| [PATCH 04/11] fuse: rework fuse_readpages() [message #47952 is a reply to message #47948] |
Wed, 19 September 2012 16:32   |
Maxim Patlasov
Messages: 45
Registered: July 2012
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Member |
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The patch uses 'nr_pages' argument of fuse_readpages() as heuristics for the
number of page pointers to allocate.
This can be improved further by taking in consideration fc->max_read and gaps
between page indices, but it's not clear whether it's worthy or not.
Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com>
---
fs/fuse/file.c | 16 ++++++++++++++--
1 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 214e13e..a618371 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -641,6 +641,7 @@ struct fuse_fill_data {
struct fuse_req *req;
struct file *file;
struct inode *inode;
+ unsigned nr_pages;
};
static int fuse_readpages_fill(void *_data, struct page *page)
@@ -656,16 +657,25 @@ static int fuse_readpages_fill(void *_data, struct page *page)
(req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
(req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
req->pages[req->num_pages - 1]->index + 1 != page->index)) {
+ int nr_alloc = min_t(unsigned, data->nr_pages,
+ FUSE_MAX_PAGES_PER_REQ);
fuse_send_readpages(req, data->file);
- data->req = req = fuse_get_req(fc, FUSE_MAX_PAGES_PER_REQ);
+ data->req = req = fuse_get_req(fc, nr_alloc);
if (IS_ERR(req)) {
unlock_page(page);
return PTR_ERR(req);
}
}
+
+ if (WARN_ON(req->num_pages >= req->max_pages)) {
+ fuse_put_request(fc, req);
+ return -EIO;
+ }
+
page_cache_get(page);
req->pages[req->num_pages] = page;
req->num_pages++;
+ data->nr_pages--;
return 0;
}
@@ -676,6 +686,7 @@ static int fuse_readpages(struct file *file, struct address_space *mapping,
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_fill_data data;
int err;
+ int nr_alloc = min_t(unsigned, nr_pages, FUSE_MAX_PAGES_PER_REQ);
err = -EIO;
if (is_bad_inode(inode))
@@ -683,7 +694,8 @@ static int fuse_readpages(struct file *file, struct address_space *mapping,
data.file = file;
data.inode = inode;
- data.req = fuse_get_req(fc, FUSE_MAX_PAGES_PER_REQ);
+ data.req = fuse_get_req(fc, nr_alloc);
+ data.nr_pages = nr_pages;
err = PTR_ERR(data.req);
if (IS_ERR(data.req))
goto out;
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