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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [win-pv-devel] [PATCH 13/15] Re-work EVTCHN Trigger
By re-working the event channel poll callback to add pending channels to a
list and then service them, we can tidy up Trigger by forcibly appending a
channel to the same list and then scheduling a DPC on the correct cpu to
service in the list (unless an interrupt callback came along in the interim
and did the job).
Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
---
src/xenbus/evtchn.c | 212 ++++++++++++++++++++++++++++++++++++----------------
1 file changed, 148 insertions(+), 64 deletions(-)
diff --git a/src/xenbus/evtchn.c b/src/xenbus/evtchn.c
index 81f97e4..437bfac 100644
--- a/src/xenbus/evtchn.c
+++ b/src/xenbus/evtchn.c
@@ -75,6 +75,7 @@ struct _XENBUS_EVTCHN_CHANNEL {
ULONG Magic;
KSPIN_LOCK Lock;
LIST_ENTRY ListEntry;
+ LIST_ENTRY PendingListEntry;
PVOID Caller;
PKSERVICE_ROUTINE Callback;
PVOID Argument;
@@ -105,6 +106,7 @@ struct _XENBUS_EVTCHN_CONTEXT {
BOOLEAN UseEvtchnFifoAbi;
PXENBUS_HASH_TABLE Table;
LIST_ENTRY List;
+ LIST_ENTRY PendingList[MAXIMUM_PROCESSORS];
KDPC Dpc[MAXIMUM_PROCESSORS];
};
@@ -308,6 +310,8 @@ EvtchnOpen(
LocalPort = Channel->LocalPort;
+ InitializeListHead(&Channel->PendingListEntry);
+
status = XENBUS_EVTCHN_ABI(PortEnable,
&Context->EvtchnAbi,
LocalPort);
@@ -342,6 +346,9 @@ fail4:
fail3:
Error("fail3\n");
+ ASSERT(IsListEmpty(&Channel->PendingListEntry));
+ RtlZeroMemory(&Channel->PendingListEntry, sizeof (LIST_ENTRY));
+
Channel->LocalPort = 0;
Channel->Mask = FALSE;
RtlZeroMemory(&Channel->Parameters, sizeof (XENBUS_EVTCHN_PARAMETERS));
@@ -430,6 +437,102 @@ fail1:
return status;
}
+static BOOLEAN
+EvtchnPollCallback(
+ IN PVOID Argument,
+ IN ULONG LocalPort
+ )
+{
+ PXENBUS_EVTCHN_CONTEXT Context = Argument;
+ ULONG Cpu;
+ PXENBUS_EVTCHN_CHANNEL Channel;
+ BOOLEAN Pending;
+ NTSTATUS status;
+
+ ASSERT3U(KeGetCurrentIrql(), >=, DISPATCH_LEVEL);
+ Cpu = KeGetCurrentProcessorNumber();
+
+ status = HashTableLookup(Context->Table,
+ LocalPort,
+ (PULONG_PTR)&Channel);
+ if (!NT_SUCCESS(status))
+ goto done;
+
+ ASSERT3U(Channel->LocalPort, ==, LocalPort);
+
+ Pending = !IsListEmpty(&Channel->PendingListEntry);
+
+ if (!Pending)
+ InsertTailList(&Context->PendingList[Cpu],
+ &Channel->PendingListEntry);
+
+done:
+ return FALSE;
+}
+
+static BOOLEAN
+EvtchnPoll(
+ IN PXENBUS_EVTCHN_CONTEXT Context,
+ IN ULONG Cpu
+ )
+{
+ BOOLEAN DoneSomething;
+
+ (VOID) XENBUS_EVTCHN_ABI(Poll,
+ &Context->EvtchnAbi,
+ Cpu,
+ EvtchnPollCallback,
+ Context);
+
+ DoneSomething = FALSE;
+ while (!IsListEmpty(&Context->PendingList[Cpu])) {
+ PLIST_ENTRY ListEntry;
+ PXENBUS_EVTCHN_CHANNEL Channel;
+
+ ListEntry = RemoveHeadList(&Context->PendingList[Cpu]);
+ ASSERT(ListEntry != &Context->PendingList[Cpu]);
+
+ InitializeListHead(ListEntry);
+
+ Channel = CONTAINING_RECORD(ListEntry,
+ XENBUS_EVTCHN_CHANNEL,
+ PendingListEntry);
+ if (Channel->Mask)
+ XENBUS_EVTCHN_ABI(PortMask,
+ &Context->EvtchnAbi,
+ Channel->LocalPort);
+
+ XENBUS_EVTCHN_ABI(PortAck,
+ &Context->EvtchnAbi,
+ Channel->LocalPort);
+
+#pragma warning(suppress:6387) // NULL argument
+ DoneSomething |= Channel->Callback(NULL, Channel->Argument);
+ }
+
+ return DoneSomething;
+}
+
+static VOID
+EvtchnFlush(
+ IN PXENBUS_EVTCHN_CONTEXT Context,
+ IN ULONG Cpu
+ )
+{
+ PXENBUS_INTERRUPT Interrupt;
+ KIRQL Irql;
+
+ Interrupt = (Context->Affinity != 0) ? // Latched available
+ Context->LatchedInterrupt[Cpu] :
+ Context->LevelSensitiveInterrupt;
+
+ Irql = FdoAcquireInterruptLock(Context->Fdo, Interrupt);
+
+ (VOID) EvtchnPoll(Context, Cpu);
+
+ FdoReleaseInterruptLock(Context->Fdo, Interrupt, Irql);
+}
+
static
_Function_class_(KDEFERRED_ROUTINE)
_IRQL_requires_max_(DISPATCH_LEVEL)
@@ -437,7 +540,7 @@ _IRQL_requires_min_(DISPATCH_LEVEL)
_IRQL_requires_(DISPATCH_LEVEL)
_IRQL_requires_same_
VOID
-EvtchnCallback(
+EvtchnDpc(
IN PKDPC Dpc,
IN PVOID _Context,
IN PVOID Argument1,
@@ -445,23 +548,24 @@ EvtchnCallback(
)
{
PXENBUS_EVTCHN_CONTEXT Context = _Context;
- PXENBUS_EVTCHN_CHANNEL Channel = Argument1;
- PXENBUS_INTERRUPT Interrupt;
- KIRQL Irql;
+ ULONG Cpu;
UNREFERENCED_PARAMETER(Dpc);
+ UNREFERENCED_PARAMETER(Argument1);
UNREFERENCED_PARAMETER(Argument2);
- Interrupt = (Context->Affinity != 0) ? // Latched available
- Context->LatchedInterrupt[Channel->Cpu] :
- Context->LevelSensitiveInterrupt;
+ ASSERT3U(KeGetCurrentIrql(), >=, DISPATCH_LEVEL);
+ Cpu = KeGetCurrentProcessorNumber();
- Irql = FdoAcquireInterruptLock(Context->Fdo, Interrupt);
+ KeAcquireSpinLockAtDpcLevel(&Context->Lock);
-#pragma warning(suppress:6387) // NULL argument
- (VOID) Channel->Callback(NULL, Channel->Argument);
+ if (Context->References == 0)
+ goto done;
- FdoReleaseInterruptLock(Context->Fdo, Interrupt, Irql);
+ EvtchnFlush(Context, Cpu);
+
+done:
+ KeReleaseSpinLockFromDpcLevel(&Context->Lock);
}
static VOID
@@ -473,15 +577,35 @@ EvtchnTrigger(
PXENBUS_EVTCHN_CONTEXT Context = Interface->Context;
PKDPC Dpc;
KIRQL Irql;
+ ULONG Cpu;
+ PXENBUS_INTERRUPT Interrupt;
+ BOOLEAN Pending;
ASSERT3U(Channel->Magic, ==, XENBUS_EVTCHN_CHANNEL_MAGIC);
KeAcquireSpinLock(&Channel->Lock, &Irql);
+ Cpu = Channel->Cpu;
+ KeReleaseSpinLock(&Channel->Lock, Irql);
- Dpc = &Context->Dpc[Channel->Cpu];
- KeInsertQueueDpc(Dpc, Channel, NULL);
+ Interrupt = (Context->Affinity != 0) ? // Latched available
+ Context->LatchedInterrupt[Cpu] :
+ Context->LevelSensitiveInterrupt;
- KeReleaseSpinLock(&Channel->Lock, Irql);
+ Irql = FdoAcquireInterruptLock(Context->Fdo, Interrupt);
+
+ Pending = !IsListEmpty(&Channel->PendingListEntry);
+
+ if (!Pending)
+ InsertTailList(&Context->PendingList[Cpu],
+ &Channel->PendingListEntry);
+
+ FdoReleaseInterruptLock(Context->Fdo, Interrupt, Irql);
+
+ if (Pending)
+ return;
+
+ Dpc = &Context->Dpc[Cpu];
+ KeInsertQueueDpc(Dpc, NULL, NULL);
}
static VOID
@@ -597,6 +721,9 @@ EvtchnClose(
Channel->Cpu = 0;
+ ASSERT(IsListEmpty(&Channel->PendingListEntry));
+ RtlZeroMemory(&Channel->PendingListEntry, sizeof (LIST_ENTRY));
+
Channel->LocalPort = 0;
Channel->Mask = FALSE;
RtlZeroMemory(&Channel->Parameters, sizeof (XENBUS_EVTCHN_PARAMETERS));
@@ -629,49 +756,6 @@ EvtchnGetPort(
return Channel->LocalPort;
}
-static BOOLEAN
-EvtchnPollCallback(
- IN PVOID Argument,
- IN ULONG LocalPort
- )
-{
- PXENBUS_EVTCHN_CONTEXT Context = Argument;
- PXENBUS_EVTCHN_CHANNEL Channel;
- BOOLEAN DoneSomething;
- NTSTATUS status;
-
- DoneSomething = FALSE;
-
- status = HashTableLookup(Context->Table,
- LocalPort,
- (PULONG_PTR)&Channel);
-
- if (!NT_SUCCESS(status)) {
- Warning("[%d]: INVALID PORT\n", LocalPort);
-
- XENBUS_EVTCHN_ABI(PortMask,
- &Context->EvtchnAbi,
- LocalPort);
-
- goto done;
- }
-
- if (Channel->Mask)
- XENBUS_EVTCHN_ABI(PortMask,
- &Context->EvtchnAbi,
- LocalPort);
-
- XENBUS_EVTCHN_ABI(PortAck,
- &Context->EvtchnAbi,
- LocalPort);
-
-#pragma warning(suppress:6387) // NULL argument
- DoneSomething = Channel->Callback(NULL, Channel->Argument);
-
-done:
- return DoneSomething;
-}
-
static
_Function_class_(KSERVICE_ROUTINE)
__drv_requiresIRQL(HIGH_LEVEL)
@@ -691,15 +775,10 @@ EvtchnInterruptCallback(
Cpu = KeGetCurrentProcessorNumber();
DoneSomething = FALSE;
-
while (XENBUS_SHARED_INFO(UpcallPending,
&Context->SharedInfoInterface,
Cpu))
- DoneSomething |= XENBUS_EVTCHN_ABI(Poll,
- &Context->EvtchnAbi,
- Cpu,
- EvtchnPollCallback,
- Context);
+ DoneSomething |= EvtchnPoll(Context, Cpu);
return DoneSomething;
}
@@ -1131,6 +1210,8 @@ EvtchnRelease(
Cpu = KeNumberProcessors;
while (--Cpu >= 0) {
+ EvtchnFlush(Context, Cpu);
+
FdoFreeInterrupt(Fdo, Context->LatchedInterrupt[Cpu]);
Context->LatchedInterrupt[Cpu] = NULL;
}
@@ -1274,7 +1355,9 @@ EvtchnInitialize(
for (Cpu = 0; Cpu < MAXIMUM_PROCESSORS; Cpu++) {
PKDPC Dpc = &(*Context)->Dpc[Cpu];
- KeInitializeDpc(Dpc, EvtchnCallback, *Context);
+ InitializeListHead(&(*Context)->PendingList[Cpu]);
+
+ KeInitializeDpc(Dpc, EvtchnDpc, *Context);
KeSetTargetProcessorDpc(Dpc, (CCHAR)Cpu);
}
@@ -1395,6 +1478,7 @@ EvtchnTeardown(
RtlZeroMemory(&Context->Dpc, sizeof (KDPC) * MAXIMUM_PROCESSORS);
RtlZeroMemory(&Context->Lock, sizeof (KSPIN_LOCK));
RtlZeroMemory(&Context->List, sizeof (LIST_ENTRY));
+ RtlZeroMemory(&Context->PendingList, sizeof (LIST_ENTRY) *
MAXIMUM_PROCESSORS);
RtlZeroMemory(&Context->SharedInfoInterface,
sizeof (XENBUS_SHARED_INFO_INTERFACE));
--
2.1.1
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