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mm/ksm: convert get_mergeable_page() from follow_page() to folio_walk

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Let's use folio_walk instead, for example avoiding taking temporary folio
references if the folio does not even apply and getting rid of one more
follow_page() user.

Note that zeropages obviously don't apply: old code could just have
specified FOLL_DUMP.  Anon folios are never secretmem, so we don't care
about losing the check in follow_page().

Link: https://lkml.kernel.org/r/20240802155524.517137-6-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
David Hildenbrand 2024-08-02 17:55:18 +02:00 committed by Andrew Morton
parent 7dff875c94
commit 184e916c62
1 changed files with 14 additions and 12 deletions
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26
mm/ksm.c
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@ -767,26 +767,28 @@ static struct page *get_mergeable_page(struct ksm_rmap_item *rmap_item)
struct mm_struct *mm = rmap_item->mm;
unsigned long addr = rmap_item->address;
struct vm_area_struct *vma;
struct page *page;
struct page *page = NULL;
struct folio_walk fw;
struct folio *folio;
mmap_read_lock(mm);
vma = find_mergeable_vma(mm, addr);
if (!vma)
goto out;
page = follow_page(vma, addr, FOLL_GET);
if (IS_ERR_OR_NULL(page))
goto out;
if (is_zone_device_page(page))
goto out_putpage;
if (PageAnon(page)) {
folio = folio_walk_start(&fw, vma, addr, 0);
if (folio) {
if (!folio_is_zone_device(folio) &&
folio_test_anon(folio)) {
folio_get(folio);
page = fw.page;
}
folio_walk_end(&fw, vma);
}
out:
if (page) {
flush_anon_page(vma, page, addr);
flush_dcache_page(page);
} else {
out_putpage:
put_page(page);
out:
page = NULL;
}
mmap_read_unlock(mm);
return page;