Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965129Ab2JZPvo (ORCPT ); Fri, 26 Oct 2012 11:51:44 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:23371 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964956Ab2JZPvl (ORCPT ); Fri, 26 Oct 2012 11:51:41 -0400 Subject: [PATCH 12/12] fuse: optimize __fuse_direct_io() To: miklos@szeredi.hu From: Maxim Patlasov Cc: fuse-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, devel@openvz.org Date: Fri, 26 Oct 2012 19:50:36 +0400 Message-ID: <20121026155034.18931.10408.stgit@maximpc.sw.ru> In-Reply-To: <20121026152957.18931.46330.stgit@maximpc.sw.ru> References: <20121026152957.18931.46330.stgit@maximpc.sw.ru> User-Agent: StGit/0.15 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2848 Lines: 79 __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 --- fs/fuse/file.c | 25 +++++++++++++++++++++---- 1 files changed, 21 insertions(+), 4 deletions(-) diff --git a/fs/fuse/file.c b/fs/fuse/file.c index fad8c7b..1a9ae5a 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; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/