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mm/swapfile: remove stale reuse_swap_page()

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All users are gone, let's remove it.  We'll let SWP_STABLE_WRITES stick
around for now, as it might come in handy in the near future.

Link: https://lkml.kernel.org/r/20220131162940.210846-8-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Hildenbrand 2022-03-24 18:13:50 -07:00 committed by Linus Torvalds
parent 363106c4ce
commit 03104c2c5d
2 changed files with 0 additions and 108 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/linux/swap.h
View File

@ -515,7 +515,6 @@ extern int __swp_swapcount(swp_entry_t entry);
extern int swp_swapcount(swp_entry_t entry);
extern struct swap_info_struct *page_swap_info(struct page *);
extern struct swap_info_struct *swp_swap_info(swp_entry_t entry);
extern bool reuse_swap_page(struct page *);
extern int try_to_free_swap(struct page *);
struct backing_dev_info;
extern int init_swap_address_space(unsigned int type, unsigned long nr_pages);
@ -681,9 +680,6 @@ static inline int swp_swapcount(swp_entry_t entry)
return 0;
}
#define reuse_swap_page(page) \
(page_trans_huge_mapcount(page) == 1)
static inline int try_to_free_swap(struct page *page)
{
return 0;

104
mm/swapfile.c
View File

@ -1167,16 +1167,6 @@ out:
return NULL;
}
static struct swap_info_struct *swap_info_get(swp_entry_t entry)
{
struct swap_info_struct *p;
p = _swap_info_get(entry);
if (p)
spin_lock(&p->lock);
return p;
}
static struct swap_info_struct *swap_info_get_cont(swp_entry_t entry,
struct swap_info_struct *q)
{
@ -1601,100 +1591,6 @@ static bool page_swapped(struct page *page)
return false;
}
static int page_trans_huge_map_swapcount(struct page *page,
int *total_swapcount)
{
int i, map_swapcount, _total_swapcount;
unsigned long offset = 0;
struct swap_info_struct *si;
struct swap_cluster_info *ci = NULL;
unsigned char *map = NULL;
int swapcount = 0;
/* hugetlbfs shouldn't call it */
VM_BUG_ON_PAGE(PageHuge(page), page);
if (!IS_ENABLED(CONFIG_THP_SWAP) || likely(!PageTransCompound(page))) {
if (PageSwapCache(page))
swapcount = page_swapcount(page);
if (total_swapcount)
*total_swapcount = swapcount;
return swapcount + page_trans_huge_mapcount(page);
}
page = compound_head(page);
_total_swapcount = map_swapcount = 0;
if (PageSwapCache(page)) {
swp_entry_t entry;
entry.val = page_private(page);
si = _swap_info_get(entry);
if (si) {
map = si->swap_map;
offset = swp_offset(entry);
}
}
if (map)
ci = lock_cluster(si, offset);
for (i = 0; i < HPAGE_PMD_NR; i++) {
int mapcount = atomic_read(&page[i]._mapcount) + 1;
if (map) {
swapcount = swap_count(map[offset + i]);
_total_swapcount += swapcount;
}
map_swapcount = max(map_swapcount, mapcount + swapcount);
}
unlock_cluster(ci);
if (PageDoubleMap(page))
map_swapcount -= 1;
if (total_swapcount)
*total_swapcount = _total_swapcount;
return map_swapcount + compound_mapcount(page);
}
/*
* We can write to an anon page without COW if there are no other references
* to it. And as a side-effect, free up its swap: because the old content
* on disk will never be read, and seeking back there to write new content
* later would only waste time away from clustering.
*/
bool reuse_swap_page(struct page *page)
{
int count, total_swapcount;
VM_BUG_ON_PAGE(!PageLocked(page), page);
if (unlikely(PageKsm(page)))
return false;
count = page_trans_huge_map_swapcount(page, &total_swapcount);
if (count == 1 && PageSwapCache(page) &&
(likely(!PageTransCompound(page)) ||
/* The remaining swap count will be freed soon */
total_swapcount == page_swapcount(page))) {
if (!PageWriteback(page)) {
page = compound_head(page);
delete_from_swap_cache(page);
SetPageDirty(page);
} else {
swp_entry_t entry;
struct swap_info_struct *p;
entry.val = page_private(page);
p = swap_info_get(entry);
if (p->flags & SWP_STABLE_WRITES) {
spin_unlock(&p->lock);
return false;
}
spin_unlock(&p->lock);
}
}
return count <= 1;
}
/*
* If swap is getting full, or if there are no more mappings of this page,
* then try_to_free_swap is called to free its swap space.