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filemap: Convert filemap_get_read_batch() to use a folio_batch 

This change ripples all the way through the filemap_read() call chain and
removes a lot of messing about converting folios to pages and back again.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
This commit is contained in:
Matthew Wilcox (Oracle) 2021-12-06 15:25:33 -05:00
parent d996fc7f61
commit 25d6a23e8d
1 changed files with 33 additions and 32 deletions
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65
mm/filemap.c
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@ -2325,16 +2325,16 @@ static void shrink_readahead_size_eio(struct file_ra_state *ra)
}
/*
* filemap_get_read_batch - Get a batch of pages for read
* filemap_get_read_batch - Get a batch of folios for read
*
* Get a batch of pages which represent a contiguous range of bytes
* in the file. No tail pages will be returned. If @index is in the
* middle of a THP, the entire THP will be returned. The last page in
* the batch may have Readahead set or be not Uptodate so that the
* caller can take the appropriate action.
* Get a batch of folios which represent a contiguous range of bytes in
* the file. No exceptional entries will be returned. If @index is in
* the middle of a folio, the entire folio will be returned. The last
* folio in the batch may have the readahead flag set or the uptodate flag
* clear so that the caller can take the appropriate action.
*/
static void filemap_get_read_batch(struct address_space *mapping,
pgoff_t index, pgoff_t max, struct pagevec *pvec)
pgoff_t index, pgoff_t max, struct folio_batch *fbatch)
{
XA_STATE(xas, &mapping->i_pages, index);
struct folio *folio;
@ -2349,9 +2349,9 @@ static void filemap_get_read_batch(struct address_space *mapping,
goto retry;
if (unlikely(folio != xas_reload(&xas)))
goto put_page;
goto put_folio;
if (!pagevec_add(pvec, &folio->page))
if (!folio_batch_add(fbatch, folio))
break;
if (!folio_test_uptodate(folio))
break;
@ -2360,7 +2360,7 @@ static void filemap_get_read_batch(struct address_space *mapping,
xas.xa_index = folio->index + folio_nr_pages(folio) - 1;
xas.xa_offset = (xas.xa_index >> xas.xa_shift) & XA_CHUNK_MASK;
continue;
put_page:
put_folio:
folio_put(folio);
retry:
xas_reset(&xas);
@ -2475,7 +2475,7 @@ unlock_mapping:
static int filemap_create_folio(struct file *file,
struct address_space *mapping, pgoff_t index,
struct pagevec *pvec)
struct folio_batch *fbatch)
{
struct folio *folio;
int error;
@ -2510,7 +2510,7 @@ static int filemap_create_folio(struct file *file,
goto error;
filemap_invalidate_unlock_shared(mapping);
pagevec_add(pvec, &folio->page);
folio_batch_add(fbatch, folio);
return 0;
error:
filemap_invalidate_unlock_shared(mapping);
@ -2531,7 +2531,7 @@ static int filemap_readahead(struct kiocb *iocb, struct file *file,
}
static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter,
struct pagevec *pvec)
struct folio_batch *fbatch)
{
struct file *filp = iocb->ki_filp;
struct address_space *mapping = filp->f_mapping;
@ -2546,32 +2546,33 @@ retry:
if (fatal_signal_pending(current))
return -EINTR;
filemap_get_read_batch(mapping, index, last_index, pvec);
if (!pagevec_count(pvec)) {
filemap_get_read_batch(mapping, index, last_index, fbatch);
if (!folio_batch_count(fbatch)) {
if (iocb->ki_flags & IOCB_NOIO)
return -EAGAIN;
page_cache_sync_readahead(mapping, ra, filp, index,
last_index - index);
filemap_get_read_batch(mapping, index, last_index, pvec);
filemap_get_read_batch(mapping, index, last_index, fbatch);
}
if (!pagevec_count(pvec)) {
if (!folio_batch_count(fbatch)) {
if (iocb->ki_flags & (IOCB_NOWAIT | IOCB_WAITQ))
return -EAGAIN;
err = filemap_create_folio(filp, mapping,
iocb->ki_pos >> PAGE_SHIFT, pvec);
iocb->ki_pos >> PAGE_SHIFT, fbatch);
if (err == AOP_TRUNCATED_PAGE)
goto retry;
return err;
}
folio = page_folio(pvec->pages[pagevec_count(pvec) - 1]);
folio = fbatch->folios[folio_batch_count(fbatch) - 1];
if (folio_test_readahead(folio)) {
err = filemap_readahead(iocb, filp, mapping, folio, last_index);
if (err)
goto err;
}
if (!folio_test_uptodate(folio)) {
if ((iocb->ki_flags & IOCB_WAITQ) && pagevec_count(pvec) > 1)
if ((iocb->ki_flags & IOCB_WAITQ) &&
folio_batch_count(fbatch) > 1)
iocb->ki_flags |= IOCB_NOWAIT;
err = filemap_update_page(iocb, mapping, iter, folio);
if (err)
@ -2582,7 +2583,7 @@ retry:
err:
if (err < 0)
folio_put(folio);
if (likely(--pvec->nr))
if (likely(--fbatch->nr))
return 0;
if (err == AOP_TRUNCATED_PAGE)
goto retry;
@ -2609,7 +2610,7 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
struct file_ra_state *ra = &filp->f_ra;
struct address_space *mapping = filp->f_mapping;
struct inode *inode = mapping->host;
struct pagevec pvec;
struct folio_batch fbatch;
int i, error = 0;
bool writably_mapped;
loff_t isize, end_offset;
@ -2620,7 +2621,7 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
return 0;
iov_iter_truncate(iter, inode->i_sb->s_maxbytes);
pagevec_init(&pvec);
folio_batch_init(&fbatch);
do {
cond_resched();
@ -2636,7 +2637,7 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
if (unlikely(iocb->ki_pos >= i_size_read(inode)))
break;
error = filemap_get_pages(iocb, iter, &pvec);
error = filemap_get_pages(iocb, iter, &fbatch);
if (error < 0)
break;
@ -2650,7 +2651,7 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
*/
isize = i_size_read(inode);
if (unlikely(iocb->ki_pos >= isize))
goto put_pages;
goto put_folios;
end_offset = min_t(loff_t, isize, iocb->ki_pos + iter->count);
/*
@ -2665,10 +2666,10 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
*/
if (iocb->ki_pos >> PAGE_SHIFT !=
ra->prev_pos >> PAGE_SHIFT)
mark_page_accessed(pvec.pages[0]);
folio_mark_accessed(fbatch.folios[0]);
for (i = 0; i < pagevec_count(&pvec); i++) {
struct folio *folio = page_folio(pvec.pages[i]);
for (i = 0; i < folio_batch_count(&fbatch); i++) {
struct folio *folio = fbatch.folios[i];
size_t fsize = folio_size(folio);
size_t offset = iocb->ki_pos & (fsize - 1);
size_t bytes = min_t(loff_t, end_offset - iocb->ki_pos,
@ -2698,10 +2699,10 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
break;
}
}
put_pages:
for (i = 0; i < pagevec_count(&pvec); i++)
put_page(pvec.pages[i]);
pagevec_reinit(&pvec);
put_folios:
for (i = 0; i < folio_batch_count(&fbatch); i++)
folio_put(fbatch.folios[i]);
folio_batch_init(&fbatch);
} while (iov_iter_count(iter) && iocb->ki_pos < isize && !error);
file_accessed(filp);