Re: [Intel-gfx] [patch V2 03/29] lib/stackdepot: Provide functions which operate on plain storage arrays

2019-04-20 Thread Mike Rapoport
On Thu, Apr 18, 2019 at 10:41:22AM +0200, Thomas Gleixner wrote:
> The struct stack_trace indirection in the stack depot functions is a truly
> pointless excercise which requires horrible code at the callsites.
> 
> Provide interfaces based on plain storage arrays.
> 
> Signed-off-by: Thomas Gleixner 
> Acked-by: Alexander Potapenko 
> ---
>  include/linux/stackdepot.h |4 ++
>  lib/stackdepot.c   |   66 
> -
>  2 files changed, 51 insertions(+), 19 deletions(-)
> 
> --- a/include/linux/stackdepot.h
> +++ b/include/linux/stackdepot.h
> @@ -26,7 +26,11 @@ typedef u32 depot_stack_handle_t;
>  struct stack_trace;
> 
>  depot_stack_handle_t depot_save_stack(struct stack_trace *trace, gfp_t 
> flags);
> +depot_stack_handle_t stack_depot_save(unsigned long *entries,
> +   unsigned int nr_entries, gfp_t gfp_flags);
> 
>  void depot_fetch_stack(depot_stack_handle_t handle, struct stack_trace 
> *trace);
> +unsigned int stack_depot_fetch(depot_stack_handle_t handle,
> +unsigned long **entries);
> 
>  #endif
> --- a/lib/stackdepot.c
> +++ b/lib/stackdepot.c
> @@ -194,40 +194,56 @@ static inline struct stack_record *find_
>   return NULL;
>  }
> 
> -void depot_fetch_stack(depot_stack_handle_t handle, struct stack_trace 
> *trace)
> +/**
> + * stack_depot_fetch - Fetch stack entries from a depot
> + *

Nit: kernel-doc will complain about missing description of @handle.

> + * @entries: Pointer to store the entries address
> + */
> +unsigned int stack_depot_fetch(depot_stack_handle_t handle,
> +unsigned long **entries)
>  {
>   union handle_parts parts = { .handle = handle };
>   void *slab = stack_slabs[parts.slabindex];
>   size_t offset = parts.offset << STACK_ALLOC_ALIGN;
>   struct stack_record *stack = slab + offset;
> 
> - trace->nr_entries = trace->max_entries = stack->size;
> - trace->entries = stack->entries;
> - trace->skip = 0;
> + *entries = stack->entries;
> + return stack->size;
> +}
> +EXPORT_SYMBOL_GPL(stack_depot_fetch);
> +
> +void depot_fetch_stack(depot_stack_handle_t handle, struct stack_trace 
> *trace)
> +{
> + unsigned int nent = stack_depot_fetch(handle, >entries);
> +
> + trace->max_entries = trace->nr_entries = nent;
>  }
>  EXPORT_SYMBOL_GPL(depot_fetch_stack);
> 
>  /**
> - * depot_save_stack - save stack in a stack depot.
> - * @trace - the stacktrace to save.
> - * @alloc_flags - flags for allocating additional memory if required.
> + * stack_depot_save - Save a stack trace from an array
>   *
> - * Returns the handle of the stack struct stored in depot.
> + * @entries: Pointer to storage array
> + * @nr_entries:  Size of the storage array
> + * @alloc_flags: Allocation gfp flags
> + *
> + * Returns the handle of the stack struct stored in depot

Can you please s/Returns/Return:/ so that kernel-doc will recognize this as
return section.

>   */
> -depot_stack_handle_t depot_save_stack(struct stack_trace *trace,
> - gfp_t alloc_flags)
> +depot_stack_handle_t stack_depot_save(unsigned long *entries,
> +   unsigned int nr_entries,
> +   gfp_t alloc_flags)
>  {
> - u32 hash;
> - depot_stack_handle_t retval = 0;
>   struct stack_record *found = NULL, **bucket;
> - unsigned long flags;
> + depot_stack_handle_t retval = 0;
>   struct page *page = NULL;
>   void *prealloc = NULL;
> + unsigned long flags;
> + u32 hash;
> 
> - if (unlikely(trace->nr_entries == 0))
> + if (unlikely(nr_entries == 0))
>   goto fast_exit;
> 
> - hash = hash_stack(trace->entries, trace->nr_entries);
> + hash = hash_stack(entries, nr_entries);
>   bucket = _table[hash & STACK_HASH_MASK];
> 
>   /*
> @@ -235,8 +251,8 @@ depot_stack_handle_t depot_save_stack(st
>* The smp_load_acquire() here pairs with smp_store_release() to
>* |bucket| below.
>*/
> - found = find_stack(smp_load_acquire(bucket), trace->entries,
> -trace->nr_entries, hash);
> + found = find_stack(smp_load_acquire(bucket), entries,
> +nr_entries, hash);
>   if (found)
>   goto exit;
> 
> @@ -264,10 +280,10 @@ depot_stack_handle_t depot_save_stack(st
> 
>   spin_lock_irqsave(_lock, flags);
> 
> - found = find_stack(*bucket, trace->entries, trace->nr_entries, hash);
> + found = find_stack(*bucket, entries, nr_entries, hash);
>   if (!found) {
>   struct stack_record *new =
> - depot_alloc_stack(trace->entries, trace->nr_entries,
> + depot_alloc_stack(entries, nr_entries,
> hash, , alloc_flags);
>   if (new) {
>   new->next = *bucket;
> @@ 

Re: [Intel-gfx] [patch V2 03/29] lib/stackdepot: Provide functions which operate on plain storage arrays

2019-04-18 Thread Thomas Gleixner
On Thu, 18 Apr 2019, Mike Rapoport wrote:
> On Thu, Apr 18, 2019 at 10:41:22AM +0200, Thomas Gleixner wrote:
> > 
> > -void depot_fetch_stack(depot_stack_handle_t handle, struct stack_trace 
> > *trace)
> > +/**
> > + * stack_depot_fetch - Fetch stack entries from a depot
> > + *
> 
> Nit: kernel-doc will complain about missing description of @handle.

Duh.

> > + * @entries:   Pointer to store the entries address
> > + */
> 
> Can you please s/Returns/Return:/ so that kernel-doc will recognize this as
> return section.

Sure thing.

Thanks,

tglx
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[Intel-gfx] [patch V2 03/29] lib/stackdepot: Provide functions which operate on plain storage arrays

2019-04-18 Thread Thomas Gleixner
The struct stack_trace indirection in the stack depot functions is a truly
pointless excercise which requires horrible code at the callsites.

Provide interfaces based on plain storage arrays.

Signed-off-by: Thomas Gleixner 
Acked-by: Alexander Potapenko 
---
 include/linux/stackdepot.h |4 ++
 lib/stackdepot.c   |   66 -
 2 files changed, 51 insertions(+), 19 deletions(-)

--- a/include/linux/stackdepot.h
+++ b/include/linux/stackdepot.h
@@ -26,7 +26,11 @@ typedef u32 depot_stack_handle_t;
 struct stack_trace;
 
 depot_stack_handle_t depot_save_stack(struct stack_trace *trace, gfp_t flags);
+depot_stack_handle_t stack_depot_save(unsigned long *entries,
+ unsigned int nr_entries, gfp_t gfp_flags);
 
 void depot_fetch_stack(depot_stack_handle_t handle, struct stack_trace *trace);
+unsigned int stack_depot_fetch(depot_stack_handle_t handle,
+  unsigned long **entries);
 
 #endif
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -194,40 +194,56 @@ static inline struct stack_record *find_
return NULL;
 }
 
-void depot_fetch_stack(depot_stack_handle_t handle, struct stack_trace *trace)
+/**
+ * stack_depot_fetch - Fetch stack entries from a depot
+ *
+ * @entries:   Pointer to store the entries address
+ */
+unsigned int stack_depot_fetch(depot_stack_handle_t handle,
+  unsigned long **entries)
 {
union handle_parts parts = { .handle = handle };
void *slab = stack_slabs[parts.slabindex];
size_t offset = parts.offset << STACK_ALLOC_ALIGN;
struct stack_record *stack = slab + offset;
 
-   trace->nr_entries = trace->max_entries = stack->size;
-   trace->entries = stack->entries;
-   trace->skip = 0;
+   *entries = stack->entries;
+   return stack->size;
+}
+EXPORT_SYMBOL_GPL(stack_depot_fetch);
+
+void depot_fetch_stack(depot_stack_handle_t handle, struct stack_trace *trace)
+{
+   unsigned int nent = stack_depot_fetch(handle, >entries);
+
+   trace->max_entries = trace->nr_entries = nent;
 }
 EXPORT_SYMBOL_GPL(depot_fetch_stack);
 
 /**
- * depot_save_stack - save stack in a stack depot.
- * @trace - the stacktrace to save.
- * @alloc_flags - flags for allocating additional memory if required.
+ * stack_depot_save - Save a stack trace from an array
  *
- * Returns the handle of the stack struct stored in depot.
+ * @entries:   Pointer to storage array
+ * @nr_entries:Size of the storage array
+ * @alloc_flags:   Allocation gfp flags
+ *
+ * Returns the handle of the stack struct stored in depot
  */
-depot_stack_handle_t depot_save_stack(struct stack_trace *trace,
-   gfp_t alloc_flags)
+depot_stack_handle_t stack_depot_save(unsigned long *entries,
+ unsigned int nr_entries,
+ gfp_t alloc_flags)
 {
-   u32 hash;
-   depot_stack_handle_t retval = 0;
struct stack_record *found = NULL, **bucket;
-   unsigned long flags;
+   depot_stack_handle_t retval = 0;
struct page *page = NULL;
void *prealloc = NULL;
+   unsigned long flags;
+   u32 hash;
 
-   if (unlikely(trace->nr_entries == 0))
+   if (unlikely(nr_entries == 0))
goto fast_exit;
 
-   hash = hash_stack(trace->entries, trace->nr_entries);
+   hash = hash_stack(entries, nr_entries);
bucket = _table[hash & STACK_HASH_MASK];
 
/*
@@ -235,8 +251,8 @@ depot_stack_handle_t depot_save_stack(st
 * The smp_load_acquire() here pairs with smp_store_release() to
 * |bucket| below.
 */
-   found = find_stack(smp_load_acquire(bucket), trace->entries,
-  trace->nr_entries, hash);
+   found = find_stack(smp_load_acquire(bucket), entries,
+  nr_entries, hash);
if (found)
goto exit;
 
@@ -264,10 +280,10 @@ depot_stack_handle_t depot_save_stack(st
 
spin_lock_irqsave(_lock, flags);
 
-   found = find_stack(*bucket, trace->entries, trace->nr_entries, hash);
+   found = find_stack(*bucket, entries, nr_entries, hash);
if (!found) {
struct stack_record *new =
-   depot_alloc_stack(trace->entries, trace->nr_entries,
+   depot_alloc_stack(entries, nr_entries,
  hash, , alloc_flags);
if (new) {
new->next = *bucket;
@@ -297,4 +313,16 @@ depot_stack_handle_t depot_save_stack(st
 fast_exit:
return retval;
 }
+EXPORT_SYMBOL_GPL(stack_depot_save);
+
+/**
+ * depot_save_stack - save stack in a stack depot.
+ * @trace - the stacktrace to save.
+ * @alloc_flags - flags for allocating additional memory if required.
+ */
+depot_stack_handle_t depot_save_stack(struct stack_trace *trace,