From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: [PATCHv2 10/10] xen/balloon: pre-allocate p2m entries for ballooned pages Date: Fri, 24 Jul 2015 12:47:48 +0100 Message-ID: <1437738468-24110-11-git-send-email-david.vrabel__31683.5319078111$1437740187$gmane$org@citrix.com> References: <1437738468-24110-1-git-send-email-david.vrabel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1ZIbso-0004cx-Pa for xen-devel@lists.xenproject.org; Fri, 24 Jul 2015 12:15:22 +0000 In-Reply-To: <1437738468-24110-1-git-send-email-david.vrabel@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xenproject.org Cc: Daniel Kiper , linux-kernel@vger.kernel.org, linux-mm@kvack.org, David Vrabel , Boris Ostrovsky List-Id: xen-devel@lists.xenproject.org Pages returned by alloc_xenballooned_pages() will be used for grant mapping which will call set_phys_to_machine() (in PV guests). Ballooned pages are set as INVALID_P2M_ENTRY in the p2m and thus may be using the (shared) missing tables and a subsequent set_phys_to_machine() will need to allocate new tables. Since the grant mapping may be done from a context that cannot sleep, the p2m entries must already be allocated. Signed-off-by: David Vrabel --- drivers/xen/balloon.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index fd6970f3..8932d10 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -541,6 +541,7 @@ int alloc_xenballooned_pages(int nr_pages, struct page **pages) { int pgno = 0; struct page *page; + int ret = -ENOMEM; mutex_lock(&balloon_mutex); @@ -550,6 +551,11 @@ int alloc_xenballooned_pages(int nr_pages, struct page **pages) page = balloon_retrieve(true); if (page) { pages[pgno++] = page; +#ifdef CONFIG_XEN_HAVE_PVMMU + ret = xen_alloc_p2m_entry(page_to_pfn(page)); + if (ret < 0) + goto out_undo; +#endif } else { enum bp_state st; @@ -576,7 +582,7 @@ int alloc_xenballooned_pages(int nr_pages, struct page **pages) out_undo: mutex_unlock(&balloon_mutex); free_xenballooned_pages(pgno, pages); - return -ENOMEM; + return ret; } EXPORT_SYMBOL(alloc_xenballooned_pages); -- 2.1.4