From patchwork Thu Jul 12 06:41:03 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mel Gorman X-Patchwork-Id: 170552 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 7BB932C0218 for ; Thu, 12 Jul 2012 16:42:13 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758814Ab2GLGlb (ORCPT ); Thu, 12 Jul 2012 02:41:31 -0400 Received: from cantor2.suse.de ([195.135.220.15]:40103 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758755Ab2GLGlX (ORCPT ); Thu, 12 Jul 2012 02:41:23 -0400 Received: from relay2.suse.de (unknown [195.135.220.254]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx2.suse.de (Postfix) with ESMTP id 6A44AA4D57; Thu, 12 Jul 2012 08:41:22 +0200 (CEST) From: Mel Gorman To: Andrew Morton Cc: Linux-MM , Linux-Netdev , Linux-NFS , LKML , David Miller , Trond Myklebust , Neil Brown , Christoph Hellwig , Peter Zijlstra , Mike Christie , Eric B Munson , Sebastian Andrzej Siewior , Mel Gorman Subject: [PATCH 09/12] nfs: disable data cache revalidation for swapfiles Date: Thu, 12 Jul 2012 07:41:03 +0100 Message-Id: <1342075266-29593-10-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 1.7.9.2 In-Reply-To: <1342075266-29593-1-git-send-email-mgorman@suse.de> References: <1342075266-29593-1-git-send-email-mgorman@suse.de> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The VM does not like PG_private set on PG_swapcache pages. As suggested by Trond in http://lkml.org/lkml/2006/8/25/348, this patch disables NFS data cache revalidation on swap files. as it does not make sense to have other clients change the file while it is being used as swap. This avoids setting PG_private on swap pages, since there ought to be no further races with invalidate_inode_pages2() to deal with. Since we cannot set PG_private we cannot use page->private which is already used by PG_swapcache pages to store the nfs_page. Thus augment the new nfs_page_find_request logic. Signed-off-by: Peter Zijlstra Signed-off-by: Mel Gorman Acked-by: Rik van Riel --- fs/nfs/inode.c | 4 ++++ fs/nfs/write.c | 49 +++++++++++++++++++++++++++++++++++-------------- 2 files changed, 39 insertions(+), 14 deletions(-) diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c index 4d02a25..3db1ab7 100644 --- a/fs/nfs/inode.c +++ b/fs/nfs/inode.c @@ -883,6 +883,10 @@ int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping) struct nfs_inode *nfsi = NFS_I(inode); int ret = 0; + /* swapfiles are not supposed to be shared. */ + if (IS_SWAPFILE(inode)) + goto out; + if (nfs_mapping_need_revalidate_inode(inode)) { ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode); if (ret < 0) diff --git a/fs/nfs/write.c b/fs/nfs/write.c index d0feca3..974e9c2 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -139,15 +139,28 @@ static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error) set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags); } -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; - if (PagePrivate(page)) { + if (PagePrivate(page)) req = (struct nfs_page *)page_private(page); - if (req != NULL) - kref_get(&req->wb_kref); + else if (unlikely(PageSwapCache(page))) { + struct nfs_page *freq, *t; + + /* Linearly search the commit list for the correct req */ + list_for_each_entry_safe(freq, t, &nfsi->commit_info.list, wb_list) { + if (freq->wb_page == page) { + req = freq; + break; + } + } } + + if (req) + kref_get(&req->wb_kref); + return req; } @@ -157,7 +170,7 @@ static struct nfs_page *nfs_page_find_request(struct page *page) struct nfs_page *req = NULL; spin_lock(&inode->i_lock); - req = nfs_page_find_request_locked(page); + req = nfs_page_find_request_locked(NFS_I(inode), page); spin_unlock(&inode->i_lock); return req; } @@ -258,7 +271,7 @@ static struct nfs_page *nfs_find_and_lock_request(struct page *page, bool nonblo spin_lock(&inode->i_lock); for (;;) { - req = nfs_page_find_request_locked(page); + req = nfs_page_find_request_locked(NFS_I(inode), page); if (req == NULL) break; if (nfs_lock_request(req)) @@ -413,9 +426,15 @@ static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req) spin_lock(&inode->i_lock); if (!nfsi->npages && NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE)) inode->i_version++; - set_bit(PG_MAPPED, &req->wb_flags); - 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))) { + set_bit(PG_MAPPED, &req->wb_flags); + SetPagePrivate(req->wb_page); + set_page_private(req->wb_page, (unsigned long)req); + } nfsi->npages++; kref_get(&req->wb_kref); spin_unlock(&inode->i_lock); @@ -432,9 +451,11 @@ static void nfs_inode_remove_request(struct nfs_page *req) BUG_ON (!NFS_WBACK_BUSY(req)); spin_lock(&inode->i_lock); - set_page_private(req->wb_page, 0); - ClearPagePrivate(req->wb_page); - clear_bit(PG_MAPPED, &req->wb_flags); + if (likely(!PageSwapCache(req->wb_page))) { + set_page_private(req->wb_page, 0); + ClearPagePrivate(req->wb_page); + clear_bit(PG_MAPPED, &req->wb_flags); + } nfsi->npages--; spin_unlock(&inode->i_lock); nfs_release_request(req); @@ -730,7 +751,7 @@ static struct nfs_page *nfs_try_to_update_request(struct inode *inode, spin_lock(&inode->i_lock); for (;;) { - req = nfs_page_find_request_locked(page); + req = nfs_page_find_request_locked(NFS_I(inode), page); if (req == NULL) goto out_unlock; @@ -1744,7 +1765,7 @@ int nfs_wb_page_cancel(struct inode *inode, struct page *page) */ int nfs_wb_page(struct inode *inode, struct page *page) { - loff_t range_start = page_offset(page); + loff_t range_start = page_file_offset(page); loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1); struct writeback_control wbc = { .sync_mode = WB_SYNC_ALL,