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virtio/vhost-user: dynamically assign VhostUserHostNotifiers

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At a couple of hundred bytes per notifier allocating one for every
potential queue is very wasteful as most devices only have a few
queues. Instead of having this handled statically dynamically assign
them and track in a GPtrArray.

[AJB: it's hard to trigger the vhost notifiers code, I assume as it
requires a KVM guest with appropriate backend]

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220321153037.3622127-14-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Alex Bennée 2022-03-21 15:30:37 +00:00 • committed by Michael S. Tsirkin
parent 56534930b5
commit 503e355465
3 changed files with 108 additions and 18 deletions
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42
include/hw/virtio/vhost-user.h
View file

@ -11,21 +11,61 @@
#include "chardev/char-fe.h"
#include "hw/virtio/virtio.h"
/**
* VhostUserHostNotifier - notifier information for one queue
* @rcu: rcu_head for cleanup
* @mr: memory region of notifier
* @addr: current mapped address
* @unmap_addr: address to be un-mapped
* @idx: virtioqueue index
*
* The VhostUserHostNotifier entries are re-used. When an old mapping
* is to be released it is moved to @unmap_addr and @addr is replaced.
* Once the RCU process has completed the unmap @unmap_addr is
* cleared.
*/
typedef struct VhostUserHostNotifier {
struct rcu_head rcu;
MemoryRegion mr;
void *addr;
void *unmap_addr;
int idx;
} VhostUserHostNotifier;
/**
* VhostUserState - shared state for all vhost-user devices
* @chr: the character backend for the socket
* @notifiers: GPtrArray of @VhostUserHostnotifier
* @memory_slots:
*/
typedef struct VhostUserState {
CharBackend *chr;
VhostUserHostNotifier notifier[VIRTIO_QUEUE_MAX];
GPtrArray *notifiers;
int memory_slots;
bool supports_config;
} VhostUserState;
/**
* vhost_user_init() - initialise shared vhost_user state
* @user: allocated area for storing shared state
* @chr: the chardev for the vhost socket
* @errp: error handle
*
* User can either directly g_new() space for the state or embed
* VhostUserState in their larger device structure and just point to
* it.
*
* Return: true on success, false on error while setting errp.
*/
bool vhost_user_init(VhostUserState *user, CharBackend *chr, Error **errp);
/**
* vhost_user_cleanup() - cleanup state
* @user: ptr to use state
*
* Cleans up shared state and notifiers, callee is responsible for
* freeing the @VhostUserState memory itself.
*/
void vhost_user_cleanup(VhostUserState *user);
#endif