Convert __add_to_page_cache_locked() into __filemap_add_folio().
Add an assertion to it that (for !hugetlbfs), the folio is naturally
aligned within the file.  Move the prototype from mm.h to pagemap.h.
Convert add_to_page_cache_lru() into filemap_add_folio().  Add a
compatibility wrapper for unconverted callers.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Reimplement __page_cache_alloc as a wrapper around filemap_alloc_folio
to allow filesystems to be converted at our leisure.  Increases
kernel text size by 133 bytes, mostly in cachefiles_read_backing_file().
pagecache_get_page() shrinks by 32 bytes, though.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

The __folio_alloc(), __folio_alloc_node() and folio_alloc() functions
are mostly for type safety, but they also ensure that the page allocator
allocates a compound page and initialises the deferred list if the page
is large enough to have one.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Reimplement lru_cache_add() as a wrapper around folio_add_lru().
Saves 159 bytes of kernel text due to removing calls to compound_head().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

This saves five calls to compound_head(), totalling 60 bytes of text.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

This is the folio equivalent of page_evictable().  Unfortunately, it's
different from !folio_test_unevictable(), but I think it's used in places
where you have to be a VM expert and can reasonably be expected to know
the difference.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

This nets us 178 bytes of savings from removing calls to compound_head.
The three callers all grow a little, but each of them will be converted
to use folios soon, so that's fine.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

The pointers stored in the page cache are folios, by definition.
This change comes with a behaviour change -- callers of readahead_folio()
are no longer required to put the page reference themselves.  This matches
how readpage works, rather than matching how readpages used to work.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

This is the folio equivalent of page_mkwrite_check_truncate().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Howells <dhowells@redhat.com>

Reimplement i_blocks_per_page() as a wrapper around i_blocks_per_folio().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Reimplement redirty_page_for_writepage() as a wrapper around
folio_redirty_for_writepage().  Account the number of pages in the
folio, add kernel-doc and move the prototype to writeback.h.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Account the number of pages in the folio that we're redirtying.
Turn account_page_dirty() into a wrapper around it.  Also turn
the comment on folio_account_redirty() into kernel-doc and
edit it slightly so it makes sense to its potential callers.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Transform clear_page_dirty_for_io() into folio_clear_dirty_for_io()
and add a compatibility wrapper.  Also move the declaration to pagemap.h
as this is page cache functionality that doesn't need to be used by the
rest of the kernel.

Increases the size of the kernel by 79 bytes.  While we remove a few
calls to compound_head(), we add a call to folio_nr_pages() to get the
stats correct for the eventual support of multi-page folios.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Turn __cancel_dirty_page() into __folio_cancel_dirty() and add wrappers.
Move the prototypes into pagemap.h since this is page cache functionality.
Saves 44 bytes of kernel text in total; 33 bytes from __folio_cancel_dirty
and 11 from two callers of cancel_dirty_page().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Get the statistics right; compound pages were being accounted as a
single page.  This didn't matter before now as no filesystem which
supported compound pages did writeback.  Also move the declaration
to pagemap.h since this is part of the page cache.  Add a wrapper for
account_page_cleaned().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Reimplement __set_page_dirty_nobuffers() as a wrapper around
filemap_dirty_folio().  Eventually folio_mark_dirty() will pass
the folio's mapping to the address space's ->dirty_folio()
operation, so add the parameter to filemap_dirty_folio() now.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Rename writeback_dirty_page() to writeback_dirty_folio() and
wait_on_page_writeback() to folio_wait_writeback().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Turn __set_page_dirty() into a wrapper around __folio_mark_dirty().
Convert account_page_dirtied() into folio_account_dirtied() and account
the number of pages in the folio to support multi-page folios.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Reimplement set_page_dirty() as a wrapper around folio_mark_dirty().
There is no change to filesystems as they were already being called
with the compound_head of the page being marked dirty.  We avoid
several calls to compound_head(), both statically (through
using folio_test_dirty() instead of PageDirty() and dynamically by
calling folio_mapping() instead of page_mapping().

Also return bool instead of int to show the range of values actually
returned, and add kernel-doc.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Rename set_page_writeback() to folio_start_writeback() to match
folio_end_writeback().  Do not bother with wrappers that return void;
callers are perfectly capable of ignoring return values.

Add wrappers for set_page_writeback(), set_page_writeback_keepwrite() and
test_set_page_writeback() for compatibililty with existing filesystems.
The main advantage of this patch is getting the statistics right,
although it does eliminate a couple of calls to compound_head().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

test_clear_page_writeback() is actually an mm-internal function, although
it's named as if it's a pagecache function.  Move it to mm/internal.h,
rename it to __folio_end_writeback() and change the return type to bool.

The conversion from page to folio is mostly about accounting the number
of pages being written back, although it does eliminate a couple of
calls to compound_head().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Allow for accounting N pages at once instead of one page at a time.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

When batching events (such as writing back N pages in a single I/O), it
is better to do one flex_proportion operation instead of N.  There is
only one caller of __fprop_inc_percpu_max(), and it's the one we're
going to change in the next patch, so rename it instead of adding a
compatibility wrapper.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>

Make this look like the newly renamed vmstat functions.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

This is the folio equivalent of migrate_page_copy(), which is retained
as a wrapper for filesystems which are not yet converted to folios.
Also convert copy_huge_page() to folio_copy().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Turn migrate_page_states() into a wrapper around folio_migrate_flags().
Also convert two functions only called from folio_migrate_flags() to
be folio-based.  ksm_migrate_page() becomes folio_migrate_ksm() and
copy_page_owner() becomes folio_copy_owner().  folio_migrate_flags()
alone shrinks by two thirds -- 1967 bytes down to 642 bytes.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Reimplement migrate_page_move_mapping() as a wrapper around
folio_migrate_mapping().  Saves 193 bytes of kernel text.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Transform page_mkclean() into folio_mkclean() and add a page_mkclean()
wrapper around folio_mkclean().

folio_mkclean is 15 bytes smaller than page_mkclean, but the kernel
is enlarged by 33 bytes due to inlining page_folio() into each caller.
This will go away once the callers are converted to use folio_mkclean().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Convert mark_page_accessed() to folio_mark_accessed().  It already
operated on the entire compound page, but now we can avoid calling
compound_head quite so many times.  Shrinks the function from 424 bytes
to 295 bytes (shrinking by 129 bytes).  The compatibility wrapper is 30
bytes, plus the 8 bytes for the exported symbol means the kernel shrinks
by 91 bytes.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

This replaces activate_page() and eliminates lots of calls to
compound_head().  Saves net 118 bytes of kernel text.  There are still
some redundant calls to page_folio() here which will be removed when
pagevec_lru_move_fn() is converted to use folios.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Idle page tracking is handled through page_ext on 32-bit architectures.
Add folio equivalents for 32-bit and move all the page compatibility
parts to common code.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>

As a default implementation, call arch_make_page_accessible n times.
If an architecture can do better, it can override this.

Also move the default implementation of arch_make_page_accessible()
from gfp.h to mm.h.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

This allows us to map a portion of a folio.  Callers can only expect
to access up to the next page boundary.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

This is a default implementation which calls flush_dcache_page() on
each page in the folio.  If architectures can do better, they should
implement their own version of it.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Convert __page_rmapping to folio_raw_mapping and move it to mm/internal.h.
It's only a couple of instructions (load and mask), so it's definitely
going to be cheaper to inline it than call it.  Leave page_rmapping
out of line.  Change page_anon_vma() to not call folio_raw_mapping() --
it's more efficient to do the subtraction than the mask.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

This is the folio equivalent of page_to_pfn().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

This function already assumed it was being passed a head page.  No real
change here, except that thp_nr_pages() compiles away on kernels with
THP compiled out while folio_nr_pages() is always present.  Also convert
page_memcg_rcu() to folio_memcg_rcu().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

These are the folio equivalents of relock_page_lruvec_irq() and
folio_lruvec_relock_irqsave().  Also convert page_matches_lruvec()
to folio_matches_lruvec().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

These are the folio equivalents of lock_page_lruvec() and similar
functions.  Also convert lruvec_memcg_debug() to take a folio.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

This replaces mem_cgroup_page_lruvec().  All callers converted.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>