mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-02 15:18:19 +00:00
be1cb55a07
We need to keep the default context state around to instantiate new contexts (aka golden rendercontext), and we also keep it pinned while the engine is active so that we can quickly reset a hanging context. However, the default contexts are large enough to merit keeping in swappable memory as opposed to kernel memory, so we store them inside shmemfs. Currently, we use the normal GEM objects to create the default context image, but we can throw away all but the shmemfs file. This greatly simplifies the tricky power management code which wants to run underneath the normal GT locking, and we definitely do not want to use any high level objects that may appear to recurse back into the GT. Though perhaps the primary advantage of the complex GEM object is that we aggressively cache the mapping, but here we are recreating the vm_area everytime time we unpark. At the worst, we add a lightweight cache, but first find a microbenchmark that is impacted. Having started to create some utility functions to make working with shmemfs objects easier, we can start putting them to wider use, where GEM objects are overkill, such as storing persistent error state. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Matthew Auld <matthew.auld@intel.com> Cc: Ramalingam C <ramalingam.c@intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200429172429.6054-1-chris@chris-wilson.co.uk
63 lines
1.1 KiB
C
63 lines
1.1 KiB
C
// SPDX-License-Identifier: MIT
|
|
/*
|
|
* Copyright © 2020 Intel Corporation
|
|
*/
|
|
|
|
/* Just a quick and causal check of the shmem_utils API */
|
|
|
|
static int igt_shmem_basic(void *ignored)
|
|
{
|
|
u32 datum = 0xdeadbeef, result;
|
|
struct file *file;
|
|
u32 *map;
|
|
int err;
|
|
|
|
file = shmem_create_from_data("mock", &datum, sizeof(datum));
|
|
if (IS_ERR(file))
|
|
return PTR_ERR(file);
|
|
|
|
result = 0;
|
|
err = shmem_read(file, 0, &result, sizeof(result));
|
|
if (err)
|
|
goto out_file;
|
|
|
|
if (result != datum) {
|
|
pr_err("Incorrect read back from shmemfs: %x != %x\n",
|
|
result, datum);
|
|
err = -EINVAL;
|
|
goto out_file;
|
|
}
|
|
|
|
result = 0xc0ffee;
|
|
err = shmem_write(file, 0, &result, sizeof(result));
|
|
if (err)
|
|
goto out_file;
|
|
|
|
map = shmem_pin_map(file);
|
|
if (!map) {
|
|
err = -ENOMEM;
|
|
goto out_file;
|
|
}
|
|
|
|
if (*map != result) {
|
|
pr_err("Incorrect read back via mmap of last write: %x != %x\n",
|
|
*map, result);
|
|
err = -EINVAL;
|
|
goto out_map;
|
|
}
|
|
|
|
out_map:
|
|
shmem_unpin_map(file, map);
|
|
out_file:
|
|
fput(file);
|
|
return err;
|
|
}
|
|
|
|
int shmem_utils_mock_selftests(void)
|
|
{
|
|
static const struct i915_subtest tests[] = {
|
|
SUBTEST(igt_shmem_basic),
|
|
};
|
|
|
|
return i915_subtests(tests, NULL);
|
|
}
|