gem_concurrent_blit: Don't call igt_require() outside of a subtest/fixture

gem_concurrent_blit tries to ensure that it doesn't try and run a test
that would grind the system to a halt, i.e. unexpectedly cause swap
thrashing. It currently calls intel_require_memory(), but outside of
the subtest (as the tests use fork, it cannot do requirement testing
within the test children) - but intel_require_memory() calls
igt_require() and triggers and abort. Wrapping that initial require
within an igt_fixture() stops the abort(), but also prevents any further
testing.

This patch restructures the requirement checking to ordinary conditions,
which though allowing the test to run, also prevents listing of subtests
on machines which cannot handle them.

3 files changed, 85 insertions, 38 deletions

diff --git a/lib/igt_aux.h b/lib/igt_aux.h
index 95028665..82bd5962 100644
--- a/lib/igt_aux.h
+++ b/lib/igt_aux.h
@@ -86,6 +86,8 @@ uint64_t intel_get_avail_ram_mb(void);
 uint64_t intel_get_total_ram_mb(void);
 uint64_t intel_get_total_swap_mb(void);
 
+int __intel_check_memory(uint32_t count, uint64_t size, unsigned mode,
+			 uint64_t *out_required, uint64_t *out_total);
 void intel_require_memory(uint32_t count, uint64_t size, unsigned mode);
 #define CHECK_RAM 0x1
 #define CHECK_SWAP 0x2
diff --git a/lib/intel_os.c b/lib/intel_os.c
index 06361f4c..64e37222 100644
--- a/lib/intel_os.c
+++ b/lib/intel_os.c
@@ -192,6 +192,38 @@ intel_get_total_swap_mb(void)
 	return retval / (1024*1024);
 }
 
+int __intel_check_memory(uint32_t count, uint64_t size, unsigned mode,
+			 uint64_t *out_required, uint64_t *out_total)
+{
+/* rough estimate of how many bytes the kernel requires to track each object */
+#define KERNEL_BO_OVERHEAD 512
+	uint64_t required, total;
+
+	required = count;
+	required *= size + KERNEL_BO_OVERHEAD;
+	required = ALIGN(required, 4096);
+
+	igt_debug("Checking %'u surfaces of size %'llu bytes (total %'llu) against %s%s\n",
+		  count, (long long)size, (long long)required,
+		  mode & (CHECK_RAM | CHECK_SWAP) ? "RAM" : "",
+		  mode & CHECK_SWAP ? " + swap": "");
+
+	total = 0;
+	if (mode & (CHECK_RAM | CHECK_SWAP))
+		total += intel_get_avail_ram_mb();
+	if (mode & CHECK_SWAP)
+		total += intel_get_total_swap_mb();
+	total *= 1024 * 1024;
+
+	if (out_required)
+		*out_required = required;
+
+	if (out_total)
+		*out_total = total;
+
+	return required < total;
+}
+
 /**
  * intel_require_memory:
  * @count: number of surfaces that will be created
@@ -217,27 +249,10 @@ intel_get_total_swap_mb(void)
  */
 void intel_require_memory(uint32_t count, uint64_t size, unsigned mode)
 {
-/* rough estimate of how many bytes the kernel requires to track each object */
-#define KERNEL_BO_OVERHEAD 512
 	uint64_t required, total;
 
-	required = count;
-	required *= size + KERNEL_BO_OVERHEAD;
-	required = ALIGN(required, 4096);
-
-	igt_debug("Checking %'u surfaces of size %'llu bytes (total %'llu) against %s%s\n",
-		  count, (long long)size, (long long)required,
-		  mode & (CHECK_RAM | CHECK_SWAP) ? "RAM" : "",
-		  mode & CHECK_SWAP ? " + swap": "");
-
-	total = 0;
-	if (mode & (CHECK_RAM | CHECK_SWAP))
-		total += intel_get_avail_ram_mb();
-	if (mode & CHECK_SWAP)
-		total += intel_get_total_swap_mb();
-	total *= 1024 * 1024;
-
-	igt_skip_on_f(total <= required,
+	igt_skip_on_f(!__intel_check_memory(count, size, mode,
+					    &required, &total),
 		      "Estimated that we need %'llu bytes for the test, but only have %'llu bytes available (%s%s)\n",
 		      (long long)required, (long long)total,
 		      mode & (CHECK_RAM | CHECK_SWAP) ? "RAM" : "",
diff --git a/tests/gem_concurrent_all.c b/tests/gem_concurrent_all.c
index 558b9c13..a7db23cb 100644
--- a/tests/gem_concurrent_all.c
+++ b/tests/gem_concurrent_all.c
@@ -155,9 +155,9 @@ static bool can_create_stolen(void)
 static drm_intel_bo *
 (*create_func)(drm_intel_bufmgr *bufmgr, uint64_t size);
 
-static void create_cpu_require(void)
+static bool create_cpu_require(void)
 {
-	igt_require(create_func != create_stolen_bo);
+	return create_func != create_stolen_bo;
 }
 
 static drm_intel_bo *
@@ -375,7 +375,7 @@ gpu_cmp_bo(drm_intel_bo *bo, uint32_t val, int width, int height, drm_intel_bo *
 
 const struct access_mode {
 	const char *name;
-	void (*require)(void);
+	bool (*require)(void);
 	void (*set_bo)(drm_intel_bo *bo, uint32_t val, int w, int h);
 	void (*cmp_bo)(drm_intel_bo *bo, uint32_t val, int w, int h, drm_intel_bo *tmp);
 	drm_intel_bo *(*create_bo)(drm_intel_bufmgr *bufmgr, int width, int height);
@@ -1321,24 +1321,22 @@ run_basic_modes(const char *prefix,
 }
 
 static void
-run_modes(const char *style, const struct access_mode *mode)
+run_modes(const char *style, const struct access_mode *mode, unsigned allow_mem)
 {
-	if (mode->require)
-		mode->require();
-
-	igt_debug("%s: using 2x%d buffers, each 1MiB\n", style, num_buffers);
-	intel_require_memory(2*num_buffers, 1024*1024, CHECK_RAM);
+	if (mode->require && !mode->require())
+		return;
 
-	if (all) {
-		run_basic_modes(style, mode, "", run_single);
+	igt_debug("%s: using 2x%d buffers, each 1MiB\n",
+			style, num_buffers);
+	if (!__intel_check_memory(2*num_buffers, 1024*1024, allow_mem,
+				  NULL, NULL))
+		return;
 
-		igt_fork_signal_helper();
-		run_basic_modes(style, mode, "-interruptible", run_interruptible);
-		igt_stop_signal_helper();
-	}
+	run_basic_modes(style, mode, "", run_single);
+	run_basic_modes(style, mode, "-forked", run_forked);
 
 	igt_fork_signal_helper();
-	run_basic_modes(style, mode, "-forked", run_forked);
+	run_basic_modes(style, mode, "-interruptible", run_interruptible);
 	run_basic_modes(style, mode, "-bomb", run_bomb);
 	igt_stop_signal_helper();
 }
@@ -1355,6 +1353,8 @@ igt_main
 		{ "stolen-", create_stolen_bo, can_create_stolen },
 		{ NULL, NULL }
 	}, *c;
+	uint64_t pin_sz = 0;
+	void *pinned = NULL;
 	int i;
 
 	igt_skip_on_simulation();
@@ -1381,7 +1381,7 @@ igt_main
 		if (c->require()) {
 			snprintf(name, sizeof(name), "%s%s", c->name, "small");
 			for (i = 0; i < ARRAY_SIZE(access_modes); i++)
-				run_modes(name, &access_modes[i]);
+				run_modes(name, &access_modes[i], CHECK_RAM);
 		}
 
 		igt_fixture {
@@ -1391,7 +1391,7 @@ igt_main
 		if (c->require()) {
 			snprintf(name, sizeof(name), "%s%s", c->name, "thrash");
 			for (i = 0; i < ARRAY_SIZE(access_modes); i++)
-				run_modes(name, &access_modes[i]);
+				run_modes(name, &access_modes[i], CHECK_RAM);
 		}
 
 		igt_fixture {
@@ -1401,7 +1401,37 @@ igt_main
 		if (c->require()) {
 			snprintf(name, sizeof(name), "%s%s", c->name, "full");
 			for (i = 0; i < ARRAY_SIZE(access_modes); i++)
-				run_modes(name, &access_modes[i]);
+				run_modes(name, &access_modes[i], CHECK_RAM);
+		}
+
+		igt_fixture {
+			num_buffers = gem_mappable_aperture_size() / (1024 * 1024);
+			pin_sz = intel_get_avail_ram_mb() - num_buffers;
+
+			igt_debug("Pinning %ld MiB\n", pin_sz);
+			pin_sz *= 1024 * 1024;
+
+			if (posix_memalign(&pinned, 4096, pin_sz) ||
+			    mlock(pinned, pin_sz) ||
+			    madvise(pinned, pin_sz, MADV_DONTFORK)) {
+				free(pinned);
+				pinned = NULL;
+			}
+			igt_require(pinned);
+		}
+
+		if (c->require()) {
+			snprintf(name, sizeof(name), "%s%s", c->name, "swap");
+			for (i = 0; i < ARRAY_SIZE(access_modes); i++)
+				run_modes(name, &access_modes[i], CHECK_RAM | CHECK_SWAP);
+		}
+
+		igt_fixture {
+			if (pinned) {
+				munlock(pinned, pin_sz);
+				free(pinned);
+				pinned = NULL;
+			}
 		}
 	}
 }