From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751311AbXBUPgJ (ORCPT ); Wed, 21 Feb 2007 10:36:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161292AbXBUPfm (ORCPT ); Wed, 21 Feb 2007 10:35:42 -0500 Received: from mx1.redhat.com ([66.187.233.31]:55888 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161280AbXBUPfU (ORCPT ); Wed, 21 Feb 2007 10:35:20 -0500 Message-Id: <20070221144844.179417000@taijtu.programming.kicks-ass.net> References: <20070221144304.512721000@taijtu.programming.kicks-ass.net> User-Agent: quilt/0.46-1 Date: Wed, 21 Feb 2007 15:43:31 +0100 From: Peter Zijlstra To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org Cc: Peter Zijlstra , Trond Myklebust , Thomas Graf , David Miller Subject: [PATCH 27/29] nfs: disable data cache revalidation for swapfiles Content-Disposition: inline; filename=nfs-swapper.patch Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Do as Trond suggested: http://lkml.org/lkml/2006/8/25/348 Disable NFS data cache revalidation on swap files since it doesn't really make sense to have other clients change the file while you are using it. Thereby we can stop setting PG_private on swap pages, since there ought to be no further races with invalidate_inode_pages2() to deal with. And since we cannot set PG_private we cannot use page->private (which is already used by PG_swapcache pages anyway) to store the nfs_page. Thus augment the new nfs_page_find_request logic. Signed-off-by: Peter Zijlstra Cc: Trond Myklebust --- fs/nfs/inode.c | 6 ++++++ fs/nfs/write.c | 35 +++++++++++++++++++++++------------ 2 files changed, 29 insertions(+), 12 deletions(-) Index: linux-2.6-git/fs/nfs/inode.c =================================================================== --- linux-2.6-git.orig/fs/nfs/inode.c 2007-02-21 11:04:08.000000000 +0100 +++ linux-2.6-git/fs/nfs/inode.c 2007-02-21 11:52:21.000000000 +0100 @@ -719,6 +719,12 @@ int nfs_revalidate_mapping_nolock(struct struct nfs_inode *nfsi = NFS_I(inode); int ret = 0; + /* + * swapfiles are not supposed to be shared. + */ + if (IS_SWAPFILE(inode)) + goto out; + if ((nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) || nfs_attribute_timeout(inode) || NFS_STALE(inode)) { ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode); Index: linux-2.6-git/fs/nfs/write.c =================================================================== --- linux-2.6-git.orig/fs/nfs/write.c 2007-02-21 11:52:17.000000000 +0100 +++ linux-2.6-git/fs/nfs/write.c 2007-02-21 11:53:18.000000000 +0100 @@ -107,7 +107,7 @@ void nfs_writedata_release(void *wdata) nfs_writedata_free(wdata); } -static struct nfs_page *nfs_page_find_request_locked(struct page *page) +static struct nfs_page *nfs_page_find_request_locked(struct nfs_inode *nfsi, struct page *page) { struct nfs_page *req = NULL; @@ -115,6 +115,10 @@ static struct nfs_page *nfs_page_find_re req = (struct nfs_page *)page_private(page); if (req != NULL) atomic_inc(&req->wb_count); + } else if (unlikely(PageSwapCache(page))) { + req = radix_tree_lookup(&nfsi->nfs_page_tree, page_file_index(page)); + if (req != NULL) + atomic_inc(&req->wb_count); } return req; } @@ -122,10 +126,11 @@ static struct nfs_page *nfs_page_find_re static struct nfs_page *nfs_page_find_request(struct page *page) { struct nfs_page *req = NULL; - spinlock_t *req_lock = &NFS_I(page_file_mapping(page)->host)->req_lock; + struct nfs_inode *nfsi = NFS_I(page_file_mapping(page)->host); + spinlock_t *req_lock = &nfsi->req_lock; spin_lock(req_lock); - req = nfs_page_find_request_locked(page); + req = nfs_page_find_request_locked(nfsi, page); spin_unlock(req_lock); return req; } @@ -248,12 +253,13 @@ static void nfs_end_page_writeback(struc static int nfs_page_mark_flush(struct page *page) { struct nfs_page *req; - spinlock_t *req_lock = &NFS_I(page_file_mapping(page)->host)->req_lock; + struct nfs_inode *nfsi = NFS_I(page_file_mapping(page)->host); + spinlock_t *req_lock = &nfsi->req_lock; int ret; spin_lock(req_lock); for(;;) { - req = nfs_page_find_request_locked(page); + req = nfs_page_find_request_locked(nfsi, page); if (req == NULL) { spin_unlock(req_lock); return 1; @@ -368,8 +374,14 @@ static int nfs_inode_add_request(struct if (nfs_have_delegation(inode, FMODE_WRITE)) nfsi->change_attr++; } - SetPagePrivate(req->wb_page); - set_page_private(req->wb_page, (unsigned long)req); + /* + * Swap-space should not get truncated. Hence no need to plug the race + * with invalidate/truncate. + */ + if (likely(!PageSwapCache(req->wb_page))) { + SetPagePrivate(req->wb_page); + set_page_private(req->wb_page, (unsigned long)req); + } nfsi->npages++; atomic_inc(&req->wb_count); return 0; @@ -386,8 +398,10 @@ static void nfs_inode_remove_request(str BUG_ON (!NFS_WBACK_BUSY(req)); spin_lock(&nfsi->req_lock); - set_page_private(req->wb_page, 0); - ClearPagePrivate(req->wb_page); + if (likely(!PageSwapCache(req->wb_page))) { + set_page_private(req->wb_page, 0); + ClearPagePrivate(req->wb_page); + } radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index); nfsi->npages--; if (!nfsi->npages) { @@ -600,7 +614,7 @@ static struct nfs_page * nfs_update_requ * A request for the page we wish to update */ spin_lock(&nfsi->req_lock); - req = nfs_page_find_request_locked(page); + req = nfs_page_find_request_locked(nfsi, page); if (req) { if (!nfs_lock_request_dontget(req)) { int error; @@ -1472,8 +1486,6 @@ int nfs_wb_page_priority(struct inode *i if (ret < 0) goto out; } - if (!PagePrivate(page)) - return 0; ret = nfs_sync_mapping_wait(page_file_mapping(page), &wbc, how); if (ret >= 0) return 0; --