From 5565a9d884327ac45d49041f1b846dac273e110c Mon Sep 17 00:00:00 2001 From: Maxim Patlasov Date: Fri, 26 Oct 2012 19:50:36 +0400 Subject: [PATCH] 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 Signed-off-by: Miklos Szeredi --- fs/fuse/file.c | 25 +++++++++++++++++++++---- 1 file 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; } -- 2.20.1