From: Tvrtko Ursulin Date: Wed, 26 Sep 2018 08:03:53 +0000 (+0100) Subject: drm/i915: Trim partial view sg lists X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=f8e57863f81f962a1837d6a17825752de5bc23f7;p=linux.git drm/i915: Trim partial view sg lists Partial views are small but there can be many of them, and since the sg list space for them is allocated pessimistically, we can save some slab by trimming the unused tail entries. Signed-off-by: Tvrtko Ursulin Cc: Chris Wilson Cc: Joonas Lahtinen Reviewed-by: Chris Wilson Link: https://patchwork.freedesktop.org/patch/msgid/20180926080353.20867-1-tvrtko.ursulin@linux.intel.com --- diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 9e185f0a822ae..ab52657cc3d0b 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -2325,6 +2325,8 @@ static inline struct scatterlist *__sg_next(struct scatterlist *sg) (((__iter).curr += PAGE_SIZE) >= (__iter).max) ? \ (__iter) = __sgt_iter(__sg_next((__iter).sgp), false), 0 : 0) +bool i915_sg_trim(struct sg_table *orig_st); + static inline unsigned int i915_sg_page_sizes(struct scatterlist *sg) { unsigned int page_sizes; diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 627b1c8a7ea3b..28e943ee8b5e6 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -2491,7 +2491,7 @@ unlock: mutex_unlock(&obj->mm.lock); } -static bool i915_sg_trim(struct sg_table *orig_st) +bool i915_sg_trim(struct sg_table *orig_st) { struct sg_table new_st; struct scatterlist *sg, *new_sg; diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c index f6c7ab413081e..1ec721c205812 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.c +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -3835,6 +3835,8 @@ intel_partial_pages(const struct i915_ggtt_view *view, count -= len >> PAGE_SHIFT; if (count == 0) { sg_mark_end(sg); + i915_sg_trim(st); /* Drop any unused tail entries. */ + return st; }