linux-toradex.git/arch/tile/mm/pgtable.c, branch v4.10

mm: move most file-based accounting to the node

2016-07-28T23:07:41+00:00

There are now a number of accounting oddities such as mapped file pages
being accounted for on the node while the total number of file pages are
accounted on the zone.  This can be coped with to some extent but it's
confusing so this patch moves the relevant file-based accounted.  Due to
throttling logic in the page allocator for reliable OOM detection, it is
still necessary to track dirty and writeback pages on a per-zone basis.

[mgorman@techsingularity.net: fix NR_ZONE_WRITE_PENDING accounting]
  Link: http://lkml.kernel.org/r/1468404004-5085-5-git-send-email-mgorman@techsingularity.net
Link: http://lkml.kernel.org/r/1467970510-21195-20-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman 
Acked-by: Vlastimil Babka 
Acked-by: Michal Hocko 
Cc: Hillf Danton 
Acked-by: Johannes Weiner 
Cc: Joonsoo Kim 
Cc: Minchan Kim 
Cc: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: move page mapped accounting to the node

2016-07-28T23:07:41+00:00

Reclaim makes decisions based on the number of pages that are mapped but
it's mixing node and zone information.  Account NR_FILE_MAPPED and
NR_ANON_PAGES pages on the node.

Link: http://lkml.kernel.org/r/1467970510-21195-18-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman 
Acked-by: Vlastimil Babka 
Acked-by: Michal Hocko 
Cc: Hillf Danton 
Acked-by: Johannes Weiner 
Cc: Joonsoo Kim 
Cc: Minchan Kim 
Cc: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm, vmscan: move LRU lists to node

2016-07-28T23:07:41+00:00

This moves the LRU lists from the zone to the node and related data such
as counters, tracing, congestion tracking and writeback tracking.

Unfortunately, due to reclaim and compaction retry logic, it is
necessary to account for the number of LRU pages on both zone and node
logic.  Most reclaim logic is based on the node counters but the retry
logic uses the zone counters which do not distinguish inactive and
active sizes.  It would be possible to leave the LRU counters on a
per-zone basis but it's a heavier calculation across multiple cache
lines that is much more frequent than the retry checks.

Other than the LRU counters, this is mostly a mechanical patch but note
that it introduces a number of anomalies.  For example, the scans are
per-zone but using per-node counters.  We also mark a node as congested
when a zone is congested.  This causes weird problems that are fixed
later but is easier to review.

In the event that there is excessive overhead on 32-bit systems due to
the nodes being on LRU then there are two potential solutions

1. Long-term isolation of highmem pages when reclaim is lowmem

   When pages are skipped, they are immediately added back onto the LRU
   list. If lowmem reclaim persisted for long periods of time, the same
   highmem pages get continually scanned. The idea would be that lowmem
   keeps those pages on a separate list until a reclaim for highmem pages
   arrives that splices the highmem pages back onto the LRU. It potentially
   could be implemented similar to the UNEVICTABLE list.

   That would reduce the skip rate with the potential corner case is that
   highmem pages have to be scanned and reclaimed to free lowmem slab pages.

2. Linear scan lowmem pages if the initial LRU shrink fails

   This will break LRU ordering but may be preferable and faster during
   memory pressure than skipping LRU pages.

Link: http://lkml.kernel.org/r/1467970510-21195-4-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman 
Acked-by: Johannes Weiner 
Acked-by: Vlastimil Babka 
Cc: Hillf Danton 
Cc: Joonsoo Kim 
Cc: Michal Hocko 
Cc: Minchan Kim 
Cc: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

tile: get rid of superfluous __GFP_REPEAT

2016-06-25T00:23:52+00:00

__GFP_REPEAT has a rather weak semantic but since it has been introduced
around 2.6.12 it has been ignored for low order allocations.

pgtable_alloc_one uses __GFP_REPEAT flag for L2_USER_PGTABLE_ORDER but
the order is either 0 or 3 if L2_KERNEL_PGTABLE_SHIFT for HPAGE_SHIFT.
This means that this flag has never been actually useful here because it
has always been used only for PAGE_ALLOC_COSTLY requests.

Link: http://lkml.kernel.org/r/1464599699-30131-16-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko 
Acked-by: Chris Metcalf  [for tile]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

tile: Use the more common pr_warn instead of pr_warning

2014-11-11T20:51:42+00:00

And other message logging neatening.

Other miscellanea:

o coalesce formats
o realign arguments
o standardize a couple of macros
o use __func__ instead of embedding the function name

Signed-off-by: Joe Perches 
Signed-off-by: Chris Metcalf

tile: handle pgtable_page_ctor() fail

2013-11-15T00:32:19+00:00

Signed-off-by: Kirill A. Shutemov 
Acked-by: Chris Metcalf 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

tile: use pmd_pfn() instead of casting via pte_t

2013-09-13T15:14:25+00:00

Signed-off-by: Chris Metcalf

tile: add virt_to_kpte() API and clean up and document behavior

2013-09-03T18:52:13+00:00

We use virt_to_pte(NULL, va) a lot, which isn't very obvious.
I added virt_to_kpte(va) as a more obvious wrapper function,
that also validates the va as being a kernel adddress.

And, I fixed the semantics of virt_to_pte() so that we handle
the pud and pmd the same way, and we now document the fact that
we handle the final pte level differently.

Signed-off-by: Chris Metcalf

tile: handle super huge pages in virt_to_pte

2013-08-30T15:57:02+00:00

This tile-specific API had a minor bug, in that if a super huge (>4GB)
page mapped a particular address range, we wouldn't handle it correctly.
As part of fixing that bug, I also cleaned up some of the pud and pmd
accessors to make them more consistent.

Signed-off-by: Chris Metcalf

tile: remove set/clear_fixmap APIs

2013-08-30T15:56:38+00:00

Nothing in the codebase was using them, and as written they took
"unsigned long" as the physical address rather than "phys_addr_t",
which is wrong on tilepro anyway.  Rather than fixing stale APIs,
just remove them; if there's ever demand for them on this platform,
we can put them back.

Signed-off-by: Chris Metcalf