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mm/readahead: pass readahead_control to force_page_cache_ra 

Reimplement force_page_cache_readahead() as a wrapper around
force_page_cache_ra().  Pass the existing readahead_control from
page_cache_sync_readahead().

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric Biggers <ebiggers@google.com>
Link: https://lkml.kernel.org/r/20200903140844.14194-7-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Howells 2020-10-15 20:06:24 -07:00 committed by Linus Torvalds
parent 6e4af69ae9
commit 7b3df3b9ac
2 changed files with 19 additions and 12 deletions
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13
mm/internal.h
View File

@ -49,10 +49,15 @@ void unmap_page_range(struct mmu_gather *tlb,
unsigned long addr, unsigned long end,
struct zap_details *details);
void force_page_cache_readahead(struct address_space *, struct file *,
pgoff_t index, unsigned long nr_to_read);
void do_page_cache_ra(struct readahead_control *,
unsigned long nr_to_read, unsigned long lookahead_size);
void do_page_cache_ra(struct readahead_control *, unsigned long nr_to_read,
unsigned long lookahead_size);
void force_page_cache_ra(struct readahead_control *, unsigned long nr);
static inline void force_page_cache_readahead(struct address_space *mapping,
struct file *file, pgoff_t index, unsigned long nr_to_read)
{
DEFINE_READAHEAD(ractl, file, mapping, index);
force_page_cache_ra(&ractl, nr_to_read);
}
/*
* Submit IO for the read-ahead request in file_ra_state.

18
mm/readahead.c
View File

@ -271,13 +271,13 @@ void do_page_cache_ra(struct readahead_control *ractl,
* Chunk the readahead into 2 megabyte units, so that we don't pin too much
* memory at once.
*/
void force_page_cache_readahead(struct address_space *mapping,
struct file *file, pgoff_t index, unsigned long nr_to_read)
void force_page_cache_ra(struct readahead_control *ractl,
unsigned long nr_to_read)
{
DEFINE_READAHEAD(ractl, file, mapping, index);
struct address_space *mapping = ractl->mapping;
struct backing_dev_info *bdi = inode_to_bdi(mapping->host);
struct file_ra_state *ra = &file->f_ra;
unsigned long max_pages;
struct file_ra_state *ra = &ractl->file->f_ra;
unsigned long max_pages, index;
if (unlikely(!mapping->a_ops->readpage && !mapping->a_ops->readpages &&
!mapping->a_ops->readahead))
@ -287,14 +287,16 @@ void force_page_cache_readahead(struct address_space *mapping,
* If the request exceeds the readahead window, allow the read to
* be up to the optimal hardware IO size
*/
index = readahead_index(ractl);
max_pages = max_t(unsigned long, bdi->io_pages, ra->ra_pages);
nr_to_read = min(nr_to_read, max_pages);
nr_to_read = min_t(unsigned long, nr_to_read, max_pages);
while (nr_to_read) {
unsigned long this_chunk = (2 * 1024 * 1024) / PAGE_SIZE;
if (this_chunk > nr_to_read)
this_chunk = nr_to_read;
do_page_cache_ra(&ractl, this_chunk, 0);
ractl->_index = index;
do_page_cache_ra(ractl, this_chunk, 0);
index += this_chunk;
nr_to_read -= this_chunk;
@ -576,7 +578,7 @@ void page_cache_sync_readahead(struct address_space *mapping,
/* be dumb */
if (filp && (filp->f_mode & FMODE_RANDOM)) {
force_page_cache_readahead(mapping, filp, index, req_count);
force_page_cache_ra(&ractl, req_count);
return;
}