diff options
author | Kent Overstreet <kent.overstreet@linux.dev> | 2024-02-05 23:09:25 -0500 |
---|---|---|
committer | Kent Overstreet <kent.overstreet@linux.dev> | 2024-02-06 01:07:16 -0500 |
commit | f3f005c76eb5636542a8f5b137bd1904d57e8f86 (patch) | |
tree | ecada3604cb1668411386264ed92d0e61536a93a /linux | |
parent | 1ef396b684a419b5a50ab215103486d189068800 (diff) |
Update bcachefs sources to 50847e296b34 bcachefs: Check subvol <-> inode pointers in check_inode()
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Diffstat (limited to 'linux')
-rw-r--r-- | linux/darray.c | 27 | ||||
-rw-r--r-- | linux/mean_and_variance.c | 167 | ||||
-rw-r--r-- | linux/mempool.c | 13 | ||||
-rw-r--r-- | linux/sort.c | 368 | ||||
-rw-r--r-- | linux/time_stats.c | 373 |
5 files changed, 948 insertions, 0 deletions
diff --git a/linux/darray.c b/linux/darray.c new file mode 100644 index 00000000..80e77959 --- /dev/null +++ b/linux/darray.c @@ -0,0 +1,27 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * (C) 2022-2024 Kent Overstreet <kent.overstreet@linux.dev> + */ + +#include <linux/darray.h> +#include <linux/log2.h> +#include <linux/slab.h> + +int __darray_resize_slowpath(darray_char *d, size_t element_size, size_t new_size, gfp_t gfp) +{ + if (new_size > d->size) { + new_size = roundup_pow_of_two(new_size); + + void *data = kvmalloc_array(new_size, element_size, gfp); + if (!data) + return -ENOMEM; + + memcpy(data, d->data, d->size * element_size); + if (d->data != d->preallocated) + kvfree(d->data); + d->data = data; + d->size = new_size; + } + + return 0; +} diff --git a/linux/mean_and_variance.c b/linux/mean_and_variance.c new file mode 100644 index 00000000..b93d150d --- /dev/null +++ b/linux/mean_and_variance.c @@ -0,0 +1,167 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Functions for incremental mean and variance. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * Copyright © 2022 Daniel B. Hill + * + * Author: Daniel B. Hill <daniel@gluo.nz> + * + * Description: + * + * This is includes some incremental algorithms for mean and variance calculation + * + * Derived from the paper: https://fanf2.user.srcf.net/hermes/doc/antiforgery/stats.pdf + * + * Create a struct and if it's the weighted variant set the w field (weight = 2^k). + * + * Use mean_and_variance[_weighted]_update() on the struct to update it's state. + * + * Use the mean_and_variance[_weighted]_get_* functions to calculate the mean and variance, some computation + * is deferred to these functions for performance reasons. + * + * see lib/math/mean_and_variance_test.c for examples of usage. + * + * DO NOT access the mean and variance fields of the weighted variants directly. + * DO NOT change the weight after calling update. + */ + +#include <linux/bug.h> +#include <linux/compiler.h> +#include <linux/export.h> +#include <linux/limits.h> +#include <linux/math.h> +#include <linux/math64.h> +#include <linux/mean_and_variance.h> +#include <linux/module.h> + +u128_u u128_div(u128_u n, u64 d) +{ + u128_u r; + u64 rem; + u64 hi = u128_hi(n); + u64 lo = u128_lo(n); + u64 h = hi & ((u64) U32_MAX << 32); + u64 l = (hi & (u64) U32_MAX) << 32; + + r = u128_shl(u64_to_u128(div64_u64_rem(h, d, &rem)), 64); + r = u128_add(r, u128_shl(u64_to_u128(div64_u64_rem(l + (rem << 32), d, &rem)), 32)); + r = u128_add(r, u64_to_u128(div64_u64_rem(lo + (rem << 32), d, &rem))); + return r; +} +EXPORT_SYMBOL_GPL(u128_div); + +/** + * mean_and_variance_get_mean() - get mean from @s + * @s: mean and variance number of samples and their sums + */ +s64 mean_and_variance_get_mean(struct mean_and_variance s) +{ + return s.n ? div64_u64(s.sum, s.n) : 0; +} +EXPORT_SYMBOL_GPL(mean_and_variance_get_mean); + +/** + * mean_and_variance_get_variance() - get variance from @s1 + * @s1: mean and variance number of samples and sums + * + * see linked pdf equation 12. + */ +u64 mean_and_variance_get_variance(struct mean_and_variance s1) +{ + if (s1.n) { + u128_u s2 = u128_div(s1.sum_squares, s1.n); + u64 s3 = abs(mean_and_variance_get_mean(s1)); + + return u128_lo(u128_sub(s2, u128_square(s3))); + } else { + return 0; + } +} +EXPORT_SYMBOL_GPL(mean_and_variance_get_variance); + +/** + * mean_and_variance_get_stddev() - get standard deviation from @s + * @s: mean and variance number of samples and their sums + */ +u32 mean_and_variance_get_stddev(struct mean_and_variance s) +{ + return int_sqrt64(mean_and_variance_get_variance(s)); +} +EXPORT_SYMBOL_GPL(mean_and_variance_get_stddev); + +/** + * mean_and_variance_weighted_update() - exponentially weighted variant of mean_and_variance_update() + * @s: mean and variance number of samples and their sums + * @x: new value to include in the &mean_and_variance_weighted + * + * see linked pdf: function derived from equations 140-143 where alpha = 2^w. + * values are stored bitshifted for performance and added precision. + */ +void mean_and_variance_weighted_update(struct mean_and_variance_weighted *s, + s64 x, bool initted, u8 weight) +{ + // previous weighted variance. + u8 w = weight; + u64 var_w0 = s->variance; + // new value weighted. + s64 x_w = x << w; + s64 diff_w = x_w - s->mean; + s64 diff = fast_divpow2(diff_w, w); + // new mean weighted. + s64 u_w1 = s->mean + diff; + + if (!initted) { + s->mean = x_w; + s->variance = 0; + } else { + s->mean = u_w1; + s->variance = ((var_w0 << w) - var_w0 + ((diff_w * (x_w - u_w1)) >> w)) >> w; + } +} +EXPORT_SYMBOL_GPL(mean_and_variance_weighted_update); + +/** + * mean_and_variance_weighted_get_mean() - get mean from @s + * @s: mean and variance number of samples and their sums + */ +s64 mean_and_variance_weighted_get_mean(struct mean_and_variance_weighted s, + u8 weight) +{ + return fast_divpow2(s.mean, weight); +} +EXPORT_SYMBOL_GPL(mean_and_variance_weighted_get_mean); + +/** + * mean_and_variance_weighted_get_variance() -- get variance from @s + * @s: mean and variance number of samples and their sums + */ +u64 mean_and_variance_weighted_get_variance(struct mean_and_variance_weighted s, + u8 weight) +{ + // always positive don't need fast divpow2 + return s.variance >> weight; +} +EXPORT_SYMBOL_GPL(mean_and_variance_weighted_get_variance); + +/** + * mean_and_variance_weighted_get_stddev() - get standard deviation from @s + * @s: mean and variance number of samples and their sums + */ +u32 mean_and_variance_weighted_get_stddev(struct mean_and_variance_weighted s, + u8 weight) +{ + return int_sqrt64(mean_and_variance_weighted_get_variance(s, weight)); +} +EXPORT_SYMBOL_GPL(mean_and_variance_weighted_get_stddev); + +MODULE_AUTHOR("Daniel B. Hill"); +MODULE_LICENSE("GPL"); diff --git a/linux/mempool.c b/linux/mempool.c index 74d4fbb3..74ed17bf 100644 --- a/linux/mempool.c +++ b/linux/mempool.c @@ -522,6 +522,19 @@ void mempool_kfree(void *element, void *pool_data) } EXPORT_SYMBOL(mempool_kfree); +void *mempool_kvmalloc(gfp_t gfp_mask, void *pool_data) +{ + size_t size = (size_t)pool_data; + return kvmalloc(size, gfp_mask); +} +EXPORT_SYMBOL(mempool_kvmalloc); + +void mempool_kvfree(void *element, void *pool_data) +{ + kvfree(element); +} +EXPORT_SYMBOL(mempool_kvfree); + /* * A simple mempool-backed page allocator that allocates pages * of the order specified by pool_data. diff --git a/linux/sort.c b/linux/sort.c new file mode 100644 index 00000000..ffa4817b --- /dev/null +++ b/linux/sort.c @@ -0,0 +1,368 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * A fast, small, non-recursive O(n log n) sort for the Linux kernel + * + * This performs n*log2(n) + 0.37*n + o(n) comparisons on average, + * and 1.5*n*log2(n) + O(n) in the (very contrived) worst case. + * + * Glibc qsort() manages n*log2(n) - 1.26*n for random inputs (1.63*n + * better) at the expense of stack usage and much larger code to avoid + * quicksort's O(n^2) worst case. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/types.h> +#include <linux/export.h> +#include <linux/sort.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); +} + +/** + * parent - given the offset of the child, find the offset of the parent. + * @i: the offset of the heap element whose parent is sought. Non-zero. + * @lsbit: a precomputed 1-bit mask, equal to "size & -size" + * @size: size of each element + * + * In terms of array indexes, the parent of element j = @i/@size is simply + * (j-1)/2. But when working in byte offsets, we can't use implicit + * truncation of integer divides. + * + * Fortunately, we only need one bit of the quotient, not the full divide. + * @size has a least significant bit. That bit will be clear if @i is + * an even multiple of @size, and set if it's an odd multiple. + * + * Logically, we're doing "if (i & lsbit) i -= size;", but since the + * branch is unpredictable, it's done with a bit of clever branch-free + * code instead. + */ +__attribute_const__ __always_inline +static size_t parent(size_t i, unsigned int lsbit, size_t size) +{ + i -= size; + i -= size & -(i & lsbit); + return i / 2; +} + +/** + * sort_r - sort an array of elements + * @base: pointer to data to sort + * @num: number of elements + * @size: size of each element + * @cmp_func: pointer to comparison function + * @swap_func: pointer to swap function or NULL + * @priv: third argument passed to comparison function + * + * This function does a heapsort on the given array. You may provide + * a swap_func function if you need to do something more than a memory + * copy (e.g. fix up pointers or auxiliary data), but the built-in swap + * avoids a slow retpoline and so is significantly faster. + * + * Sorting time is O(n log n) both on average and worst-case. While + * quicksort is slightly faster on average, it suffers from exploitable + * O(n*n) worst-case behavior and extra memory requirements that make + * it less suitable for kernel use. + */ +void sort_r(void *base, size_t num, size_t size, + cmp_r_func_t cmp_func, + swap_r_func_t swap_func, + const void *priv) +{ + /* pre-scale counters for performance */ + size_t n = num * size, a = (num/2) * size; + const unsigned int lsbit = size & -size; /* Used to find parent */ + + if (!a) /* num < 2 || size == 0 */ + return; + + /* 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; + } + + /* + * Loop invariants: + * 1. elements [a,n) satisfy the heap property (compare greater than + * all of their children), + * 2. elements [n,num*size) are sorted, and + * 3. a <= b <= c <= d <= n (whenever they are valid). + */ + for (;;) { + size_t b, c, d; + + if (a) /* Building heap: sift down --a */ + a -= size; + else if (n -= size) /* Sorting: Extract root to --n */ + do_swap(base, base + n, size, swap_func, priv); + else /* Sort complete */ + break; + + /* + * Sift element at "a" down into heap. This is the + * "bottom-up" variant, which significantly reduces + * calls to cmp_func(): we find the sift-down path all + * the way to the leaves (one compare per level), then + * backtrack to find where to insert the target element. + * + * Because elements tend to sift down close to the leaves, + * this uses fewer compares than doing two per level + * on the way down. (A bit more than half as many on + * average, 3/4 worst-case.) + */ + for (b = a; c = 2*b + size, (d = c + size) < n;) + b = do_cmp(base + c, base + d, cmp_func, priv) >= 0 ? c : d; + if (d == n) /* Special case last leaf with no sibling */ + b = c; + + /* Now backtrack from "b" to the correct location for "a" */ + while (b != a && do_cmp(base + a, base + b, cmp_func, priv) >= 0) + b = parent(b, lsbit, size); + c = b; /* Where "a" belongs */ + while (b != a) { /* Shift it into place */ + b = parent(b, lsbit, size); + do_swap(base + b, base + c, size, swap_func, priv); + } + } +} +EXPORT_SYMBOL(sort_r); + +#include <linux/eytzinger.h> + +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); + } + } +} +EXPORT_SYMBOL_GPL(eytzinger0_sort_r); + +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); +} +EXPORT_SYMBOL_GPL(eytzinger0_sort); diff --git a/linux/time_stats.c b/linux/time_stats.c new file mode 100644 index 00000000..0b90c80c --- /dev/null +++ b/linux/time_stats.c @@ -0,0 +1,373 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/eytzinger.h> +#include <linux/jiffies.h> +#include <linux/module.h> +#include <linux/percpu.h> +#include <linux/preempt.h> +#include <linux/time.h> +#include <linux/time_stats.h> +#include <linux/spinlock.h> + +static const struct time_unit time_units[] = { + { "ns", 1 }, + { "us", NSEC_PER_USEC }, + { "ms", NSEC_PER_MSEC }, + { "s", NSEC_PER_SEC }, + { "m", (u64) NSEC_PER_SEC * 60}, + { "h", (u64) NSEC_PER_SEC * 3600}, + { "d", (u64) NSEC_PER_SEC * 3600 * 24}, + { "w", (u64) NSEC_PER_SEC * 3600 * 24 * 7}, + { "y", (u64) NSEC_PER_SEC * ((3600 * 24 * 7 * 365) + (3600 * (24 / 4) * 7))}, /* 365.25d */ + { "eon", U64_MAX }, +}; + +const struct time_unit *pick_time_units(u64 ns) +{ + const struct time_unit *u; + + for (u = time_units; + u + 1 < time_units + ARRAY_SIZE(time_units) && + ns >= u[1].nsecs << 1; + u++) + ; + + return u; +} +EXPORT_SYMBOL_GPL(pick_time_units); + +static void quantiles_update(struct quantiles *q, u64 v) +{ + unsigned i = 0; + + while (i < ARRAY_SIZE(q->entries)) { + struct quantile_entry *e = q->entries + i; + + if (unlikely(!e->step)) { + e->m = v; + e->step = max_t(unsigned, v / 2, 1024); + } else if (e->m > v) { + e->m = e->m >= e->step + ? e->m - e->step + : 0; + } else if (e->m < v) { + e->m = e->m + e->step > e->m + ? e->m + e->step + : U32_MAX; + } + + if ((e->m > v ? e->m - v : v - e->m) < e->step) + e->step = max_t(unsigned, e->step / 2, 1); + + if (v >= e->m) + break; + + i = eytzinger0_child(i, v > e->m); + } +} + +static inline void time_stats_update_one(struct time_stats *stats, + u64 start, u64 end) +{ + u64 duration, freq; + bool initted = stats->last_event != 0; + + if (time_after64(end, start)) { + struct quantiles *quantiles = time_stats_to_quantiles(stats); + + duration = end - start; + mean_and_variance_update(&stats->duration_stats, duration); + mean_and_variance_weighted_update(&stats->duration_stats_weighted, + duration, initted, TIME_STATS_MV_WEIGHT); + stats->max_duration = max(stats->max_duration, duration); + stats->min_duration = min(stats->min_duration, duration); + stats->total_duration += duration; + + if (quantiles) + quantiles_update(quantiles, duration); + } + + if (stats->last_event && time_after64(end, stats->last_event)) { + freq = end - stats->last_event; + mean_and_variance_update(&stats->freq_stats, freq); + mean_and_variance_weighted_update(&stats->freq_stats_weighted, + freq, initted, TIME_STATS_MV_WEIGHT); + stats->max_freq = max(stats->max_freq, freq); + stats->min_freq = min(stats->min_freq, freq); + } + + stats->last_event = end; +} + +void __time_stats_clear_buffer(struct time_stats *stats, + struct time_stat_buffer *b) +{ + for (struct time_stat_buffer_entry *i = b->entries; + i < b->entries + ARRAY_SIZE(b->entries); + i++) + time_stats_update_one(stats, i->start, i->end); + b->nr = 0; +} +EXPORT_SYMBOL_GPL(__time_stats_clear_buffer); + +static noinline void time_stats_clear_buffer(struct time_stats *stats, + struct time_stat_buffer *b) +{ + unsigned long flags; + + spin_lock_irqsave(&stats->lock, flags); + __time_stats_clear_buffer(stats, b); + spin_unlock_irqrestore(&stats->lock, flags); +} + +void __time_stats_update(struct time_stats *stats, u64 start, u64 end) +{ + unsigned long flags; + + if (!stats->buffer) { + spin_lock_irqsave(&stats->lock, flags); + time_stats_update_one(stats, start, end); + + if (mean_and_variance_weighted_get_mean(stats->freq_stats_weighted, TIME_STATS_MV_WEIGHT) < 32 && + stats->duration_stats.n > 1024) + stats->buffer = + alloc_percpu_gfp(struct time_stat_buffer, + GFP_ATOMIC); + spin_unlock_irqrestore(&stats->lock, flags); + } else { + struct time_stat_buffer *b; + + preempt_disable(); + b = this_cpu_ptr(stats->buffer); + + BUG_ON(b->nr >= ARRAY_SIZE(b->entries)); + b->entries[b->nr++] = (struct time_stat_buffer_entry) { + .start = start, + .end = end + }; + + if (unlikely(b->nr == ARRAY_SIZE(b->entries))) + time_stats_clear_buffer(stats, b); + preempt_enable(); + } +} +EXPORT_SYMBOL_GPL(__time_stats_update); + +#include <linux/seq_buf.h> + +static void seq_buf_time_units_aligned(struct seq_buf *out, u64 ns) +{ + const struct time_unit *u = pick_time_units(ns); + + seq_buf_printf(out, "%8llu %s", div64_u64(ns, u->nsecs), u->name); +} + +static inline u64 time_stats_lifetime(const struct time_stats *stats) +{ + return local_clock() - stats->start_time; +} + +void time_stats_to_seq_buf(struct seq_buf *out, struct time_stats *stats, + const char *epoch_name, unsigned int flags) +{ + struct quantiles *quantiles = time_stats_to_quantiles(stats); + s64 f_mean = 0, d_mean = 0; + u64 f_stddev = 0, d_stddev = 0; + u64 lifetime = time_stats_lifetime(stats); + + if (stats->buffer) { + int cpu; + + spin_lock_irq(&stats->lock); + for_each_possible_cpu(cpu) + __time_stats_clear_buffer(stats, per_cpu_ptr(stats->buffer, cpu)); + spin_unlock_irq(&stats->lock); + } + + if (stats->freq_stats.n) { + /* avoid divide by zero */ + f_mean = mean_and_variance_get_mean(stats->freq_stats); + f_stddev = mean_and_variance_get_stddev(stats->freq_stats); + d_mean = mean_and_variance_get_mean(stats->duration_stats); + d_stddev = mean_and_variance_get_stddev(stats->duration_stats); + } else if (flags & TIME_STATS_PRINT_NO_ZEROES) { + /* unless we didn't want zeroes anyway */ + return; + } + + seq_buf_printf(out, "count: %llu\n", stats->duration_stats.n); + seq_buf_printf(out, "lifetime: "); + seq_buf_time_units_aligned(out, lifetime); + seq_buf_printf(out, "\n"); + + seq_buf_printf(out, " since %-12s recent\n", epoch_name); + + seq_buf_printf(out, "duration of events\n"); + + seq_buf_printf(out, " min: "); + seq_buf_time_units_aligned(out, stats->min_duration); + seq_buf_printf(out, "\n"); + + seq_buf_printf(out, " max: "); + seq_buf_time_units_aligned(out, stats->max_duration); + seq_buf_printf(out, "\n"); + + seq_buf_printf(out, " total: "); + seq_buf_time_units_aligned(out, stats->total_duration); + seq_buf_printf(out, "\n"); + + seq_buf_printf(out, " mean: "); + seq_buf_time_units_aligned(out, d_mean); + seq_buf_time_units_aligned(out, mean_and_variance_weighted_get_mean(stats->duration_stats_weighted, TIME_STATS_MV_WEIGHT)); + seq_buf_printf(out, "\n"); + + seq_buf_printf(out, " stddev: "); + seq_buf_time_units_aligned(out, d_stddev); + seq_buf_time_units_aligned(out, mean_and_variance_weighted_get_stddev(stats->duration_stats_weighted, TIME_STATS_MV_WEIGHT)); + seq_buf_printf(out, "\n"); + + seq_buf_printf(out, "time between events\n"); + + seq_buf_printf(out, " min: "); + seq_buf_time_units_aligned(out, stats->min_freq); + seq_buf_printf(out, "\n"); + + seq_buf_printf(out, " max: "); + seq_buf_time_units_aligned(out, stats->max_freq); + seq_buf_printf(out, "\n"); + + seq_buf_printf(out, " mean: "); + seq_buf_time_units_aligned(out, f_mean); + seq_buf_time_units_aligned(out, mean_and_variance_weighted_get_mean(stats->freq_stats_weighted, TIME_STATS_MV_WEIGHT)); + seq_buf_printf(out, "\n"); + + seq_buf_printf(out, " stddev: "); + seq_buf_time_units_aligned(out, f_stddev); + seq_buf_time_units_aligned(out, mean_and_variance_weighted_get_stddev(stats->freq_stats_weighted, TIME_STATS_MV_WEIGHT)); + seq_buf_printf(out, "\n"); + + if (quantiles) { + int i = eytzinger0_first(NR_QUANTILES); + const struct time_unit *u = + pick_time_units(quantiles->entries[i].m); + u64 last_q = 0; + + seq_buf_printf(out, "quantiles (%s):\t", u->name); + eytzinger0_for_each(i, NR_QUANTILES) { + bool is_last = eytzinger0_next(i, NR_QUANTILES) == -1; + + u64 q = max(quantiles->entries[i].m, last_q); + seq_buf_printf(out, "%llu ", div_u64(q, u->nsecs)); + if (is_last) + seq_buf_printf(out, "\n"); + last_q = q; + } + } +} +EXPORT_SYMBOL_GPL(time_stats_to_seq_buf); + +void time_stats_to_json(struct seq_buf *out, struct time_stats *stats, + const char *epoch_name, unsigned int flags) +{ + struct quantiles *quantiles = time_stats_to_quantiles(stats); + s64 f_mean = 0, d_mean = 0; + u64 f_stddev = 0, d_stddev = 0; + + if (stats->buffer) { + int cpu; + + spin_lock_irq(&stats->lock); + for_each_possible_cpu(cpu) + __time_stats_clear_buffer(stats, per_cpu_ptr(stats->buffer, cpu)); + spin_unlock_irq(&stats->lock); + } + + if (stats->freq_stats.n) { + /* avoid divide by zero */ + f_mean = mean_and_variance_get_mean(stats->freq_stats); + f_stddev = mean_and_variance_get_stddev(stats->freq_stats); + d_mean = mean_and_variance_get_mean(stats->duration_stats); + d_stddev = mean_and_variance_get_stddev(stats->duration_stats); + } else if (flags & TIME_STATS_PRINT_NO_ZEROES) { + /* unless we didn't want zeroes anyway */ + return; + } + + seq_buf_printf(out, "{\n"); + seq_buf_printf(out, " \"epoch\": \"%s\",\n", epoch_name); + seq_buf_printf(out, " \"count\": %llu,\n", stats->duration_stats.n); + + seq_buf_printf(out, " \"duration_ns\": {\n"); + seq_buf_printf(out, " \"min\": %llu,\n", stats->min_duration); + seq_buf_printf(out, " \"max\": %llu,\n", stats->max_duration); + seq_buf_printf(out, " \"total\": %llu,\n", stats->total_duration); + seq_buf_printf(out, " \"mean\": %llu,\n", d_mean); + seq_buf_printf(out, " \"stddev\": %llu\n", d_stddev); + seq_buf_printf(out, " },\n"); + + d_mean = mean_and_variance_weighted_get_mean(stats->duration_stats_weighted, TIME_STATS_MV_WEIGHT); + d_stddev = mean_and_variance_weighted_get_stddev(stats->duration_stats_weighted, TIME_STATS_MV_WEIGHT); + + seq_buf_printf(out, " \"duration_ewma_ns\": {\n"); + seq_buf_printf(out, " \"mean\": %llu,\n", d_mean); + seq_buf_printf(out, " \"stddev\": %llu\n", d_stddev); + seq_buf_printf(out, " },\n"); + + seq_buf_printf(out, " \"frequency_ns\": {\n"); + seq_buf_printf(out, " \"min\": %llu,\n", stats->min_freq); + seq_buf_printf(out, " \"max\": %llu,\n", stats->max_freq); + seq_buf_printf(out, " \"mean\": %llu,\n", f_mean); + seq_buf_printf(out, " \"stddev\": %llu\n", f_stddev); + seq_buf_printf(out, " },\n"); + + f_mean = mean_and_variance_weighted_get_mean(stats->freq_stats_weighted, TIME_STATS_MV_WEIGHT); + f_stddev = mean_and_variance_weighted_get_stddev(stats->freq_stats_weighted, TIME_STATS_MV_WEIGHT); + + seq_buf_printf(out, " \"frequency_ewma_ns\": {\n"); + seq_buf_printf(out, " \"mean\": %llu,\n", f_mean); + seq_buf_printf(out, " \"stddev\": %llu\n", f_stddev); + + if (quantiles) { + u64 last_q = 0; + + /* close frequency_ewma_ns but signal more items */ + seq_buf_printf(out, " },\n"); + + seq_buf_printf(out, " \"quantiles_ns\": [\n"); + eytzinger0_for_each(i, NR_QUANTILES) { + bool is_last = eytzinger0_next(i, NR_QUANTILES) == -1; + + u64 q = max(quantiles->entries[i].m, last_q); + seq_buf_printf(out, " %llu", q); + if (!is_last) + seq_buf_printf(out, ", "); + last_q = q; + } + seq_buf_printf(out, " ]\n"); + } else { + /* close frequency_ewma_ns without dumping further */ + seq_buf_printf(out, " }\n"); + } + + seq_buf_printf(out, "}\n"); +} +EXPORT_SYMBOL_GPL(time_stats_to_json); + +void time_stats_exit(struct time_stats *stats) +{ + free_percpu(stats->buffer); +} +EXPORT_SYMBOL_GPL(time_stats_exit); + +void time_stats_init(struct time_stats *stats) +{ + memset(stats, 0, sizeof(*stats)); + stats->min_duration = U64_MAX; + stats->min_freq = U64_MAX; + stats->start_time = local_clock(); + spin_lock_init(&stats->lock); +} +EXPORT_SYMBOL_GPL(time_stats_init); + +MODULE_AUTHOR("Kent Overstreet"); +MODULE_LICENSE("GPL"); |