linux-toradex.git/mm/highmem.c, branch v4.10

mm/highmem: make nr_free_highpages() handles all highmem zones by itself

2016-05-20T02:12:14+00:00

nr_free_highpages() manually adds statistics per each highmem zone and
returns a total value for them.  Whenever we add a new highmem zone, we
need to consider this function and it's really troublesome.  Make it
handle all highmem zones by itself.

Signed-off-by: Joonsoo Kim 
Reviewed-by: Aneesh Kumar K.V 
Cc: Rik van Riel 
Cc: Johannes Weiner 
Cc: Mel Gorman 
Cc: Laura Abbott 
Cc: Minchan Kim 
Cc: Marek Szyprowski 
Cc: Michal Nazarewicz 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/highmem: make kmap cache coloring aware

2014-08-07T01:01:22+00:00

User-visible effect:
 Architectures that choose this method of maintaining cache coherency
(MIPS and xtensa currently) are able to use high memory on cores with
aliasing data cache.  Without this fix such architectures can not use
high memory (in case of xtensa it means that at most 128 MBytes of
physical memory is available).

The problem:
 VIPT cache with way size larger than MMU page size may suffer from
aliasing problem: a single physical address accessed via different
virtual addresses may end up in multiple locations in the cache.
Virtual mappings of a physical address that always get cached in
different cache locations are said to have different colors.  L1 caching
hardware usually doesn't handle this situation leaving it up to
software.  Software must avoid this situation as it leads to data
corruption.

What can be done:
 One way to handle this is to flush and invalidate data cache every time
page mapping changes color.  The other way is to always map physical
page at a virtual address with the same color.  Low memory pages already
have this property.  Giving architecture a way to control color of high
memory page mapping allows reusing of existing low memory cache alias
handling code.

How this is done with this patch:
 Provide hooks that allow architectures with aliasing cache to align
mapping address of high pages according to their color.  Such
architectures may enforce similar coloring of low- and high-memory page
mappings and reuse existing cache management functions to support
highmem.

This code is based on the implementation of similar feature for MIPS by
Leonid Yegoshin.

Signed-off-by: Max Filippov 
Cc: Leonid Yegoshin 
Cc: Chris Zankel 
Cc: Marc Gauthier 
Cc: David Rientjes 
Cc: Steven Hill 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2012-12-20T16:37:05+00:00

Pull virtio update from Rusty Russell:
 "Some nice cleanups, and even a patch my wife did as a "live" demo for
  Latinoware 2012.

  There's a slightly non-trivial merge in virtio-net, as we cleaned up
  the virtio add_buf interface while DaveM accepted the mq virtio-net
  patches."

* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (27 commits)
  virtio_console: Add support for remoteproc serial
  virtio_console: Merge struct buffer_token into struct port_buffer
  virtio: add drv_to_virtio to make code clearly
  virtio: use dev_to_virtio wrapper in virtio
  virtio-mmio: Fix irq parsing in command line parameter
  virtio_console: Free buffers from out-queue upon close
  virtio: Convert dev_printk(KERN_ to dev_(
  virtio_console: Use kmalloc instead of kzalloc
  virtio_console: Free buffer if splice fails
  virtio: tools: make it clear that virtqueue_add_buf() no longer returns > 0
  virtio: scsi: make it clear that virtqueue_add_buf() no longer returns > 0
  virtio: rpmsg: make it clear that virtqueue_add_buf() no longer returns > 0
  virtio: net: make it clear that virtqueue_add_buf() no longer returns > 0
  virtio: console: make it clear that virtqueue_add_buf() no longer returns > 0
  virtio: make virtqueue_add_buf() returning 0 on success, not capacity.
  virtio: console: don't rely on virtqueue_add_buf() returning capacity.
  virtio_net: don't rely on virtqueue_add_buf() returning capacity.
  virtio-net: remove unused skb_vnet_hdr->num_sg field
  virtio-net: correct capacity math on ring full
  virtio: move queue_index and num_free fields into core struct virtqueue.
  ...

mm, highmem: get virtual address of the page using PKMAP_ADDR()

2012-12-12T01:22:24+00:00

In flush_all_zero_pkmaps(), we have an index of the pkmap associated with
the page.  Using this index, we can simply get virtual address of the
page.  So change it.

Signed-off-by: Joonsoo Kim 
Cc: Mel Gorman 
Reviewed-by: Minchan Kim 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm, highmem: remove page_address_pool list

2012-12-12T01:22:24+00:00

We can find free page_address_map instance without the page_address_pool.
So remove it.

Signed-off-by: Joonsoo Kim 
Cc: Mel Gorman 
Reviewed-by: Minchan Kim 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm, highmem: remove useless pool_lock

2012-12-12T01:22:24+00:00

The pool_lock protects the page_address_pool from concurrent access.  But,
access to the page_address_pool is already protected by kmap_lock.  So
remove it.

Signed-off-by: Joonsoo Kim 
Cc: Mel Gorman 
Reviewed-by: Minchan Kin 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm, highmem: use PKMAP_NR() to calculate an index of pkmap

2012-12-12T01:22:24+00:00

To calculate an index of pkmap, using PKMAP_NR() is more understandable
and maintainable, so change it.

Signed-off-by: Joonsoo Kim 
Cc: Mel Gorman 
Reviewed-by: Minchan Kim 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: highmem: don't treat PKMAP_ADDR(LAST_PKMAP) as a highmem address

2012-11-16T22:33:04+00:00

kmap_to_page returns the corresponding struct page for a virtual address
of an arbitrary mapping.  This works by checking whether the address
falls in the pkmap region and using the pkmap page tables instead of the
linear mapping if appropriate.

Unfortunately, the bounds checking means that PKMAP_ADDR(LAST_PKMAP) is
incorrectly treated as a highmem address and we can end up walking off
the end of pkmap_page_table and subsequently passing junk to pte_page.

This patch fixes the bound check to stay within the pkmap tables.

Signed-off-by: Will Deacon 
Cc: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: highmem: export kmap_to_page for modules

2012-10-22T07:49:24+00:00

Some virtio device drivers (9p) need to translate high virtual addresses
to physical addresses, which are inserted into the virtqueue for
processing by userspace.

This patch exports the kmap_to_page symbol, so that the affected drivers
can be compiled as modules.

Cc: stable@kernel.org
Signed-off-by: Will Deacon 
Signed-off-by: Rusty Russell

mm: add support for direct_IO to highmem pages

2012-08-01T01:42:47+00:00

The patch "mm: add support for a filesystem to activate swap files and use
direct_IO for writing swap pages" added support for using direct_IO to
write swap pages but it is insufficient for highmem pages.

To support highmem pages, this patch kmaps() the page before calling the
direct_IO() handler.  As direct_IO deals with virtual addresses an
additional helper is necessary for get_kernel_pages() to lookup the struct
page for a kmap virtual address.

Signed-off-by: Mel Gorman 
Acked-by: Rik van Riel 
Cc: Christoph Hellwig 
Cc: David S. Miller 
Cc: Eric B Munson 
Cc: Eric Paris 
Cc: James Morris 
Cc: Mel Gorman 
Cc: Mike Christie 
Cc: Neil Brown 
Cc: Peter Zijlstra 
Cc: Sebastian Andrzej Siewior 
Cc: Trond Myklebust 
Cc: Xiaotian Feng 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds