folio_alloc_noprof) wasn't calling the _noprof version, causing
allocations to be accounted here instead of to the caller

Link: https://lkml.kernel.org/r/20240901202459.4867-1-kent.overstreet@linux.devSigned-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

This patch tries to cleanup some function description:

  * function name mismatch
  * parameter name mismatch
  * parameter all end up with ':'
  * not prefix '*' if parameter is a pointer

There is still some missing description of parameters, I didn't add them
since I am not sure the exact meaning.

Link: https://lkml.kernel.org/r/20240830220400.2007-1-richard.weiyang@gmail.comSigned-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

When page del from buddy and need expand, it will account free_pages in
zone's migratetype.

The current way is to subtract the page number of the current order when
deleting, and then add it back when expanding.

This is unnecessary, as when migrating the same type, we can directly
record the difference between the high-order pages and the expand added,
and then subtract it directly.

This patch merge that, only when del and expand done, then account
free_pages.

Link: https://lkml.kernel.org/r/20240826064048.187790-1-link@vivo.comSigned-off-by: Huan Yang <link@vivo.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

It was recently observed at [1] that during the folio unmapping stage of
migration, when the PTEs are cleared, a racing thread faulting on that
folio may increase the refcount of the folio, sleep on the folio lock (the
migration path has the lock), and migration ultimately fails when
asserting the actual refcount against the expected.  Thereby, the
migration selftest fails on shared-anon mappings.  The above enforces the
fact that migration is a best-effort service, therefore, it is wrong to
fail the test for just a single failure; hence, fail the test after 100
consecutive failures (where 100 is still a subjective choice).  Note that,
this has no effect on the execution time of the test since that is
controlled by a timeout.

[1] https://lore.kernel.org/all/20240801081657.1386743-1-dev.jain@arm.com/

Link: https://lkml.kernel.org/r/20240830051609.4037834-1-dev.jain@arm.comSigned-off-by: Dev Jain <dev.jain@arm.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Tested-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

list_head can be initialized automatically with LIST_HEAD() instead of
calling INIT_LIST_HEAD().  Here we can simplify the code.

Link: https://lkml.kernel.org/r/20240828041216.1222582-1-lihongbo22@huawei.comSigned-off-by: Hongbo Li <lihongbo22@huawei.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

If disabled, THPs faulted in or collapsed will not be added to
_deferred_list, and therefore won't be considered for splitting under
memory pressure if underused.

Link: https://lkml.kernel.org/r/20240830100438.3623486-7-usamaarif642@gmail.comSigned-off-by: Usama Arif <usamaarif642@gmail.com>
Cc: Alexander Zhu <alexlzhu@fb.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Shuang Zhai <zhais@google.com>
Cc: Shuang Zhai <szhai2@cs.rochester.edu>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

This is an attempt to mitigate the issue of running out of memory when THP
is always enabled.  During runtime whenever a THP is being faulted in
(__do_huge_pmd_anonymous_page) or collapsed by khugepaged
(collapse_huge_page), the THP is added to _deferred_list.  Whenever memory
reclaim happens in linux, the kernel runs the deferred_split shrinker
which goes through the _deferred_list.

If the folio was partially mapped, the shrinker attempts to split it.  If
the folio is not partially mapped, the shrinker checks if the THP was
underused, i.e.  how many of the base 4K pages of the entire THP were
zero-filled.  If this number goes above a certain threshold (decided by
/sys/kernel/mm/transparent_hugepage/khugepaged/max_ptes_none), the
shrinker will attempt to split that THP.  Then at remap time, the pages
that were zero-filled are mapped to the shared zeropage, hence saving
memory.

Link: https://lkml.kernel.org/r/20240830100438.3623486-6-usamaarif642@gmail.comSigned-off-by: Usama Arif <usamaarif642@gmail.com>
Suggested-by: Rik van Riel <riel@surriel.com>
Co-authored-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alexander Zhu <alexlzhu@fb.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Shuang Zhai <zhais@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Shuang Zhai <szhai2@cs.rochester.edu>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Currently folio->_deferred_list is used to keep track of partially_mapped
folios that are going to be split under memory pressure.  In the next
patch, all THPs that are faulted in and collapsed by khugepaged are also
going to be tracked using _deferred_list.

This patch introduces a pageflag to be able to distinguish between
partially mapped folios and others in the deferred_list at split time in
deferred_split_scan.  Its needed as __folio_remove_rmap decrements
_mapcount, _large_mapcount and _entire_mapcount, hence it won't be
possible to distinguish between partially mapped folios and others in
deferred_split_scan.

Eventhough it introduces an extra flag to track if the folio is partially
mapped, there is no functional change intended with this patch and the
flag is not useful in this patch itself, it will become useful in the next
patch when _deferred_list has non partially mapped folios.

Link: https://lkml.kernel.org/r/20240830100438.3623486-5-usamaarif642@gmail.comSigned-off-by: Usama Arif <usamaarif642@gmail.com>
Cc: Alexander Zhu <alexlzhu@fb.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Shuang Zhai <zhais@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Shuang Zhai <szhai2@cs.rochester.edu>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

When a THP is split, any subpage that is zero-filled will be mapped to the
shared zeropage, hence saving memory.  Add selftest to verify this by
allocating zero-filled THP and comparing RssAnon before and after split.

Link: https://lkml.kernel.org/r/20240830100438.3623486-4-usamaarif642@gmail.comSigned-off-by: Alexander Zhu <alexlzhu@fb.com>
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Acked-by: Rik van Riel <riel@surriel.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Shuang Zhai <zhais@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Shuang Zhai <szhai2@cs.rochester.edu>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Patch series "mm: split underused THPs", v5.

The current upstream default policy for THP is always.  However, Meta uses
madvise in production as the current THP=always policy vastly
overprovisions THPs in sparsely accessed memory areas, resulting in
excessive memory pressure and premature OOM killing.  Using madvise +
relying on khugepaged has certain drawbacks over THP=always.  Using
madvise hints mean THPs aren't "transparent" and require userspace
changes.  Waiting for khugepaged to scan memory and collapse pages into
THP can be slow and unpredictable in terms of performance (i.e.  you dont
know when the collapse will happen), while production environments require
predictable performance.  If there is enough memory available, its better
for both performance and predictability to have a THP from fault time,
i.e.  THP=always rather than wait for khugepaged to collapse it, and deal
with sparsely populated THPs when the system is running out of memory.

This patch series is an attempt to mitigate the issue of running out of
memory when THP is always enabled.  During runtime whenever a THP is being
faulted in or collapsed by khugepaged, the THP is added to a list. 
Whenever memory reclaim happens, the kernel runs the deferred_split
shrinker which goes through the list and checks if the THP was underused,
i.e.  how many of the base 4K pages of the entire THP were zero-filled. 
If this number goes above a certain threshold, the shrinker will attempt
to split that THP.  Then at remap time, the pages that were zero-filled
are mapped to the shared zeropage, hence saving memory.  This method
avoids the downside of wasting memory in areas where THP is sparsely
filled when THP is always enabled, while still providing the upside THPs
like reduced TLB misses without having to use madvise.

Meta production workloads that were CPU bound (>99% CPU utilzation) were
tested with THP shrinker.  The results after 2 hours are as follows:

                            | THP=madvise |  THP=always   | THP=always
                            |             |               | + shrinker series
                            |             |               | + max_ptes_none=409
-----------------------------------------------------------------------------
Performance improvement     |      -      |    +1.8%      |     +1.7%
(over THP=madvise)          |             |               |
-----------------------------------------------------------------------------
Memory usage                |    54.6G    | 58.8G (+7.7%) |   55.9G (+2.4%)
-----------------------------------------------------------------------------
max_ptes_none=409 means that any THP that has more than 409 out of 512
(80%) zero filled filled pages will be split.

To test out the patches, the below commands without the shrinker will
invoke OOM killer immediately and kill stress, but will not fail with the
shrinker:

echo 450 > /sys/kernel/mm/transparent_hugepage/khugepaged/max_ptes_none
mkdir /sys/fs/cgroup/test
echo $$ > /sys/fs/cgroup/test/cgroup.procs
echo 20M > /sys/fs/cgroup/test/memory.max
echo 0 > /sys/fs/cgroup/test/memory.swap.max
# allocate twice memory.max for each stress worker and touch 40/512 of
# each THP, i.e. vm-stride 50K.
# With the shrinker, max_ptes_none of 470 and below won't invoke OOM
# killer.
# Without the shrinker, OOM killer is invoked immediately irrespective
# of max_ptes_none value and kills stress.
stress --vm 1 --vm-bytes 40M --vm-stride 50K


This patch (of 5):

Here being unused means containing only zeros and inaccessible to
userspace.  When splitting an isolated thp under reclaim or migration, the
unused subpages can be mapped to the shared zeropage, hence saving memory.
This is particularly helpful when the internal fragmentation of a thp is
high, i.e.  it has many untouched subpages.

This is also a prerequisite for THP low utilization shrinker which will be
introduced in later patches, where underutilized THPs are split, and the
zero-filled pages are freed saving memory.

Link: https://lkml.kernel.org/r/20240830100438.3623486-1-usamaarif642@gmail.com
Link: https://lkml.kernel.org/r/20240830100438.3623486-3-usamaarif642@gmail.comSigned-off-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Tested-by: Shuang Zhai <zhais@google.com>
Cc: Alexander Zhu <alexlzhu@fb.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Shuang Zhai <szhai2@cs.rochester.edu>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Three points for this change:

1. We should consolidate all warnings in one place. Currently, the
   order > 1 warning is in the hotpath, while others are in less
   likely scenarios. Moving all warnings to the slowpath will reduce
   the overhead for order > 1 and increase the visibility of other
   warnings.

2. We currently have two warnings for order: one for order > 1 in
   the hotpath and another for order > costly_order in the laziest
   path. I suggest standardizing on order > 1 since it's been in
   use for a long time.

3. We don't need to check for __GFP_NOWARN in this case. __GFP_NOWARN
   is meant to suppress allocation failure reports, but here we're
   dealing with bug detection, not allocation failures. So replace
   WARN_ON_ONCE_GFP by WARN_ON_ONCE.

[v-songbaohua@oppo.com: also update the doc for __GFP_NOFAIL with order > 1]
  Link: https://lkml.kernel.org/r/20240903223935.1697-1-21cnbao@gmail.com
Link: https://lkml.kernel.org/r/20240830202823.21478-4-21cnbao@gmail.comSigned-off-by: Barry Song <v-songbaohua@oppo.com>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: "Eugenio Pérez" <eperezma@redhat.com>
Cc: Hailong.Liu <hailong.liu@oppo.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Xie Yongji <xieyongji@bytedance.com>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Non-blocking allocation with __GFP_NOFAIL is not supported and may still
result in NULL pointers (if we don't return NULL, we result in busy-loop
within non-sleepable contexts):

static inline struct page *
__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
						struct alloc_context *ac)
{
	...
	/*
	 * Make sure that __GFP_NOFAIL request doesn't leak out and make sure
	 * we always retry
	 */
	if (gfp_mask & __GFP_NOFAIL) {
		/*
		 * All existing users of the __GFP_NOFAIL are blockable, so warn
		 * of any new users that actually require GFP_NOWAIT
		 */
		if (WARN_ON_ONCE_GFP(!can_direct_reclaim, gfp_mask))
			goto fail;
		...
	}
	...
fail:
	warn_alloc(gfp_mask, ac->nodemask,
			"page allocation failure: order:%u", order);
got_pg:
	return page;
}

Highlight this in the documentation of __GFP_NOFAIL so that non-mm
subsystems can reject any illegal usage of __GFP_NOFAIL with GFP_ATOMIC,
GFP_NOWAIT, etc.

Link: https://lkml.kernel.org/r/20240830202823.21478-3-21cnbao@gmail.comSigned-off-by: Barry Song <v-songbaohua@oppo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Eugenio Pérez" <eperezma@redhat.com>
Cc: Hailong.Liu <hailong.liu@oppo.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Xie Yongji <xieyongji@bytedance.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Patch series "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL
and improve related doc and warn", v4.

__GFP_NOFAIL carries the semantics of never failing, so its callers do not
check the return value:

  %__GFP_NOFAIL: The VM implementation _must_ retry infinitely: the caller
  cannot handle allocation failures. The allocation could block
  indefinitely but will never return with failure. Testing for
  failure is pointless.

However, __GFP_NOFAIL can sometimes fail if it exceeds size limits or is
used with GFP_ATOMIC/GFP_NOWAIT in a non-sleepable context.  This patchset
handles illegal using __GFP_NOFAIL together with GFP_ATOMIC lacking
__GFP_DIRECT_RECLAIM(without this, we can't do anything to reclaim memory
to satisfy the nofail requirement) and improve related document and
warnings.

The proper size limits for __GFP_NOFAIL will be handled separately after
more discussions.


This patch (of 3):

mm doesn't support non-blockable __GFP_NOFAIL allocation.  Because
persisting in providing __GFP_NOFAIL services for non-block users who
cannot perform direct memory reclaim may only result in an endless busy
loop.

Therefore, in such cases, the current mm-core may directly return a NULL
pointer:

static inline struct page *
__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
                                                struct alloc_context *ac)
{
        ...
        if (gfp_mask & __GFP_NOFAIL) {
                /*
                 * All existing users of the __GFP_NOFAIL are blockable, so warn
                 * of any new users that actually require GFP_NOWAIT
                 */
                if (WARN_ON_ONCE_GFP(!can_direct_reclaim, gfp_mask))
                        goto fail;
                ...
        }
        ...
fail:
        warn_alloc(gfp_mask, ac->nodemask,
                        "page allocation failure: order:%u", order);
got_pg:
        return page;
}

Unfortuantely, vpda does that nofail allocation under non-sleepable lock. 
A possible way to fix that is to move the pages allocation out of the lock
into the caller, but having to allocate a huge number of pages and
auxiliary page array seems to be problematic as well per Tetsuon: " You
should implement proper error handling instead of using __GFP_NOFAIL if
count can become large."

So I chose another way, which does not release kernel bounce pages when
user tries to register userspace bounce pages.  Then we can avoid
allocating in paths where failure is not expected.(e.g in the release). 
We pay this for more memory usage as we don't release kernel bounce pages
but further optimizations could be done on top.

[v-songbaohua@oppo.com: Refine the changelog]
Link: https://lkml.kernel.org/r/20240830202823.21478-1-21cnbao@gmail.com
Link: https://lkml.kernel.org/r/20240830202823.21478-2-21cnbao@gmail.com
Fixes: 6c77ed22 ("vduse: Support using userspace pages as bounce buffer")
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Reviewed-by: Xie Yongji <xieyongji@bytedance.com>
Tested-by: Xie Yongji <xieyongji@bytedance.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hailong.Liu <hailong.liu@oppo.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yafang Shao <laoar.shao@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Eugenio Pérez" <eperezma@redhat.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

The mutex array pointer shares a cacheline with the spinlock:
ffffffff84187480 B hugetlb_fault_mutex_table
ffffffff84187488 B hugetlb_lock

This is because the former is annotated with a macro forcing cacheline
alignment.  I suspect it was meant to be the variant which on top of it
makes sure the object does not share the cacheline with anyone.

Since array pointer itself is de facto read-only such an annotation does
not make sense there anyway.  Instead mark it __ro_after_init along with
the size var.

Do however move the spinlock out of the way.

[akpm@linux-foundation.org: move section directives to the end of the definitions, per convention]
[akpm@linux-foundation.org: DEFINE_SPINLOCK doesn't permit section modifiers at end-of-definition]
Link: https://lkml.kernel.org/r/20240828160704.1425767-1-mjguzik@gmail.comSigned-off-by: Mateusz Guzik <mjguzik@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Although shmem_get_folio_gfp() is correctly putting inodes on the
shrinklist according to the folio size, shmem_unused_huge_shrink() was
still dealing with that shrinklist in terms of HPAGE_PMD_SIZE.

Generalize that; and to handle the mixture of sizes more sensibly,
shmem_alloc_and_add_folio() give it a number of pages to be freed
(approximate: no need to minimize that with an exact calculation) instead
of a number of inodes to split.

[akpm@linux-foundation.org: comment tweak, per David]
Link: https://lkml.kernel.org/r/d8c40850-6774-7a93-1e2c-8d941683b260@google.comSigned-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

There has been a long-standing and very minor off-by-one, where
shmem_get_folio_gfp() decides if a large folio extends beyond i_size far
enough to leave a page or more for freeing later under pressure.

This is not something needed for stable: but it will be proportionately
more significant as support for smaller large folios is added, and is best
fixed before duplicating the check in other places.

Link: https://lkml.kernel.org/r/d8e75079-af2d-8519-56df-6be1dccc247a@google.com
Fixes: 779750d2 ("shmem: split huge pages beyond i_size under memory pressure")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Just do what mt_dump_range64() does.

Dump the error message based on format.

Link: https://lkml.kernel.org/r/20240826012422.29935-2-richard.weiyang@gmail.comSigned-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mt_dump_arange64() only applies to an entry whose type is maple_arange_64,
in which mte_is_leaf() must return false.

Since mte_is_leaf() here is always false, we can remove this condition
check.

Link: https://lkml.kernel.org/r/20240826012422.29935-1-richard.weiyang@gmail.comSigned-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

We added a public Google calendar for easy sharing of DAMON bi-weekly
meetups[1].  Add it to the official document for a better visibility.

[1] https://lore.kernel.org/all/20240717235812.53087-1-sj@kernel.org/

Link: https://lkml.kernel.org/r/20240826015741.80707-4-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

maintainer-profile.rst for DAMON separates the links and target
definitions.  It is not really necessary, and only makes the readability
worse.  At least the definitions need the section title (say,
"References").  Just add the links in place on the doc.

Link: https://lkml.kernel.org/r/20240826015741.80707-3-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Patch series "Docs/damon: update GitHub repo URLs and maintainer-profile".

Replace GitHub URLS on DAMON documents for none-kernel parts DAMON repos
with new ones[1] via the first patch.  With following two patches,
wordsmith maitnainer-profile for better readability, and document the
Google clendsar for bi-weekly meetups, respectively.

[1] https://lore.kernel.org/20240813232158.83903-1-sj@kernel.org


This patch (of 3):

GitHub repos for non-kernel parts of DAMON project including 'damo',
'damon-tests' and 'damoos' will be moved[1] from 'awslabs' org to
'damonitor', by 2024-09-05.  Update related URLs in kernel tree.

[1] https://lore.kernel.org/20240813232158.83903-1-sj@kernel.org

Link: https://lkml.kernel.org/r/20240826015741.80707-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20240826015741.80707-2-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

This reverts commit 0742cadf5e4c ("mm/damon/lru_sort: adjust local
variable to dynamic allocation").

The commit was introduced to avoid unnecessary usage of stack memory for
per-scheme region priorities histogram buffer.  The fix is nice, but the
point of the fix looks not very clear if the commit message is not read
together.  That's mainly because the buffer is a private field, which
means it is hidden from the DAMON API users.  That's not the fault of the
fix but the underlying data structure.

Now the per-scheme histogram buffer is gone, so the problem that the
commit was fixing is also removed.  The use of kmemdup() has no more point
but just making the code bit difficult to understand.  Revert the fix.

Link: https://lkml.kernel.org/r/20240826042323.87025-5-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Nobody is reading from or writing to the per-scheme region priorities
histogram buffer.  It is only wasting memory.  Remove it.

Link: https://lkml.kernel.org/r/20240826042323.87025-4-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Replace the usage of per-quota region priorities histogram buffer with the
per-context one.  After this change, the per-quota histogram is not used
by anyone, and hence it is ready to be removed.

Link: https://lkml.kernel.org/r/20240826042323.87025-3-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Patch series "replace per-quota region priorities histogram buffer with
per-context one".

Each DAMOS quota (struct damos_quota) maintains a histogram for total
regions size per its prioritization score.  DAMOS calcultes minimum
prioritization score of regions that are ok to apply the DAMOS action to
while respecting the quota.  The histogram is constructed only for the
calculation of the minimum score in damos_adjust_quota() for each quota
which called by kdamond_fn().

Hence, there is no real reason to have per-quota histogram.  Only
per-kdamond histogram is needed, since parallel kdamonds could have races
otherwise.  The current implementation is only wasting the memory, and can
easily cause unintended stack usage[1].

So, introducing a per-kdamond histogram and replacing the per-quota one
with it would be the right solution for the issue.  However, supporting
multiple DAMON contexts per kdamond is still an ongoing work[2] without a
clear estimated time of arrival.  Meanwhile, per-context histogram could
be an effective and straightforward solution having no blocker.  Let's fix
the problem first in the way.


This patch (of 4):

Introduce per-context buffer for region priority scores-total size
histogram.  Same to the per-quota one (->histogram of struct damos_quota),
the new buffer is hidden from DAMON API users by being defined as a
private field of DAMON context structure.  It is dynamically allocated and
de-allocated at the beginning and ending of the execution of the kdamond
by kdamond_fn() itself.

[1] commit 0742cadf5e4c ("mm/damon/lru_sort: adjust local variable to dynamic allocation")
[2] https://lore.kernel.org/20240531122320.909060-1-yorha.op@gmail.com

Link: https://lkml.kernel.org/r/20240826042323.87025-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20240826042323.87025-2-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

There are no more callers of putback_lru_page(), remove it.

Link: https://lkml.kernel.org/r/20240826065814.1336616-7-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

There are no more callers of isolate_lru_page(), remove it.

[wangkefeng.wang@huawei.com: convert page to folio in comment and document, per Matthew]
  Link: https://lkml.kernel.org/r/20240826144114.1928071-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240826065814.1336616-6-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Saves a couple of calls to compound_head() and remove last two callers of
putback_lru_page().

Link: https://lkml.kernel.org/r/20240826065814.1336616-5-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

The page for migrate_device_unmap() already has a reference, so it is safe
to convert the page to folio to save a few calls to compound_head(), which
removes the last isolate_lru_page() call.

Link: https://lkml.kernel.org/r/20240826065814.1336616-4-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Save two calls to compound_head() and use folio throughout.

Link: https://lkml.kernel.org/r/20240826065814.1336616-3-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Patch series "mm: finish isolate/putback_lru_page()".

Convert to use more folios in migrate_device.c, then we could remove
isolate_lru_page() and putback_lru_page().  


This patch (of 6):

Save a few calls to compound_head() and use folio throughout.

Link: https://lkml.kernel.org/r/20240826065814.1336616-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240826065814.1336616-2-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Retrieve a folio from the page cache rather than a page.  Saves a couple
of conversions between page & folio.

Link: https://lkml.kernel.org/r/20240826202138.3804238-1-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

When a THP is added to the deferred_list due to partially mapped, its
partial pages are unused, leading to wasted memory and potentially
increasing memory reclamation pressure.

Detailing the specifics of how unmapping occurs is quite difficult and not
that useful, so we adopt a simple approach: each time a THP enters the
deferred_list, we increment the count by 1; whenever it leaves for any
reason, we decrement the count by 1.

Link: https://lkml.kernel.org/r/20240824010441.21308-3-21cnbao@gmail.comSigned-off-by: Barry Song <v-songbaohua@oppo.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Chuanhua Han <hanchuanhua@oppo.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuai Yuan <yuanshuai@oppo.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Patch series "mm: count the number of anonymous THPs per size", v4.

Knowing the number of transparent anon THPs in the system is crucial
for performance analysis. It helps in understanding the ratio and
distribution of THPs versus small folios throughout the system.

Additionally, partial unmapping by userspace can lead to significant waste
of THPs over time and increase memory reclamation pressure. We need this
information for comprehensive system tuning.


This patch (of 2):

Let's track for each anonymous THP size, how many of them are currently
allocated.  We'll track the complete lifespan of an anon THP, starting
when it becomes an anon THP ("large anon folio") (->mapping gets set),
until it gets freed (->mapping gets cleared).

Introduce a new "nr_anon" counter per THP size and adjust the
corresponding counter in the following cases:
* We allocate a new THP and call folio_add_new_anon_rmap() to map
   it the first time and turn it into an anon THP.
* We split an anon THP into multiple smaller ones.
* We migrate an anon THP, when we prepare the destination.
* We free an anon THP back to the buddy.

Note that AnonPages in /proc/meminfo currently tracks the total number of
*mapped* anonymous *pages*, and therefore has slightly different
semantics.  In the future, we might also want to track "nr_anon_mapped"
for each THP size, which might be helpful when comparing it to the number
of allocated anon THPs (long-term pinning, stuck in swapcache, memory
leaks, ...).

Further note that for now, we only track anon THPs after they got their
->mapping set, for example via folio_add_new_anon_rmap().  If we would
allocate some in the swapcache, they will only show up in the statistics
for now after they have been mapped to user space the first time, where we
call folio_add_new_anon_rmap().

[akpm@linux-foundation.org: documentation fixups, per David]
  Link: https://lkml.kernel.org/r/3e8add35-e26b-443b-8a04-1078f4bc78f6@redhat.com
Link: https://lkml.kernel.org/r/20240824010441.21308-1-21cnbao@gmail.com
Link: https://lkml.kernel.org/r/20240824010441.21308-2-21cnbao@gmail.comSigned-off-by: Barry Song <v-songbaohua@oppo.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Chuanhua Han <hanchuanhua@oppo.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuai Yuan <yuanshuai@oppo.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Previously we had a situation where shmem mTHP controls and stats were not
exposed for some supported sizes and were exposed for some unsupported
sizes.  So let's clean that up.

Anon mTHP can support all large orders [2, PMD_ORDER].  But shmem can
support all large orders [1, MAX_PAGECACHE_ORDER].  However, per-size
shmem controls and stats were previously being exposed for all the anon
mTHP orders, meaning order-1 was not present, and for arm64 64K base
pages, orders 12 and 13 were exposed but were not supported internally.

Tidy this all up by defining ctrl and stats attribute groups for anon and
file separately.  Anon ctrl and stats groups are populated for all orders
in THP_ORDERS_ALL_ANON and file ctrl and stats groups are populated for
all orders in THP_ORDERS_ALL_FILE_DEFAULT.

Additionally, create "any" ctrl and stats attribute groups which are
populated for all orders in (THP_ORDERS_ALL_ANON |
THP_ORDERS_ALL_FILE_DEFAULT).  swpout stats use this since they apply to
anon and shmem.

The side-effect of all this is that different hugepage-*kB directories
contain different sets of controls and stats, depending on which memory
types support that size.  This approach is preferred over the alternative,
which is to populate dummy controls and stats for memory types that do not
support a given size.

[ryan.roberts@arm.com: file pages and shmem can also be split]
  Link: https://lkml.kernel.org/r/f7ced14c-8bc5-405f-bee7-94f63980f525@arm.comLink: https://lkml.kernel.org/r/20240808111849.651867-3-ryan.roberts@arm.comSigned-off-by: Ryan Roberts <ryan.roberts@arm.com>
Tested-by: Barry Song <baohua@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Patch series "Shmem mTHP controls and stats improvements", v3.

This is a small series to tidy up the way the shmem controls and stats are
exposed.  These patches were previously part of the series at [2], but I
decided to split them out since they can go in independently.


This patch (of 2):

Let's move count_mthp_stat() so that it's always defined, even when THP is
disabled.  Previously uses of the function in files such as shmem.c, which
are compiled even when THP is disabled, required ugly THP ifdeferry.  With
this cleanup, we can remove those ifdefs and the function resolves to a
nop when THP is disabled.

I shortly plan to call count_mthp_stat() from more THP-invariant source
files.

Link: https://lkml.kernel.org/r/20240808111849.651867-1-ryan.roberts@arm.com
Link: https://lkml.kernel.org/r/20240808111849.651867-2-ryan.roberts@arm.comSigned-off-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: Barry Song <baohua@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Lance Yang <ioworker0@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Use the isolate_folio_to_list() to unify hugetlb/LRU/non-LRU folio
isolation, which cleanup code a bit and save a few calls to
compound_head().

[wangkefeng.wang@huawei.com: various fixes]
  Link: https://lkml.kernel.org/r/20240829150500.2599549-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240827114728.3212578-6-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Add isolate_folio_to_list() helper to try to isolate HugeTLB, no-LRU
movable and LRU folios to a list, which will be reused by
do_migrate_range() from memory hotplug soon, also drop the
mf_isolate_folio() since we could directly use new helper in the
soft_offline_in_use_page().

Link: https://lkml.kernel.org/r/20240827114728.3212578-5-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Tested-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Commit b15c8726 ("hwpoison, memory_hotplug: allow hwpoisoned pages to
be offlined") don't handle the hugetlb pages, the endless loop still occur
if offline a hwpoison hugetlb page, luckly, after the commit e591ef7d
("mm, hwpoison,hugetlb,memory_hotplug: hotremove memory section with
hwpoisoned hugepage"), the HPageMigratable of hugetlb page will be
cleared, and the hwpoison hugetlb page will be skipped in
scan_movable_pages(), so the endless loop issue is fixed.

However if the HPageMigratable() check passed(without reference and lock),
the hugetlb page may be hwpoisoned, it won't cause issue since the
hwpoisoned page will be handled correctly in the next movable pages scan
loop, and it will be isolated in do_migrate_range() but fails to migrate. 
In order to avoid the unnecessary isolation and unify all hwpoisoned page
handling, let's unconditionally check hwpoison firstly, and if it is a
hwpoisoned hugetlb page, try to unmap it as the catch all safety net like
normal page does.

Link: https://lkml.kernel.org/r/20240827114728.3212578-4-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Add unmap_poisoned_folio() helper which will be reused by
do_migrate_range() from memory hotplug soon.

[akpm@linux-foundation.org: whitespace tweak, per Miaohe Lin]
  Link: https://lkml.kernel.org/r/1f80c7e3-c30d-1ac1-6a36-d1a5f5907f7c@huawei.com
Link: https://lkml.kernel.org/r/20240827114728.3212578-3-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>