From: "Michael S. Tsirkin" <mst@redhat.com>
To: Frank Swiderski <fes@google.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>,
riel@redhat.com, Andrea Arcangeli <aarcange@redhat.com>,
virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
mikew@google.com
Subject: Re: [PATCH] Add a page cache-backed balloon device driver.
Date: Thu, 30 Aug 2012 11:57:24 +0300 [thread overview]
Message-ID: <20120830085724.GF10269@redhat.com> (raw)
In-Reply-To: <1340742778-11282-1-git-send-email-fes@google.com>
On Tue, Jun 26, 2012 at 01:32:58PM -0700, Frank Swiderski wrote:
> +static void fill_balloon(struct virtio_balloon *vb, size_t num)
> +{
> + int err;
> +
> + /* We can only do one array worth at a time. */
> + num = min(num, ARRAY_SIZE(vb->pfns));
> +
> + for (vb->num_pfns = 0; vb->num_pfns < num; vb->num_pfns++) {
> + struct page *page;
> + unsigned long inode_pfn = find_available_inode_page(vb);
> + /* Should always be able to find a page. */
> + BUG_ON(!inode_pfn);
> + page = read_mapping_page(the_inode.inode.i_mapping, inode_pfn,
> + NULL);
> + if (IS_ERR(page)) {
> + if (printk_ratelimit())
> + dev_printk(KERN_INFO, &vb->vdev->dev,
> + "Out of puff! Can't get %zu pages\n",
> + num);
> + break;
> + }
> +
> + /* Set the page to be dirty */
> + set_page_dirty(page);
> +
> + vb->pfns[vb->num_pfns] = page_to_pfn(page);
> + }
> +
> + /* Didn't get any? Oh well. */
> + if (vb->num_pfns == 0)
> + return;
Went to look at this driver, and noticed caller will re-invoke
this immediately if this triggers, so we busy-wait
re-trying this. When does read_mapping_page fail?
Is there any condition we could wait on?
--
MST
next prev parent reply other threads:[~2012-08-30 8:56 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-26 20:32 [PATCH] Add a page cache-backed balloon device driver Frank Swiderski
2012-06-26 20:40 ` Rik van Riel
2012-06-26 21:31 ` Frank Swiderski
2012-06-26 21:45 ` Rik van Riel
2012-06-26 23:45 ` Frank Swiderski
2012-06-27 9:04 ` Michael S. Tsirkin
2012-06-26 21:47 ` Michael S. Tsirkin
2012-06-26 23:21 ` Frank Swiderski
2012-06-27 9:02 ` Michael S. Tsirkin
2012-07-02 0:29 ` Rusty Russell
2012-09-03 6:35 ` Paolo Bonzini
2012-09-06 1:35 ` Rusty Russell
2012-06-26 21:41 ` Michael S. Tsirkin
2012-06-27 2:56 ` Rusty Russell
2012-06-27 15:48 ` Frank Swiderski
2012-06-27 16:06 ` Michael S. Tsirkin
2012-06-27 16:08 ` Frank Swiderski
2012-06-27 9:40 ` Amit Shah
2012-08-30 8:57 ` Michael S. Tsirkin [this message]
2012-09-03 15:09 ` Avi Kivity
2012-09-10 9:05 ` Michael S. Tsirkin
2012-09-10 17:37 ` Mike Waychison
2012-09-10 18:04 ` Rik van Riel
2012-09-10 18:29 ` Mike Waychison
2012-09-10 19:59 ` Michael S. Tsirkin
2012-09-10 20:49 ` Mike Waychison
2012-09-10 21:10 ` Michael S. Tsirkin
2012-10-30 15:29 ` Michael S. Tsirkin
2012-10-30 16:25 ` Mike Waychison
2012-09-12 5:25 ` Rusty Russell
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