linux.git/mm/Kconfig, branch v5.13

mm,memory_hotplug: allocate memmap from the added memory range

2021-05-05T18:27:26+00:00

Physical memory hotadd has to allocate a memmap (struct page array) for
the newly added memory section.  Currently, alloc_pages_node() is used
for those allocations.

This has some disadvantages:
 a) an existing memory is consumed for that purpose
    (eg: ~2MB per 128MB memory section on x86_64)
    This can even lead to extreme cases where system goes OOM because
    the physically hotplugged memory depletes the available memory before
    it is onlined.
 b) if the whole node is movable then we have off-node struct pages
    which has performance drawbacks.
 c) It might be there are no PMD_ALIGNED chunks so memmap array gets
    populated with base pages.

This can be improved when CONFIG_SPARSEMEM_VMEMMAP is enabled.

Vmemap page tables can map arbitrary memory.  That means that we can
reserve a part of the physically hotadded memory to back vmemmap page
tables.  This implementation uses the beginning of the hotplugged memory
for that purpose.

There are some non-obviously things to consider though.

Vmemmap pages are allocated/freed during the memory hotplug events
(add_memory_resource(), try_remove_memory()) when the memory is
added/removed.  This means that the reserved physical range is not
online although it is used.  The most obvious side effect is that
pfn_to_online_page() returns NULL for those pfns.  The current design
expects that this should be OK as the hotplugged memory is considered a
garbage until it is onlined.  For example hibernation wouldn't save the
content of those vmmemmaps into the image so it wouldn't be restored on
resume but this should be OK as there no real content to recover anyway
while metadata is reachable from other data structures (e.g.  vmemmap
page tables).

The reserved space is therefore (de)initialized during the {on,off}line
events (mhp_{de}init_memmap_on_memory).  That is done by extracting page
allocator independent initialization from the regular onlining path.
The primary reason to handle the reserved space outside of
{on,off}line_pages is to make each initialization specific to the
purpose rather than special case them in a single function.

As per above, the functions that are introduced are:

 - mhp_init_memmap_on_memory:
   Initializes vmemmap pages by calling move_pfn_range_to_zone(), calls
   kasan_add_zero_shadow(), and onlines as many sections as vmemmap pages
   fully span.

 - mhp_deinit_memmap_on_memory:
   Offlines as many sections as vmemmap pages fully span, removes the
   range from zhe zone by remove_pfn_range_from_zone(), and calls
   kasan_remove_zero_shadow() for the range.

The new function memory_block_online() calls mhp_init_memmap_on_memory()
before doing the actual online_pages().  Should online_pages() fail, we
clean up by calling mhp_deinit_memmap_on_memory().  Adjusting of
present_pages is done at the end once we know that online_pages()
succedeed.

On offline, memory_block_offline() needs to unaccount vmemmap pages from
present_pages() before calling offline_pages().  This is necessary because
offline_pages() tears down some structures based on the fact whether the
node or the zone become empty.  If offline_pages() fails, we account back
vmemmap pages.  If it succeeds, we call mhp_deinit_memmap_on_memory().

Hot-remove:

 We need to be careful when removing memory, as adding and
 removing memory needs to be done with the same granularity.
 To check that this assumption is not violated, we check the
 memory range we want to remove and if a) any memory block has
 vmemmap pages and b) the range spans more than a single memory
 block, we scream out loud and refuse to proceed.

 If all is good and the range was using memmap on memory (aka vmemmap pages),
 we construct an altmap structure so free_hugepage_table does the right
 thing and calls vmem_altmap_free instead of free_pagetable.

Link: https://lkml.kernel.org/r/20210421102701.25051-5-osalvador@suse.de
Signed-off-by: Oscar Salvador 
Reviewed-by: David Hildenbrand 
Acked-by: Michal Hocko 
Cc: Anshuman Khandual 
Cc: Pavel Tatashin 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: generalize ARCH_ENABLE_MEMORY_[HOTPLUG|HOTREMOVE]

2021-05-05T18:27:25+00:00

ARCH_ENABLE_MEMORY_[HOTPLUG|HOTREMOVE] configs have duplicate
definitions on platforms that subscribe them.  Instead, just make them
generic options which can be selected on applicable platforms.

Link: https://lkml.kernel.org/r/1617259448-22529-4-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual 
Acked-by: Catalin Marinas 	[arm64]
Acked-by: Heiko Carstens 		[s390]
Cc: Will Deacon 
Cc: Michael Ellerman 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Vasily Gorbik 
Cc: Christian Borntraeger 
Cc: Yoshinori Sato 
Cc: Rich Felker 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Cc: Albert Ou 
Cc: Alexander Viro 
Cc: Arnd Bergmann 
Cc: Borislav Petkov 
Cc: Helge Deller 
Cc: "James E.J. Bottomley" 
Cc: Palmer Dabbelt 
Cc: Paul Walmsley 
Cc: Russell King 
Cc: Thomas Bogendoerfer 
Cc: Vineet Gupta 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: generalize ARCH_HAS_CACHE_LINE_SIZE

2021-05-05T18:27:25+00:00

Patch series "mm: some config cleanups", v2.

This series contains config cleanup patches which reduces code
duplication across platforms and also improves maintainability.  There
is no functional change intended with this series.

This patch (of 6):

ARCH_HAS_CACHE_LINE_SIZE config has duplicate definitions on platforms
that subscribe it.  Instead, just make it a generic option which can be
selected on applicable platforms.  This change reduces code duplication
and makes it cleaner.

Link: https://lkml.kernel.org/r/1617259448-22529-1-git-send-email-anshuman.khandual@arm.com
Link: https://lkml.kernel.org/r/1617259448-22529-2-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual 
Acked-by: Catalin Marinas 	[arm64]
Acked-by: Vineet Gupta 		[arc]
Cc: Will Deacon 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Borislav Petkov 
Cc: "H. Peter Anvin" 
Cc: Albert Ou 
Cc: Alexander Viro 
Cc: Arnd Bergmann 
Cc: Benjamin Herrenschmidt 
Cc: Christian Borntraeger 
Cc: Heiko Carstens 
Cc: Helge Deller 
Cc: "James E.J. Bottomley" 
Cc: Michael Ellerman 
Cc: Palmer Dabbelt 
Cc: Paul Mackerras 
Cc: Paul Walmsley 
Cc: Rich Felker 
Cc: Russell King 
Cc: Thomas Bogendoerfer 
Cc: Vasily Gorbik 
Cc: Yoshinori Sato 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: cma: support sysfs

2021-05-05T18:27:24+00:00

Since CMA is getting used more widely, it's more important to keep
monitoring CMA statistics for system health since it's directly related to
user experience.

This patch introduces sysfs statistics for CMA, in order to provide some
basic monitoring of the CMA allocator.

 * the number of CMA page successful allocations
 * the number of CMA page allocation failures

These two values allow the user to calcuate the allocation
failure rate for each CMA area.

e.g.)
  /sys/kernel/mm/cma/WIFI/alloc_pages_[success|fail]
  /sys/kernel/mm/cma/SENSOR/alloc_pages_[success|fail]
  /sys/kernel/mm/cma/BLUETOOTH/alloc_pages_[success|fail]

The cma_stat was intentionally allocated by dynamic allocation
to harmonize with kobject lifetime management.
https://lore.kernel.org/linux-mm/YCOAmXqt6dZkCQYs@kroah.com/

Link: https://lkml.kernel.org/r/20210324230759.2213957-1-minchan@kernel.org
Link: https://lore.kernel.org/linux-mm/20210316100433.17665-1-colin.king@canonical.com/
Signed-off-by: Minchan Kim 
Signed-off-by: Colin Ian King 

Tested-by: Dmitry Osipenko 
Reviewed-by: Dmitry Osipenko 
Reviewed-by: Greg Kroah-Hartman 
Reviewed-by: John Hubbard 
Tested-by: Anders Roxell 
Cc: Suren Baghdasaryan 
Cc: John Dias 
Cc: Matthew Wilcox (Oracle) 
Cc: Colin Ian King 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: generalize HUGETLB_PAGE_SIZE_VARIABLE

2021-05-05T18:27:20+00:00

HUGETLB_PAGE_SIZE_VARIABLE need not be defined for each individual
platform subscribing it.  Instead just make it generic.

Link: https://lkml.kernel.org/r/1614914928-22039-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual 
Suggested-by: Christoph Hellwig 
Reviewed-by: Christoph Hellwig 
Acked-by: Michael Ellerman 	[powerpc]
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Christophe Leroy 
Cc: Mike Kravetz 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/Kconfig: remove default DISCONTIGMEM_MANUAL

2021-04-30T18:20:43+00:00

Commit 214496cb18700fd7 ("ia64: make SPARSEMEM default and disable
DISCONTIGMEM") removed the last enabler of ARCH_DISCONTIGMEM_DEFAULT,
hence the memory model can no longer default to DISCONTIGMEM_MANUAL.

Link: https://lkml.kernel.org/r/20210312141208.3465520-1-geert@linux-m68k.org
Signed-off-by: Geert Uytterhoeven 
Reviewed-by: Mike Rapoport 
Reviewed-by: David Hildenbrand 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: add a io_mapping_map_user helper

2021-04-30T18:20:39+00:00

Add a helper that calls remap_pfn_range for an struct io_mapping, relying
on the pgprot pre-validation done when creating the mapping instead of
doing it at runtime.

Link: https://lkml.kernel.org/r/20210326055505.1424432-3-hch@lst.de
Signed-off-by: Christoph Hellwig 
Cc: Chris Wilson 
Cc: Daniel Vetter 
Cc: Jani Nikula 
Cc: Joonas Lahtinen 
Cc: Peter Zijlstra 
Cc: Rodrigo Vivi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

block: remove BLK_BOUNCE_ISA support

2021-04-06T15:28:17+00:00

Remove the BLK_BOUNCE_ISA support now that all users are gone.

Signed-off-by: Christoph Hellwig 
Acked-by: Martin K. Petersen 
Reviewed-by: Hannes Reinecke 
Link: https://lore.kernel.org/r/20210331073001.46776-7-hch@lst.de
Signed-off-by: Jens Axboe

media: videobuf2: Move frame_vector into media subsystem

2021-01-12T13:15:31+00:00

It's the only user. This also garbage collects the CONFIG_FRAME_VECTOR
symbol from all over the tree (well just one place, somehow omap media
driver still had this in its Kconfig, despite not using it).

Reviewed-by: John Hubbard 
Acked-by: Hans Verkuil 
Acked-by: Mauro Carvalho Chehab 
Acked-by: Tomasz Figa 
Signed-off-by: Daniel Vetter 
Cc: Jason Gunthorpe 
Cc: Pawel Osciak 
Cc: Marek Szyprowski 
Cc: Kyungmin Park 
Cc: Tomasz Figa 
Cc: Mauro Carvalho Chehab 
Cc: Andrew Morton 
Cc: John Hubbard 
Cc: Jérôme Glisse 
Cc: Jan Kara 
Cc: Dan Williams 
Cc: linux-mm@kvack.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: linux-media@vger.kernel.org
Cc: Daniel Vetter 
Signed-off-by: Daniel Vetter 
Link: https://patchwork.freedesktop.org/patch/msgid/20201127164131.2244124-7-daniel.vetter@ffwll.ch

mm/Kconfig: fix spelling mistake "whats" -> "what's"

2020-12-19T19:25:41+00:00

There is a spelling mistake in the Kconfig help text. Fix it.

Link: https://lkml.kernel.org/r/20201217172717.58203-1-colin.king@canonical.com
Signed-off-by: Colin Ian King 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds