linux-toradex.git/mm/vmstat.c, branch v5.0-rc3

mm: convert zone->managed_pages to atomic variable

2018-12-28T20:11:47+00:00

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 patch converts zone->managed_pages.  Subsequent patches will convert
totalram_panges, totalhigh_pages and eventually managed_page_count_lock
will be removed.

Main motivation was that managed_page_count_lock handling was complicating
things.  It was discussed in length here,
https://lore.kernel.org/patchwork/patch/995739/#1181785 So it seemes
better to remove the lock and convert variables to atomic, with preventing
poteintial store-to-read tearing as a bonus.

Link: http://lkml.kernel.org/r/1542090790-21750-3-git-send-email-arunks@codeaurora.org
Signed-off-by: Arun KS 
Suggested-by: Michal Hocko 
Suggested-by: Vlastimil Babka 
Reviewed-by: Konstantin Khlebnikov 
Reviewed-by: David Hildenbrand 
Acked-by: Michal Hocko 
Acked-by: Vlastimil Babka 
Reviewed-by: Pavel Tatashin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/vmstat.c: fix NUMA statistics updates

2018-11-18T18:15:10+00:00

Scan through the whole array to see if an update is needed.  While we're
at it, use sizeof() to be safe against any possible type changes in the
future.

The bug here is that we wouldn't sync per-cpu counters into global ones
if there was an update of numa_stats for higher cpus.  Highly
theoretical one though because it is much more probable that zone_stats
are updated so we would refresh anyway.  So I wouldn't bother to mark
this for stable, yet something nice to fix.

[mhocko@suse.com: changelog enhancement]
Link: http://lkml.kernel.org/r/1541601517-17282-1-git-send-email-janne.huttunen@nokia.com
Fixes: 1d90ca897cb0 ("mm: update NUMA counter threshold size")
Signed-off-by: Janne Huttunen 
Acked-by: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/vmstat.c: assert that vmstat_text is in sync with stat_items_size

2018-10-26T23:26:35+00:00

Having two gigantic arrays that must manually be kept in sync, including
ifdefs, isn't exactly robust.  To make it easier to catch such issues in
the future, add a BUILD_BUG_ON().

Link: http://lkml.kernel.org/r/20181001143138.95119-3-jannh@google.com
Signed-off-by: Jann Horn 
Reviewed-by: Kees Cook 
Reviewed-by: Andrew Morton 
Acked-by: Roman Gushchin 
Acked-by: Michal Hocko 
Cc: Davidlohr Bueso 
Cc: Oleg Nesterov 
Cc: Christoph Lameter 
Cc: Kemi Wang 
Cc: Andy Lutomirski 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: workingset: add vmstat counter for shadow nodes

2018-10-26T23:26:33+00:00

Make it easier to catch bugs in the shadow node shrinker by adding a
counter for the shadow nodes in circulation.

[akpm@linux-foundation.org: assert that irqs are disabled, for __inc_lruvec_page_state()]
[akpm@linux-foundation.org: s/WARN_ON_ONCE/VM_WARN_ON_ONCE/, per Johannes]
Link: http://lkml.kernel.org/r/20181009184732.762-4-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner 
Reviewed-by: Andrew Morton 
Acked-by: Peter Zijlstra (Intel) 
Cc: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: workingset: tell cache transitions from workingset thrashing

2018-10-26T23:26:32+00:00

Refaults happen during transitions between workingsets as well as in-place
thrashing.  Knowing the difference between the two has a range of
applications, including measuring the impact of memory shortage on the
system performance, as well as the ability to smarter balance pressure
between the filesystem cache and the swap-backed workingset.

During workingset transitions, inactive cache refaults and pushes out
established active cache.  When that active cache isn't stale, however,
and also ends up refaulting, that's bonafide thrashing.

Introduce a new page flag that tells on eviction whether the page has been
active or not in its lifetime.  This bit is then stored in the shadow
entry, to classify refaults as transitioning or thrashing.

How many page->flags does this leave us with on 32-bit?

	20 bits are always page flags

	21 if you have an MMU

	23 with the zone bits for DMA, Normal, HighMem, Movable

	29 with the sparsemem section bits

	30 if PAE is enabled

	31 with this patch.

So on 32-bit PAE, that leaves 1 bit for distinguishing two NUMA nodes.  If
that's not enough, the system can switch to discontigmem and re-gain the 6
or 7 sparsemem section bits.

Link: http://lkml.kernel.org/r/20180828172258.3185-3-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner 
Acked-by: Peter Zijlstra (Intel) 
Tested-by: Daniel Drake 
Tested-by: Suren Baghdasaryan 
Cc: Christopher Lameter 
Cc: Ingo Molnar 
Cc: Johannes Weiner 
Cc: Mike Galbraith 
Cc: Peter Enderborg 
Cc: Randy Dunlap 
Cc: Shakeel Butt 
Cc: Tejun Heo 
Cc: Vinayak Menon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: rename and change semantics of nr_indirectly_reclaimable_bytes

2018-10-26T23:26:32+00:00

The vmstat counter NR_INDIRECTLY_RECLAIMABLE_BYTES was introduced by
commit eb59254608bc ("mm: introduce NR_INDIRECTLY_RECLAIMABLE_BYTES") with
the goal of accounting objects that can be reclaimed, but cannot be
allocated via a SLAB_RECLAIM_ACCOUNT cache.  This is now possible via
kmalloc() with __GFP_RECLAIMABLE flag, and the dcache external names user
is converted.

The counter is however still useful for accounting direct page allocations
(i.e.  not slab) with a shrinker, such as the ION page pool.  So keep it,
and:

- change granularity to pages to be more like other counters; sub-page
  allocations should be able to use kmalloc
- rename the counter to NR_KERNEL_MISC_RECLAIMABLE
- expose the counter again in vmstat as "nr_kernel_misc_reclaimable"; we can
  again remove the check for not printing "hidden" counters

Link: http://lkml.kernel.org/r/20180731090649.16028-5-vbabka@suse.cz
Signed-off-by: Vlastimil Babka 
Acked-by: Christoph Lameter 
Acked-by: Roman Gushchin 
Cc: Vijayanand Jitta 
Cc: Laura Abbott 
Cc: Sumit Semwal 
Cc: David Rientjes 
Cc: Johannes Weiner 
Cc: Joonsoo Kim 
Cc: Matthew Wilcox 
Cc: Mel Gorman 
Cc: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/vmstat.c: skip NR_TLB_REMOTE_FLUSH* properly

2018-10-05T23:32:05+00:00

5dd0b16cdaff ("mm/vmstat: Make NR_TLB_REMOTE_FLUSH_RECEIVED available even
on UP") made the availability of the NR_TLB_REMOTE_FLUSH* counters inside
the kernel unconditional to reduce #ifdef soup, but (either to avoid
showing dummy zero counters to userspace, or because that code was missed)
didn't update the vmstat_array, meaning that all following counters would
be shown with incorrect values.

This only affects kernel builds with
CONFIG_VM_EVENT_COUNTERS=y && CONFIG_DEBUG_TLBFLUSH=y && CONFIG_SMP=n.

Link: http://lkml.kernel.org/r/20181001143138.95119-2-jannh@google.com
Fixes: 5dd0b16cdaff ("mm/vmstat: Make NR_TLB_REMOTE_FLUSH_RECEIVED available even on UP")
Signed-off-by: Jann Horn 
Reviewed-by: Kees Cook 
Reviewed-by: Andrew Morton 
Acked-by: Michal Hocko 
Acked-by: Roman Gushchin 
Cc: Davidlohr Bueso 
Cc: Oleg Nesterov 
Cc: Christoph Lameter 
Cc: Kemi Wang 
Cc: Andy Lutomirski 
Cc: Ingo Molnar 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

mm/vmstat.c: fix outdated vmstat_text

2018-10-05T23:32:05+00:00

7a9cdebdcc17 ("mm: get rid of vmacache_flush_all() entirely") removed the
VMACACHE_FULL_FLUSHES statistics, but didn't remove the corresponding
entry in vmstat_text.  This causes an out-of-bounds access in
vmstat_show().

Luckily this only affects kernels with CONFIG_DEBUG_VM_VMACACHE=y, which
is probably very rare.

Link: http://lkml.kernel.org/r/20181001143138.95119-1-jannh@google.com
Fixes: 7a9cdebdcc17 ("mm: get rid of vmacache_flush_all() entirely")
Signed-off-by: Jann Horn 
Reviewed-by: Kees Cook 
Reviewed-by: Andrew Morton 
Acked-by: Michal Hocko 
Acked-by: Roman Gushchin 
Cc: Davidlohr Bueso 
Cc: Oleg Nesterov 
Cc: Christoph Lameter 
Cc: Kemi Wang 
Cc: Andy Lutomirski 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

Revert mm/vmstat.c: fix vmstat_update() preemption BUG

2018-06-28T18:16:44+00:00

Revert commit c7f26ccfb2c3 ("mm/vmstat.c: fix vmstat_update() preemption
BUG").  Steven saw a "using smp_processor_id() in preemptible" message
and added a preempt_disable() section around it to keep it quiet.  This
is not the right thing to do it does not fix the real problem.

vmstat_update() is invoked by a kworker on a specific CPU.  This worker
it bound to this CPU.  The name of the worker was "kworker/1:1" so it
should have been a worker which was bound to CPU1.  A worker which can
run on any CPU would have a `u' before the first digit.

smp_processor_id() can be used in a preempt-enabled region as long as
the task is bound to a single CPU which is the case here.  If it could
run on an arbitrary CPU then this is the problem we have an should seek
to resolve.

Not only this smp_processor_id() must not be migrated to another CPU but
also refresh_cpu_vm_stats() which might access wrong per-CPU variables.
Not to mention that other code relies on the fact that such a worker
runs on one specific CPU only.

Therefore revert that commit and we should look instead what broke the
affinity mask of the kworker.

Link: http://lkml.kernel.org/r/20180504104451.20278-1-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior 
Cc: Steven J. Hill 
Cc: Tejun Heo 
Cc: Vlastimil Babka 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

proc: introduce proc_create_seq{,_data}

2018-05-16T05:23:35+00:00

Variants of proc_create{,_data} that directly take a struct seq_operations
argument and drastically reduces the boilerplate code in the callers.

All trivial callers converted over.

Signed-off-by: Christoph Hellwig