[PATCH v3] drm/xe: Add a xe_bo subtest for shrinking / swapping
Nathan Chancellor
nathan at kernel.org
Fri Sep 13 19:56:49 UTC 2024
Hi Thomas,
On Mon, Sep 09, 2024 at 10:56:54AM +0200, Thomas Hellström wrote:
> Add a subtest that tries to allocate twice the amount of
> buffer object memory available, write data to it and then read
> all the data back verifying data integrity.
> In order to be able to do this on systems that
> have no or not enough swap-space available, allocate some memory
> as purgeable, and introduce a function to purge such memory from
> the TTM swap_notify path.
>
> this test is intended to add test coverage to the current
> bo swap path and upcoming shrinking path.
>
> The test has previously been part of the xe bo shrinker series.
>
> v2:
> - Skip test if the execution time is expected to be too long.
> - Minor code cleanups.
>
> v3:
> - Print random seed. (Matthew Auld)
>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Cc: Matthew Brost <matthew.brost at intel.com>
> Cc: Matthew Auld <matthew.auld at intel.com>
> Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
> Reviewed-by: Matthew Auld <matthew.auld at intel.com>
...
> diff --git a/drivers/gpu/drm/xe/tests/xe_bo.c b/drivers/gpu/drm/xe/tests/xe_bo.c
> index 8dac069483e8..7d3fd720478b 100644
> --- a/drivers/gpu/drm/xe/tests/xe_bo.c
> +++ b/drivers/gpu/drm/xe/tests/xe_bo.c
...
> +/*
> + * Try to create system bos corresponding to twice the amount
> + * of available system memory to test shrinker functionality.
> + * If no swap space is available to accommodate the
> + * memory overcommit, mark bos purgeable.
> + */
> +static int shrink_test_run_device(struct xe_device *xe)
> +{
> + struct kunit *test = kunit_get_current_test();
> + LIST_HEAD(bos);
> + struct xe_bo_link *link, *next;
> + struct sysinfo si;
> + size_t ram, ram_and_swap, purgeable, alloced, to_alloc, limit;
> + unsigned int interrupted = 0, successful = 0, count = 0;
> + struct rnd_state prng;
> + u64 rand_seed;
> + bool failed = false;
> +
> + rand_seed = get_random_u64();
> + prandom_seed_state(&prng, rand_seed);
> + kunit_info(test, "Random seed is 0x%016llx.\n",
> + (unsigned long long)rand_seed);
> +
> + /* Skip if execution time is expected to be too long. */
> +
> + limit = SZ_32G;
> + /* IGFX with flat CCS needs to copy when swapping / shrinking */
> + if (!IS_DGFX(xe) && xe_device_has_flat_ccs(xe))
> + limit = SZ_16G;
> +
> + si_meminfo(&si);
> + ram = (size_t)si.freeram * si.mem_unit;
> + if (ram > limit) {
> + kunit_skip(test, "Too long expected execution time.\n");
> + return 0;
> + }
> + to_alloc = ram * 2;
> +
> + ram_and_swap = ram + get_nr_swap_pages() * PAGE_SIZE;
> + if (to_alloc > ram_and_swap)
> + purgeable = to_alloc - ram_and_swap;
> + purgeable += purgeable / 5;
> +
> + kunit_info(test, "Free ram is %lu bytes. Will allocate twice of that.\n",
> + (unsigned long)ram);
> + for (alloced = 0; alloced < to_alloc; alloced += XE_BO_SHRINK_SIZE) {
> + struct xe_bo *bo;
> + unsigned int mem_type;
> + struct xe_ttm_tt *xe_tt;
> +
> + link = kzalloc(sizeof(*link), GFP_KERNEL);
> + if (!link) {
> + KUNIT_FAIL(test, "Unexpected link allocation failure\n");
> + failed = true;
> + break;
> + }
> +
> + INIT_LIST_HEAD(&link->link);
> +
> + /* We can create bos using WC caching here. But it is slower. */
> + bo = xe_bo_create_user(xe, NULL, NULL, XE_BO_SHRINK_SIZE,
> + DRM_XE_GEM_CPU_CACHING_WB,
> + XE_BO_FLAG_SYSTEM);
> + if (IS_ERR(bo)) {
> + if (bo != ERR_PTR(-ENOMEM) && bo != ERR_PTR(-ENOSPC) &&
> + bo != ERR_PTR(-EINTR) && bo != ERR_PTR(-ERESTARTSYS))
> + KUNIT_FAIL(test, "Error creating bo: %pe\n", bo);
> + kfree(link);
> + failed = true;
> + break;
> + }
> + xe_bo_lock(bo, false);
> + xe_tt = container_of(bo->ttm.ttm, typeof(*xe_tt), ttm);
> +
> + /*
> + * Allocate purgeable bos first, because if we do it the
> + * other way around, they may not be subject to swapping...
> + */
> + if (alloced < purgeable) {
> + xe_tt->purgeable = true;
> + bo->ttm.priority = 0;
> + } else {
> + int ret = shrink_test_fill_random(bo, &prng, link);
> +
> + if (ret) {
> + xe_bo_unlock(bo);
> + xe_bo_put(bo);
> + KUNIT_FAIL(test, "Error filling bo with random data: %pe\n",
> + ERR_PTR(ret));
> + kfree(link);
> + failed = true;
> + break;
> + }
> + }
> +
> + mem_type = bo->ttm.resource->mem_type;
> + xe_bo_unlock(bo);
> + link->bo = bo;
> + list_add_tail(&link->link, &bos);
> +
> + if (mem_type != XE_PL_TT) {
> + KUNIT_FAIL(test, "Bo in incorrect memory type: %u\n",
> + bo->ttm.resource->mem_type);
> + failed = true;
> + }
> + cond_resched();
> + if (signal_pending(current))
> + break;
> + }
This function introduces three warnings with clang:
$ make -skj"$(nproc)" ARCH=i386 LLVM=1 allmodconfig drivers/gpu/drm/xe/xe_bo.o
...
In file included from drivers/gpu/drm/xe/xe_bo.c:2406:
drivers/gpu/drm/xe/tests/xe_bo.c:456:10: error: implicit conversion from 'unsigned long long' to 'size_t' (aka 'unsigned int') changes value from 34359738368 to 0 [-Werror,-Wconstant-conversion]
456 | limit = SZ_32G;
| ~ ^~~~~~
include/linux/sizes.h:49:19: note: expanded from macro 'SZ_32G'
49 | #define SZ_32G _AC(0x800000000, ULL)
| ^~~~~~~~~~~~~~~~~~~~~
include/uapi/linux/const.h:21:18: note: expanded from macro '_AC'
21 | #define _AC(X,Y) __AC(X,Y)
| ^~~~~~~~~
include/uapi/linux/const.h:20:20: note: expanded from macro '__AC'
20 | #define __AC(X,Y) (X##Y)
| ^~~~
<scratch space>:31:1: note: expanded from here
31 | 0x800000000ULL
| ^~~~~~~~~~~~~~
In file included from drivers/gpu/drm/xe/xe_bo.c:2406:
drivers/gpu/drm/xe/tests/xe_bo.c:459:11: error: implicit conversion from 'unsigned long long' to 'size_t' (aka 'unsigned int') changes value from 17179869184 to 0 [-Werror,-Wconstant-conversion]
459 | limit = SZ_16G;
| ~ ^~~~~~
include/linux/sizes.h:48:19: note: expanded from macro 'SZ_16G'
48 | #define SZ_16G _AC(0x400000000, ULL)
| ^~~~~~~~~~~~~~~~~~~~~
include/uapi/linux/const.h:21:18: note: expanded from macro '_AC'
21 | #define _AC(X,Y) __AC(X,Y)
| ^~~~~~~~~
include/uapi/linux/const.h:20:20: note: expanded from macro '__AC'
20 | #define __AC(X,Y) (X##Y)
| ^~~~
<scratch space>:32:1: note: expanded from here
32 | 0x400000000ULL
| ^~~~~~~~~~~~~~
In file included from drivers/gpu/drm/xe/xe_bo.c:2406:
drivers/gpu/drm/xe/tests/xe_bo.c:470:6: error: variable 'purgeable' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
470 | if (to_alloc > ram_and_swap)
| ^~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/xe/tests/xe_bo.c:472:2: note: uninitialized use occurs here
472 | purgeable += purgeable / 5;
| ^~~~~~~~~
drivers/gpu/drm/xe/tests/xe_bo.c:470:2: note: remove the 'if' if its condition is always true
470 | if (to_alloc > ram_and_swap)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
471 | purgeable = to_alloc - ram_and_swap;
drivers/gpu/drm/xe/tests/xe_bo.c:443:37: note: initialize the variable 'purgeable' to silence this warning
443 | size_t ram, ram_and_swap, purgeable, alloced, to_alloc, limit;
| ^
| = 0
3 errors generated.
I tried to make GCC show the same warnings with an explicit
-Wmaybe-uninitialized but only the overflow warnings show up (is
purgeable always set because of the if condition?):
$ make -skj"$(nproc)" ARCH=i386 CROSS_COMPILE=i386-linux- KCFLAGS=-Wmaybe-uninitialized allmodconfig drivers/gpu/drm/xe/xe_bo.o
In file included from include/vdso/const.h:5,
from include/linux/const.h:4,
from include/linux/bits.h:5,
from include/linux/ratelimit_types.h:5,
from include/linux/printk.h:9,
from include/asm-generic/bug.h:22,
from arch/x86/include/asm/bug.h:99,
from include/linux/bug.h:5,
from include/linux/mmdebug.h:5,
from include/linux/mm.h:6,
from include/linux/pagemap.h:8,
from include/drm/ttm/ttm_tt.h:30,
from drivers/gpu/drm/xe/xe_bo.h:9,
from drivers/gpu/drm/xe/xe_bo.c:6:
drivers/gpu/drm/xe/tests/xe_bo.c: In function 'shrink_test_run_device':
include/uapi/linux/const.h:20:25: error: conversion from 'long long unsigned int' to 'size_t' {aka 'unsigned int'} changes value from '34359738368' to '0' [-Werror=overflow]
20 | #define __AC(X,Y) (X##Y)
| ^
include/uapi/linux/const.h:21:25: note: in expansion of macro '__AC'
21 | #define _AC(X,Y) __AC(X,Y)
| ^~~~
include/linux/sizes.h:49:41: note: in expansion of macro '_AC'
49 | #define SZ_32G _AC(0x800000000, ULL)
| ^~~
drivers/gpu/drm/xe/tests/xe_bo.c:456:17: note: in expansion of macro 'SZ_32G'
456 | limit = SZ_32G;
| ^~~~~~
include/uapi/linux/const.h:20:25: error: conversion from 'long long unsigned int' to 'size_t' {aka 'unsigned int'} changes value from '17179869184' to '0' [-Werror=overflow]
20 | #define __AC(X,Y) (X##Y)
| ^
include/uapi/linux/const.h:21:25: note: in expansion of macro '__AC'
21 | #define _AC(X,Y) __AC(X,Y)
| ^~~~
include/linux/sizes.h:48:41: note: in expansion of macro '_AC'
48 | #define SZ_16G _AC(0x400000000, ULL)
| ^~~
drivers/gpu/drm/xe/tests/xe_bo.c:459:25: note: in expansion of macro 'SZ_16G'
459 | limit = SZ_16G;
| ^~~~~~
cc1: all warnings being treated as errors
Cheers,
Nathan
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