wlmmemgraph.c File Reference

#include "wlm_graph_shared.h"
#include <libbase/libbase.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

Include dependency graph for wlmmemgraph.c:

Classes
struct	memgraph_state_t

Macros
#define	LINE_BUFFER_SIZE   256
#define	MEMINFO_FIELD_COUNT   5
#define	MEM_CATEGORY_COUNT   3
#define	LABEL_BUFFER_SIZE   16
#define	KB_PER_MB   1024UL
#define	KB_PER_GB   (1024UL * 1024)
#define	KB_PER_TB   (1024UL * 1024 * 1024)
#define	LABEL_MATCH(literal)

Enumerations
enum	{ MEM_CATEGORY_CACHED = 0 , MEM_CATEGORY_BUFFERS = 1 , MEM_CATEGORY_USED = 2 }

Functions
static void	_memgraph_lut_init (uint32_t lut[256])
static void	_state_free (void *app_state)
static void	_format_memory_size (char *buf, const size_t buf_size, const unsigned long kb)
static const char *	_label_fn (void *app_state)
static wlm_graph_read_result_t	_stats_read_fn (void *app_state, wlm_graph_values_t *values)
int	main (const int argc, const char **argv)

Variables
static const char	_app_name [] = "wlmmemgraph"
static const char	_app_help []

Detailed Description

Memory usage graph dock-app for wlmaker.

Copyright

Copyright 2026 Google LLC

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

https://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Macro Definition Documentation

KB_PER_GB

#define KB_PER_GB   (1024UL * 1024)

Kilobytes per gigabyte.

KB_PER_MB

#define KB_PER_MB   1024UL

Kilobytes per megabyte.

KB_PER_TB

#define KB_PER_TB   (1024UL * 1024 * 1024)

Kilobytes per terabyte.

LABEL_BUFFER_SIZE

#define LABEL_BUFFER_SIZE   16

Maximum length of the label string.

LABEL_MATCH

#define LABEL_MATCH

(

literal

)

Value:

(sizeof(literal) - 1 == label_len && 0 == memcmp(line, literal, sizeof(literal) - 1))

Matches line label against a string literal.

Compares label_len bytes of line against the literal. Used for parsing /proc/meminfo where each line has format "Label: value kB".

Parameters

literal

String literal to match against.

LINE_BUFFER_SIZE

#define LINE_BUFFER_SIZE   256

Line buffer size for /proc/meminfo parsing.

MEM_CATEGORY_COUNT

#define MEM_CATEGORY_COUNT   3

Number of memory categories tracked.

MEMINFO_FIELD_COUNT

#define MEMINFO_FIELD_COUNT   5

Number of fields to parse from /proc/meminfo.

Enumeration Type Documentation

anonymous enum

anonymous enum

Memory category indices.

Enumerator
MEM_CATEGORY_CACHED	Cached (including SReclaimable).
MEM_CATEGORY_BUFFERS	Buffers.
MEM_CATEGORY_USED	Used (non-reclaimable).

Function Documentation

_format_memory_size()

void _format_memory_size ( char * buf, const size_t buf_size, const unsigned long kb )

static

Formats memory size with appropriate suffix (GB, MB, kB).

Parameters

buf	Output buffer.
buf_size	Size of output buffer.
kb	Memory size in kilobytes.

_label_fn()

const char * _label_fn ( void * app_state )

static

Returns the formatted memory usage label.

_memgraph_lut_init()

void _memgraph_lut_init ( uint32_t lut[256] )

static

Generates blue-to-green gradient LUT (256 entries).

With 3 memory categories, only indices 0, 127, and 255 are sampled (mapping count 1, 2, 3 respectively). The full 256 entries are required by the API but only 3 discrete colors matter for this use case.

Parameters

lut	Output LUT array (256 entries).

_state_free()

void _state_free ( void * app_state )

static

Frees all allocated state.

_stats_read_fn()

wlm_graph_read_result_t _stats_read_fn ( void * app_state, wlm_graph_values_t * values )

static

Reads memory statistics from /proc/meminfo.

Parses MemTotal, MemFree, Buffers, Cached, and SReclaimable to compute per-category usage percentages.

Parameters

app_state	App state (memgraph_state_t pointer).
values	Buffer to fill (may reallocate data/num).

Returns

WLM_GRAPH_READ_OK on success, WLM_GRAPH_READ_ERROR on error.

main()

int main	(	const int	argc,
		const char **	argv )

Main program.

Variable Documentation

_app_help

const char _app_help[]

static

Initial value:

                        =
"Displays memory usage as a scrolling graph.\n"
"\n"
"Shows stacked memory categories:\n"
"  - Cached: top of graph (dark blue)\n"
"  - Buffers: middle of graph (dark cyan)\n"
"  - Used: bottom of graph (green)\n"
"\n"
"The label displays total memory usage."

Application help.

_app_name

const char _app_name[] = "wlmmemgraph"

static

Application name.