From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Dongli Zhang <dongli.zhang@oracle.com>,
xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org
Cc: jgross@suse.com, paul.durrant@citrix.com, wei.liu2@citrix.com,
konrad.wilk@oracle.com, roger.pau@citrix.com,
srinivas.eeda@oracle.com
Subject: Re: [PATCH 2/6] xenbus: implement the xenwatch multithreading framework
Date: Sun, 16 Sep 2018 17:20:04 -0400 [thread overview]
Message-ID: <affabca4-0683-f088-7b25-d239ff882fa0@oracle.com> (raw)
In-Reply-To: <1536910456-13337-3-git-send-email-dongli.zhang@oracle.com>
On 9/14/18 3:34 AM, Dongli Zhang wrote:
>
> +
> +/* Running in the context of default xenwatch kthread. */
> +void mtwatch_create_domain(domid_t domid)
> +{
> + struct mtwatch_domain *domain;
> +
> + if (!domid) {
> + pr_err("Default xenwatch thread is for dom0\n");
> + return;
> + }
> +
> + spin_lock(&mtwatch_info->domain_lock);
> +
> + domain = mtwatch_find_domain(domid);
> + if (domain) {
> + atomic_inc(&domain->refcnt);
> + spin_unlock(&mtwatch_info->domain_lock);
> + return;
> + }
> +
> + domain = kzalloc(sizeof(*domain), GFP_ATOMIC);
Is there a reason (besides this being done under spinlock) for using
GFP_ATOMIC? If domain_lock is the only reason I'd probably drop the lock
and do GFP_KERNEL.
> + if (!domain) {
> + spin_unlock(&mtwatch_info->domain_lock);
> + pr_err("Failed to allocate memory for mtwatch thread %d\n",
> + domid);
> + return;
This needs to return an error code, I think. Or do you want to fall back
to shared xenwatch thread?
> + }
> +
> + domain->domid = domid;
> + atomic_set(&domain->refcnt, 1);
> + mutex_init(&domain->domain_mutex);
> + INIT_LIST_HEAD(&domain->purge_node);
> +
> + init_waitqueue_head(&domain->events_wq);
> + spin_lock_init(&domain->events_lock);
> + INIT_LIST_HEAD(&domain->events);
> +
> + list_add_tail_rcu(&domain->list_node, &mtwatch_info->domain_list);
> +
> + hlist_add_head_rcu(&domain->hash_node,
> + &mtwatch_info->domain_hash[MTWATCH_HASH(domid)]);
> +
> + spin_unlock(&mtwatch_info->domain_lock);
> +
> + domain->task = kthread_run(mtwatch_thread, domain,
> + "xen-mtwatch-%d", domid);
> +
> + if (!domain->task) {
> + pr_err("mtwatch kthread creation is failed\n");
> + domain->state = MTWATCH_DOMAIN_DOWN;
Why not clean up right here?
> +
> + return;
> + }
> +
> + domain->state = MTWATCH_DOMAIN_UP;
> +}
> +
> +
> void unregister_xenbus_watch(struct xenbus_watch *watch)
> {
> struct xs_watch_event *event, *tmp;
> @@ -831,6 +1100,9 @@ void unregister_xenbus_watch(struct xenbus_watch *watch)
>
> if (current->pid != xenwatch_pid)
> mutex_unlock(&xenwatch_mutex);
> +
> + if (xen_mtwatch && watch->get_domid)
> + unregister_mtwatch(watch);
I may not be understanding the logic flow here, but if we successfully
removed/unregistered/purged the watch from mtwatch lists, do we still
need to try removing it from watch_events list below?
-boris
next prev parent reply other threads:[~2018-09-16 21:20 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-14 7:34 Introduce xenwatch multithreading (mtwatch) Dongli Zhang
2018-09-14 7:34 ` [PATCH 1/6] xenbus: prepare data structures and parameter for xenwatch multithreading Dongli Zhang
2018-09-14 8:11 ` Paul Durrant
2018-09-14 13:40 ` [Xen-devel] " Dongli Zhang
2018-09-14 8:32 ` Juergen Gross
2018-09-14 13:57 ` [Xen-devel] " Dongli Zhang
2018-09-14 14:10 ` Juergen Gross
2018-09-16 20:17 ` Boris Ostrovsky
2018-09-17 1:20 ` Dongli Zhang
2018-09-17 19:08 ` Boris Ostrovsky
2018-09-25 5:14 ` Dongli Zhang
2018-09-25 20:19 ` Boris Ostrovsky
2018-09-26 2:57 ` [Xen-devel] " Dongli Zhang
2018-09-14 7:34 ` [PATCH 2/6] xenbus: implement the xenwatch multithreading framework Dongli Zhang
2018-09-14 8:45 ` Paul Durrant
2018-09-14 14:09 ` [Xen-devel] " Dongli Zhang
2018-09-14 8:56 ` Juergen Gross
2018-09-16 21:20 ` Boris Ostrovsky [this message]
2018-09-17 1:48 ` [Xen-devel] " Dongli Zhang
2018-09-17 20:00 ` Boris Ostrovsky
2018-09-14 7:34 ` [PATCH 3/6] xenbus: dispatch per-domU watch event to per-domU xenwatch thread Dongli Zhang
2018-09-14 9:01 ` Juergen Gross
2018-09-17 20:09 ` Boris Ostrovsky
2018-09-14 7:34 ` [PATCH 4/6] xenbus: process otherend_watch event at 'state' entry in xenwatch multithreading Dongli Zhang
2018-09-14 9:04 ` Juergen Gross
2018-09-14 7:34 ` [PATCH 5/6] xenbus: process be_watch events " Dongli Zhang
2018-09-14 9:12 ` Juergen Gross
2018-09-14 14:18 ` [Xen-devel] " Dongli Zhang
2018-09-14 14:26 ` Juergen Gross
2018-09-14 14:29 ` Dongli Zhang
2018-09-14 14:44 ` Juergen Gross
2018-09-19 6:15 ` Dongli Zhang
2018-09-19 8:01 ` Juergen Gross
2018-09-19 12:27 ` Dongli Zhang
2018-09-19 12:44 ` Juergen Gross
2018-09-14 14:33 ` Dongli Zhang
2018-09-14 7:34 ` [PATCH 6/6] drivers: enable xenwatch multithreading for xen-netback and xen-blkback driver Dongli Zhang
2018-09-14 9:16 ` Juergen Gross
2018-09-14 9:38 ` Wei Liu
2018-09-14 9:56 ` Roger Pau Monné
2018-09-14 8:16 ` Introduce xenwatch multithreading (mtwatch) Paul Durrant
2018-09-14 9:18 ` Juergen Gross
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=affabca4-0683-f088-7b25-d239ff882fa0@oracle.com \
--to=boris.ostrovsky@oracle.com \
--cc=dongli.zhang@oracle.com \
--cc=jgross@suse.com \
--cc=konrad.wilk@oracle.com \
--cc=linux-kernel@vger.kernel.org \
--cc=paul.durrant@citrix.com \
--cc=roger.pau@citrix.com \
--cc=srinivas.eeda@oracle.com \
--cc=wei.liu2@citrix.com \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).