From 50b38bc4d39aa6fa5639aabcccfb828c19b89278 Mon Sep 17 00:00:00 2001 From: Mika Kuoppala Date: Fri, 5 Jul 2019 22:52:04 +0100 Subject: [PATCH] drm/i915/gtt: Introduce release_pd_entry By encapsulating the locking upper level and used check for entry into a helper function, we can use it in all callsites. v2: get rid of atomic_reads on lower level clears (Chris) Cc: Chris Wilson Signed-off-by: Mika Kuoppala Reviewed-by: Chris Wilson Signed-off-by: Chris Wilson Link: https://patchwork.freedesktop.org/patch/msgid/20190705215204.4559-4-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_gem_gtt.c | 114 +++++++++++++----------------------- 1 file changed, 42 insertions(+), 72 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c index 0a55b09..236c964 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.c +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -811,7 +811,25 @@ __clear_pd_entry(struct i915_page_directory * const pd, __set_pd_entry((pd), (pde), px_base(to), gen8_pde_encode) #define clear_pd_entry(pd, pde, to) \ - __clear_pd_entry((pd), (pde), px_base(to), gen8_pde_encode) + __clear_pd_entry((pd), (pde), (to), gen8_pde_encode) + +static bool +release_pd_entry(struct i915_page_directory * const pd, + const unsigned short pde, + atomic_t *counter, + struct i915_page_dma * const scratch) +{ + bool free = false; + + spin_lock(&pd->lock); + if (atomic_dec_and_test(counter)) { + clear_pd_entry(pd, pde, scratch); + free = true; + } + spin_unlock(&pd->lock); + + return free; +} /* * PDE TLBs are a pain to invalidate on GEN8+. When we modify @@ -827,11 +845,11 @@ static void mark_tlbs_dirty(struct i915_ppgtt *ppgtt) /* Removes entries from a single page table, releasing it if it's empty. * Caller can use the return value to update higher-level entries. */ -static bool gen8_ppgtt_clear_pt(const struct i915_address_space *vm, +static void gen8_ppgtt_clear_pt(const struct i915_address_space *vm, struct i915_page_table *pt, u64 start, u64 length) { - unsigned int num_entries = gen8_pte_count(start, length); + const unsigned int num_entries = gen8_pte_count(start, length); gen8_pte_t *vaddr; vaddr = kmap_atomic_px(pt); @@ -839,10 +857,11 @@ static bool gen8_ppgtt_clear_pt(const struct i915_address_space *vm, kunmap_atomic(vaddr); GEM_BUG_ON(num_entries > atomic_read(&pt->used)); - return !atomic_sub_return(num_entries, &pt->used); + + atomic_sub(num_entries, &pt->used); } -static bool gen8_ppgtt_clear_pd(struct i915_address_space *vm, +static void gen8_ppgtt_clear_pd(struct i915_address_space *vm, struct i915_page_directory *pd, u64 start, u64 length) { @@ -850,30 +869,20 @@ static bool gen8_ppgtt_clear_pd(struct i915_address_space *vm, u32 pde; gen8_for_each_pde(pt, pd, start, length, pde) { - bool free = false; - GEM_BUG_ON(pt == vm->scratch_pt); - if (!gen8_ppgtt_clear_pt(vm, pt, start, length)) - continue; - - spin_lock(&pd->lock); - if (!atomic_read(&pt->used)) { - clear_pd_entry(pd, pde, vm->scratch_pt); - free = true; - } - spin_unlock(&pd->lock); - if (free) + atomic_inc(&pt->used); + gen8_ppgtt_clear_pt(vm, pt, start, length); + if (release_pd_entry(pd, pde, &pt->used, + px_base(vm->scratch_pt))) free_pt(vm, pt); } - - return !atomic_read(&pd->used); } /* Removes entries from a single page dir pointer, releasing it if it's empty. * Caller can use the return value to update higher-level entries */ -static bool gen8_ppgtt_clear_pdp(struct i915_address_space *vm, +static void gen8_ppgtt_clear_pdp(struct i915_address_space *vm, struct i915_page_directory * const pdp, u64 start, u64 length) { @@ -881,24 +890,14 @@ static bool gen8_ppgtt_clear_pdp(struct i915_address_space *vm, unsigned int pdpe; gen8_for_each_pdpe(pd, pdp, start, length, pdpe) { - bool free = false; - GEM_BUG_ON(pd == vm->scratch_pd); - if (!gen8_ppgtt_clear_pd(vm, pd, start, length)) - continue; - - spin_lock(&pdp->lock); - if (!atomic_read(&pd->used)) { - clear_pd_entry(pdp, pdpe, vm->scratch_pd); - free = true; - } - spin_unlock(&pdp->lock); - if (free) + atomic_inc(&pd->used); + gen8_ppgtt_clear_pd(vm, pd, start, length); + if (release_pd_entry(pdp, pdpe, &pd->used, + px_base(vm->scratch_pd))) free_pd(vm, pd); } - - return !atomic_read(&pdp->used); } static void gen8_ppgtt_clear_3lvl(struct i915_address_space *vm, @@ -922,19 +921,12 @@ static void gen8_ppgtt_clear_4lvl(struct i915_address_space *vm, GEM_BUG_ON(!i915_vm_is_4lvl(vm)); gen8_for_each_pml4e(pdp, pml4, start, length, pml4e) { - bool free = false; GEM_BUG_ON(pdp == vm->scratch_pdp); - if (!gen8_ppgtt_clear_pdp(vm, pdp, start, length)) - continue; - - spin_lock(&pml4->lock); - if (!atomic_read(&pdp->used)) { - clear_pd_entry(pml4, pml4e, vm->scratch_pdp); - free = true; - } - spin_unlock(&pml4->lock); - if (free) + atomic_inc(&pdp->used); + gen8_ppgtt_clear_pdp(vm, pdp, start, length); + if (release_pd_entry(pml4, pml4e, &pdp->used, + px_base(vm->scratch_pdp))) free_pd(vm, pdp); } } @@ -1457,17 +1449,8 @@ static int gen8_ppgtt_alloc_pdp(struct i915_address_space *vm, goto out; unwind_pd: - if (alloc) { - free_pd(vm, alloc); - alloc = NULL; - } - spin_lock(&pdp->lock); - if (atomic_dec_and_test(&pd->used)) { - GEM_BUG_ON(alloc); - alloc = pd; /* defer the free to after the lock */ - clear_pd_entry(pdp, pdpe, vm->scratch_pd); - } - spin_unlock(&pdp->lock); + if (release_pd_entry(pdp, pdpe, &pd->used, px_base(vm->scratch_pd))) + free_pd(vm, pd); unwind: gen8_ppgtt_clear_pdp(vm, pdp, from, start - from); out: @@ -1530,17 +1513,8 @@ static int gen8_ppgtt_alloc_4lvl(struct i915_address_space *vm, goto out; unwind_pdp: - if (alloc) { - free_pd(vm, alloc); - alloc = NULL; - } - spin_lock(&pml4->lock); - if (atomic_dec_and_test(&pdp->used)) { - GEM_BUG_ON(alloc); - alloc = pdp; /* defer the free until after the lock */ - clear_pd_entry(pml4, pml4e, vm->scratch_pdp); - } - spin_unlock(&pml4->lock); + if (release_pd_entry(pml4, pml4e, &pdp->used, px_base(vm->scratch_pdp))) + free_pd(vm, pdp); unwind: gen8_ppgtt_clear_4lvl(vm, from, start - from); out: @@ -1570,11 +1544,7 @@ static int gen8_preallocate_top_level_pdp(struct i915_ppgtt *ppgtt) return 0; unwind: - start -= from; - gen8_for_each_pdpe(pd, pdp, from, start, pdpe) { - clear_pd_entry(pdp, pdpe, vm->scratch_pd); - free_pd(vm, pd); - } + gen8_ppgtt_clear_pdp(vm, pdp, from, start - from); atomic_set(&pdp->used, 0); return -ENOMEM; } -- 2.7.4