linux.git/mm/highmem.c, branch v5.17

Merge tag 'folio-5.16b' of git://git.infradead.org/users/willy/pagecache

2021-11-25T18:13:56+00:00

Pull folio fixes from Matthew Wilcox:
 "In the course of preparing the folio changes for iomap for next merge
  window, we discovered some problems that would be nice to address now:

   - Renaming multi-page folios to large folios.

     mapping_multi_page_folio_support() is just a little too long, so we
     settled on mapping_large_folio_support(). That meant renaming, eg
     folio_test_multi() to folio_test_large().

     Rename AS_THP_SUPPORT to match

   - I hadn't included folio wrappers for zero_user_segments(), etc.
     Also, multi-page^W^W large folio support is now independent of
     CONFIG_TRANSPARENT_HUGEPAGE, so machines with HIGHMEM always need
     to fall back to the out-of-line zero_user_segments().

     Remove FS_THP_SUPPORT to match

   - The build bots finally got round to telling me that I missed a
     couple of architectures when adding flush_dcache_folio(). Christoph
     suggested that we just add linux/cacheflush.h and not rely on
     asm-generic/cacheflush.h"

* tag 'folio-5.16b' of git://git.infradead.org/users/willy/pagecache:
  mm: Add functions to zero portions of a folio
  fs: Rename AS_THP_SUPPORT and mapping_thp_support
  fs: Remove FS_THP_SUPPORT
  mm: Remove folio_test_single
  mm: Rename folio_test_multi to folio_test_large
  Add linux/cacheflush.h

kmap_local: don't assume kmap PTEs are linear arrays in memory

2021-11-20T18:35:54+00:00

The kmap_local conversion broke the ARM architecture, because the new
code assumes that all PTEs used for creating kmaps form a linear array
in memory, and uses array indexing to look up the kmap PTE belonging to
a certain kmap index.

On ARM, this cannot work, not only because the PTE pages may be
non-adjacent in memory, but also because ARM/!LPAE interleaves hardware
entries and extended entries (carrying software-only bits) in a way that
is not compatible with array indexing.

Fortunately, this only seems to affect configurations with more than 8
CPUs, due to the way the per-CPU kmap slots are organized in memory.

Work around this by permitting an architecture to set a Kconfig symbol
that signifies that the kmap PTEs do not form a lineary array in memory,
and so the only way to locate the appropriate one is to walk the page
tables.

Link: https://lore.kernel.org/linux-arm-kernel/20211026131249.3731275-1-ardb@kernel.org/
Link: https://lkml.kernel.org/r/20211116094737.7391-1-ardb@kernel.org
Fixes: 2a15ba82fa6c ("ARM: highmem: Switch to generic kmap atomic")
Signed-off-by: Ard Biesheuvel 
Reported-by: Quanyang Wang 
Reviewed-by: Linus Walleij 
Acked-by: Russell King (Oracle) 
Cc: Thomas Gleixner 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: Add functions to zero portions of a folio

2021-11-18T20:05:56+00:00

These functions are wrappers around zero_user_segments(), which means
that zero_user_segments() can now be called for compound pages even when
CONFIG_TRANSPARENT_HUGEPAGE is disabled.

Use 'xend' as the name of the parameter to indicate that this is an
excluded end, not the more usual included end.  Excluding the end makes
more sense to the callers, but can cause confusion to readers who are
more used to seeing included ends.

Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Darrick J. Wong

Merge branch 'akpm' (patches from Andrew)

2021-11-06T21:08:17+00:00

Merge misc updates from Andrew Morton:
 "257 patches.

  Subsystems affected by this patch series: scripts, ocfs2, vfs, and
  mm (slab-generic, slab, slub, kconfig, dax, kasan, debug, pagecache,
  gup, swap, memcg, pagemap, mprotect, mremap, iomap, tracing, vmalloc,
  pagealloc, memory-failure, hugetlb, userfaultfd, vmscan, tools,
  memblock, oom-kill, hugetlbfs, migration, thp, readahead, nommu, ksm,
  vmstat, madvise, memory-hotplug, rmap, zsmalloc, highmem, zram,
  cleanups, kfence, and damon)"

* emailed patches from Andrew Morton : (257 commits)
  mm/damon: remove return value from before_terminate callback
  mm/damon: fix a few spelling mistakes in comments and a pr_debug message
  mm/damon: simplify stop mechanism
  Docs/admin-guide/mm/pagemap: wordsmith page flags descriptions
  Docs/admin-guide/mm/damon/start: simplify the content
  Docs/admin-guide/mm/damon/start: fix a wrong link
  Docs/admin-guide/mm/damon/start: fix wrong example commands
  mm/damon/dbgfs: add adaptive_targets list check before enable monitor_on
  mm/damon: remove unnecessary variable initialization
  Documentation/admin-guide/mm/damon: add a document for DAMON_RECLAIM
  mm/damon: introduce DAMON-based Reclamation (DAMON_RECLAIM)
  selftests/damon: support watermarks
  mm/damon/dbgfs: support watermarks
  mm/damon/schemes: activate schemes based on a watermarks mechanism
  tools/selftests/damon: update for regions prioritization of schemes
  mm/damon/dbgfs: support prioritization weights
  mm/damon/vaddr,paddr: support pageout prioritization
  mm/damon/schemes: prioritize regions within the quotas
  mm/damon/selftests: support schemes quotas
  mm/damon/dbgfs: support quotas of schemes
  ...

mm/highmem: remove deprecated kmap_atomic

2021-11-06T20:30:43+00:00

kmap_atomic() is being deprecated in favor of kmap_local_page().

Replace the uses of kmap_atomic() within the highmem code.

On profiling clear_huge_page() using ftrace an improvement of 62% was
observed on the below setup.

Setup:-
Below data has been collected on Qualcomm's SM7250 SoC THP enabled
(kernel v4.19.113) with only CPU-0(Cortex-A55) and CPU-7(Cortex-A76)
switched on and set to max frequency, also DDR set to perf governor.

FTRACE Data:-

Base data:-
Number of iterations: 48
Mean of allocation time: 349.5 us
std deviation: 74.5 us

v4 data:-
Number of iterations: 48
Mean of allocation time: 131 us
std deviation: 32.7 us

The following simple userspace experiment to allocate
100MB(BUF_SZ) of pages and writing to it gave us a good insight,
we observed an improvement of 42% in allocation and writing timings.
-------------------------------------------------------------
Test code snippet
-------------------------------------------------------------
      clock_start();
      buf = malloc(BUF_SZ); /* Allocate 100 MB of memory */

        for(i=0; i < BUF_SZ_PAGES; i++)
        {
                *((int *)(buf + (i*PAGE_SIZE))) = 1;
        }
      clock_end();
-------------------------------------------------------------

Malloc test timings for 100MB anon allocation:-

Base data:-
Number of iterations: 100
Mean of allocation time: 31831 us
std deviation: 4286 us

v4 data:-
Number of iterations: 100
Mean of allocation time: 18193 us
std deviation: 4915 us

[willy@infradead.org: fix zero_user_segments()]
  Link: https://lkml.kernel.org/r/YYVhHCJcm2DM2G9u@casper.infradead.org

Link: https://lkml.kernel.org/r/20210204073255.20769-2-prathu.baronia@oneplus.com
Signed-off-by: Ira Weiny 
Signed-off-by: Prathu Baronia 
Cc: Thomas Gleixner 
Cc: Matthew Wilcox 
Cc: Peter Zijlstra 
Cc: Randy Dunlap 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: remove spurious blkdev.h includes

2021-10-18T12:17:01+00:00

Various files have acquired spurious includes of  over
time.  Remove them.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Johannes Thumshirn 
Link: https://lore.kernel.org/r/20210920123328.1399408-5-hch@lst.de
Signed-off-by: Jens Axboe

mm: in_irq() cleanup

2021-09-08T18:50:24+00:00

Replace the obsolete and ambiguos macro in_irq() with new macro
in_hardirq().

Link: https://lkml.kernel.org/r/20210813145245.86070-1-changbin.du@gmail.com
Signed-off-by: Changbin Du 
Acked-by: Catalin Marinas 	[kmemleak]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: fix typos in comments

2021-05-07T07:26:35+00:00

Fix ~94 single-word typos in locking code comments, plus a few
very obvious grammar mistakes.

Link: https://lkml.kernel.org/r/20210322212624.GA1963421@gmail.com
Link: https://lore.kernel.org/r/20210322205203.GB1959563@gmail.com
Signed-off-by: Ingo Molnar 
Reviewed-by: Matthew Wilcox (Oracle) 
Reviewed-by: Randy Dunlap 
Cc: Bhaskar Chowdhury 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/highmem.c: fix coding style issue

2021-05-05T18:27:27+00:00

Delete/add some blank lines and some blank spaces

Link: https://lkml.kernel.org/r/20210311095015.14277-1-songqiang@uniontech.com
Signed-off-by: songqiang 
Reviewed-by: David Hildenbrand 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/highmem: fix CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP

2021-03-25T16:22:55+00:00

The kernel test robot found that __kmap_local_sched_out() was not
correctly skipping the guard pages when DEBUG_KMAP_LOCAL_FORCE_MAP was
set.[1] This was due to DEBUG_HIGHMEM check being used.

Change the configuration check to be correct.

[1] https://lore.kernel.org/lkml/20210304083825.GB17830@xsang-OptiPlex-9020/

Link: https://lkml.kernel.org/r/20210318230657.1497881-1-ira.weiny@intel.com
Fixes: 0e91a0c6984c ("mm/highmem: Provide CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP")
Signed-off-by: Ira Weiny 
Reported-by: kernel test robot 
Reviewed-by: Thomas Gleixner 
Cc: Thomas Gleixner 
Cc: Oliver Sang 
Cc: Chaitanya Kulkarni 
Cc: David Sterba 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds