tests: add gem_mmap_offset_exhaustion

This also adds a gem_madvise helper to lib/drmtest.c

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

lib/drmtest.c

@@ -289,6 +289,20 @@ uint64_t gem_mappable_aperture_size(void)
 	return pci_dev->regions[bar].size;
 }
 
+int gem_madvise(int fd, uint32_t handle, int state)
+{
+	struct drm_i915_gem_madvise madv;
+	int ret;
+
+	madv.handle = handle;
+	madv.madv = state;
+	madv.retained = 1;
+	ret = drmIoctl(fd, DRM_IOCTL_I915_GEM_MADVISE, &madv);
+	assert(ret == 0);
+
+	return madv.retained;
+}
+
 /* signal interrupt helpers */
 static pid_t signal_helper = -1;
 long long int sig_stat;

lib/drmtest.h

@@ -51,6 +51,7 @@ uint32_t gem_create(int fd, int size);
 void *gem_mmap(int fd, uint32_t handle, int size, int prot);
 uint64_t gem_aperture_size(int fd);
 uint64_t gem_mappable_aperture_size(void);
+int gem_madvise(int fd, uint32_t handle, int state);
 
 /* generally useful helpers */
 void drmtest_fork_signal_helper(void);

tests/Makefile.am

@@ -18,6 +18,7 @@ TESTS_progs = \
 	gem_ringfill \
 	gem_mmap \
 	gem_mmap_gtt \
+	gem_mmap_offset_exhaustion \
 	gem_pwrite \
 	gem_pread_after_blit \
 	gem_tiled_pread \

tests/gem_mmap_offset_exhaustion.c

@@ -0,0 +1,96 @@
+/*
+ * Copyright © 2012 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.
+ *
+ * Authors:
+ *    Daniel Vetter <daniel.vetter@ffwll.ch>
+ *
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include "drm.h"
+#include "i915_drm.h"
+#include "drmtest.h"
+
+#define OBJECT_SIZE (1024*1024)
+
+/* Testcase: checks whether the kernel handles mmap offset exhaustion correctly
+ *
+ * Currently the kernel doesn't reap the mmap offset of purged objects, albeit
+ * there's nothing that prevents it ABI-wise and it helps to get out of corners
+ * (because drm_mm is only 32bit on 32bit archs unfortunately.
+ *
+ * Note that on 64bit machines we have plenty of address space (because drm_mm
+ * uses unsigned long).
+ */
+
+static void
+create_and_map_bo(int fd)
+{
+	uint32_t handle;
+	char *ptr;
+
+	handle = gem_create(fd, OBJECT_SIZE);
+
+	ptr = gem_mmap(fd, handle, OBJECT_SIZE, PROT_READ | PROT_WRITE);
+
+	if (!ptr) {
+		fprintf(stderr, "mmap failed\n");
+		assert(ptr);
+	}
+
+	/* touch it to force it into the gtt */
+	*ptr = 0;
+
+	/* but then unmap it again because we only have limited address space on
+	 * 32 bit */
+	munmap(ptr, OBJECT_SIZE);
+
+	/* we happily leak objects to exhaust mmap offset space, the kernel will
+	 * reap backing storage. */
+	gem_madvise(fd, handle, I915_MADV_DONTNEED);
+}
+
+int main(int argc, char **argv)
+{
+	int fd, i;
+
+	fd = drm_open_any();
+
+	/* we have 32bit of address space, so try to fit one MB more
+	 * than that. */
+	for (i = 0; i < 4096 + 1; i++)
+		create_and_map_bo(fd);
+
+	close(fd);
+
+	return 0;
+}