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filemap: Return only folios from find_get_entries()
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The callers have all been converted to work on folios, so convert
find_get_entries() to return a batch of folios instead of pages.
We also now return multiple large folios in a single call.

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Reviewed-by: William Kucharski <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
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Matthew Wilcox (Oracle) committed Jan 8, 2022
1 parent 25d6a23 commit 0e499ed
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Showing 5 changed files with 59 additions and 69 deletions.
2 changes: 0 additions & 2 deletions include/linux/pagemap.h
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Original file line number Diff line number Diff line change
Expand Up @@ -592,8 +592,6 @@ static inline struct page *find_subpage(struct page *head, pgoff_t index)
return head + (index & (thp_nr_pages(head) - 1));
}

unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
pgoff_t end, struct pagevec *pvec, pgoff_t *indices);
unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start,
pgoff_t end, unsigned int nr_pages,
struct page **pages);
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43 changes: 11 additions & 32 deletions mm/filemap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2015,57 +2015,36 @@ static inline struct folio *find_get_entry(struct xa_state *xas, pgoff_t max,
* @mapping: The address_space to search
* @start: The starting page cache index
* @end: The final page index (inclusive).
* @pvec: Where the resulting entries are placed.
* @fbatch: Where the resulting entries are placed.
* @indices: The cache indices corresponding to the entries in @entries
*
* find_get_entries() will search for and return a batch of entries in
* the mapping. The entries are placed in @pvec. find_get_entries()
* takes a reference on any actual pages it returns.
* the mapping. The entries are placed in @fbatch. find_get_entries()
* takes a reference on any actual folios it returns.
*
* The search returns a group of mapping-contiguous page cache entries
* with ascending indexes. There may be holes in the indices due to
* not-present pages.
* The entries have ascending indexes. The indices may not be consecutive
* due to not-present entries or large folios.
*
* Any shadow entries of evicted pages, or swap entries from
* Any shadow entries of evicted folios, or swap entries from
* shmem/tmpfs, are included in the returned array.
*
* If it finds a Transparent Huge Page, head or tail, find_get_entries()
* stops at that page: the caller is likely to have a better way to handle
* the compound page as a whole, and then skip its extent, than repeatedly
* calling find_get_entries() to return all its tails.
*
* Return: the number of pages and shadow entries which were found.
* Return: The number of entries which were found.
*/
unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
pgoff_t end, struct pagevec *pvec, pgoff_t *indices)
pgoff_t end, struct folio_batch *fbatch, pgoff_t *indices)
{
XA_STATE(xas, &mapping->i_pages, start);
struct folio *folio;
unsigned int ret = 0;
unsigned nr_entries = PAGEVEC_SIZE;

rcu_read_lock();
while ((folio = find_get_entry(&xas, end, XA_PRESENT)) != NULL) {
struct page *page = &folio->page;
/*
* Terminate early on finding a THP, to allow the caller to
* handle it all at once; but continue if this is hugetlbfs.
*/
if (!xa_is_value(folio) && folio_test_large(folio) &&
!folio_test_hugetlb(folio)) {
page = folio_file_page(folio, xas.xa_index);
nr_entries = ret + 1;
}

indices[ret] = xas.xa_index;
pvec->pages[ret] = page;
if (++ret == nr_entries)
indices[fbatch->nr] = xas.xa_index;
if (!folio_batch_add(fbatch, folio))
break;
}
rcu_read_unlock();

pvec->nr = ret;
return ret;
return folio_batch_count(fbatch);
}

/**
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4 changes: 4 additions & 0 deletions mm/internal.h
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,8 @@
#include <linux/pagemap.h>
#include <linux/tracepoint-defs.h>

struct folio_batch;

/*
* The set of flags that only affect watermark checking and reclaim
* behaviour. This is used by the MM to obey the caller constraints
Expand Down Expand Up @@ -92,6 +94,8 @@ static inline void force_page_cache_readahead(struct address_space *mapping,

unsigned find_lock_entries(struct address_space *mapping, pgoff_t start,
pgoff_t end, struct pagevec *pvec, pgoff_t *indices);
unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
pgoff_t end, struct folio_batch *fbatch, pgoff_t *indices);
void filemap_free_folio(struct address_space *mapping, struct folio *folio);
int truncate_inode_folio(struct address_space *mapping, struct folio *folio);

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36 changes: 20 additions & 16 deletions mm/shmem.c
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Original file line number Diff line number Diff line change
Expand Up @@ -920,6 +920,7 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
unsigned int partial_start = lstart & (PAGE_SIZE - 1);
unsigned int partial_end = (lend + 1) & (PAGE_SIZE - 1);
struct pagevec pvec;
struct folio_batch fbatch;
pgoff_t indices[PAGEVEC_SIZE];
long nr_swaps_freed = 0;
pgoff_t index;
Expand Down Expand Up @@ -987,11 +988,12 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
if (start >= end)
return;

folio_batch_init(&fbatch);
index = start;
while (index < end) {
cond_resched();

if (!find_get_entries(mapping, index, end - 1, &pvec,
if (!find_get_entries(mapping, index, end - 1, &fbatch,
indices)) {
/* If all gone or hole-punch or unfalloc, we're done */
if (index == start || end != -1)
Expand All @@ -1000,14 +1002,14 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
index = start;
continue;
}
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *page = pvec.pages[i];
for (i = 0; i < folio_batch_count(&fbatch); i++) {
struct folio *folio = fbatch.folios[i];

index = indices[i];
if (xa_is_value(page)) {
if (xa_is_value(folio)) {
if (unfalloc)
continue;
if (shmem_free_swap(mapping, index, page)) {
if (shmem_free_swap(mapping, index, folio)) {
/* Swap was replaced by page: retry */
index--;
break;
Expand All @@ -1016,33 +1018,35 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
continue;
}

lock_page(page);
folio_lock(folio);

if (!unfalloc || !PageUptodate(page)) {
if (page_mapping(page) != mapping) {
if (!unfalloc || !folio_test_uptodate(folio)) {
struct page *page = folio_file_page(folio,
index);
if (folio_mapping(folio) != mapping) {
/* Page was replaced by swap: retry */
unlock_page(page);
folio_unlock(folio);
index--;
break;
}
VM_BUG_ON_PAGE(PageWriteback(page), page);
VM_BUG_ON_FOLIO(folio_test_writeback(folio),
folio);
if (shmem_punch_compound(page, start, end))
truncate_inode_folio(mapping,
page_folio(page));
truncate_inode_folio(mapping, folio);
else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
/* Wipe the page and don't get stuck */
clear_highpage(page);
flush_dcache_page(page);
set_page_dirty(page);
folio_mark_dirty(folio);
if (index <
round_up(start, HPAGE_PMD_NR))
start = index + 1;
}
}
unlock_page(page);
folio_unlock(folio);
}
pagevec_remove_exceptionals(&pvec);
pagevec_release(&pvec);
folio_batch_remove_exceptionals(&fbatch);
folio_batch_release(&fbatch);
index++;
}

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43 changes: 24 additions & 19 deletions mm/truncate.c
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Original file line number Diff line number Diff line change
Expand Up @@ -108,6 +108,13 @@ static void truncate_exceptional_pvec_entries(struct address_space *mapping,
pvec->nr = j;
}

static void truncate_folio_batch_exceptionals(struct address_space *mapping,
struct folio_batch *fbatch, pgoff_t *indices)
{
truncate_exceptional_pvec_entries(mapping, (struct pagevec *)fbatch,
indices);
}

/*
* Invalidate exceptional entry if easily possible. This handles exceptional
* entries for invalidate_inode_pages().
Expand Down Expand Up @@ -297,6 +304,7 @@ void truncate_inode_pages_range(struct address_space *mapping,
unsigned int partial_start; /* inclusive */
unsigned int partial_end; /* exclusive */
struct pagevec pvec;
struct folio_batch fbatch;
pgoff_t indices[PAGEVEC_SIZE];
pgoff_t index;
int i;
Expand Down Expand Up @@ -379,10 +387,11 @@ void truncate_inode_pages_range(struct address_space *mapping,
if (start >= end)
goto out;

folio_batch_init(&fbatch);
index = start;
for ( ; ; ) {
cond_resched();
if (!find_get_entries(mapping, index, end - 1, &pvec,
if (!find_get_entries(mapping, index, end - 1, &fbatch,
indices)) {
/* If all gone from start onwards, we're done */
if (index == start)
Expand All @@ -392,16 +401,14 @@ void truncate_inode_pages_range(struct address_space *mapping,
continue;
}

for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *page = pvec.pages[i];
struct folio *folio;
for (i = 0; i < folio_batch_count(&fbatch); i++) {
struct folio *folio = fbatch.folios[i];

/* We rely upon deletion not changing page->index */
index = indices[i];

if (xa_is_value(page))
if (xa_is_value(folio))
continue;
folio = page_folio(page);

folio_lock(folio);
VM_BUG_ON_FOLIO(!folio_contains(folio, index), folio);
Expand All @@ -410,8 +417,8 @@ void truncate_inode_pages_range(struct address_space *mapping,
folio_unlock(folio);
index = folio_index(folio) + folio_nr_pages(folio) - 1;
}
truncate_exceptional_pvec_entries(mapping, &pvec, indices);
pagevec_release(&pvec);
truncate_folio_batch_exceptionals(mapping, &fbatch, indices);
folio_batch_release(&fbatch);
index++;
}

Expand Down Expand Up @@ -625,7 +632,7 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
pgoff_t start, pgoff_t end)
{
pgoff_t indices[PAGEVEC_SIZE];
struct pagevec pvec;
struct folio_batch fbatch;
pgoff_t index;
int i;
int ret = 0;
Expand All @@ -635,23 +642,21 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
if (mapping_empty(mapping))
goto out;

pagevec_init(&pvec);
folio_batch_init(&fbatch);
index = start;
while (find_get_entries(mapping, index, end, &pvec, indices)) {
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *page = pvec.pages[i];
struct folio *folio;
while (find_get_entries(mapping, index, end, &fbatch, indices)) {
for (i = 0; i < folio_batch_count(&fbatch); i++) {
struct folio *folio = fbatch.folios[i];

/* We rely upon deletion not changing folio->index */
index = indices[i];

if (xa_is_value(page)) {
if (xa_is_value(folio)) {
if (!invalidate_exceptional_entry2(mapping,
index, page))
index, folio))
ret = -EBUSY;
continue;
}
folio = page_folio(page);

if (!did_range_unmap && folio_mapped(folio)) {
/*
Expand Down Expand Up @@ -684,8 +689,8 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
ret = ret2;
folio_unlock(folio);
}
pagevec_remove_exceptionals(&pvec);
pagevec_release(&pvec);
folio_batch_remove_exceptionals(&fbatch);
folio_batch_release(&fbatch);
cond_resched();
index++;
}
Expand Down

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