pytest: don't run tests marked slow_test at all if VALGRIND and SLOW_MACHINE.

diff --git a/contrib/pyln-testing/pyln/testing/utils.py b/contrib/pyln-testing/pyln/testing/utils.py
index 8607cd9b..732bd7b4 100644
--- a/contrib/pyln-testing/pyln/testing/utils.py
+++ b/contrib/pyln-testing/pyln/testing/utils.py
@@ -841,7 +841,7 @@ class PrettyPrintingLightningRpc(LightningRpc):
 
 
 class LightningNode(object):
-    def __init__(self, node_id, lightning_dir, bitcoind, executor, valgrind, may_fail=False,
+    def __init__(self, node_id, lightning_dir, bitcoind, executor, may_fail=False,
                  may_reconnect=False,
                  broken_log=None,
                  allow_warning=False,
@@ -900,7 +900,7 @@ class LightningNode(object):
             self.daemon.opts["dev-debugger"] = dbgvar
         if os.getenv("DEBUG_LIGHTNINGD"):
             self.daemon.opts["dev-debug-self"] = None
-        if valgrind:
+        if VALGRIND:
             self.daemon.env["LIGHTNINGD_DEV_NO_BACKTRACE"] = "1"
             self.daemon.opts["dev-no-plugin-checksum"] = None
         else:
@@ -926,7 +926,7 @@ class LightningNode(object):
         dsn = db.get_dsn()
         if dsn is not None:
             self.daemon.opts['wallet'] = dsn
-        if valgrind:
+        if VALGRIND:
             trace_skip_pattern = '*python*,*bitcoin-cli*,*elements-cli*,*cln-grpc*,*clnrest*,*wss-proxy*,*cln-bip353*,*reckless'
             if not valgrind_plugins:
                 trace_skip_pattern += ',*plugins*'
@@ -1653,10 +1653,6 @@ class NodeFactory(object):
     """
     def __init__(self, request, testname, bitcoind, executor, directory,
                  db_provider, node_cls, jsonschemas):
-        if request.node.get_closest_marker("slow_test") and SLOW_MACHINE:
-            self.valgrind = False
-        else:
-            self.valgrind = VALGRIND
         self.testname = testname
 
         # Set test name in environment for coverage file organization
@@ -1755,7 +1751,7 @@ class NodeFactory(object):
         db = self.db_provider.get_db(os.path.join(lightning_dir, TEST_NETWORK), self.testname, node_id)
         db.provider = self.db_provider
         node = self.node_cls(
-            node_id, lightning_dir, self.bitcoind, self.executor, self.valgrind, db=db,
+            node_id, lightning_dir, self.bitcoind, self.executor, db=db,
             port=port, grpc_port=grpc_port, options=options, may_fail=may_fail or expect_fail,
             jsonschemas=self.jsonschemas,
             **kwargs
@@ -1872,7 +1868,7 @@ class NodeFactory(object):
             # leak detection upsets VALGRIND by reading uninitialized mem,
             # and valgrind adds extra fds.
             # If it's dead, we'll catch it below.
-            if not self.valgrind:
+            if not VALGRIND:
                 try:
                     # This also puts leaks in log.
                     leaks = self.nodes[i].rpc.dev_memleak()['leaks']
diff --git a/tests/conftest.py b/tests/conftest.py
index 02905074..dcbd43ca 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,6 +1,6 @@
 import pytest
 
-from pyln.testing.utils import EXPERIMENTAL_DUAL_FUND
+from pyln.testing.utils import EXPERIMENTAL_DUAL_FUND, VALGRIND, SLOW_MACHINE
 
 
 # This function is based upon the example of how to
@@ -37,3 +37,5 @@ def pytest_runtest_setup(item):
     else:  # If there's no openchannel marker, skip if EXP_DF
         if EXPERIMENTAL_DUAL_FUND:
             pytest.skip('v1-only test, EXPERIMENTAL_DUAL_FUND=1')
+    if "slow_test" in item.keywords and VALGRIND and SLOW_MACHINE:
+        pytest.skip("Skipping slow tests under VALGRIND")
diff --git a/tests/test_closing.py b/tests/test_closing.py
index 3a7c3164..f3c7dbee 100644
--- a/tests/test_closing.py
+++ b/tests/test_closing.py
@@ -1,7 +1,7 @@
 from fixtures import *  # noqa: F401,F403
 from pyln.client import RpcError, Millisatoshi
 from shutil import copyfile
-from pyln.testing.utils import SLOW_MACHINE
+from pyln.testing.utils import SLOW_MACHINE, VALGRIND
 from utils import (
     only_one, sync_blockheight, wait_for, TIMEOUT,
     account_balance, first_channel_id, closing_fee, TEST_NETWORK,
@@ -3232,7 +3232,7 @@ def test_permfail(node_factory, bitcoind):
 def test_shutdown(node_factory):
     # Fail, in that it will exit before cleanup.
     l1 = node_factory.get_node(may_fail=True)
-    if not node_factory.valgrind:
+    if not VALGRIND:
         leaks = l1.rpc.dev_memleak()['leaks']
         if len(leaks):
             raise Exception("Node {} has memory leaks: {}"
diff --git a/tests/test_connection.py b/tests/test_connection.py
index 05724c51..78261f71 100644
--- a/tests/test_connection.py
+++ b/tests/test_connection.py
@@ -13,7 +13,7 @@ from utils import (
     mine_funding_to_announce, first_scid,
     CHANNEL_SIZE
 )
-from pyln.testing.utils import SLOW_MACHINE, VALGRIND, EXPERIMENTAL_DUAL_FUND, FUNDAMOUNT, RUST
+from pyln.testing.utils import VALGRIND, EXPERIMENTAL_DUAL_FUND, FUNDAMOUNT, RUST
 
 import os
 import pytest
@@ -1463,7 +1463,7 @@ def test_funding_v2_corners(node_factory, bitcoind):
     assert l1.rpc.openchannel_update(start['channel_id'], start['psbt'])['commitments_secured']
 
 
-@unittest.skipIf(SLOW_MACHINE and not VALGRIND, "Way too taxing on CI machines")
+@pytest.mark.slow_test
 @pytest.mark.openchannel('v1')
 def test_funding_cancel_race(node_factory, bitcoind, executor):
     l1 = node_factory.get_node()
@@ -1474,7 +1474,7 @@ def test_funding_cancel_race(node_factory, bitcoind, executor):
     bitcoind.generate_block(1)
     wait_for(lambda: len(l1.rpc.listfunds()["outputs"]) != 0)
 
-    if node_factory.valgrind:
+    if VALGRIND:
         num = 5
     else:
         num = 100
@@ -1536,7 +1536,7 @@ def test_funding_cancel_race(node_factory, bitcoind, executor):
     assert num_cancel == len(nodes)
 
     # We should have raced at least once!
-    if not node_factory.valgrind:
+    if not VALGRIND:
         assert num_cancel > 0
         assert num_complete > 0
 
@@ -1544,7 +1544,7 @@ def test_funding_cancel_race(node_factory, bitcoind, executor):
     executor.map(lambda n: n.stop(), node_factory.nodes)
 
 
-@unittest.skipIf(SLOW_MACHINE and not VALGRIND, "Way too taxing on CI machines")
+@pytest.mark.slow_test
 @pytest.mark.openchannel('v2')
 def test_funding_v2_cancel_race(node_factory, bitcoind, executor):
     l1 = node_factory.get_node()
@@ -1555,7 +1555,7 @@ def test_funding_v2_cancel_race(node_factory, bitcoind, executor):
     bitcoind.generate_block(1)
     wait_for(lambda: len(l1.rpc.listfunds()["outputs"]) != 0)
 
-    if node_factory.valgrind:
+    if VALGRIND:
         num = 5
     else:
         num = 100
@@ -1610,7 +1610,7 @@ def test_funding_v2_cancel_race(node_factory, bitcoind, executor):
     print("Cancelled {} complete {}".format(num_cancel, num_complete))
 
     # We should have raced at least once!
-    if not node_factory.valgrind:
+    if not VALGRIND:
         assert num_cancel > 0
         assert num_complete > 0
 
@@ -3452,7 +3452,7 @@ def test_feerate_stress(node_factory, executor):
 @pytest.mark.slow_test
 def test_pay_disconnect_stress(node_factory, executor):
     """Expose race in htlc restoration in channeld: 50% chance of failure"""
-    if node_factory.valgrind:
+    if VALGRIND:
         NUM_RUNS = 2
     else:
         NUM_RUNS = 5
diff --git a/tests/test_plugin.py b/tests/test_plugin.py
index f02bd807..1b549926 100644
--- a/tests/test_plugin.py
+++ b/tests/test_plugin.py
@@ -2983,7 +2983,7 @@ def test_autoclean(node_factory):
 
     # Under valgrind in CI, it can 50 seconds between creating invoice
     # and restarting.
-    if node_factory.valgrind:
+    if VALGRIND:
         short_timeout = 10
         longer_timeout = 60
     else:
diff --git a/tests/test_reckless.py b/tests/test_reckless.py
index 7fb04d74..275960d5 100644
--- a/tests/test_reckless.py
+++ b/tests/test_reckless.py
@@ -2,7 +2,7 @@ from fixtures import *  # noqa: F401,F403
 import subprocess
 from pathlib import PosixPath, Path
 import socket
-from pyln.testing.utils import VALGRIND, SLOW_MACHINE
+from pyln.testing.utils import VALGRIND
 import pytest
 import os
 import re
@@ -352,7 +352,7 @@ def test_tag_install(node_factory):
 
 
 @pytest.mark.flaky(reruns=5)
-@unittest.skipIf(VALGRIND and SLOW_MACHINE, "node too slow for starting plugin under valgrind")
+@pytest.mark.slow_test
 def test_reckless_uv_install(node_factory):
     node = get_reckless_node(node_factory)
     node.start()