@@ -65,6 +65,8 @@ struct _XENSTORE_WATCH
/* Path being watched. */
CHAR8 *Node;
+
+ BOOLEAN Triggered;
};
#define XENSTORE_WATCH_FROM_LINK(l) \
@@ -86,13 +88,6 @@ typedef struct {
struct {
CHAR8 *Body;
} Reply;
-
- /* Queued watch events. */
- struct {
- XENSTORE_WATCH *Handle;
- CONST CHAR8 **Vector;
- UINT32 VectorSize;
- } Watch;
} u;
} XENSTORE_MESSAGE;
#define XENSTORE_MESSAGE_FROM_LINK(r) \
@@ -133,14 +128,6 @@ typedef struct {
/** Lock protecting the registered watches list. */
EFI_LOCK RegisteredWatchesLock;
- /**
- * List of pending watch callback events.
- */
- LIST_ENTRY WatchEvents;
-
- /** Lock protecting the watch calback list. */
- EFI_LOCK WatchEventsLock;
-
/**
* The event channel for communicating with the
* XenStore service.
@@ -630,29 +617,32 @@ XenStoreProcessMessage (
Body[Message->Header.len] = '\0';
if (Message->Header.type == XS_WATCH_EVENT) {
- VOID *ConvertedToken;
+ CONST CHAR8 *WatchEventPath;
+ CONST CHAR8 *WatchEventToken;
+ VOID *ConvertedToken;
+ XENSTORE_WATCH *Watch;
- Message->u.Watch.Vector = Split(Body, Message->Header.len,
- &Message->u.Watch.VectorSize);
+ //
+ // Parse WATCH_EVENT messages
+ // <path>\0<token>\0
+ //
+ WatchEventPath = Body;
+ WatchEventToken = WatchEventPath + AsciiStrSize (WatchEventPath);
- ConvertedToken =
- (VOID *) AsciiStrHexToUintn (Message->u.Watch.Vector[XS_WATCH_TOKEN]);
+ ConvertedToken = (VOID *) AsciiStrHexToUintn (WatchEventToken);
EfiAcquireLock (&xs.RegisteredWatchesLock);
- Message->u.Watch.Handle = XenStoreFindWatch (ConvertedToken);
- DEBUG ((EFI_D_INFO, "XenStore: Watch event %a\n",
- Message->u.Watch.Vector[XS_WATCH_TOKEN]));
- if (Message->u.Watch.Handle != NULL) {
- EfiAcquireLock (&xs.WatchEventsLock);
- InsertHeadList (&xs.WatchEvents, &Message->Link);
- EfiReleaseLock (&xs.WatchEventsLock);
+ Watch = XenStoreFindWatch (ConvertedToken);
+ DEBUG ((DEBUG_INFO, "XenStore: Watch event %a\n", WatchEventToken));
+ if (Watch != NULL) {
+ Watch->Triggered = TRUE;
} else {
DEBUG ((EFI_D_WARN, "XenStore: Watch handle %a not found\n",
- Message->u.Watch.Vector[XS_WATCH_TOKEN]));
- FreePool((VOID*)Message->u.Watch.Vector);
- FreePool(Message);
+ WatchEventToken));
}
EfiReleaseLock (&xs.RegisteredWatchesLock);
+ FreePool (Message);
+ FreePool (Body);
} else {
Message->u.Reply.Body = Body;
EfiAcquireLock (&xs.ReplyLock);
@@ -936,40 +926,29 @@ XenStoreUnwatch (
STATIC
XENSTORE_STATUS
XenStoreWaitWatch (
- VOID *Token
+ IN VOID *Token
)
{
- XENSTORE_MESSAGE *Message;
- LIST_ENTRY *Entry = NULL;
- LIST_ENTRY *Last = NULL;
+ XENSTORE_WATCH *Watch;
XENSTORE_STATUS Status;
+ EfiAcquireLock (&xs.RegisteredWatchesLock);
+ Watch = XenStoreFindWatch (Token);
+ EfiReleaseLock (&xs.RegisteredWatchesLock);
+ if (Watch == NULL) {
+ return XENSTORE_STATUS_EINVAL;
+ }
+
while (TRUE) {
- EfiAcquireLock (&xs.WatchEventsLock);
- if (IsListEmpty (&xs.WatchEvents) ||
- Last == GetFirstNode (&xs.WatchEvents)) {
- EfiReleaseLock (&xs.WatchEventsLock);
- Status = XenStoreProcessMessage ();
- if (Status != XENSTORE_STATUS_SUCCESS && Status != XENSTORE_STATUS_EAGAIN) {
- return Status;
- }
- continue;
+ if (Watch->Triggered) {
+ Watch->Triggered = FALSE;
+ return XENSTORE_STATUS_SUCCESS;
}
- for (Entry = GetFirstNode (&xs.WatchEvents);
- Entry != Last && !IsNull (&xs.WatchEvents, Entry);
- Entry = GetNextNode (&xs.WatchEvents, Entry)) {
- Message = XENSTORE_MESSAGE_FROM_LINK (Entry);
- if (Message->u.Watch.Handle == Token) {
- RemoveEntryList (Entry);
- EfiReleaseLock (&xs.WatchEventsLock);
- FreePool((VOID*)Message->u.Watch.Vector);
- FreePool(Message);
- return XENSTORE_STATUS_SUCCESS;
- }
+ Status = XenStoreProcessMessage ();
+ if (Status != XENSTORE_STATUS_SUCCESS && Status != XENSTORE_STATUS_EAGAIN) {
+ return Status;
}
- Last = GetFirstNode (&xs.WatchEvents);
- EfiReleaseLock (&xs.WatchEventsLock);
}
}
@@ -1052,12 +1031,10 @@ XenStoreInit (
xs.XenStore, xs.EventChannel));
InitializeListHead (&xs.ReplyList);
- InitializeListHead (&xs.WatchEvents);
InitializeListHead (&xs.RegisteredWatches);
EfiInitializeLock (&xs.ReplyLock, TPL_NOTIFY);
EfiInitializeLock (&xs.RegisteredWatchesLock, TPL_NOTIFY);
- EfiInitializeLock (&xs.WatchEventsLock, TPL_NOTIFY);
/* Initialize the shared memory rings to talk to xenstored */
Status = XenStoreInitComms (&xs);
@@ -1088,23 +1065,6 @@ XenStoreDeinit (
}
}
- //
- // Emptying the list WatchEvents, but this list should already be empty after
- // having cleanup the list RegisteredWatches.
- //
- if (!IsListEmpty (&xs.WatchEvents)) {
- LIST_ENTRY *Entry;
- DEBUG ((DEBUG_WARN, "XenStore: WatchEvents is not empty, cleaning up...\n"));
- Entry = GetFirstNode (&xs.WatchEvents);
- while (!IsNull (&xs.WatchEvents, Entry)) {
- XENSTORE_MESSAGE *Message = XENSTORE_MESSAGE_FROM_LINK (Entry);
- Entry = GetNextNode (&xs.WatchEvents, Entry);
- RemoveEntryList (&Message->Link);
- FreePool ((VOID*)Message->u.Watch.Vector);
- FreePool (Message);
- }
- }
-
if (!IsListEmpty (&xs.ReplyList)) {
XENSTORE_MESSAGE *Message;
LIST_ENTRY *Entry;
@@ -1382,7 +1342,6 @@ XenStoreUnregisterWatch (
)
{
CHAR8 Token[sizeof (Watch) * 2 + 1];
- LIST_ENTRY *Entry;
ASSERT (Watch->Signature == XENSTORE_WATCH_SIGNATURE);
@@ -1397,20 +1356,6 @@ XenStoreUnregisterWatch (
AsciiSPrint (Token, sizeof (Token), "%p", (VOID *) Watch);
XenStoreUnwatch (Watch->Node, Token);
- /* Cancel pending watch events. */
- EfiAcquireLock (&xs.WatchEventsLock);
- Entry = GetFirstNode (&xs.WatchEvents);
- while (!IsNull (&xs.WatchEvents, Entry)) {
- XENSTORE_MESSAGE *Message = XENSTORE_MESSAGE_FROM_LINK (Entry);
- Entry = GetNextNode (&xs.WatchEvents, Entry);
- if (Message->u.Watch.Handle == Watch) {
- RemoveEntryList (&Message->Link);
- FreePool ((VOID*)Message->u.Watch.Vector);
- FreePool (Message);
- }
- }
- EfiReleaseLock (&xs.WatchEventsLock);
-
FreePool (Watch->Node);
FreePool (Watch);
}
This patch rework the reception of xenstore watch event to avoid allocation. Instead of queuing watch events, we simply mark a XENSTORE_WATCH as "triggered". We don't need to know how many time we received the event, only that it happened. That avoid to allocate a XENSTORE_MESSAGE for every watch events. Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2190 Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> --- OvmfPkg/XenBusDxe/XenStore.c | 125 ++++++++++------------------------- 1 file changed, 35 insertions(+), 90 deletions(-)