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lib/stackdepot: put functions in logical order 

Patch series "lib/stackdepot: fixes and clean-ups", v2.

A set of fixes, comments, and clean-ups I came up with while reading
the stack depot code.


This patch (of 18):

Put stack depot functions' declarations and definitions in a more logical
order:

1. Functions that save stack traces into stack depot.
2. Functions that fetch and print stack traces.
3. stack_depot_get_extra_bits that operates on stack depot handles
   and does not interact with the stack depot storage.

No functional changes.

Link: https://lkml.kernel.org/r/cover.1676063693.git.andreyknvl@google.com
Link: https://lkml.kernel.org/r/daca1319b665d826b94c596b992a8d8117846147.1676063693.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Andrey Konovalov 2023-02-10 22:15:49 +01:00 committed by Andrew Morton
parent 6bdfc60cf0
commit 15ef6a982f
2 changed files with 165 additions and 164 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
include/linux/stackdepot.h
View File

@ -14,17 +14,13 @@
#include <linux/gfp.h>
typedef u32 depot_stack_handle_t;
/*
* Number of bits in the handle that stack depot doesn't use. Users may store
* information in them.
*/
#define STACK_DEPOT_EXTRA_BITS 5
depot_stack_handle_t __stack_depot_save(unsigned long *entries,
unsigned int nr_entries,
unsigned int extra_bits,
gfp_t gfp_flags, bool can_alloc);
/*
* Every user of stack depot has to call stack_depot_init() during its own init
* when it's decided that it will be calling stack_depot_save() later. This is
@ -59,17 +55,22 @@ static inline void stack_depot_want_early_init(void) { }
static inline int stack_depot_early_init(void) { return 0; }
#endif
depot_stack_handle_t __stack_depot_save(unsigned long *entries,
unsigned int nr_entries,
unsigned int extra_bits,
gfp_t gfp_flags, bool can_alloc);
depot_stack_handle_t stack_depot_save(unsigned long *entries,
unsigned int nr_entries, gfp_t gfp_flags);
unsigned int stack_depot_fetch(depot_stack_handle_t handle,
unsigned long **entries);
unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle);
void stack_depot_print(depot_stack_handle_t stack);
int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size,
int spaces);
void stack_depot_print(depot_stack_handle_t stack);
unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle);
#endif

314
lib/stackdepot.c
View File

@ -79,84 +79,6 @@ static int next_slab_inited;
static size_t depot_offset;
static DEFINE_RAW_SPINLOCK(depot_lock);
unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle)
{
union handle_parts parts = { .handle = handle };
return parts.extra;
}
EXPORT_SYMBOL(stack_depot_get_extra_bits);
static bool init_stack_slab(void **prealloc)
{
if (!*prealloc)
return false;
/*
* This smp_load_acquire() pairs with smp_store_release() to
* |next_slab_inited| below and in depot_alloc_stack().
*/
if (smp_load_acquire(&next_slab_inited))
return true;
if (stack_slabs[depot_index] == NULL) {
stack_slabs[depot_index] = *prealloc;
*prealloc = NULL;
} else {
/* If this is the last depot slab, do not touch the next one. */
if (depot_index + 1 < STACK_ALLOC_MAX_SLABS) {
stack_slabs[depot_index + 1] = *prealloc;
*prealloc = NULL;
}
/*
* This smp_store_release pairs with smp_load_acquire() from
* |next_slab_inited| above and in stack_depot_save().
*/
smp_store_release(&next_slab_inited, 1);
}
return true;
}
/* Allocation of a new stack in raw storage */
static struct stack_record *
depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc)
{
struct stack_record *stack;
size_t required_size = struct_size(stack, entries, size);
required_size = ALIGN(required_size, 1 << STACK_ALLOC_ALIGN);
if (unlikely(depot_offset + required_size > STACK_ALLOC_SIZE)) {
if (unlikely(depot_index + 1 >= STACK_ALLOC_MAX_SLABS)) {
WARN_ONCE(1, "Stack depot reached limit capacity");
return NULL;
}
depot_index++;
depot_offset = 0;
/*
* smp_store_release() here pairs with smp_load_acquire() from
* |next_slab_inited| in stack_depot_save() and
* init_stack_slab().
*/
if (depot_index + 1 < STACK_ALLOC_MAX_SLABS)
smp_store_release(&next_slab_inited, 0);
}
init_stack_slab(prealloc);
if (stack_slabs[depot_index] == NULL)
return NULL;
stack = stack_slabs[depot_index] + depot_offset;
stack->hash = hash;
stack->size = size;
stack->handle.slabindex = depot_index;
stack->handle.offset = depot_offset >> STACK_ALLOC_ALIGN;
stack->handle.valid = 1;
stack->handle.extra = 0;
memcpy(stack->entries, entries, flex_array_size(stack, entries, size));
depot_offset += required_size;
return stack;
}
/* one hash table bucket entry per 16kB of memory */
#define STACK_HASH_SCALE 14
/* limited between 4k and 1M buckets */
@ -270,6 +192,76 @@ int stack_depot_init(void)
}
EXPORT_SYMBOL_GPL(stack_depot_init);
static bool init_stack_slab(void **prealloc)
{
if (!*prealloc)
return false;
/*
* This smp_load_acquire() pairs with smp_store_release() to
* |next_slab_inited| below and in depot_alloc_stack().
*/
if (smp_load_acquire(&next_slab_inited))
return true;
if (stack_slabs[depot_index] == NULL) {
stack_slabs[depot_index] = *prealloc;
*prealloc = NULL;
} else {
/* If this is the last depot slab, do not touch the next one. */
if (depot_index + 1 < STACK_ALLOC_MAX_SLABS) {
stack_slabs[depot_index + 1] = *prealloc;
*prealloc = NULL;
}
/*
* This smp_store_release pairs with smp_load_acquire() from
* |next_slab_inited| above and in stack_depot_save().
*/
smp_store_release(&next_slab_inited, 1);
}
return true;
}
/* Allocation of a new stack in raw storage */
static struct stack_record *
depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc)
{
struct stack_record *stack;
size_t required_size = struct_size(stack, entries, size);
required_size = ALIGN(required_size, 1 << STACK_ALLOC_ALIGN);
if (unlikely(depot_offset + required_size > STACK_ALLOC_SIZE)) {
if (unlikely(depot_index + 1 >= STACK_ALLOC_MAX_SLABS)) {
WARN_ONCE(1, "Stack depot reached limit capacity");
return NULL;
}
depot_index++;
depot_offset = 0;
/*
* smp_store_release() here pairs with smp_load_acquire() from
* |next_slab_inited| in stack_depot_save() and
* init_stack_slab().
*/
if (depot_index + 1 < STACK_ALLOC_MAX_SLABS)
smp_store_release(&next_slab_inited, 0);
}
init_stack_slab(prealloc);
if (stack_slabs[depot_index] == NULL)
return NULL;
stack = stack_slabs[depot_index] + depot_offset;
stack->hash = hash;
stack->size = size;
stack->handle.slabindex = depot_index;
stack->handle.offset = depot_offset >> STACK_ALLOC_ALIGN;
stack->handle.valid = 1;
stack->handle.extra = 0;
memcpy(stack->entries, entries, flex_array_size(stack, entries, size));
depot_offset += required_size;
return stack;
}
/* Calculate hash for a stack */
static inline u32 hash_stack(unsigned long *entries, unsigned int size)
{
@ -309,85 +301,6 @@ static inline struct stack_record *find_stack(struct stack_record *bucket,
return NULL;
}
/**
* stack_depot_snprint - print stack entries from a depot into a buffer
*
* @handle: Stack depot handle which was returned from
* stack_depot_save().
* @buf: Pointer to the print buffer
*
* @size: Size of the print buffer
*
* @spaces: Number of leading spaces to print
*
* Return: Number of bytes printed.
*/
int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size,
int spaces)
{
unsigned long *entries;
unsigned int nr_entries;
nr_entries = stack_depot_fetch(handle, &entries);
return nr_entries ? stack_trace_snprint(buf, size, entries, nr_entries,
spaces) : 0;
}
EXPORT_SYMBOL_GPL(stack_depot_snprint);
/**
* stack_depot_print - print stack entries from a depot
*
* @stack: Stack depot handle which was returned from
* stack_depot_save().
*
*/
void stack_depot_print(depot_stack_handle_t stack)
{
unsigned long *entries;
unsigned int nr_entries;
nr_entries = stack_depot_fetch(stack, &entries);
if (nr_entries > 0)
stack_trace_print(entries, nr_entries, 0);
}
EXPORT_SYMBOL_GPL(stack_depot_print);
/**
* stack_depot_fetch - Fetch stack entries from a depot
*
* @handle: Stack depot handle which was returned from
* stack_depot_save().
* @entries: Pointer to store the entries address
*
* Return: The number of trace entries for this depot.
*/
unsigned int stack_depot_fetch(depot_stack_handle_t handle,
unsigned long **entries)
{
union handle_parts parts = { .handle = handle };
void *slab;
size_t offset = parts.offset << STACK_ALLOC_ALIGN;
struct stack_record *stack;
*entries = NULL;
if (!handle)
return 0;
if (parts.slabindex > depot_index) {
WARN(1, "slab index %d out of bounds (%d) for stack id %08x\n",
parts.slabindex, depot_index, handle);
return 0;
}
slab = stack_slabs[parts.slabindex];
if (!slab)
return 0;
stack = slab + offset;
*entries = stack->entries;
return stack->size;
}
EXPORT_SYMBOL_GPL(stack_depot_fetch);
/**
* __stack_depot_save - Save a stack trace from an array
*
@ -533,3 +446,90 @@ depot_stack_handle_t stack_depot_save(unsigned long *entries,
return __stack_depot_save(entries, nr_entries, 0, alloc_flags, true);
}
EXPORT_SYMBOL_GPL(stack_depot_save);
/**
* stack_depot_fetch - Fetch stack entries from a depot
*
* @handle: Stack depot handle which was returned from
* stack_depot_save().
* @entries: Pointer to store the entries address
*
* Return: The number of trace entries for this depot.
*/
unsigned int stack_depot_fetch(depot_stack_handle_t handle,
unsigned long **entries)
{
union handle_parts parts = { .handle = handle };
void *slab;
size_t offset = parts.offset << STACK_ALLOC_ALIGN;
struct stack_record *stack;
*entries = NULL;
if (!handle)
return 0;
if (parts.slabindex > depot_index) {
WARN(1, "slab index %d out of bounds (%d) for stack id %08x\n",
parts.slabindex, depot_index, handle);
return 0;
}
slab = stack_slabs[parts.slabindex];
if (!slab)
return 0;
stack = slab + offset;
*entries = stack->entries;
return stack->size;
}
EXPORT_SYMBOL_GPL(stack_depot_fetch);
/**
* stack_depot_print - print stack entries from a depot
*
* @stack: Stack depot handle which was returned from
* stack_depot_save().
*
*/
void stack_depot_print(depot_stack_handle_t stack)
{
unsigned long *entries;
unsigned int nr_entries;
nr_entries = stack_depot_fetch(stack, &entries);
if (nr_entries > 0)
stack_trace_print(entries, nr_entries, 0);
}
EXPORT_SYMBOL_GPL(stack_depot_print);
/**
* stack_depot_snprint - print stack entries from a depot into a buffer
*
* @handle: Stack depot handle which was returned from
* stack_depot_save().
* @buf: Pointer to the print buffer
*
* @size: Size of the print buffer
*
* @spaces: Number of leading spaces to print
*
* Return: Number of bytes printed.
*/
int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size,
int spaces)
{
unsigned long *entries;
unsigned int nr_entries;
nr_entries = stack_depot_fetch(handle, &entries);
return nr_entries ? stack_trace_snprint(buf, size, entries, nr_entries,
spaces) : 0;
}
EXPORT_SYMBOL_GPL(stack_depot_snprint);
unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle)
{
union handle_parts parts = { .handle = handle };
return parts.extra;
}
EXPORT_SYMBOL(stack_depot_get_extra_bits);