lib: Extract mlock probing

We already have the routine we need in drv_suspend. Let's move it to lib
and use it in the mlocking tests. We can also make it a bit faster if we
tweak the initial step and initial amount.
(I think it's safe to assume that we should be able to lock 3/4
of RAM, this cuts the probe time on my 32G SKL - from ~530s to ~180s)

v2: Use available mem, amend step, also lock outside of fork,
    early exit if the assumption is wrong (Chris)
    Update the function name in doc (Ewelina)
v3: Total for pin, available for initial lock (Chris)

Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ewelina Musial <ewelina.musial@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ewelina Musial <ewelina.musial@intel.com>

1 files changed, 11 insertions, 33 deletions

diff --git a/tests/drv_suspend.c b/tests/drv_suspend.c
index 9a9ff200..b4212dca 100644
--- a/tests/drv_suspend.c
+++ b/tests/drv_suspend.c
@@ -163,52 +163,30 @@ test_sysfs_reader(bool hibernate)
 static void
 test_shrink(int fd, unsigned int mode)
 {
-	uint64_t *can_mlock, pin;
+	void *mem;
+	size_t size;
 
 	gem_quiescent_gpu(fd);
 	intel_purge_vm_caches(fd);
 
-	pin = (intel_get_total_ram_mb() + 1) << 20;
-
-	igt_debug("Total memory %'"PRIu64" B (%'"PRIu64" MiB)\n",
-		  pin, pin >> 20);
-	can_mlock = mmap(NULL, pin, PROT_WRITE, MAP_SHARED | MAP_ANON, -1, 0);
-	igt_require(can_mlock != MAP_FAILED);
-
-	/* Lock all the system memory, forcing the driver into swap and OOM */
-	for (uint64_t inc = 64 << 20; inc >= 4 << 10; inc >>= 1) {
-		igt_debug("Testing+ %'"PRIu64" B (%'"PRIu64" MiB)\n",
-			  *can_mlock, *can_mlock >> 20);
-
-		igt_fork(child, 1) {
-			for (uint64_t bytes = *can_mlock;
-			     bytes <= pin;
-			     bytes += inc) {
-				if (mlock(can_mlock, bytes))
-					break;
-
-				*can_mlock = bytes;
-				__sync_synchronize();
-			}
-		}
-		__igt_waitchildren();
-	}
+	size = intel_get_total_pinnable_mem();
+	igt_require(size > 64 << 20);
+	size -= 64 << 20;
 
-	intel_purge_vm_caches(fd);
+	mem = mmap(NULL, size, PROT_READ, MAP_SHARED | MAP_ANON, -1, 0);
 
-	igt_require(*can_mlock > 64 << 20);
-	*can_mlock -= 64 << 20;
+	intel_purge_vm_caches(fd);
 
 	igt_debug("Locking %'"PRIu64" B (%'"PRIu64" MiB)\n",
-		  *can_mlock, *can_mlock >> 20);
-	igt_assert(!mlock(can_mlock, *can_mlock));
+		  size, size >> 20);
+	igt_assert(!mlock(mem, size));
 	igt_info("Locked %'"PRIu64" B (%'"PRIu64" MiB)\n",
-		 *can_mlock, *can_mlock >> 20);
+		 size, size >> 20);
 
 	intel_purge_vm_caches(fd);
 	igt_system_suspend_autoresume(mode, SUSPEND_TEST_NONE);
 
-	munmap(can_mlock, pin);
+	munmap(mem, size);
 }
 
 static void