linux-stable.git/include/linux/hugetlb.h, branch v5.12.2

mm/hugetlb: change hugetlb_reserve_pages() to type bool

2021-02-24T21:38:35+00:00

While reviewing a bug in hugetlb_reserve_pages, it was noticed that all
callers ignore the return value.  Any failure is considered an ENOMEM
error by the callers.

Change the function to be of type bool.  The function will return true if
the reservation was successful, false otherwise.  Callers currently assume
a zero return code indicates success.  Change the callers to look for true
to indicate success.  No functional change, only code cleanup.

Link: https://lkml.kernel.org/r/20201221192542.15732-1-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz 
Reviewed-by: Matthew Wilcox (Oracle) 
Cc: David Hildenbrand 
Cc: Dan Carpenter 
Cc: Michal Hocko 
Cc: Davidlohr Bueso 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

include/linux/hugetlb.h: add synchronization information for new hugetlb specific flags

2021-02-24T21:38:34+00:00

Add comments, no functional change.

Link: https://lkml.kernel.org/r/62a80585-2a73-10cc-4a2d-5721540d4ad2@oracle.com
Signed-off-by: Mike Kravetz 
Acked-by: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

hugetlb: convert PageHugeFreed to HPageFreed flag

2021-02-24T21:38:34+00:00

Use new hugetlb specific HPageFreed flag to replace the PageHugeFreed
interfaces.

Link: https://lkml.kernel.org/r/20210122195231.324857-6-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz 
Reviewed-by: Oscar Salvador 
Reviewed-by: Muchun Song 
Acked-by: Michal Hocko 
Cc: David Hildenbrand 
Cc: Matthew Wilcox 
Cc: Miaohe Lin 
Cc: Michal Hocko 
Cc: Naoya Horiguchi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

hugetlb: convert PageHugeTemporary() to HPageTemporary flag

2021-02-24T21:38:34+00:00

Use new hugetlb specific HPageTemporary flag to replace the
PageHugeTemporary() interfaces.  PageHugeTemporary does contain a
PageHuge() check.  However, this interface is only used within hugetlb
code where we know we are dealing with a hugetlb page.  Therefore, the
check can be eliminated.

Link: https://lkml.kernel.org/r/20210122195231.324857-5-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz 
Reviewed-by: Oscar Salvador 
Reviewed-by: Muchun Song 
Acked-by: Michal Hocko 
Cc: David Hildenbrand 
Cc: Matthew Wilcox 
Cc: Miaohe Lin 
Cc: Naoya Horiguchi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

hugetlb: convert page_huge_active() HPageMigratable flag

2021-02-24T21:38:34+00:00

Use the new hugetlb page specific flag HPageMigratable to replace the
page_huge_active interfaces.  By it's name, page_huge_active implied that
a huge page was on the active list.  However, that is not really what code
checking the flag wanted to know.  It really wanted to determine if the
huge page could be migrated.  This happens when the page is actually added
to the page cache and/or task page table.  This is the reasoning behind
the name change.

The VM_BUG_ON_PAGE() calls in the *_huge_active() interfaces are not
really necessary as we KNOW the page is a hugetlb page.  Therefore, they
are removed.

The routine page_huge_active checked for PageHeadHuge before testing the
active bit.  This is unnecessary in the case where we hold a reference or
lock and know it is a hugetlb head page.  page_huge_active is also called
without holding a reference or lock (scan_movable_pages), and can race
with code freeing the page.  The extra check in page_huge_active shortened
the race window, but did not prevent the race.  Offline code calling
scan_movable_pages already deals with these races, so removing the check
is acceptable.  Add comment to racy code.

[songmuchun@bytedance.com: remove set_page_huge_active() declaration from include/linux/hugetlb.h]
  Link: https://lkml.kernel.org/r/CAMZfGtUda+KoAZscU0718TN61cSFwp4zy=y2oZ=+6Z2TAZZwng@mail.gmail.com

Link: https://lkml.kernel.org/r/20210122195231.324857-3-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz 
Reviewed-by: Oscar Salvador 
Reviewed-by: Muchun Song 
Reviewed-by: Miaohe Lin 
Acked-by: Michal Hocko 
Cc: David Hildenbrand 
Cc: Matthew Wilcox 
Cc: Naoya Horiguchi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

hugetlb: use page.private for hugetlb specific page flags

2021-02-24T21:38:34+00:00

Patch series "create hugetlb flags to consolidate state", v3.

While discussing a series of hugetlb fixes in [1], it became evident that
the hugetlb specific page state information is stored in a somewhat
haphazard manner.  Code dealing with state information would be easier to
read, understand and maintain if this information was stored in a
consistent manner.

This series uses page.private of the hugetlb head page for storing a set
of hugetlb specific page flags.  Routines are priovided for test, set and
clear of the flags.

[1] https://lore.kernel.org/r/20210106084739.63318-1-songmuchun@bytedance.com

This patch (of 4):

As hugetlbfs evolved, state information about hugetlb pages was added.
One 'convenient' way of doing this was to use available fields in tail
pages.  Over time, it has become difficult to know the meaning or contents
of fields simply by looking at a small bit of code.  Sometimes, the naming
is just confusing.  For example: The PagePrivate flag indicates a huge
page reservation was consumed and needs to be restored if an error is
encountered and the page is freed before it is instantiated.  The
page.private field contains the pointer to a subpool if the page is
associated with one.

In an effort to make the code more readable, use page.private to contain
hugetlb specific page flags.  These flags will have test, set and clear
functions similar to those used for 'normal' page flags.  More
importantly, an enum of flag values will be created with names that
actually reflect their purpose.

In this patch,
- Create infrastructure for hugetlb specific page flag functions
- Move subpool pointer to page[1].private to make way for flags
  Create routines with meaningful names to modify subpool field
- Use new HPageRestoreReserve flag instead of PagePrivate

Conversion of other state information will happen in subsequent patches.

Link: https://lkml.kernel.org/r/20210122195231.324857-1-mike.kravetz@oracle.com
Link: https://lkml.kernel.org/r/20210122195231.324857-2-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz 
Reviewed-by: Oscar Salvador 
Acked-by: Michal Hocko 
Cc: Naoya Horiguchi 
Cc: Muchun Song 
Cc: David Hildenbrand 
Cc: Matthew Wilcox 
Cc: Miaohe Lin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/hugetlb: fix some comment typos

2021-02-24T21:38:32+00:00

Fix typos sasitfy to satisfy, reservtion to reservation, hugegpage to
hugepage and uniprocesor to uniprocessor in comments.

Link: https://lkml.kernel.org/r/20210128112028.64831-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin 
Reviewed-by: Souptick Joarder 
Cc: Mike Kravetz 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: hugetlbfs: fix cannot migrate the fallocated HugeTLB page

2021-02-05T19:03:47+00:00

If a new hugetlb page is allocated during fallocate it will not be
marked as active (set_page_huge_active) which will result in a later
isolate_huge_page failure when the page migration code would like to
move that page.  Such a failure would be unexpected and wrong.

Only export set_page_huge_active, just leave clear_page_huge_active as
static.  Because there are no external users.

Link: https://lkml.kernel.org/r/20210115124942.46403-3-songmuchun@bytedance.com
Fixes: 70c3547e36f5 (hugetlbfs: add hugetlbfs_fallocate())
Signed-off-by: Muchun Song 
Acked-by: Michal Hocko 
Reviewed-by: Mike Kravetz 
Reviewed-by: Oscar Salvador 
Cc: David Hildenbrand 
Cc: Yang Shi 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: and drivers core: Convert hugetlb_report_node_meminfo to sysfs_emit

2020-10-02T11:16:33+00:00

Convert the unbound sprintf in hugetlb_report_node_meminfo to use
sysfs_emit_at so that no possible overrun of a PAGE_SIZE buf can occur.

Signed-off-by: Joe Perches 
Acked-by: Mike Kravetz 
Link: https://lore.kernel.org/r/894b351b82da6013cde7f36ff4b5493cd0ec30d0.1600285923.git.joe@perches.com
Signed-off-by: Greg Kroah-Hartman

mm/hugetlb: make hugetlb migration callback CMA aware

2020-08-12T17:58:02+00:00

new_non_cma_page() in gup.c requires to allocate the new page that is not
on the CMA area.  new_non_cma_page() implements it by using allocation
scope APIs.

However, there is a work-around for hugetlb.  Normal hugetlb page
allocation API for migration is alloc_huge_page_nodemask().  It consists
of two steps.  First is dequeing from the pool.  Second is, if there is no
available page on the queue, allocating by using the page allocator.

new_non_cma_page() can't use this API since first step (deque) isn't aware
of scope API to exclude CMA area.  So, new_non_cma_page() exports hugetlb
internal function for the second step, alloc_migrate_huge_page(), to
global scope and uses it directly.  This is suboptimal since hugetlb pages
on the queue cannot be utilized.

This patch tries to fix this situation by making the deque function on
hugetlb CMA aware.  In the deque function, CMA memory is skipped if
PF_MEMALLOC_NOCMA flag is found.

Signed-off-by: Joonsoo Kim 
Signed-off-by: Andrew Morton 
Acked-by: Mike Kravetz 
Acked-by: Vlastimil Babka 
Acked-by: Michal Hocko 
Cc: "Aneesh Kumar K . V" 
Cc: Christoph Hellwig 
Cc: Naoya Horiguchi 
Cc: Roman Gushchin 
Link: http://lkml.kernel.org/r/1596180906-8442-2-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds