From: David Vrabel <david.vrabel@citrix.com>
To: xen-devel@lists.xenproject.org
Cc: Keir Fraser <keir@xen.org>, Tim Deegan <tim@xen.org>,
David Vrabel <david.vrabel@citrix.com>,
Jan Beulich <jbeulich@suse.com>,
Ian Campbell <ian.campbell@citrix.com>
Subject: [PATCHv2 2/5] evtchn: simplify port_is_valid()
Date: Mon, 15 Jun 2015 16:48:16 +0100 [thread overview]
Message-ID: <1434383299-21833-3-git-send-email-david.vrabel@citrix.com> (raw)
In-Reply-To: <1434383299-21833-1-git-send-email-david.vrabel@citrix.com>
By keeping a count of the number of currently valid event channels,
port_is_valid() can be simplified.
d->valid_evtchns can also be tested without holding d->event_lock which
will be useful later on.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
---
v2:
- Used unsigned int for d->valid_evtchns.
---
xen/common/event_channel.c | 3 +++
xen/include/xen/event.h | 4 +---
xen/include/xen/sched.h | 5 +++--
3 files changed, 7 insertions(+), 5 deletions(-)
diff --git a/xen/common/event_channel.c b/xen/common/event_channel.c
index 947880f..fd48646 100644
--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -189,6 +189,8 @@ static int get_free_port(struct domain *d)
return -ENOMEM;
bucket_from_port(d, port) = chn;
+ write_atomic(&d->valid_evtchns, d->valid_evtchns + EVTCHNS_PER_BUCKET);
+
return port;
}
@@ -1254,6 +1256,7 @@ int evtchn_init(struct domain *d)
d->evtchn = alloc_evtchn_bucket(d, 0);
if ( !d->evtchn )
return -ENOMEM;
+ d->valid_evtchns = EVTCHNS_PER_BUCKET;
spin_lock_init_prof(d, event_lock);
if ( get_free_port(d) != 0 )
diff --git a/xen/include/xen/event.h b/xen/include/xen/event.h
index 690f865..a08ecdb 100644
--- a/xen/include/xen/event.h
+++ b/xen/include/xen/event.h
@@ -91,9 +91,7 @@ static inline bool_t port_is_valid(struct domain *d, unsigned int p)
return 0;
if ( !d->evtchn )
return 0;
- if ( p < EVTCHNS_PER_BUCKET )
- return 1;
- return group_from_port(d, p) != NULL && bucket_from_port(d, p) != NULL;
+ return p < read_atomic(&d->valid_evtchns);
}
static inline struct evtchn *evtchn_from_port(struct domain *d, unsigned int p)
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 80c6f62..604d047 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -336,8 +336,9 @@ struct domain
/* Event channel information. */
struct evtchn *evtchn; /* first bucket only */
struct evtchn **evtchn_group[NR_EVTCHN_GROUPS]; /* all other buckets */
- unsigned int max_evtchns;
- unsigned int max_evtchn_port;
+ unsigned int max_evtchns; /* number supported by ABI */
+ unsigned int max_evtchn_port; /* max permitted port number */
+ unsigned int valid_evtchns; /* number of allocated event channels */
spinlock_t event_lock;
const struct evtchn_port_ops *evtchn_port_ops;
struct evtchn_fifo_domain *evtchn_fifo;
--
1.7.10.4
next prev parent reply other threads:[~2015-06-15 16:38 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-15 15:48 [PATCHv2 0/5] evtchn: Improve scalebility David Vrabel
2015-06-15 15:48 ` [PATCHv2 1/5] evtchn: factor out freeing an event channel David Vrabel
2015-06-15 15:48 ` David Vrabel [this message]
2015-06-15 15:57 ` [PATCHv2 2/5] evtchn: simplify port_is_valid() Ian Campbell
2015-06-15 15:59 ` David Vrabel
2015-06-15 16:09 ` Ian Campbell
2015-06-15 15:48 ` [PATCHv2 3/5] evtchn: use a per-event channel lock for sending events David Vrabel
2015-06-16 9:18 ` Jan Beulich
2015-06-16 9:34 ` David Vrabel
2015-06-16 9:51 ` Jan Beulich
2015-06-16 9:57 ` David Vrabel
2015-06-16 15:19 ` David Vrabel
2015-06-16 15:58 ` David Vrabel
2015-06-16 16:19 ` Jan Beulich
2015-06-16 16:39 ` David Vrabel
2015-06-17 7:05 ` Jan Beulich
2015-06-16 16:06 ` Jan Beulich
2015-06-15 15:48 ` [PATCHv2 4/5] evtchn: remove the locking when unmasking an event channel David Vrabel
2015-06-16 9:19 ` Jan Beulich
2015-06-16 9:40 ` David Vrabel
2015-06-15 15:48 ` [PATCHv2 5/5] evtchn: pad struct evtchn to 64 bytes David Vrabel
2015-06-16 9:22 ` Jan Beulich
2015-06-16 11:14 ` Julien Grall
2015-06-16 11:59 ` Jan Beulich
2015-06-16 12:57 ` Julien Grall
2015-06-16 13:13 ` David Vrabel
2015-06-16 13:27 ` Julien Grall
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