* [PATCH 0/3] tools/accounting: refactor delay fields and share format_timespec()
@ 2026-07-11 9:31 wang.yaxin
2026-07-11 9:32 ` [PATCH 1/3] delaytop: refactor repetitive delay fields into array with enum wang.yaxin
` (3 more replies)
0 siblings, 4 replies; 6+ messages in thread
From: wang.yaxin @ 2026-07-11 9:31 UTC (permalink / raw)
To: akpm, fan.yu9, yang.yang29
Cc: corbet, linux-kernel, linux-doc, xu.xin16, wang.yaxin
From: Wang Yaxin <wang.yaxin@zte.com.cn>
- Convert per-field delay members in struct task_info to an array indexed
by enum delay_type, eliminating offsetof() pointer arithmetic.
- Factor out a common format_timespec() implementation shared by getdelays
and delaytop, using strftime for cleaner timestamp formatting.
- Replace the complex sizeof/ULL/shift Y2038 guard with a direct narrowing
truncation check ((long long)time_sec != ts->tv_sec).
Wang Yaxin (3):
delaytop: refactor repetitive delay fields into array with enum
tools/accounting: factor out shared format_timespec() implementation
tools/accounting: simplify 32-bit time_t overflow check in
format_timespec()
tools/accounting/Makefile | 12 +-
tools/accounting/delaytop.c | 261 +++++++++-----------------
tools/accounting/format_timespec.c | 37 ++++
tools/accounting/format_timespec.h | 9 +
tools/accounting/getdelays.c | 32 +---
tools/include/uapi/linux/time_types.h | 18 ++
6 files changed, 169 insertions(+), 200 deletions(-)
create mode 100644 tools/accounting/format_timespec.c
create mode 100644 tools/accounting/format_timespec.h
create mode 100644 tools/include/uapi/linux/time_types.h
--
2.27.0
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 1/3] delaytop: refactor repetitive delay fields into array with enum
2026-07-11 9:31 [PATCH 0/3] tools/accounting: refactor delay fields and share format_timespec() wang.yaxin
@ 2026-07-11 9:32 ` wang.yaxin
2026-07-14 3:07 ` xu.xin16
2026-07-11 9:33 ` [PATCH 2/3] tools/accounting: factor out shared format_timespec() implementation wang.yaxin
` (2 subsequent siblings)
3 siblings, 1 reply; 6+ messages in thread
From: wang.yaxin @ 2026-07-11 9:32 UTC (permalink / raw)
To: wang.yaxin
Cc: akpm, fan.yu9, yang.yang29, corbet, linux-kernel, linux-doc, xu.xin16
From: Wang Yaxin <wang.yaxin@zte.com.cn>
Replace the 9 groups of (count, delay_total, delay_max, delay_max_ts)
named fields in struct task_info with a struct delay_metrics array
indexed by enum delay_type. This eliminates all unsafe pointer
arithmetic via offsetof() from compare_tasks(),
field_delay_max_and_ts(), and get_field_delay_values().
The struct field_desc now stores an enum delay_type index instead of
four separate unsigned long offset values.
Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
---
tools/accounting/delaytop.c | 220 +++++++++++++++---------------------
1 file changed, 88 insertions(+), 132 deletions(-)
diff --git a/tools/accounting/delaytop.c b/tools/accounting/delaytop.c
index 1c40bb477320..f1d26ff98792 100644
--- a/tools/accounting/delaytop.c
+++ b/tools/accounting/delaytop.c
@@ -61,31 +61,51 @@
#define MAX_MSG_SIZE 1024
#define MAX_TASKS 1000
#define MAX_BUF_LEN 256
-#define SET_TASK_STAT(task_count, field) tasks[task_count].field = stats.field
#define BOOL_FPRINT(stream, fmt, ...) \
({ \
int ret = fprintf(stream, fmt, ##__VA_ARGS__); \
ret >= 0; \
})
-#define TASK_AVG(task, field) average_ms((task).field##_delay_total, (task).field##_count)
+#define TASK_AVG(task, type) \
+ average_ms((task).delays[DELAY_##type].delay_total, \
+ (task).delays[DELAY_##type].count)
#define PSI_LINE_FORMAT "%-12s %6.1f%%/%6.1f%%/%6.1f%%/%8llu(ms)\n"
#define DELAY_FMT_DEFAULT "%8.2f %8.2f %8.2f %8.2f\n"
#define DELAY_FMT_MEMVERBOSE "%8.2f %8.2f %8.2f %8.2f %8.2f %8.2f\n"
-#define SORT_FIELD(name, cmd, modes) \
- {#name, #cmd, \
- offsetof(struct task_info, name##_delay_total), \
- offsetof(struct task_info, name##_count), \
- offsetof(struct task_info, name##_delay_max), \
- offsetof(struct task_info, name##_delay_max_ts), \
- modes}
-#define SORT_FIELD_NO_MAX(name, cmd, modes) \
- {#name, #cmd, \
- offsetof(struct task_info, name##_delay_total), \
- offsetof(struct task_info, name##_count), \
- 0, \
- 0, \
- modes}
-#define END_FIELD {NULL, 0, 0, 0, 0, 0, 0}
+#define COPY_DELAY(task_idx, type, stats_prefix) \
+ do { \
+ tasks[task_idx].delays[DELAY_##type].count = \
+ stats.stats_prefix##_count; \
+ tasks[task_idx].delays[DELAY_##type].delay_total = \
+ stats.stats_prefix##_delay_total; \
+ tasks[task_idx].delays[DELAY_##type].delay_max = \
+ stats.stats_prefix##_delay_max; \
+ tasks[task_idx].delays[DELAY_##type].delay_max_ts = \
+ stats.stats_prefix##_delay_max_ts; \
+ } while (0)
+#define SORT_FIELD(name, cmd, type, modes, has_max) \
+ {#name, #cmd, type, modes, has_max}
+#define END_FIELD {NULL, 0, 0, 0, false}
+
+enum delay_type {
+ DELAY_CPU,
+ DELAY_BLKIO,
+ DELAY_SWAPIN,
+ DELAY_FREEPAGES,
+ DELAY_THRASHING,
+ DELAY_COMPACT,
+ DELAY_WPCOPY,
+ DELAY_IRQ,
+ DELAY_MEM,
+ NUM_DELAY_TYPES
+};
+
+struct delay_metrics {
+ unsigned long long count;
+ unsigned long long delay_total;
+ unsigned long long delay_max;
+ struct __kernel_timespec delay_max_ts;
+};
/* Display mode types */
#define MODE_TYPE_ALL (0xFFFFFFFF)
@@ -116,40 +136,7 @@ struct task_info {
int pid;
int tgid;
char command[TASK_COMM_LEN];
- unsigned long long cpu_count;
- unsigned long long cpu_delay_total;
- unsigned long long cpu_delay_max;
- struct __kernel_timespec cpu_delay_max_ts;
- unsigned long long blkio_count;
- unsigned long long blkio_delay_total;
- unsigned long long blkio_delay_max;
- struct __kernel_timespec blkio_delay_max_ts;
- unsigned long long swapin_count;
- unsigned long long swapin_delay_total;
- unsigned long long swapin_delay_max;
- struct __kernel_timespec swapin_delay_max_ts;
- unsigned long long freepages_count;
- unsigned long long freepages_delay_total;
- unsigned long long freepages_delay_max;
- struct __kernel_timespec freepages_delay_max_ts;
- unsigned long long thrashing_count;
- unsigned long long thrashing_delay_total;
- unsigned long long thrashing_delay_max;
- struct __kernel_timespec thrashing_delay_max_ts;
- unsigned long long compact_count;
- unsigned long long compact_delay_total;
- unsigned long long compact_delay_max;
- struct __kernel_timespec compact_delay_max_ts;
- unsigned long long wpcopy_count;
- unsigned long long wpcopy_delay_total;
- unsigned long long wpcopy_delay_max;
- struct __kernel_timespec wpcopy_delay_max_ts;
- unsigned long long irq_count;
- unsigned long long irq_delay_total;
- unsigned long long irq_delay_max;
- struct __kernel_timespec irq_delay_max_ts;
- unsigned long long mem_count;
- unsigned long long mem_delay_total;
+ struct delay_metrics delays[NUM_DELAY_TYPES];
};
/* Container statistics structure */
@@ -165,11 +152,9 @@ struct container_stats {
struct field_desc {
const char *name; /* Field name for cmdline argument */
const char *cmd_char; /* Interactive command */
- unsigned long total_offset; /* Offset of total delay in task_info */
- unsigned long count_offset; /* Offset of count in task_info */
- unsigned long max_offset; /* Offset of max delay in task_info */
- unsigned long max_ts_offset; /* Offset of max delay timestamp in task_info */
+ enum delay_type type; /* Index into task_info.delays[] */
size_t supported_modes; /* Supported display modes */
+ bool has_max; /* Whether this field has max/ts */
};
/* Program settings structure */
@@ -193,15 +178,15 @@ static int task_count;
static int running = 1;
static struct container_stats container_stats;
static const struct field_desc sort_fields[] = {
- SORT_FIELD(cpu, c, MODE_DEFAULT | MODE_TYPE),
- SORT_FIELD(blkio, i, MODE_DEFAULT | MODE_TYPE),
- SORT_FIELD(irq, q, MODE_DEFAULT | MODE_TYPE),
- SORT_FIELD_NO_MAX(mem, m, MODE_DEFAULT | MODE_MEMVERBOSE),
- SORT_FIELD(swapin, s, MODE_MEMVERBOSE | MODE_TYPE),
- SORT_FIELD(freepages, r, MODE_MEMVERBOSE | MODE_TYPE),
- SORT_FIELD(thrashing, t, MODE_MEMVERBOSE | MODE_TYPE),
- SORT_FIELD(compact, p, MODE_MEMVERBOSE | MODE_TYPE),
- SORT_FIELD(wpcopy, w, MODE_MEMVERBOSE | MODE_TYPE),
+ SORT_FIELD(cpu, c, DELAY_CPU, MODE_DEFAULT | MODE_TYPE, true),
+ SORT_FIELD(blkio, i, DELAY_BLKIO, MODE_DEFAULT | MODE_TYPE, true),
+ SORT_FIELD(irq, q, DELAY_IRQ, MODE_DEFAULT | MODE_TYPE, true),
+ SORT_FIELD(mem, m, DELAY_MEM, MODE_DEFAULT | MODE_MEMVERBOSE, false),
+ SORT_FIELD(swapin, s, DELAY_SWAPIN, MODE_MEMVERBOSE | MODE_TYPE, true),
+ SORT_FIELD(freepages, r, DELAY_FREEPAGES, MODE_MEMVERBOSE | MODE_TYPE, true),
+ SORT_FIELD(thrashing, t, DELAY_THRASHING, MODE_MEMVERBOSE | MODE_TYPE, true),
+ SORT_FIELD(compact, p, DELAY_COMPACT, MODE_MEMVERBOSE | MODE_TYPE, true),
+ SORT_FIELD(wpcopy, w, DELAY_WPCOPY, MODE_MEMVERBOSE | MODE_TYPE, true),
END_FIELD
};
static int sort_selected;
@@ -433,20 +418,20 @@ static void parse_args(int argc, char **argv)
/* Calculate average delay in milliseconds for overall memory */
static void set_mem_delay_total(struct task_info *t)
{
- t->mem_delay_total = t->swapin_delay_total +
- t->freepages_delay_total +
- t->thrashing_delay_total +
- t->compact_delay_total +
- t->wpcopy_delay_total;
+ t->delays[DELAY_MEM].delay_total = t->delays[DELAY_SWAPIN].delay_total +
+ t->delays[DELAY_FREEPAGES].delay_total +
+ t->delays[DELAY_THRASHING].delay_total +
+ t->delays[DELAY_COMPACT].delay_total +
+ t->delays[DELAY_WPCOPY].delay_total;
}
static void set_mem_count(struct task_info *t)
{
- t->mem_count = t->swapin_count +
- t->freepages_count +
- t->thrashing_count +
- t->compact_count +
- t->wpcopy_count;
+ t->delays[DELAY_MEM].count = t->delays[DELAY_SWAPIN].count +
+ t->delays[DELAY_FREEPAGES].count +
+ t->delays[DELAY_THRASHING].count +
+ t->delays[DELAY_COMPACT].count +
+ t->delays[DELAY_WPCOPY].count;
}
/* Create a raw netlink socket and bind */
@@ -758,38 +743,14 @@ static void fetch_and_fill_task_info(int pid, const char *comm)
strncpy(tasks[task_count].command, comm,
TASK_COMM_LEN - 1);
tasks[task_count].command[TASK_COMM_LEN - 1] = '\0';
- SET_TASK_STAT(task_count, cpu_count);
- SET_TASK_STAT(task_count, cpu_delay_total);
- SET_TASK_STAT(task_count, cpu_delay_max);
- SET_TASK_STAT(task_count, cpu_delay_max_ts);
- SET_TASK_STAT(task_count, blkio_count);
- SET_TASK_STAT(task_count, blkio_delay_total);
- SET_TASK_STAT(task_count, blkio_delay_max);
- SET_TASK_STAT(task_count, blkio_delay_max_ts);
- SET_TASK_STAT(task_count, swapin_count);
- SET_TASK_STAT(task_count, swapin_delay_total);
- SET_TASK_STAT(task_count, swapin_delay_max);
- SET_TASK_STAT(task_count, swapin_delay_max_ts);
- SET_TASK_STAT(task_count, freepages_count);
- SET_TASK_STAT(task_count, freepages_delay_total);
- SET_TASK_STAT(task_count, freepages_delay_max);
- SET_TASK_STAT(task_count, freepages_delay_max_ts);
- SET_TASK_STAT(task_count, thrashing_count);
- SET_TASK_STAT(task_count, thrashing_delay_total);
- SET_TASK_STAT(task_count, thrashing_delay_max);
- SET_TASK_STAT(task_count, thrashing_delay_max_ts);
- SET_TASK_STAT(task_count, compact_count);
- SET_TASK_STAT(task_count, compact_delay_total);
- SET_TASK_STAT(task_count, compact_delay_max);
- SET_TASK_STAT(task_count, compact_delay_max_ts);
- SET_TASK_STAT(task_count, wpcopy_count);
- SET_TASK_STAT(task_count, wpcopy_delay_total);
- SET_TASK_STAT(task_count, wpcopy_delay_max);
- SET_TASK_STAT(task_count, wpcopy_delay_max_ts);
- SET_TASK_STAT(task_count, irq_count);
- SET_TASK_STAT(task_count, irq_delay_total);
- SET_TASK_STAT(task_count, irq_delay_max);
- SET_TASK_STAT(task_count, irq_delay_max_ts);
+ COPY_DELAY(task_count, CPU, cpu);
+ COPY_DELAY(task_count, BLKIO, blkio);
+ COPY_DELAY(task_count, SWAPIN, swapin);
+ COPY_DELAY(task_count, FREEPAGES, freepages);
+ COPY_DELAY(task_count, THRASHING, thrashing);
+ COPY_DELAY(task_count, COMPACT, compact);
+ COPY_DELAY(task_count, WPCOPY, wpcopy);
+ COPY_DELAY(task_count, IRQ, irq);
set_mem_count(&tasks[task_count]);
set_mem_delay_total(&tasks[task_count]);
task_count++;
@@ -912,10 +873,10 @@ static int compare_tasks(const void *a, const void *b)
return 0;
}
- total1 = *(unsigned long long *)((char *)t1 + cfg.sort_field->total_offset);
- total2 = *(unsigned long long *)((char *)t2 + cfg.sort_field->total_offset);
- count1 = *(unsigned long long *)((char *)t1 + cfg.sort_field->count_offset);
- count2 = *(unsigned long long *)((char *)t2 + cfg.sort_field->count_offset);
+ total1 = t1->delays[cfg.sort_field->type].delay_total;
+ total2 = t2->delays[cfg.sort_field->type].delay_total;
+ count1 = t1->delays[cfg.sort_field->type].count;
+ count2 = t2->delays[cfg.sort_field->type].count;
avg1 = average_ms(total1, count1);
avg2 = average_ms(total2, count2);
@@ -929,22 +890,17 @@ static int compare_tasks(const void *a, const void *b)
static void field_delay_max_and_ts(const struct task_info *task, const struct field_desc *field,
unsigned long long *max_ns, struct __kernel_timespec *max_ts)
{
- if (!field || !field->max_offset) {
+ if (!field || !field->has_max) {
*max_ns = 0;
if (max_ts)
memset(max_ts, 0, sizeof(*max_ts));
return;
}
- *max_ns = *(unsigned long long *)((char *)task + field->max_offset);
+ *max_ns = task->delays[field->type].delay_max;
- if (max_ts) {
- if (field->max_ts_offset)
- *max_ts = *(struct __kernel_timespec *)((char *)task +
- field->max_ts_offset);
- else
- memset(max_ts, 0, sizeof(*max_ts));
- }
+ if (max_ts)
+ *max_ts = task->delays[field->type].delay_max_ts;
}
/* Get delay values for a specific field */
@@ -954,15 +910,15 @@ static void get_field_delay_values(const struct task_info *task, const struct fi
{
unsigned long long total, count, max;
- if (!field || !field->max_offset) {
+ if (!field) {
*avg_ms = 0;
*max_ms = 0;
memset(max_ts, 0, sizeof(*max_ts));
return;
}
- total = *(unsigned long long *)((char *)task + field->total_offset);
- count = *(unsigned long long *)((char *)task + field->count_offset);
+ total = task->delays[field->type].delay_total;
+ count = task->delays[field->type].count;
*avg_ms = average_ms(total, count);
field_delay_max_and_ts(task, field, &max, max_ts);
@@ -1180,18 +1136,18 @@ static void display_results(int psi_ret)
avg_ms, max_ms, format_kernel_timespec(&max_ts));
} else if (cfg.display_mode == MODE_MEMVERBOSE) {
suc &= BOOL_FPRINT(out, DELAY_FMT_MEMVERBOSE,
- TASK_AVG(tasks[i], mem),
- TASK_AVG(tasks[i], swapin),
- TASK_AVG(tasks[i], freepages),
- TASK_AVG(tasks[i], thrashing),
- TASK_AVG(tasks[i], compact),
- TASK_AVG(tasks[i], wpcopy));
+ TASK_AVG(tasks[i], MEM),
+ TASK_AVG(tasks[i], SWAPIN),
+ TASK_AVG(tasks[i], FREEPAGES),
+ TASK_AVG(tasks[i], THRASHING),
+ TASK_AVG(tasks[i], COMPACT),
+ TASK_AVG(tasks[i], WPCOPY));
} else {
suc &= BOOL_FPRINT(out, DELAY_FMT_DEFAULT,
- TASK_AVG(tasks[i], cpu),
- TASK_AVG(tasks[i], blkio),
- TASK_AVG(tasks[i], irq),
- TASK_AVG(tasks[i], mem));
+ TASK_AVG(tasks[i], CPU),
+ TASK_AVG(tasks[i], BLKIO),
+ TASK_AVG(tasks[i], IRQ),
+ TASK_AVG(tasks[i], MEM));
}
}
--
2.27.0
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 2/3] tools/accounting: factor out shared format_timespec() implementation
2026-07-11 9:31 [PATCH 0/3] tools/accounting: refactor delay fields and share format_timespec() wang.yaxin
2026-07-11 9:32 ` [PATCH 1/3] delaytop: refactor repetitive delay fields into array with enum wang.yaxin
@ 2026-07-11 9:33 ` wang.yaxin
2026-07-11 9:34 ` [PATCH 3/3] tools/accounting: simplify 32-bit time_t overflow check in format_timespec() wang.yaxin
2026-07-14 2:48 ` [PATCH 0/3] tools/accounting: refactor delay fields and share format_timespec() Andrew Morton
3 siblings, 0 replies; 6+ messages in thread
From: wang.yaxin @ 2026-07-11 9:33 UTC (permalink / raw)
To: wang.yaxin
Cc: akpm, fan.yu9, yang.yang29, corbet, linux-kernel, linux-doc, xu.xin16
From: Wang Yaxin <wang.yaxin@zte.com.cn>
The same __kernel_timespec formatting logic existed independently in
both getdelays.c and delaytop.c with minor differences (strftime vs
snprintf, __kernel_time64_t vs time_t).
Create a shared format_timespec.c/h with a canonical implementation
(strftime + time_t), remove the static copies from both files, and
link both programs against the common object.
Also simplify the Makefile with a pattern rule for %.o and a static
pattern rule for the two programs that need format_timespec.o.
Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
---
tools/accounting/Makefile | 12 ++++++++-
tools/accounting/delaytop.c | 39 +++------------------------
tools/accounting/format_timespec.c | 39 +++++++++++++++++++++++++++
tools/accounting/format_timespec.h | 9 +++++++
tools/accounting/getdelays.c | 32 ++--------------------
tools/include/uapi/linux/time_types.h | 18 +++++++++++++
6 files changed, 82 insertions(+), 67 deletions(-)
create mode 100644 tools/accounting/format_timespec.c
create mode 100644 tools/accounting/format_timespec.h
create mode 100644 tools/include/uapi/linux/time_types.h
diff --git a/tools/accounting/Makefile b/tools/accounting/Makefile
index 007c0bb8cbbb..22e690c853a5 100644
--- a/tools/accounting/Makefile
+++ b/tools/accounting/Makefile
@@ -3,8 +3,18 @@ CC := $(CROSS_COMPILE)gcc
CFLAGS := -I../include/uapi/
PROGS := getdelays procacct delaytop
+OBJS := format_timespec.o
all: $(PROGS)
+getdelays delaytop: %: %.o $(OBJS)
+ $(CC) $(CFLAGS) -o $@ $^
+
+procacct: procacct.o
+ $(CC) $(CFLAGS) -o $@ $^
+
+%.o: %.c
+ $(CC) $(CFLAGS) -c -o $@ $<
+
clean:
- rm -fr $(PROGS)
+ rm -fr $(PROGS) *.o
diff --git a/tools/accounting/delaytop.c b/tools/accounting/delaytop.c
index f1d26ff98792..1144ca325447 100644
--- a/tools/accounting/delaytop.c
+++ b/tools/accounting/delaytop.c
@@ -44,6 +44,8 @@
#include <linux/cgroupstats.h>
#include <stddef.h>
+#include "format_timespec.h"
+
#define PSI_PATH "/proc/pressure"
#define PSI_CPU_PATH "/proc/pressure/cpu"
#define PSI_MEMORY_PATH "/proc/pressure/memory"
@@ -817,41 +819,6 @@ static double average_ms(unsigned long long total, unsigned long long count)
return (double)total / 1000000.0 / count;
}
-/*
- * Format __kernel_timespec to human readable string (YYYY-MM-DDTHH:MM:SS)
- * Returns formatted string or "N/A" if timestamp is zero
- */
-static const char *format_kernel_timespec(struct __kernel_timespec *ts)
-{
- static char buffer[32];
- time_t time_sec;
- struct tm tm_info;
-
- /* Check if timestamp is zero (not set) */
- if (ts->tv_sec == 0 && ts->tv_nsec == 0)
- return "N/A";
-
- /* Avoid Y2038 truncation: check if timestamp fits in time_t on 32-bit platforms */
- if (sizeof(time_t) < sizeof(ts->tv_sec) &&
- ts->tv_sec > (__u64)((1ULL << (sizeof(time_t) * 8 - 1)) - 1))
- return "N/A";
-
- time_sec = (time_t)ts->tv_sec;
-
- if (localtime_r(&time_sec, &tm_info) == NULL)
- return "N/A";
-
- snprintf(buffer, sizeof(buffer), "%04d-%02d-%02dT%02d:%02d:%02d",
- tm_info.tm_year + 1900,
- tm_info.tm_mon + 1,
- tm_info.tm_mday,
- tm_info.tm_hour,
- tm_info.tm_min,
- tm_info.tm_sec);
-
- return buffer;
-}
-
/* Comparison function for sorting tasks */
static int compare_tasks(const void *a, const void *b)
{
@@ -1133,7 +1100,7 @@ static void display_results(int psi_ret)
&max_ms, &max_ts);
suc &= BOOL_FPRINT(out, "%12.2f %12.2f %20s\n",
- avg_ms, max_ms, format_kernel_timespec(&max_ts));
+ avg_ms, max_ms, format_timespec(&max_ts));
} else if (cfg.display_mode == MODE_MEMVERBOSE) {
suc &= BOOL_FPRINT(out, DELAY_FMT_MEMVERBOSE,
TASK_AVG(tasks[i], MEM),
diff --git a/tools/accounting/format_timespec.c b/tools/accounting/format_timespec.c
new file mode 100644
index 000000000000..1dba50cac895
--- /dev/null
+++ b/tools/accounting/format_timespec.c
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Shared __kernel_timespec formatting for tools/accounting/
+ *
+ * Formats a __kernel_timespec to an ISO 8601 timestamp string
+ * (YYYY-MM-DDTHH:MM:SS). Returns "N/A" if the timestamp is zero
+ * or does not fit in time_t.
+ */
+#include <time.h>
+#include <linux/time_types.h>
+#include "format_timespec.h"
+
+const char *format_timespec(const struct __kernel_timespec *ts)
+{
+ static char buffer[32];
+ struct tm tm_info;
+ time_t time_sec;
+
+ if (ts->tv_sec == 0 && ts->tv_nsec == 0)
+ return "N/A";
+
+ /*
+ * On 32-bit platforms time_t is 32-bit and cannot represent
+ * dates beyond Y2038. The kernel timestamp is always 64-bit,
+ * so reject values that would overflow.
+ */
+ if (sizeof(time_t) < sizeof(ts->tv_sec) &&
+ ts->tv_sec > (__u64)((1ULL << (sizeof(time_t) * 8 - 1)) - 1))
+ return "N/A";
+
+ time_sec = ts->tv_sec;
+
+ if (!localtime_r(&time_sec, &tm_info))
+ return "N/A";
+
+ strftime(buffer, sizeof(buffer), "%Y-%m-%dT%H:%M:%S", &tm_info);
+
+ return buffer;
+}
diff --git a/tools/accounting/format_timespec.h b/tools/accounting/format_timespec.h
new file mode 100644
index 000000000000..960496ebf5c2
--- /dev/null
+++ b/tools/accounting/format_timespec.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef FORMAT_TIMESPEC_H
+#define FORMAT_TIMESPEC_H
+
+#include <linux/time_types.h>
+
+const char *format_timespec(const struct __kernel_timespec *ts);
+
+#endif
diff --git a/tools/accounting/getdelays.c b/tools/accounting/getdelays.c
index 6ac30d4f96f7..d3193f670d89 100644
--- a/tools/accounting/getdelays.c
+++ b/tools/accounting/getdelays.c
@@ -30,6 +30,8 @@
#include <linux/taskstats.h>
#include <linux/cgroupstats.h>
+#include "format_timespec.h"
+
/*
* Generic macros for dealing with netlink sockets. Might be duplicated
* elsewhere. It is recommended that commercial grade applications use
@@ -221,36 +223,6 @@ static int get_family_id(int sd)
#define average_ms(t, c) (t / 1000000ULL / (c ? c : 1))
#define delay_ms(t) (t / 1000000ULL)
-/*
- * Format __kernel_timespec to human readable string (YYYY-MM-DD HH:MM:SS)
- * Returns formatted string or "N/A" if timestamp is zero
- */
-static const char *format_timespec(struct __kernel_timespec *ts)
-{
- static char buffer[32];
- struct tm tm_info;
- __kernel_time_t time_sec;
-
- /* Check if timestamp is zero (not set) */
- if (ts->tv_sec == 0 && ts->tv_nsec == 0)
- return "N/A";
-
- /* Avoid Y2038 truncation on 32-bit platforms */
- if (sizeof(time_sec) < sizeof(ts->tv_sec) &&
- ts->tv_sec > (__u64)((1ULL << (sizeof(time_sec) * 8 - 1)) - 1))
- return "N/A";
-
- time_sec = ts->tv_sec;
-
- /* Use thread-safe localtime_r */
- if (localtime_r(&time_sec, &tm_info) == NULL)
- return "N/A";
-
- strftime(buffer, sizeof(buffer), "%Y-%m-%dT%H:%M:%S", &tm_info);
-
- return buffer;
-}
-
/*
* Version compatibility note:
* Field availability depends on taskstats version (t->version),
diff --git a/tools/include/uapi/linux/time_types.h b/tools/include/uapi/linux/time_types.h
new file mode 100644
index 000000000000..375cfbdd8387
--- /dev/null
+++ b/tools/include/uapi/linux/time_types.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _TOOLS_UAPI_LINUX_TIME_TYPES_H
+#define _TOOLS_UAPI_LINUX_TIME_TYPES_H
+
+#include <linux/types.h>
+
+/*
+ * Minimal definition for use by tools/.
+ * __kernel_time64_t is always 'long long' on all architectures,
+ * so we avoid pulling in kernel-private type definitions.
+ */
+
+struct __kernel_timespec {
+ long long tv_sec;
+ long long tv_nsec;
+};
+
+#endif /* _TOOLS_UAPI_LINUX_TIME_TYPES_H */
--
2.27.0
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 3/3] tools/accounting: simplify 32-bit time_t overflow check in format_timespec()
2026-07-11 9:31 [PATCH 0/3] tools/accounting: refactor delay fields and share format_timespec() wang.yaxin
2026-07-11 9:32 ` [PATCH 1/3] delaytop: refactor repetitive delay fields into array with enum wang.yaxin
2026-07-11 9:33 ` [PATCH 2/3] tools/accounting: factor out shared format_timespec() implementation wang.yaxin
@ 2026-07-11 9:34 ` wang.yaxin
2026-07-14 2:48 ` [PATCH 0/3] tools/accounting: refactor delay fields and share format_timespec() Andrew Morton
3 siblings, 0 replies; 6+ messages in thread
From: wang.yaxin @ 2026-07-11 9:34 UTC (permalink / raw)
To: wang.yaxin
Cc: akpm, fan.yu9, yang.yang29, corbet, linux-kernel, linux-doc, xu.xin16
From: Wang Yaxin <wang.yaxin@zte.com.cn>
Replace the Y2038 overflow guard in format_timespec() with a direct
narrowing truncation check ((long long)time_sec != ts->tv_sec), which
is both simpler and more robust across platforms. Also move the
time_sec assignment earlier to avoid duplication.
While at it, fix a minor alignment issue in delaytop.c by adding a
leading space to the output format string.
Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
---
tools/accounting/delaytop.c | 2 +-
tools/accounting/format_timespec.c | 12 +++++-------
2 files changed, 6 insertions(+), 8 deletions(-)
diff --git a/tools/accounting/delaytop.c b/tools/accounting/delaytop.c
index 1144ca325447..097b57887147 100644
--- a/tools/accounting/delaytop.c
+++ b/tools/accounting/delaytop.c
@@ -1099,7 +1099,7 @@ static void display_results(int psi_ret)
get_field_delay_values(&tasks[i], cfg.type_field, &avg_ms,
&max_ms, &max_ts);
- suc &= BOOL_FPRINT(out, "%12.2f %12.2f %20s\n",
+ suc &= BOOL_FPRINT(out, " %12.2f %12.2f %20s\n",
avg_ms, max_ms, format_timespec(&max_ts));
} else if (cfg.display_mode == MODE_MEMVERBOSE) {
suc &= BOOL_FPRINT(out, DELAY_FMT_MEMVERBOSE,
diff --git a/tools/accounting/format_timespec.c b/tools/accounting/format_timespec.c
index 1dba50cac895..d7bfd307c00b 100644
--- a/tools/accounting/format_timespec.c
+++ b/tools/accounting/format_timespec.c
@@ -14,22 +14,20 @@ const char *format_timespec(const struct __kernel_timespec *ts)
{
static char buffer[32];
struct tm tm_info;
- time_t time_sec;
+ time_t time_sec = ts->tv_sec;
if (ts->tv_sec == 0 && ts->tv_nsec == 0)
return "N/A";
/*
* On 32-bit platforms time_t is 32-bit and cannot represent
- * dates beyond Y2038. The kernel timestamp is always 64-bit,
- * so reject values that would overflow.
+ * timestamps outside [INT32_MIN, INT32_MAX]. A 64-bit kernel
+ * timestamp that does not survive the narrowing truncation is
+ * rejected to avoid silent data corruption.
*/
- if (sizeof(time_t) < sizeof(ts->tv_sec) &&
- ts->tv_sec > (__u64)((1ULL << (sizeof(time_t) * 8 - 1)) - 1))
+ if ((long long)time_sec != ts->tv_sec)
return "N/A";
- time_sec = ts->tv_sec;
-
if (!localtime_r(&time_sec, &tm_info))
return "N/A";
--
2.27.0
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 0/3] tools/accounting: refactor delay fields and share format_timespec()
2026-07-11 9:31 [PATCH 0/3] tools/accounting: refactor delay fields and share format_timespec() wang.yaxin
` (2 preceding siblings ...)
2026-07-11 9:34 ` [PATCH 3/3] tools/accounting: simplify 32-bit time_t overflow check in format_timespec() wang.yaxin
@ 2026-07-14 2:48 ` Andrew Morton
3 siblings, 0 replies; 6+ messages in thread
From: Andrew Morton @ 2026-07-14 2:48 UTC (permalink / raw)
To: wang.yaxin
Cc: fan.yu9, yang.yang29, corbet, linux-kernel, linux-doc, xu.xin16
On Sat, 11 Jul 2026 17:31:12 +0800 (CST) <wang.yaxin@zte.com.cn> wrote:
> - Convert per-field delay members in struct task_info to an array indexed
> by enum delay_type, eliminating offsetof() pointer arithmetic.
>
> - Factor out a common format_timespec() implementation shared by getdelays
> and delaytop, using strftime for cleaner timestamp formatting.
>
> - Replace the complex sizeof/ULL/shift Y2038 guard with a direct narrowing
> truncation check ((long long)time_sec != ts->tv_sec).
Sounds great.
AI review might have found a couple of things. Please check it out?
https://sashiko.dev/#/patchset/20260711173112482SCQEM08VED2PT1pxUYOXk@zte.com.cn
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/3] delaytop: refactor repetitive delay fields into array with enum
2026-07-11 9:32 ` [PATCH 1/3] delaytop: refactor repetitive delay fields into array with enum wang.yaxin
@ 2026-07-14 3:07 ` xu.xin16
0 siblings, 0 replies; 6+ messages in thread
From: xu.xin16 @ 2026-07-14 3:07 UTC (permalink / raw)
To: wang.yaxin, akpm
Cc: wang.yaxin, fan.yu9, yang.yang29, corbet, linux-kernel, linux-doc
> Replace the 9 groups of (count, delay_total, delay_max, delay_max_ts)
> named fields in struct task_info with a struct delay_metrics array
> indexed by enum delay_type. This eliminates all unsafe pointer
> arithmetic via offsetof() from compare_tasks(),
> field_delay_max_and_ts(), and get_field_delay_values().
>
> The struct field_desc now stores an enum delay_type index instead of
> four separate unsigned long offset values.
>
> Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Acked-by: Xu Xin <xu.xin16@zte.com.cn>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2026-07-14 3:08 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2026-07-11 9:32 ` [PATCH 1/3] delaytop: refactor repetitive delay fields into array with enum wang.yaxin
2026-07-14 3:07 ` xu.xin16
2026-07-11 9:33 ` [PATCH 2/3] tools/accounting: factor out shared format_timespec() implementation wang.yaxin
2026-07-11 9:34 ` [PATCH 3/3] tools/accounting: simplify 32-bit time_t overflow check in format_timespec() wang.yaxin
2026-07-14 2:48 ` [PATCH 0/3] tools/accounting: refactor delay fields and share format_timespec() Andrew Morton
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