tests: Add gem_shrink

This test exercise purely to exercise the shrinker under some common
stress (i.e. paths leading to i915_gem_object_get_pages()). We try to
fill the entirely of memory split amongst many processes so that each
individual process only consumes a small fraction of RAM (less than the
mappable aperture) and a single process should not be individually
blamed.

Based on an idea to have a seperate set of memory stress tests by Piotr
Luc.

Cc: Piotr Luc <piotr.luc@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

tests/Makefile.sources

@@ -69,6 +69,7 @@ TESTS_progs_M = \
 	gem_reset_stats \
 	gem_ringfill \
 	gem_set_tiling_vs_blt \
+	gem_shrink \
 	gem_softpin \
 	gem_stolen \
 	gem_storedw_batches_loop \

tests/gem_shrink.c

@@ -0,0 +1,216 @@
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+/** @file gem_shrink.c
+ *
+ * Exercise the shrinker by overallocating GEM objects
+ */
+
+#include "igt.h"
+#include "igt_gt.h"
+
+#define igt_timeout(T) \
+	for (struct timespec t__={}; igt_seconds_elapsed(&t__) < (T); )
+
+static void get_pages(uint64_t alloc, int timeout)
+{
+	int fd = drm_open_driver(DRIVER_INTEL);
+	igt_timeout(timeout) {
+		uint32_t handle = gem_create(fd, alloc);
+		gem_set_domain(fd, handle, I915_GEM_DOMAIN_GTT, 0);
+		gem_close(fd, handle);
+	}
+	close(fd);
+}
+
+static void mmap_gtt(uint64_t alloc, int timeout)
+{
+	int fd = drm_open_driver(DRIVER_INTEL);
+	igt_timeout(timeout) {
+		uint32_t handle = gem_create(fd, alloc);
+		uint32_t *ptr = gem_mmap__gtt(fd, handle, alloc, PROT_WRITE);
+		for (int page = 0; page < alloc >>12; page++)
+			ptr[page<<10] = 0;
+		munmap(ptr, handle);
+		gem_close(fd, handle);
+	}
+	close(fd);
+}
+
+static void mmap_cpu(uint64_t alloc, int timeout)
+{
+	int fd = drm_open_driver(DRIVER_INTEL);
+	igt_timeout(timeout) {
+		uint32_t handle = gem_create(fd, alloc);
+		uint32_t *ptr = gem_mmap__cpu(fd, handle, 0, alloc, PROT_WRITE);
+		for (int page = 0; page < alloc >>12; page++)
+			ptr[page<<10] = 0;
+		munmap(ptr, handle);
+		gem_close(fd, handle);
+	}
+	close(fd);
+}
+
+static void execbuf1(uint64_t alloc, int timeout)
+{
+	const uint32_t bbe = MI_BATCH_BUFFER_END;
+	struct drm_i915_gem_exec_object2 obj;
+	struct drm_i915_gem_execbuffer2 execbuf;
+	int fd;
+
+	memset(&obj, 0, sizeof(obj));
+	memset(&execbuf, 0, sizeof(execbuf));
+	execbuf.buffers_ptr = (uintptr_t)&obj;
+	execbuf.buffer_count = 1;
+
+	fd = drm_open_driver(DRIVER_INTEL);
+	igt_timeout(timeout) {
+		obj.handle = gem_create(fd, alloc);
+		gem_write(fd, obj.handle, 0, &bbe, sizeof(bbe));
+		gem_execbuf(fd, &execbuf);
+		gem_close(fd, obj.handle);
+	}
+	close(fd);
+}
+
+static void execbufN(uint64_t alloc, int timeout)
+{
+	const uint32_t bbe = MI_BATCH_BUFFER_END;
+	struct drm_i915_gem_exec_object2 *obj;
+	struct drm_i915_gem_execbuffer2 execbuf;
+	int count = alloc >> 20;
+	int fd;
+
+	obj = calloc(alloc + 1, sizeof(&obj));
+	memset(&execbuf, 0, sizeof(execbuf));
+
+	fd = drm_open_driver(DRIVER_INTEL);
+	obj[count].handle = gem_create(fd, 4096);
+	gem_write(fd, obj[count].handle, 0, &bbe, sizeof(bbe));
+
+	igt_timeout(timeout) {
+		for (int i = 0; i < count; i++) {
+			int j = count - i - 1;
+
+			obj[j].handle = gem_create(fd, alloc >> 20);
+			execbuf.buffers_ptr = (uintptr_t)&obj[j];
+			execbuf.buffer_count = i + 1;
+			gem_execbuf(fd, &execbuf);
+		}
+
+		for (int i = 0; i < count; i++)
+			gem_close(fd, obj[i].handle);
+	}
+
+	close(fd);
+}
+
+#define SOLO 1
+#define PURGEABLE 2
+
+static struct igt_helper_process purgeable_helper;
+
+static void purgeable(void)
+{
+	while (true) {
+		int fd = drm_open_driver(DRIVER_INTEL);
+		for (int i = 0; i < 1<<16; i++) {
+			uint32_t handle = gem_create(fd, 1<<20);
+			gem_set_domain(fd, handle, I915_GEM_DOMAIN_GTT, 0);
+			gem_madvise(fd, handle, I915_MADV_DONTNEED);
+		}
+		close(fd);
+	}
+}
+
+static void run_test(int nchildren, uint64_t alloc,
+		     void (*func)(uint64_t, int), unsigned flags)
+{
+	if (flags & PURGEABLE) {
+		igt_fork_helper(&purgeable_helper)
+			purgeable();
+	}
+
+	igt_fork(child, flags & SOLO ? 1 : nchildren)
+		func(alloc, flags & SOLO ? 1 : 20);
+	igt_waitchildren();
+
+	if (flags & PURGEABLE)
+		igt_stop_helper(&purgeable_helper);
+}
+
+igt_main
+{
+	const struct test {
+		const char *name;
+		void (*func)(uint64_t, int);
+	} tests[] = {
+		{ "get-pages", get_pages },
+		{ "mmap-gtt", mmap_gtt },
+		{ "mmap-cpu", mmap_cpu },
+		{ "execbuf1", execbuf1 },
+		{ "execbufN", execbufN },
+		{ NULL },
+	};
+	const struct mode {
+		const char *suffix;
+		unsigned flags;
+	} modes[] = {
+		{ "-sanitycheck", SOLO },
+		{ "", 0 },
+		{ "-purgeable", PURGEABLE },
+		{ NULL },
+	};
+	uint64_t alloc_size = 0;
+	int num_processes = 0;
+
+	igt_skip_on_simulation();
+
+	igt_fixture {
+		uint64_t mem_size = intel_get_total_ram_mb();
+
+		/* Spawn enough processes to use all memory, but each only
+		 * uses half the available mappable aperture ~128MiB.
+		 * Individually the processes would be ok, but en masse
+		 * we expect the shrinker to start purging objects,
+		 * and possibly fail.
+		 */
+		alloc_size = gem_mappable_aperture_size() / 2;
+		num_processes = 1 + (mem_size / (alloc_size >> 20));
+
+		igt_info("Using %d processes and %'lluMiB per process\n",
+			 num_processes, (long long)(alloc_size >> 20));
+
+		intel_require_memory(num_processes, alloc_size,
+				     CHECK_SWAP | CHECK_RAM);
+	}
+
+	for(const struct test *t = tests; t->name; t++) {
+		for(const struct mode *m = modes; m->suffix; m++) {
+			igt_subtest_f("%s%s", t->name, m->suffix)
+				run_test(num_processes, alloc_size,
+					 t->func, m->flags);
+		}
+	}
+}