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authorMaxim Patlasov <mpatlasov@parallels.com>2012-10-26 19:50:36 +0400
committerMiklos Szeredi <mszeredi@suse.cz>2013-01-24 16:21:28 +0100
commit5565a9d884327ac45d49041f1b846dac273e110c (patch)
tree936c0ec109cc6c92e1264c33d8cde7ace637f97a /fs/fuse
parent7c190c8b9c0dd373cdd4d96e63306ec6e1a7115d (diff)
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fuse: optimize __fuse_direct_io()
__fuse_direct_io() allocates fuse-requests by calling fuse_get_req(fc, n). The patch calculates 'n' based on iov[] array. This is useful because allocating FUSE_MAX_PAGES_PER_REQ page pointers and descriptors for each fuse request would be waste of memory in case of iov-s of smaller size. Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Diffstat (limited to 'fs/fuse')
-rw-r--r--fs/fuse/file.c25
1 files changed, 21 insertions, 4 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index b2aa6c21e209..68e10d43bd3f 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1088,14 +1088,14 @@ static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
return 0;
}
- while (nbytes < *nbytesp && req->num_pages < FUSE_MAX_PAGES_PER_REQ) {
+ while (nbytes < *nbytesp && req->num_pages < req->max_pages) {
unsigned npages;
unsigned long user_addr = fuse_get_user_addr(ii);
unsigned offset = user_addr & ~PAGE_MASK;
size_t frag_size = fuse_get_frag_size(ii, *nbytesp - nbytes);
int ret;
- unsigned n = FUSE_MAX_PAGES_PER_REQ - req->num_pages;
+ unsigned n = req->max_pages - req->num_pages;
frag_size = min_t(size_t, frag_size, n << PAGE_SHIFT);
npages = (frag_size + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
@@ -1131,6 +1131,23 @@ static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
return 0;
}
+static inline int fuse_iter_npages(const struct iov_iter *ii_p)
+{
+ struct iov_iter ii = *ii_p;
+ int npages = 0;
+
+ while (iov_iter_count(&ii) && npages < FUSE_MAX_PAGES_PER_REQ) {
+ unsigned long user_addr = fuse_get_user_addr(&ii);
+ unsigned offset = user_addr & ~PAGE_MASK;
+ size_t frag_size = iov_iter_single_seg_count(&ii);
+
+ npages += (frag_size + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ iov_iter_advance(&ii, frag_size);
+ }
+
+ return min(npages, FUSE_MAX_PAGES_PER_REQ);
+}
+
static ssize_t __fuse_direct_io(struct file *file, const struct iovec *iov,
unsigned long nr_segs, size_t count,
loff_t *ppos, int write)
@@ -1145,7 +1162,7 @@ static ssize_t __fuse_direct_io(struct file *file, const struct iovec *iov,
iov_iter_init(&ii, iov, nr_segs, count, 0);
- req = fuse_get_req(fc, FUSE_MAX_PAGES_PER_REQ);
+ req = fuse_get_req(fc, fuse_iter_npages(&ii));
if (IS_ERR(req))
return PTR_ERR(req);
@@ -1180,7 +1197,7 @@ static ssize_t __fuse_direct_io(struct file *file, const struct iovec *iov,
break;
if (count) {
fuse_put_request(fc, req);
- req = fuse_get_req(fc, FUSE_MAX_PAGES_PER_REQ);
+ req = fuse_get_req(fc, fuse_iter_npages(&ii));
if (IS_ERR(req))
break;
}