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logging: log_output: Improve immediate mode handling

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When in immediate mode ensure that buffering is not used in log output.
Every byte is pushed to the transport.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
This commit is contained in:
Krzysztof Chruscinski 2019-11-20 14:28:06 +01:00 • committed by Andrew Boie
commit 117fab3004
4 changed files with 54 additions and 26 deletions
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3
include/logging/log_output.h
View file

@ -9,6 +9,7 @@
#include <logging/log_msg.h>
#include <sys/util.h>
#include <stdarg.h>
#include <sys/atomic.h>
#ifdef __cplusplus
extern "C" {
@ -66,7 +67,7 @@ typedef int (*log_output_func_t)(u8_t *buf, size_t size, void *ctx);
/* @brief Control block structure for log_output instance. */
struct log_output_control_block {
size_t offset;
atomic_t offset;
void *ctx;
const char *hostname;
};

11
subsys/logging/Kconfig
View file

@ -127,6 +127,17 @@ config LOG_IMMEDIATE
flawlessly in that mode because one log operation can be interrupted
by another one in the higher priority context.
if LOG_IMMEDIATE
config LOG_IMMEDIATE_CLEAN_OUTPUT
bool "Enable clean log output"
help
If enabled, interrupts are locked during whole log message processing.
As a result, processing on one log message cannot be interrupted by
another one and output is clean, not interleaved. However, enabling
this option is causing interrupts locking for significant amount of
time (up to multiple milliseconds).
endif
config LOG_ENABLE_FANCY_OUTPUT_FORMATTING
depends on MINIMAL_LIBC
bool "Format strings with minimal libc _prf() instead of _vprintk()"

42
subsys/logging/log_backend_std.h
View file

@ -8,7 +8,7 @@
#include <logging/log_msg.h>
#include <logging/log_output.h>
#include <irq.h>
#include <kernel.h>
#ifdef __cplusplus
extern "C" {
@ -76,7 +76,7 @@ log_backend_std_sync_string(const struct log_output *const log_output,
u32_t flags, struct log_msg_ids src_level,
u32_t timestamp, const char *fmt, va_list ap)
{
u32_t key;
int key;
flags |= LOG_OUTPUT_FLAG_LEVEL | LOG_OUTPUT_FLAG_TIMESTAMP;
if (IS_ENABLED(CONFIG_LOG_BACKEND_SHOW_COLOR)) {
@ -87,17 +87,21 @@ log_backend_std_sync_string(const struct log_output *const log_output,
flags |= LOG_OUTPUT_FLAG_FORMAT_TIMESTAMP;
}
key = irq_lock();
/* Even though interrupts are locked here there are still cases when
* it may lead to failure. Log output is not re-entrant and irq_lock
* does not prevent NMI or ZLI (Zero latency interrupts). If context
* is interrupted by NMI it usually means fault scenario and best that
* can be done is to flush the output and process new data.
if (IS_ENABLED(CONFIG_LOG_IMMEDIATE) &&
IS_ENABLED(CONFIG_LOG_IMMEDIATE_CLEAN_OUTPUT)) {
/* In order to ensure that one log processing is not interrupted
* by another one, lock context for whole log processing.
*/
log_output_flush(log_output);
key = irq_lock();
}
log_output_string(log_output, src_level, timestamp, fmt, ap, flags);
if (IS_ENABLED(CONFIG_LOG_IMMEDIATE) &&
IS_ENABLED(CONFIG_LOG_IMMEDIATE_CLEAN_OUTPUT)) {
irq_unlock(key);
}
}
/** @brief Synchronously process hexdump message by a standard logger backend.
*
@ -115,7 +119,7 @@ log_backend_std_sync_hexdump(const struct log_output *const log_output,
u32_t timestamp, const char *metadata,
const u8_t *data, u32_t length)
{
u32_t key;
int key;
flags |= LOG_OUTPUT_FLAG_LEVEL | LOG_OUTPUT_FLAG_TIMESTAMP;
if (IS_ENABLED(CONFIG_LOG_BACKEND_SHOW_COLOR)) {
@ -126,18 +130,22 @@ log_backend_std_sync_hexdump(const struct log_output *const log_output,
flags |= LOG_OUTPUT_FLAG_FORMAT_TIMESTAMP;
}
key = irq_lock();
/* Even though interrupts are locked here there are still cases when
* it may lead to failure. Log output is not re-entrant and irq_lock
* does not prevent NMI or ZLI (Zero latency interrupts). If context
* is interrupted by NMI it usually means fault scenario and best that
* can be done is to flush the output and process new data.
if (IS_ENABLED(CONFIG_LOG_IMMEDIATE) &&
IS_ENABLED(CONFIG_LOG_IMMEDIATE_CLEAN_OUTPUT)) {
/* In order to ensure that one log processing is not interrupted
* by another one, lock context for whole log processing.
*/
log_output_flush(log_output);
key = irq_lock();
}
log_output_hexdump(log_output, src_level, timestamp,
metadata, data, length, flags);
if (IS_ENABLED(CONFIG_LOG_IMMEDIATE) &&
IS_ENABLED(CONFIG_LOG_IMMEDIATE_CLEAN_OUTPUT)) {
irq_unlock(key);
}
}
#ifdef __cplusplus
}

16
subsys/logging/log_output.c
View file

@ -102,16 +102,23 @@ static int out_func(int c, void *ctx)
{
const struct log_output *out_ctx =
(const struct log_output *)ctx;
int idx;
out_ctx->buf[out_ctx->control_block->offset] = (u8_t)c;
out_ctx->control_block->offset++;
__ASSERT_NO_MSG(out_ctx->control_block->offset <= out_ctx->size);
if (IS_ENABLED(CONFIG_LOG_IMMEDIATE)) {
/* Backend must be thread safe in synchronous operation. */
out_ctx->func((u8_t *)&c, 1, out_ctx->control_block->ctx);
return 0;
}
if (out_ctx->control_block->offset == out_ctx->size) {
log_output_flush(out_ctx);
}
idx = atomic_inc(&out_ctx->control_block->offset);
out_ctx->buf[idx] = (u8_t)c;
__ASSERT_NO_MSG(out_ctx->control_block->offset <= out_ctx->size);
return 0;
}
@ -145,6 +152,7 @@ static void buffer_write(log_output_func_t outf, u8_t *buf, size_t len,
} while (len != 0);
}
void log_output_flush(const struct log_output *log_output)
{
buffer_write(log_output->func, log_output->buf,