From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pankaj Gupta Subject: Re: [PATCH v1 5/8] hv_balloon: mark inflated pages PG_offline Date: Tue, 20 Nov 2018 04:37:16 -0500 (EST) Message-ID: <1380154502.35259416.1542706636322.JavaMail.zimbra@redhat.com> References: <20181119101616.8901-1-david@redhat.com> <20181119101616.8901-6-david@redhat.com> <1747228.35250472.1542703532881.JavaMail.zimbra@redhat.com> <6258a58b-28c7-c055-0752-e8bd085b835f@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <6258a58b-28c7-c055-0752-e8bd085b835f@redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: David Hildenbrand Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, devel@linuxdriverproject.org, linux-fsdevel@vger.kernel.org, linux-pm@vger.kernel.org, xen-devel@lists.xenproject.org, kexec-ml , pv-drivers@vmware.com, "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Kairui Song , Vitaly Kuznetsov , Andrew Morton , Matthew Wilcox , Michal Hocko , "Michael S. Tsirkin" List-Id: linux-pm@vger.kernel.org > >> --- > >> drivers/hv/hv_balloon.c | 14 ++++++++++++-- > >> 1 file changed, 12 insertions(+), 2 deletions(-) > >> > >> diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c > >> index 211f3fe3a038..47719862e57f 100644 > >> --- a/drivers/hv/hv_balloon.c > >> +++ b/drivers/hv/hv_balloon.c > >> @@ -681,8 +681,13 @@ static struct notifier_block hv_memory_nb = { > >> /* Check if the particular page is backed and can be onlined and online > >> it. > >> */ > >> static void hv_page_online_one(struct hv_hotadd_state *has, struct page > >> *pg) > >> { > >> - if (!has_pfn_is_backed(has, page_to_pfn(pg))) > >> + if (!has_pfn_is_backed(has, page_to_pfn(pg))) { > >> + if (!PageOffline(pg)) > >> + __SetPageOffline(pg); > >> return; > >> + } > >> + if (PageOffline(pg)) > >> + __ClearPageOffline(pg); > >> > >> /* This frame is currently backed; online the page. */ > >> __online_page_set_limits(pg); > >> @@ -1201,6 +1206,7 @@ static void free_balloon_pages(struct > >> hv_dynmem_device > >> *dm, > >> > >> for (i = 0; i < num_pages; i++) { > >> pg = pfn_to_page(i + start_frame); > >> + __ClearPageOffline(pg); > > > > Just thinking, do we need to care for clearing PageOffline flag before > > freeing > > a balloon'd page? > > Yes we have to otherwise the code will crash when trying to set PageBuddy. > > (only one page type at a time may be set right now, and it makes sense. > A page that is offline cannot e.g. be a buddy page) o.k > > So PageOffline is completely managed by the page owner. Makes sense. Thanks for explaining. Pankaj > > > > > Thanks, > > Pankaj > > > -- > > Thanks, > > David / dhildenb >