[PATCH RESEND v3 2/3] drm/ttm: Reduce the number of used allocation orders for TTM pages
Thomas Hellström
thomas.hellstrom at linux.intel.com
Mon Apr 17 08:02:12 UTC 2023
Hi
On 4/14/23 12:11, Christian König wrote:
> Am 13.04.23 um 15:13 schrieb Daniel Vetter:
>> On Thu, 13 Apr 2023 at 11:46, Christian König
>> <christian.koenig at amd.com> wrote:
>>> Am 13.04.23 um 10:48 schrieb Daniel Vetter:
>>>> On Wed, 12 Apr 2023 at 16:18, Christian König
>>>> <christian.koenig at amd.com> wrote:
>>>>> Am 12.04.23 um 11:08 schrieb Daniel Vetter:
>>>>>> On Tue, 11 Apr 2023 at 15:45, Daniel Vetter <daniel at ffwll.ch> wrote:
>>>>>>> On Tue, Apr 11, 2023 at 02:11:18PM +0200, Christian König wrote:
>>>>>>>> Am 11.04.23 um 11:51 schrieb Daniel Vetter:
>>>>>>>>> On Tue, Apr 04, 2023 at 10:06:49PM +0200, Thomas Hellström wrote:
>>>>>>>>>> When swapping out, we will split multi-order pages both in
>>>>>>>>>> order to
>>>>>>>>>> move them to the swap-cache and to be able to return memory
>>>>>>>>>> to the
>>>>>>>>>> swap cache as soon as possible on a page-by-page basis.
>>>>>>>>>> Reduce the page max order to the system PMD size, as we can
>>>>>>>>>> then be nicer
>>>>>>>>>> to the system and avoid splitting gigantic pages.
>>>>>>>>>>
>>>>>>>>>> Looking forward to when we might be able to swap out PMD size
>>>>>>>>>> folios
>>>>>>>>>> without splitting, this will also be a benefit.
>>>>>>>>>>
>>>>>>>>>> v2:
>>>>>>>>>> - Include all orders up to the PMD size (Christian König)
>>>>>>>>>> v3:
>>>>>>>>>> - Avoid compilation errors for architectures with special
>>>>>>>>>> PFN_SHIFTs
>>>>>>>>>>
>>>>>>>>>> Signed-off-by: Thomas Hellström
>>>>>>>>>> <thomas.hellstrom at linux.intel.com>
>>>>>>>>>> Reviewed-by: Christian König <christian.koenig at amd.com>
>>>>>>>>> Apparently this fails on ppc build testing. Please supply
>>>>>>>>> build fix asap
>>>>>>>>> (or I guess we need to revert). I'm kinda not clear why this
>>>>>>>>> only showed
>>>>>>>>> up when I merged the drm-misc-next pr into drm-next ...
>>>>>>>> I'm really wondering this as well. It looks like PMD_SHIFT
>>>>>>>> isn't a constant
>>>>>>>> on this particular platform.
>>>>>>>>
>>>>>>>> But from what I can find in the upstream 6.2 kernel PMD_SHIFT
>>>>>>>> always seems
>>>>>>>> to be a constant.
>>>>>>>>
>>>>>>>> So how exactly can that here break?
>>>>>>> There's some in-flight patches to rework MAX_ORDER and other
>>>>>>> things in
>>>>>>> linux-next, maybe it's recent? If you check out linux-next then
>>>>>>> you need
>>>>>>> to reapply the patch (since sfr reverted it).
>>>>>> So I looked and on ppc64 PMD_SHIFT is defined in terms of
>>>>>> PTE_INDEX_SIZE, which is defined (for book3s) in terms of the
>>>>>> variable
>>>>>> __pte_index_size. This is in 6.3 already and seems pretty old.
>>>>> Ah! I missed that one, thanks.
>>>>>
>>>>>> So revert? Or fixup patch to make this work on ppc?
>>>>> I think for now just revert or change it so that we check if
>>>>> PMD_SHIFT
>>>>> is a constant.
>>>>>
>>>>> Thomas do you have any quick solution?
>>>> I guess Thomas is on vacations. Can you pls do the revert and push it
>>>> to drm-misc-next-fixes so this won't get lost?
>>> The offending patch hasn't showed up in drm-misc-next-fixes nor
>>> drm-misc-fixes yet. Looks like the branches are lacking behind.
>>>
>>> I can revert it on drm-misc-next, but I', not 100% sure that will then
>>> get picked up in time.
>> It's there now, Maarten forwarded drm-misc-next-fixes this morning.
>> That's why I pinged here again, trees are ready to land the revert :-)
>
> Just pushed it.
>
> Christian.
Thanks for fixing this. (I was on vacation). I got a "BUILD SUCCESS" for
this series based on drm-misc-next so I didn't think anything weird
would show up.
Thanks,
Thomas
>
>> -Daniel
>>
>>> Christian.
>>>
>>>> Acked-by: Daniel Vetter <daniel.vetter at ffwll.ch>
>>>>
>>>> preemptively for that. Normally I think we could wait a bit more but
>>>> it's really close to merge window PR and I don't like handing too many
>>>> open things to Dave when he's back :-)
>>>> -Daniel
>>>>
>>>>> Christian.
>>>>>
>>>>>>>>>> ---
>>>>>>>>>> drivers/gpu/drm/ttm/ttm_pool.c | 30
>>>>>>>>>> +++++++++++++++++++-----------
>>>>>>>>>> 1 file changed, 19 insertions(+), 11 deletions(-)
>>>>>>>>>>
>>>>>>>>>> diff --git a/drivers/gpu/drm/ttm/ttm_pool.c
>>>>>>>>>> b/drivers/gpu/drm/ttm/ttm_pool.c
>>>>>>>>>> index dfce896c4bae..18c342a919a2 100644
>>>>>>>>>> --- a/drivers/gpu/drm/ttm/ttm_pool.c
>>>>>>>>>> +++ b/drivers/gpu/drm/ttm/ttm_pool.c
>>>>>>>>>> @@ -47,6 +47,11 @@
>>>>>>>>>> #include "ttm_module.h"
>>>>>>>>>> +#define TTM_MAX_ORDER (PMD_SHIFT - PAGE_SHIFT)
>>>>>>>>>> +#define __TTM_DIM_ORDER (TTM_MAX_ORDER + 1)
>>>>>>>>>> +/* Some architectures have a weird PMD_SHIFT */
>>>>>>>>>> +#define TTM_DIM_ORDER (__TTM_DIM_ORDER <= MAX_ORDER ?
>>>>>>>>>> __TTM_DIM_ORDER : MAX_ORDER)
>>>>>>>>>> +
>>>>>>>>>> /**
>>>>>>>>>> * struct ttm_pool_dma - Helper object for coherent DMA
>>>>>>>>>> mappings
>>>>>>>>>> *
>>>>>>>>>> @@ -65,11 +70,11 @@ module_param(page_pool_size, ulong, 0644);
>>>>>>>>>> static atomic_long_t allocated_pages;
>>>>>>>>>> -static struct ttm_pool_type global_write_combined[MAX_ORDER];
>>>>>>>>>> -static struct ttm_pool_type global_uncached[MAX_ORDER];
>>>>>>>>>> +static struct ttm_pool_type
>>>>>>>>>> global_write_combined[TTM_DIM_ORDER];
>>>>>>>>>> +static struct ttm_pool_type global_uncached[TTM_DIM_ORDER];
>>>>>>>>>> -static struct ttm_pool_type
>>>>>>>>>> global_dma32_write_combined[MAX_ORDER];
>>>>>>>>>> -static struct ttm_pool_type global_dma32_uncached[MAX_ORDER];
>>>>>>>>>> +static struct ttm_pool_type
>>>>>>>>>> global_dma32_write_combined[TTM_DIM_ORDER];
>>>>>>>>>> +static struct ttm_pool_type
>>>>>>>>>> global_dma32_uncached[TTM_DIM_ORDER];
>>>>>>>>>> static spinlock_t shrinker_lock;
>>>>>>>>>> static struct list_head shrinker_list;
>>>>>>>>>> @@ -444,7 +449,7 @@ int ttm_pool_alloc(struct ttm_pool *pool,
>>>>>>>>>> struct ttm_tt *tt,
>>>>>>>>>> else
>>>>>>>>>> gfp_flags |= GFP_HIGHUSER;
>>>>>>>>>> - for (order = min_t(unsigned int, MAX_ORDER - 1,
>>>>>>>>>> __fls(num_pages));
>>>>>>>>>> + for (order = min_t(unsigned int, TTM_MAX_ORDER,
>>>>>>>>>> __fls(num_pages));
>>>>>>>>>> num_pages;
>>>>>>>>>> order = min_t(unsigned int, order,
>>>>>>>>>> __fls(num_pages))) {
>>>>>>>>>> struct ttm_pool_type *pt;
>>>>>>>>>> @@ -563,7 +568,7 @@ void ttm_pool_init(struct ttm_pool *pool,
>>>>>>>>>> struct device *dev,
>>>>>>>>>> if (use_dma_alloc) {
>>>>>>>>>> for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i)
>>>>>>>>>> - for (j = 0; j < MAX_ORDER; ++j)
>>>>>>>>>> + for (j = 0; j < TTM_DIM_ORDER; ++j)
>>>>>>>>>> ttm_pool_type_init(&pool->caching[i].orders[j],
>>>>>>>>>> pool,
>>>>>>>>>> i, j);
>>>>>>>>>> }
>>>>>>>>>> @@ -583,7 +588,7 @@ void ttm_pool_fini(struct ttm_pool *pool)
>>>>>>>>>> if (pool->use_dma_alloc) {
>>>>>>>>>> for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i)
>>>>>>>>>> - for (j = 0; j < MAX_ORDER; ++j)
>>>>>>>>>> + for (j = 0; j < TTM_DIM_ORDER; ++j)
>>>>>>>>>> ttm_pool_type_fini(&pool->caching[i].orders[j]);
>>>>>>>>>> }
>>>>>>>>>> @@ -637,7 +642,7 @@ static void
>>>>>>>>>> ttm_pool_debugfs_header(struct seq_file *m)
>>>>>>>>>> unsigned int i;
>>>>>>>>>> seq_puts(m, "\t ");
>>>>>>>>>> - for (i = 0; i < MAX_ORDER; ++i)
>>>>>>>>>> + for (i = 0; i < TTM_DIM_ORDER; ++i)
>>>>>>>>>> seq_printf(m, " ---%2u---", i);
>>>>>>>>>> seq_puts(m, "\n");
>>>>>>>>>> }
>>>>>>>>>> @@ -648,7 +653,7 @@ static void
>>>>>>>>>> ttm_pool_debugfs_orders(struct ttm_pool_type *pt,
>>>>>>>>>> {
>>>>>>>>>> unsigned int i;
>>>>>>>>>> - for (i = 0; i < MAX_ORDER; ++i)
>>>>>>>>>> + for (i = 0; i < TTM_DIM_ORDER; ++i)
>>>>>>>>>> seq_printf(m, " %8u",
>>>>>>>>>> ttm_pool_type_count(&pt[i]));
>>>>>>>>>> seq_puts(m, "\n");
>>>>>>>>>> }
>>>>>>>>>> @@ -751,13 +756,16 @@ int ttm_pool_mgr_init(unsigned long
>>>>>>>>>> num_pages)
>>>>>>>>>> {
>>>>>>>>>> unsigned int i;
>>>>>>>>>> + BUILD_BUG_ON(TTM_DIM_ORDER > MAX_ORDER);
>>>>>>>>>> + BUILD_BUG_ON(TTM_DIM_ORDER < 1);
>>>>>>>>>> +
>>>>>>>>>> if (!page_pool_size)
>>>>>>>>>> page_pool_size = num_pages;
>>>>>>>>>> spin_lock_init(&shrinker_lock);
>>>>>>>>>> INIT_LIST_HEAD(&shrinker_list);
>>>>>>>>>> - for (i = 0; i < MAX_ORDER; ++i) {
>>>>>>>>>> + for (i = 0; i < TTM_DIM_ORDER; ++i) {
>>>>>>>>>> ttm_pool_type_init(&global_write_combined[i], NULL,
>>>>>>>>>> ttm_write_combined, i);
>>>>>>>>>> ttm_pool_type_init(&global_uncached[i], NULL, ttm_uncached, i);
>>>>>>>>>> @@ -790,7 +798,7 @@ void ttm_pool_mgr_fini(void)
>>>>>>>>>> {
>>>>>>>>>> unsigned int i;
>>>>>>>>>> - for (i = 0; i < MAX_ORDER; ++i) {
>>>>>>>>>> + for (i = 0; i < TTM_DIM_ORDER; ++i) {
>>>>>>>>>> ttm_pool_type_fini(&global_write_combined[i]);
>>>>>>>>>> ttm_pool_type_fini(&global_uncached[i]);
>>>>>>>>>> --
>>>>>>>>>> 2.39.2
>>>>>>>>>>
>>>>>>> --
>>>>>>> Daniel Vetter
>>>>>>> Software Engineer, Intel Corporation
>>>>>>> http://blog.ffwll.ch
>>
>
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