On 6/3/25 13:27, Tvrtko Ursulin wrote:
> The default core shrink target of 128 pages (SHRINK_BATCH) is quite low
> relative to how cheap TTM pool shrinking is, and how the free pages are
> distributed in page order pools.
>
> We can make the target a bit more aggressive by making it roughly the
> average number of pages across all pools, freeing more of the cached
> pages every time shrinker core invokes our callback.
>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursu...@igalia.com>
> Cc: Christian König <christian.koe...@amd.com>
> Cc: Thomas Hellström <thomas.hellst...@linux.intel.com>
> ---
> drivers/gpu/drm/ttm/ttm_pool.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c
> index c060c90b89c0..e671812789ea 100644
> --- a/drivers/gpu/drm/ttm/ttm_pool.c
> +++ b/drivers/gpu/drm/ttm/ttm_pool.c
> @@ -1265,10 +1265,16 @@ int ttm_pool_debugfs(struct ttm_pool *pool, struct
> seq_file *m)
> }
> EXPORT_SYMBOL(ttm_pool_debugfs);
>
> +/* Free average pool number of pages. */
> +#define TTM_SHRINKER_BATCH ((1 << (MAX_PAGE_ORDER / 2)) * NR_PAGE_ORDERS)
To be honest this feels random. But I can't come up with a better idea either
and it still looks better than the default as far as I can see.
So feel free to add Reviewed-by: Christian König <christian.koe...@amd.com> to
the series.
Should I push it to drm-misc-next or do you now have commit rights?
Regards,
Christian.
> +
> /* Test the shrinker functions and dump the result */
> static int ttm_pool_debugfs_shrink_show(struct seq_file *m, void *data)
> {
> - struct shrink_control sc = { .gfp_mask = GFP_NOFS };
> + struct shrink_control sc = {
> + .gfp_mask = GFP_NOFS,
> + .nr_to_scan = TTM_SHRINKER_BATCH,
> + };
>
> fs_reclaim_acquire(GFP_KERNEL);
> seq_printf(m, "%lu/%lu\n", ttm_pool_shrinker_count(mm_shrinker, &sc),
> @@ -1326,6 +1332,7 @@ int ttm_pool_mgr_init(unsigned long num_pages)
>
> mm_shrinker->count_objects = ttm_pool_shrinker_count;
> mm_shrinker->scan_objects = ttm_pool_shrinker_scan;
> + mm_shrinker->batch = TTM_SHRINKER_BATCH;
> mm_shrinker->seeks = 1;
>
> shrinker_register(mm_shrinker);
