 1, 2, and 3.  Memory will not be
allocated from slow memory nodes 10, 11, and 12.  This differs from
default MPOL_BIND behavior in that with default MPOL_BIND the allocation
will be attempted from node closer to the local node.  One of the
reasons to specify a home node is to allow allocations from cpu less
NUMA node and its nearby NUMA nodes.

With MPOL_PREFERRED_MANY on the other hand will first try to allocate
from the closest node to node 2 from the node list 1, 2 and 3.  If those
nodes don't have enough memory, kernel will allocate from slow memory
node 10, 11 and 12 which ever is closer to node 2.

Link: https://lkml.kernel.org/r/20211202123810.267175-3-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V 
Cc: Ben Widawsky 
Cc: Dave Hansen 
Cc: Feng Tang 
Cc: Michal Hocko 
Cc: Andrea Arcangeli 
Cc: Mel Gorman 
Cc: Mike Kravetz 
Cc: Randy Dunlap 
Cc: Vlastimil Babka 
Cc: Andi Kleen 
Cc: Dan Williams 
Cc: Huang Ying 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

hugetlb: add hugetlb.*.numa_stat file

2022-01-15T14:30:29+00:00

For hugetlb backed jobs/VMs it's critical to understand the numa
information for the memory backing these jobs to deliver optimal
performance.

Currently this technically can be queried from /proc/self/numa_maps, but
there are significant issues with that.  Namely:

1. Memory can be mapped or unmapped.

2. numa_maps are per process and need to be aggregated across all
   processes in the cgroup.  For shared memory this is more involved as
   the userspace needs to make sure it doesn't double count shared
   mappings.

3. I believe querying numa_maps needs to hold the mmap_lock which adds
   to the contention on this lock.

For these reasons I propose simply adding hugetlb.*.numa_stat file,
   which shows the numa information of the cgroup similarly to
   memory.numa_stat.

On cgroup-v2:
   cat /sys/fs/cgroup/unified/test/hugetlb.2MB.numa_stat
   total=2097152 N0=2097152 N1=0

On cgroup-v1:
   cat /sys/fs/cgroup/hugetlb/test/hugetlb.2MB.numa_stat
   total=2097152 N0=2097152 N1=0
   hierarichal_total=2097152 N0=2097152 N1=0

This patch was tested manually by allocating hugetlb memory and querying
the hugetlb.*.numa_stat file of the cgroup and its parents.

[colin.i.king@googlemail.com: fix spelling mistake "hierarichal" -> "hierarchical"]
  Link: https://lkml.kernel.org/r/20211125090635.23508-1-colin.i.king@gmail.com
[keescook@chromium.org: fix copy/paste array assignment]
  Link: https://lkml.kernel.org/r/20211203065647.2819707-1-keescook@chromium.org

Link: https://lkml.kernel.org/r/20211123001020.4083653-1-almasrymina@google.com
Signed-off-by: Mina Almasry 
Signed-off-by: Colin Ian King 
Signed-off-by: Kees Cook 
Reviewed-by: Shakeel Butt 
Reviewed-by: Muchun Song 
Reviewed-by: Mike Kravetz 
Cc: Shuah Khan 
Cc: Miaohe Lin 
Cc: Oscar Salvador 
Cc: Michal Hocko 
Cc: David Rientjes 
Cc: Jue Wang 
Cc: Yang Yao 
Cc: Joanna Li 
Cc: Cannon Matthews 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds