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bcachefs: Etyzinger cleanups

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Pull out eytzinger.c and kill eytzinger_cmp_fn. We now provide
eytzinger0_sort and eytzinger0_sort_r, which use the standard cmp_func_t
and cmp_r_func_t callbacks.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2024-03-22 19:26:33 -04:00
parent bdbf953b3c
commit ca1e02f7e9
7 changed files with 285 additions and 182 deletions
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1
fs/bcachefs/Makefile
View File

@ -37,6 +37,7 @@ bcachefs-y := \
error.o \
extents.o \
extent_update.o \
eytzinger.o \
fs.o \
fs-common.o \
fs-ioctl.o \

234
fs/bcachefs/eytzinger.c Normal file
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@ -0,0 +1,234 @@
// SPDX-License-Identifier: GPL-2.0
#include "eytzinger.h"
/**
* is_aligned - is this pointer & size okay for word-wide copying?
* @base: pointer to data
* @size: size of each element
* @align: required alignment (typically 4 or 8)
*
* Returns true if elements can be copied using word loads and stores.
* The size must be a multiple of the alignment, and the base address must
* be if we do not have CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS.
*
* For some reason, gcc doesn't know to optimize "if (a & mask || b & mask)"
* to "if ((a | b) & mask)", so we do that by hand.
*/
__attribute_const__ __always_inline
static bool is_aligned(const void *base, size_t size, unsigned char align)
{
unsigned char lsbits = (unsigned char)size;
(void)base;
#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
lsbits |= (unsigned char)(uintptr_t)base;
#endif
return (lsbits & (align - 1)) == 0;
}
/**
* swap_words_32 - swap two elements in 32-bit chunks
* @a: pointer to the first element to swap
* @b: pointer to the second element to swap
* @n: element size (must be a multiple of 4)
*
* Exchange the two objects in memory. This exploits base+index addressing,
* which basically all CPUs have, to minimize loop overhead computations.
*
* For some reason, on x86 gcc 7.3.0 adds a redundant test of n at the
* bottom of the loop, even though the zero flag is still valid from the
* subtract (since the intervening mov instructions don't alter the flags).
* Gcc 8.1.0 doesn't have that problem.
*/
static void swap_words_32(void *a, void *b, size_t n)
{
do {
u32 t = *(u32 *)(a + (n -= 4));
*(u32 *)(a + n) = *(u32 *)(b + n);
*(u32 *)(b + n) = t;
} while (n);
}
/**
* swap_words_64 - swap two elements in 64-bit chunks
* @a: pointer to the first element to swap
* @b: pointer to the second element to swap
* @n: element size (must be a multiple of 8)
*
* Exchange the two objects in memory. This exploits base+index
* addressing, which basically all CPUs have, to minimize loop overhead
* computations.
*
* We'd like to use 64-bit loads if possible. If they're not, emulating
* one requires base+index+4 addressing which x86 has but most other
* processors do not. If CONFIG_64BIT, we definitely have 64-bit loads,
* but it's possible to have 64-bit loads without 64-bit pointers (e.g.
* x32 ABI). Are there any cases the kernel needs to worry about?
*/
static void swap_words_64(void *a, void *b, size_t n)
{
do {
#ifdef CONFIG_64BIT
u64 t = *(u64 *)(a + (n -= 8));
*(u64 *)(a + n) = *(u64 *)(b + n);
*(u64 *)(b + n) = t;
#else
/* Use two 32-bit transfers to avoid base+index+4 addressing */
u32 t = *(u32 *)(a + (n -= 4));
*(u32 *)(a + n) = *(u32 *)(b + n);
*(u32 *)(b + n) = t;
t = *(u32 *)(a + (n -= 4));
*(u32 *)(a + n) = *(u32 *)(b + n);
*(u32 *)(b + n) = t;
#endif
} while (n);
}
/**
* swap_bytes - swap two elements a byte at a time
* @a: pointer to the first element to swap
* @b: pointer to the second element to swap
* @n: element size
*
* This is the fallback if alignment doesn't allow using larger chunks.
*/
static void swap_bytes(void *a, void *b, size_t n)
{
do {
char t = ((char *)a)[--n];
((char *)a)[n] = ((char *)b)[n];
((char *)b)[n] = t;
} while (n);
}
/*
* The values are arbitrary as long as they can't be confused with
* a pointer, but small integers make for the smallest compare
* instructions.
*/
#define SWAP_WORDS_64 (swap_r_func_t)0
#define SWAP_WORDS_32 (swap_r_func_t)1
#define SWAP_BYTES (swap_r_func_t)2
#define SWAP_WRAPPER (swap_r_func_t)3
struct wrapper {
cmp_func_t cmp;
swap_func_t swap;
};
/*
* The function pointer is last to make tail calls most efficient if the
* compiler decides not to inline this function.
*/
static void do_swap(void *a, void *b, size_t size, swap_r_func_t swap_func, const void *priv)
{
if (swap_func == SWAP_WRAPPER) {
((const struct wrapper *)priv)->swap(a, b, (int)size);
return;
}
if (swap_func == SWAP_WORDS_64)
swap_words_64(a, b, size);
else if (swap_func == SWAP_WORDS_32)
swap_words_32(a, b, size);
else if (swap_func == SWAP_BYTES)
swap_bytes(a, b, size);
else
swap_func(a, b, (int)size, priv);
}
#define _CMP_WRAPPER ((cmp_r_func_t)0L)
static int do_cmp(const void *a, const void *b, cmp_r_func_t cmp, const void *priv)
{
if (cmp == _CMP_WRAPPER)
return ((const struct wrapper *)priv)->cmp(a, b);
return cmp(a, b, priv);
}
static inline int eytzinger0_do_cmp(void *base, size_t n, size_t size,
cmp_r_func_t cmp_func, const void *priv,
size_t l, size_t r)
{
return do_cmp(base + inorder_to_eytzinger0(l, n) * size,
base + inorder_to_eytzinger0(r, n) * size,
cmp_func, priv);
}
static inline void eytzinger0_do_swap(void *base, size_t n, size_t size,
swap_r_func_t swap_func, const void *priv,
size_t l, size_t r)
{
do_swap(base + inorder_to_eytzinger0(l, n) * size,
base + inorder_to_eytzinger0(r, n) * size,
size, swap_func, priv);
}
void eytzinger0_sort_r(void *base, size_t n, size_t size,
cmp_r_func_t cmp_func,
swap_r_func_t swap_func,
const void *priv)
{
int i, c, r;
/* called from 'sort' without swap function, let's pick the default */
if (swap_func == SWAP_WRAPPER && !((struct wrapper *)priv)->swap)
swap_func = NULL;
if (!swap_func) {
if (is_aligned(base, size, 8))
swap_func = SWAP_WORDS_64;
else if (is_aligned(base, size, 4))
swap_func = SWAP_WORDS_32;
else
swap_func = SWAP_BYTES;
}
/* heapify */
for (i = n / 2 - 1; i >= 0; --i) {
for (r = i; r * 2 + 1 < n; r = c) {
c = r * 2 + 1;
if (c + 1 < n &&
eytzinger0_do_cmp(base, n, size, cmp_func, priv, c, c + 1) < 0)
c++;
if (eytzinger0_do_cmp(base, n, size, cmp_func, priv, r, c) >= 0)
break;
eytzinger0_do_swap(base, n, size, swap_func, priv, r, c);
}
}
/* sort */
for (i = n - 1; i > 0; --i) {
eytzinger0_do_swap(base, n, size, swap_func, priv, 0, i);
for (r = 0; r * 2 + 1 < i; r = c) {
c = r * 2 + 1;
if (c + 1 < i &&
eytzinger0_do_cmp(base, n, size, cmp_func, priv, c, c + 1) < 0)
c++;
if (eytzinger0_do_cmp(base, n, size, cmp_func, priv, r, c) >= 0)
break;
eytzinger0_do_swap(base, n, size, swap_func, priv, r, c);
}
}
}
void eytzinger0_sort(void *base, size_t n, size_t size,
cmp_func_t cmp_func,
swap_func_t swap_func)
{
struct wrapper w = {
.cmp = cmp_func,
.swap = swap_func,
};
return eytzinger0_sort_r(base, n, size, _CMP_WRAPPER, SWAP_WRAPPER, &w);
}

63
fs/bcachefs/eytzinger.h
View File

@ -5,23 +5,33 @@
#include <linux/bitops.h>
#include <linux/log2.h>
#include "util.h"
#ifdef EYTZINGER_DEBUG
#define EYTZINGER_BUG_ON(cond) BUG_ON(cond)
#else
#define EYTZINGER_BUG_ON(cond)
#endif
/*
* Traversal for trees in eytzinger layout - a full binary tree layed out in an
* array
*/
/*
* One based indexing version:
* array.
*
* With one based indexing each level of the tree starts at a power of two -
* good for cacheline alignment:
* Consider using an eytzinger tree any time you would otherwise be doing binary
* search over an array. Binary search is a worst case scenario for branch
* prediction and prefetching, but in an eytzinger tree every node's children
* are adjacent in memory, thus we can prefetch children before knowing the
* result of the comparison, assuming multiple nodes fit on a cacheline.
*
* Two variants are provided, for one based indexing and zero based indexing.
*
* Zero based indexing is more convenient, but one based indexing has better
* alignment and thus better performance because each new level of the tree
* starts at a power of two, and thus if element 0 was cacheline aligned, each
* new level will be as well.
*/
static inline unsigned eytzinger1_child(unsigned i, unsigned child)
{
EBUG_ON(child > 1);
EYTZINGER_BUG_ON(child > 1);
return (i << 1) + child;
}
@ -58,7 +68,7 @@ static inline unsigned eytzinger1_last(unsigned size)
static inline unsigned eytzinger1_next(unsigned i, unsigned size)
{
EBUG_ON(i > size);
EYTZINGER_BUG_ON(i > size);
if (eytzinger1_right_child(i) <= size) {
i = eytzinger1_right_child(i);
@ -74,7 +84,7 @@ static inline unsigned eytzinger1_next(unsigned i, unsigned size)
static inline unsigned eytzinger1_prev(unsigned i, unsigned size)
{
EBUG_ON(i > size);
EYTZINGER_BUG_ON(i > size);
if (eytzinger1_left_child(i) <= size) {
i = eytzinger1_left_child(i) + 1;
@ -101,7 +111,7 @@ static inline unsigned __eytzinger1_to_inorder(unsigned i, unsigned size,
unsigned shift = __fls(size) - b;
int s;
EBUG_ON(!i || i > size);
EYTZINGER_BUG_ON(!i || i > size);
i ^= 1U << b;
i <<= 1;
@ -126,7 +136,7 @@ static inline unsigned __inorder_to_eytzinger1(unsigned i, unsigned size,
unsigned shift;
int s;
EBUG_ON(!i || i > size);
EYTZINGER_BUG_ON(!i || i > size);
/*
* sign bit trick:
@ -164,7 +174,7 @@ static inline unsigned inorder_to_eytzinger1(unsigned i, unsigned size)
static inline unsigned eytzinger0_child(unsigned i, unsigned child)
{
EBUG_ON(child > 1);
EYTZINGER_BUG_ON(child > 1);
return (i << 1) + 1 + child;
}
@ -231,11 +241,9 @@ static inline unsigned inorder_to_eytzinger0(unsigned i, unsigned size)
(_i) != -1; \
(_i) = eytzinger0_next((_i), (_size)))
typedef int (*eytzinger_cmp_fn)(const void *l, const void *r, size_t size);
/* return greatest node <= @search, or -1 if not found */
static inline ssize_t eytzinger0_find_le(void *base, size_t nr, size_t size,
eytzinger_cmp_fn cmp, const void *search)
cmp_func_t cmp, const void *search)
{
unsigned i, n = 0;
@ -244,21 +252,24 @@ static inline ssize_t eytzinger0_find_le(void *base, size_t nr, size_t size,
do {
i = n;
n = eytzinger0_child(i, cmp(search, base + i * size, size) >= 0);
n = eytzinger0_child(i, cmp(base + i * size, search) <= 0);
} while (n < nr);
if (n & 1) {
/* @i was greater than @search, return previous node: */
if (i == eytzinger0_first(nr))
return -1;
return eytzinger0_prev(i, nr);
} else {
return i;
}
}
static inline ssize_t eytzinger0_find_gt(void *base, size_t nr, size_t size,
cmp_func_t cmp, const void *search)
{
ssize_t idx = eytzinger0_find_le(base, nr, size, cmp, search);
return eytzinger0_next(idx, size);
}
#define eytzinger0_find(base, nr, size, _cmp, search) \
({ \
void *_base = (base); \
@ -269,13 +280,13 @@ static inline ssize_t eytzinger0_find_le(void *base, size_t nr, size_t size,
int _res; \
\
while (_i < _nr && \
(_res = _cmp(_search, _base + _i * _size, _size))) \
(_res = _cmp(_search, _base + _i * _size))) \
_i = eytzinger0_child(_i, _res > 0); \
_i; \
})
void eytzinger0_sort(void *, size_t, size_t,
int (*cmp_func)(const void *, const void *, size_t),
void (*swap_func)(void *, void *, size_t));
void eytzinger0_sort_r(void *, size_t, size_t,
cmp_r_func_t, swap_r_func_t, const void *);
void eytzinger0_sort(void *, size_t, size_t, cmp_func_t, swap_func_t);
#endif /* _EYTZINGER_H */

3
fs/bcachefs/journal_seq_blacklist.c
View File

@ -95,8 +95,7 @@ out:
return ret ?: bch2_blacklist_table_initialize(c);
}
static int journal_seq_blacklist_table_cmp(const void *_l,
const void *_r, size_t size)
static int journal_seq_blacklist_table_cmp(const void *_l, const void *_r)
{
const struct journal_seq_blacklist_table_entry *l = _l;
const struct journal_seq_blacklist_table_entry *r = _r;

19
fs/bcachefs/replicas.c
View File

@ -6,12 +6,15 @@
#include "replicas.h"
#include "super-io.h"
#include <linux/sort.h>
static int bch2_cpu_replicas_to_sb_replicas(struct bch_fs *,
struct bch_replicas_cpu *);
/* Some (buggy!) compilers don't allow memcmp to be passed as a pointer */
static int bch2_memcmp(const void *l, const void *r, size_t size)
static int bch2_memcmp(const void *l, const void *r, const void *priv)
{
size_t size = (size_t) priv;
return memcmp(l, r, size);
}
@ -39,7 +42,8 @@ void bch2_replicas_entry_sort(struct bch_replicas_entry_v1 *e)
static void bch2_cpu_replicas_sort(struct bch_replicas_cpu *r)
{
eytzinger0_sort(r->entries, r->nr, r->entry_size, bch2_memcmp, NULL);
eytzinger0_sort_r(r->entries, r->nr, r->entry_size,
bch2_memcmp, NULL, (void *)(size_t)r->entry_size);
}
static void bch2_replicas_entry_v0_to_text(struct printbuf *out,
@ -228,7 +232,7 @@ static inline int __replicas_entry_idx(struct bch_replicas_cpu *r,
verify_replicas_entry(search);
#define entry_cmp(_l, _r, size) memcmp(_l, _r, entry_size)
#define entry_cmp(_l, _r) memcmp(_l, _r, entry_size)
idx = eytzinger0_find(r->entries, r->nr, r->entry_size,
entry_cmp, search);
#undef entry_cmp
@ -824,10 +828,11 @@ static int bch2_cpu_replicas_validate(struct bch_replicas_cpu *cpu_r,
{
unsigned i;
sort_cmp_size(cpu_r->entries,
cpu_r->nr,
cpu_r->entry_size,
bch2_memcmp, NULL);
sort_r(cpu_r->entries,
cpu_r->nr,
cpu_r->entry_size,
bch2_memcmp, NULL,
(void *)(size_t)cpu_r->entry_size);
for (i = 0; i < cpu_r->nr; i++) {
struct bch_replicas_entry_v1 *e =

143
fs/bcachefs/util.c
View File

@ -707,149 +707,6 @@ void memcpy_from_bio(void *dst, struct bio *src, struct bvec_iter src_iter)
}
}
static int alignment_ok(const void *base, size_t align)
{
return IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ||
((unsigned long)base & (align - 1)) == 0;
}
static void u32_swap(void *a, void *b, size_t size)
{
u32 t = *(u32 *)a;
*(u32 *)a = *(u32 *)b;
*(u32 *)b = t;
}
static void u64_swap(void *a, void *b, size_t size)
{
u64 t = *(u64 *)a;
*(u64 *)a = *(u64 *)b;
*(u64 *)b = t;
}
static void generic_swap(void *a, void *b, size_t size)
{
char t;
do {
t = *(char *)a;
*(char *)a++ = *(char *)b;
*(char *)b++ = t;
} while (--size > 0);
}
static inline int do_cmp(void *base, size_t n, size_t size,
int (*cmp_func)(const void *, const void *, size_t),
size_t l, size_t r)
{
return cmp_func(base + inorder_to_eytzinger0(l, n) * size,
base + inorder_to_eytzinger0(r, n) * size,
size);
}
static inline void do_swap(void *base, size_t n, size_t size,
void (*swap_func)(void *, void *, size_t),
size_t l, size_t r)
{
swap_func(base + inorder_to_eytzinger0(l, n) * size,
base + inorder_to_eytzinger0(r, n) * size,
size);
}
void eytzinger0_sort(void *base, size_t n, size_t size,
int (*cmp_func)(const void *, const void *, size_t),
void (*swap_func)(void *, void *, size_t))
{
int i, c, r;
if (!swap_func) {
if (size == 4 && alignment_ok(base, 4))
swap_func = u32_swap;
else if (size == 8 && alignment_ok(base, 8))
swap_func = u64_swap;
else
swap_func = generic_swap;
}
/* heapify */
for (i = n / 2 - 1; i >= 0; --i) {
for (r = i; r * 2 + 1 < n; r = c) {
c = r * 2 + 1;
if (c + 1 < n &&
do_cmp(base, n, size, cmp_func, c, c + 1) < 0)
c++;
if (do_cmp(base, n, size, cmp_func, r, c) >= 0)
break;
do_swap(base, n, size, swap_func, r, c);
}
}
/* sort */
for (i = n - 1; i > 0; --i) {
do_swap(base, n, size, swap_func, 0, i);
for (r = 0; r * 2 + 1 < i; r = c) {
c = r * 2 + 1;
if (c + 1 < i &&
do_cmp(base, n, size, cmp_func, c, c + 1) < 0)
c++;
if (do_cmp(base, n, size, cmp_func, r, c) >= 0)
break;
do_swap(base, n, size, swap_func, r, c);
}
}
}
void sort_cmp_size(void *base, size_t num, size_t size,
int (*cmp_func)(const void *, const void *, size_t),
void (*swap_func)(void *, void *, size_t size))
{
/* pre-scale counters for performance */
int i = (num/2 - 1) * size, n = num * size, c, r;
if (!swap_func) {
if (size == 4 && alignment_ok(base, 4))
swap_func = u32_swap;
else if (size == 8 && alignment_ok(base, 8))
swap_func = u64_swap;
else
swap_func = generic_swap;
}
/* heapify */
for ( ; i >= 0; i -= size) {
for (r = i; r * 2 + size < n; r = c) {
c = r * 2 + size;
if (c < n - size &&
cmp_func(base + c, base + c + size, size) < 0)
c += size;
if (cmp_func(base + r, base + c, size) >= 0)
break;
swap_func(base + r, base + c, size);
}
}
/* sort */
for (i = n - size; i > 0; i -= size) {
swap_func(base, base + i, size);
for (r = 0; r * 2 + size < i; r = c) {
c = r * 2 + size;
if (c < i - size &&
cmp_func(base + c, base + c + size, size) < 0)
c += size;
if (cmp_func(base + r, base + c, size) >= 0)
break;
swap_func(base + r, base + c, size);
}
}
}
#if 0
void eytzinger1_test(void)
{

4
fs/bcachefs/util.h
View File

@ -631,10 +631,6 @@ static inline void memset_u64s_tail(void *s, int c, unsigned bytes)
memset(s + bytes, c, rem);
}
void sort_cmp_size(void *base, size_t num, size_t size,
int (*cmp_func)(const void *, const void *, size_t),
void (*swap_func)(void *, void *, size_t));
/* just the memmove, doesn't update @_nr */
#define __array_insert_item(_array, _nr, _pos) \
memmove(&(_array)[(_pos) + 1], \