Messages in this thread Patch in this message | | | Subject | [PATCH 11/11] fuse: optimize __fuse_direct_io() | From | Maxim Patlasov <> | Date | Wed, 19 Sep 2012 20:33:31 +0400 |
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__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> --- fs/fuse/file.c | 27 +++++++++++++++++++++++---- 1 files changed, 23 insertions(+), 4 deletions(-)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 5b0fa5d..5ecab19 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -1090,14 +1090,14 @@ static int fuse_get_user_pages(struct fuse_req *req, return 0; } - while (nbytes < *nbytesp && req->num_pages < FUSE_MAX_PAGES_PER_REQ) { + while (nbytes < *nbytesp && req->num_pages < req->max_pages) { int npages; unsigned long user_addr = fuse_get_ua(*iov_pp, *iov_offset_p); unsigned offset = user_addr & ~PAGE_MASK; size_t frag_size = fuse_get_fr_sz(*iov_pp, *iov_offset_p, *nbytesp - nbytes); - int n = FUSE_MAX_PAGES_PER_REQ - req->num_pages; + int 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; @@ -1138,6 +1138,24 @@ static int fuse_get_user_pages(struct fuse_req *req, return 0; } +static inline int fuse_iov_npages(const struct iovec *iov, + unsigned long nr_segs, size_t iov_offset) +{ + int npages = 0; + + while (nr_segs-- > 0 && npages < FUSE_MAX_PAGES_PER_REQ) { + unsigned long user_addr = fuse_get_ua(iov, iov_offset); + unsigned offset = user_addr & ~PAGE_MASK; + size_t frag_size = iov->iov_len - iov_offset; + + npages += (frag_size + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; + iov++; + iov_offset = 0; + } + + 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) @@ -1150,7 +1168,7 @@ static ssize_t __fuse_direct_io(struct file *file, const struct iovec *iov, struct fuse_req *req; size_t iov_offset = 0; - req = fuse_get_req(fc, FUSE_MAX_PAGES_PER_REQ); + req = fuse_get_req(fc, fuse_iov_npages(iov, nr_segs, iov_offset)); if (IS_ERR(req)) return PTR_ERR(req); @@ -1186,7 +1204,8 @@ 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_iov_npages(iov, nr_segs, iov_offset)); if (IS_ERR(req)) break; }
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