Matthew Wilcox
2020-Apr-14 15:02 UTC
[Ocfs2-devel] [PATCH v11 24/25] fuse: Convert from readpages to readahead
From: "Matthew Wilcox (Oracle)" <willy at infradead.org>
Implement the new readahead operation in fuse by using __readahead_batch()
to fill the array of pages in fuse_args_pages directly. This lets us
inline fuse_readpages_fill() into fuse_readahead().
Signed-off-by: Matthew Wilcox (Oracle) <willy at infradead.org>
Reviewed-by: Dave Chinner <dchinner at redhat.com>
Reviewed-by: William Kucharski <william.kucharski at oracle.com>
---
fs/fuse/file.c | 99 ++++++++++++++------------------------------------
1 file changed, 27 insertions(+), 72 deletions(-)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 9d67b830fb7a..db82fb29dd39 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -915,84 +915,39 @@ static void fuse_send_readpages(struct fuse_io_args *ia,
struct file *file)
fuse_readpages_end(fc, &ap->args, err);
}
-struct fuse_fill_data {
- struct fuse_io_args *ia;
- struct file *file;
- struct inode *inode;
- unsigned int nr_pages;
- unsigned int max_pages;
-};
-
-static int fuse_readpages_fill(void *_data, struct page *page)
+static void fuse_readahead(struct readahead_control *rac)
{
- struct fuse_fill_data *data = _data;
- struct fuse_io_args *ia = data->ia;
- struct fuse_args_pages *ap = &ia->ap;
- struct inode *inode = data->inode;
+ struct inode *inode = rac->mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
+ unsigned int i, max_pages, nr_pages = 0;
- fuse_wait_on_page_writeback(inode, page->index);
-
- if (ap->num_pages &&
- (ap->num_pages == fc->max_pages ||
- (ap->num_pages + 1) * PAGE_SIZE > fc->max_read ||
- ap->pages[ap->num_pages - 1]->index + 1 != page->index)) {
- data->max_pages = min_t(unsigned int, data->nr_pages,
- fc->max_pages);
- fuse_send_readpages(ia, data->file);
- data->ia = ia = fuse_io_alloc(NULL, data->max_pages);
- if (!ia) {
- unlock_page(page);
- return -ENOMEM;
- }
- ap = &ia->ap;
- }
-
- if (WARN_ON(ap->num_pages >= data->max_pages)) {
- unlock_page(page);
- fuse_io_free(ia);
- return -EIO;
- }
-
- get_page(page);
- ap->pages[ap->num_pages] = page;
- ap->descs[ap->num_pages].length = PAGE_SIZE;
- ap->num_pages++;
- data->nr_pages--;
- return 0;
-}
-
-static int fuse_readpages(struct file *file, struct address_space *mapping,
- struct list_head *pages, unsigned nr_pages)
-{
- struct inode *inode = mapping->host;
- struct fuse_conn *fc = get_fuse_conn(inode);
- struct fuse_fill_data data;
- int err;
-
- err = -EIO;
if (is_bad_inode(inode))
- goto out;
+ return;
- data.file = file;
- data.inode = inode;
- data.nr_pages = nr_pages;
- data.max_pages = min_t(unsigned int, nr_pages, fc->max_pages);
-;
- data.ia = fuse_io_alloc(NULL, data.max_pages);
- err = -ENOMEM;
- if (!data.ia)
- goto out;
+ max_pages = min(fc->max_pages, fc->max_read / PAGE_SIZE);
- err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
- if (!err) {
- if (data.ia->ap.num_pages)
- fuse_send_readpages(data.ia, file);
- else
- fuse_io_free(data.ia);
+ for (;;) {
+ struct fuse_io_args *ia;
+ struct fuse_args_pages *ap;
+
+ nr_pages = readahead_count(rac) - nr_pages;
+ if (nr_pages > max_pages)
+ nr_pages = max_pages;
+ if (nr_pages == 0)
+ break;
+ ia = fuse_io_alloc(NULL, nr_pages);
+ if (!ia)
+ return;
+ ap = &ia->ap;
+ nr_pages = __readahead_batch(rac, ap->pages, nr_pages);
+ for (i = 0; i < nr_pages; i++) {
+ fuse_wait_on_page_writeback(inode,
+ readahead_index(rac) + i);
+ ap->descs[i].length = PAGE_SIZE;
+ }
+ ap->num_pages = nr_pages;
+ fuse_send_readpages(ia, rac->file);
}
-out:
- return err;
}
static ssize_t fuse_cache_read_iter(struct kiocb *iocb, struct iov_iter *to)
@@ -3373,10 +3328,10 @@ static const struct file_operations fuse_file_operations
= {
static const struct address_space_operations fuse_file_aops = {
.readpage = fuse_readpage,
+ .readahead = fuse_readahead,
.writepage = fuse_writepage,
.writepages = fuse_writepages,
.launder_page = fuse_launder_page,
- .readpages = fuse_readpages,
.set_page_dirty = __set_page_dirty_nobuffers,
.bmap = fuse_bmap,
.direct_IO = fuse_direct_IO,
--
2.25.1
Miklos Szeredi
2020-Apr-20 11:14 UTC
[Ocfs2-devel] [PATCH v11 24/25] fuse: Convert from readpages to readahead
On Tue, Apr 14, 2020 at 5:08 PM Matthew Wilcox <willy at infradead.org> wrote:> > From: "Matthew Wilcox (Oracle)" <willy at infradead.org> > > Implement the new readahead operation in fuse by using __readahead_batch() > to fill the array of pages in fuse_args_pages directly. This lets us > inline fuse_readpages_fill() into fuse_readahead(). > > Signed-off-by: Matthew Wilcox (Oracle) <willy at infradead.org> > Reviewed-by: Dave Chinner <dchinner at redhat.com> > Reviewed-by: William Kucharski <william.kucharski at oracle.com> > --- > fs/fuse/file.c | 99 ++++++++++++++------------------------------------ > 1 file changed, 27 insertions(+), 72 deletions(-) > > diff --git a/fs/fuse/file.c b/fs/fuse/file.c > index 9d67b830fb7a..db82fb29dd39 100644 > --- a/fs/fuse/file.c > +++ b/fs/fuse/file.c > @@ -915,84 +915,39 @@ static void fuse_send_readpages(struct fuse_io_args *ia, struct file *file) > fuse_readpages_end(fc, &ap->args, err); > } > > -struct fuse_fill_data { > - struct fuse_io_args *ia; > - struct file *file; > - struct inode *inode; > - unsigned int nr_pages; > - unsigned int max_pages; > -}; > - > -static int fuse_readpages_fill(void *_data, struct page *page) > +static void fuse_readahead(struct readahead_control *rac) > { > - struct fuse_fill_data *data = _data; > - struct fuse_io_args *ia = data->ia; > - struct fuse_args_pages *ap = &ia->ap; > - struct inode *inode = data->inode; > + struct inode *inode = rac->mapping->host; > struct fuse_conn *fc = get_fuse_conn(inode); > + unsigned int i, max_pages, nr_pages = 0; > > - fuse_wait_on_page_writeback(inode, page->index); > - > - if (ap->num_pages && > - (ap->num_pages == fc->max_pages || > - (ap->num_pages + 1) * PAGE_SIZE > fc->max_read || > - ap->pages[ap->num_pages - 1]->index + 1 != page->index)) { > - data->max_pages = min_t(unsigned int, data->nr_pages, > - fc->max_pages); > - fuse_send_readpages(ia, data->file); > - data->ia = ia = fuse_io_alloc(NULL, data->max_pages); > - if (!ia) { > - unlock_page(page); > - return -ENOMEM; > - } > - ap = &ia->ap; > - } > - > - if (WARN_ON(ap->num_pages >= data->max_pages)) { > - unlock_page(page); > - fuse_io_free(ia); > - return -EIO; > - } > - > - get_page(page); > - ap->pages[ap->num_pages] = page; > - ap->descs[ap->num_pages].length = PAGE_SIZE; > - ap->num_pages++; > - data->nr_pages--; > - return 0; > -} > - > -static int fuse_readpages(struct file *file, struct address_space *mapping, > - struct list_head *pages, unsigned nr_pages) > -{ > - struct inode *inode = mapping->host; > - struct fuse_conn *fc = get_fuse_conn(inode); > - struct fuse_fill_data data; > - int err; > - > - err = -EIO; > if (is_bad_inode(inode)) > - goto out; > + return; > > - data.file = file; > - data.inode = inode; > - data.nr_pages = nr_pages; > - data.max_pages = min_t(unsigned int, nr_pages, fc->max_pages); > -; > - data.ia = fuse_io_alloc(NULL, data.max_pages); > - err = -ENOMEM; > - if (!data.ia) > - goto out; > + max_pages = min(fc->max_pages, fc->max_read / PAGE_SIZE); > > - err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data); > - if (!err) { > - if (data.ia->ap.num_pages) > - fuse_send_readpages(data.ia, file); > - else > - fuse_io_free(data.ia); > + for (;;) { > + struct fuse_io_args *ia; > + struct fuse_args_pages *ap; > + > + nr_pages = readahead_count(rac) - nr_pages;Hmm. I see what's going on here, but it's confusing. Why is __readahead_batch() decrementing the readahead count at the start, rather than at the end? At the very least it needs a comment about why nr_pages is calculated this way.> + if (nr_pages > max_pages) > + nr_pages = max_pages; > + if (nr_pages == 0) > + break; > + ia = fuse_io_alloc(NULL, nr_pages); > + if (!ia) > + return; > + ap = &ia->ap; > + nr_pages = __readahead_batch(rac, ap->pages, nr_pages); > + for (i = 0; i < nr_pages; i++) { > + fuse_wait_on_page_writeback(inode, > + readahead_index(rac) + i);What's wrong with ap->pages[i]->index? Are we trying to wean off using ->index? Thanks, Miklos