On Thu, Jul 24, 2025 at 4:52 PM <g...@suckless.org> wrote:
>
> commit 8723e8b8c69c08bae8abe02ea1f4a49758b8bdfc
> Author: drkhsh <m...@drkhsh.at>
> AuthorDate: Thu Jul 24 22:41:25 2025 +0200
> Commit: drkhsh <m...@drkhsh.at>
> CommitDate: Thu Jul 24 22:41:25 2025 +0200
>
> more concise memory calculation on Linux
>
> more flexible parsing for /proc/meminfo to take shared and reclaimable
> memory into account. this matches the output with free(1).
>
> additionally this could fix some corner cases, as the order of fields in
> /proc/meminfo is not strictly defined.
>
> slstatus:
> percent 81% free 2.5 Gi total 23.4 Gi used 19.0 Gi
>
> free(1):
> total used free shared buff/cache
> available
> Mem: 23Gi 19Gi 2.5Gi 1.3Gi 3.2Gi
> 3.6Gi
>
> diff --git a/components/ram.c b/components/ram.c
> index 15c4b74..bf71dcf 100644
> --- a/components/ram.c
> +++ b/components/ram.c
> @@ -11,36 +11,45 @@
> ram_free(const char *unused)
> {
> uintmax_t free;
> + FILE *fp;
>
> - if (pscanf("/proc/meminfo",
> - "MemTotal: %ju kB\n"
> - "MemFree: %ju kB\n"
> - "MemAvailable: %ju kB\n",
> - &free, &free, &free) != 3)
> + if (!(fp = fopen("/proc/meminfo", "r")))
> return NULL;
>
> + if (lscanf(fp, "MemFree:", "%ju kB", &free) != 1) {
> + fclose(fp);
> + return NULL;
> + }
> +
> + fclose(fp);
> return fmt_human(free * 1024, 1024);
> }
>
> const char *
> ram_perc(const char *unused)
> {
> - uintmax_t total, free, buffers, cached;
> + uintmax_t total, free, buffers, cached, shmem, sreclaimable;
> int percent;
> + FILE *fp;
> +
> + if (!(fp = fopen("/proc/meminfo", "r")))
> + return NULL;
>
> - if (pscanf("/proc/meminfo",
> - "MemTotal: %ju kB\n"
> - "MemFree: %ju kB\n"
> - "MemAvailable: %ju kB\n"
> - "Buffers: %ju kB\n"
> - "Cached: %ju kB\n",
> - &total, &free, &buffers, &buffers, &cached) != 5)
> + if (lscanf(fp, "MemTotal:", "%ju kB", &total) != 1 ||
> + lscanf(fp, "MemFree:", "%ju kB", &free) != 1 ||
> + lscanf(fp, "Buffers:", "%ju kB", &buffers) != 1 ||
> + lscanf(fp, "Cached:", "%ju kB", &cached) != 1 ||
> + lscanf(fp, "Shmem:", "%ju kB", &shmem) != 1 ||
> + lscanf(fp, "SReclaimable:", "%ju kB", &sreclaimable) !=
> 1) {
> + fclose(fp);
> return NULL;
> + }
> + fclose(fp);
>
> if (total == 0)
> return NULL;
>
> - percent = 100 * ((total - free) - (buffers + cached)) / total;
> + percent = 100 * (total - free - buffers - cached -
> sreclaimable + shmem) / total;
> return bprintf("%d", percent);
> }
>
> @@ -59,18 +68,24 @@
> const char *
> ram_used(const char *unused)
> {
> - uintmax_t total, free, buffers, cached, used;
> + uintmax_t total, free, buffers, cached, used, shmem,
> sreclaimable;
> + FILE *fp;
> +
> + if (!(fp = fopen("/proc/meminfo", "r")))
> + return NULL;
>
> - if (pscanf("/proc/meminfo",
> - "MemTotal: %ju kB\n"
> - "MemFree: %ju kB\n"
> - "MemAvailable: %ju kB\n"
> - "Buffers: %ju kB\n"
> - "Cached: %ju kB\n",
> - &total, &free, &buffers, &buffers, &cached) != 5)
> + if (lscanf(fp, "MemTotal:", "%ju kB", &total) != 1 ||
> + lscanf(fp, "MemFree:", "%ju kB", &free) != 1 ||
> + lscanf(fp, "Buffers:", "%ju kB", &buffers) != 1 ||
> + lscanf(fp, "Cached:", "%ju kB", &cached) != 1 ||
> + lscanf(fp, "Shmem:", "%ju kB", &shmem) != 1 ||
> + lscanf(fp, "SReclaimable:", "%ju kB", &sreclaimable) !=
> 1) {
> + fclose(fp);
> return NULL;
> + }
> + fclose(fp);
>
> - used = (total - free - buffers - cached);
> + used = total - free - buffers - cached - sreclaimable + shmem;
> return fmt_human(used * 1024, 1024);
> }
> #elif defined(__OpenBSD__)
> diff --git a/util.c b/util.c
> index bca9b2e..d33cf9d 100644
> --- a/util.c
> +++ b/util.c
> @@ -139,3 +139,20 @@ pscanf(const char *path, const char *fmt, ...)
>
> return (n == EOF) ? -1 : n;
> }
> +
> +int
> +lscanf(FILE *fp, const char *key, const char *fmt, void *res)
> +{
> + int n;
> + char line[256];
> +
> + n = -1;
> + while (fgets(line, sizeof(line), fp))
> + if (strncmp(line, key, strlen(key)) == 0) {
> + n = sscanf(line + strlen(key), fmt, res);
> + break;
> + }
> +
> + rewind(fp);
> + return (n == 1) ? 1 : -1;
> +}
> diff --git a/util.h b/util.h
> index cf4b027..7a960aa 100644
> --- a/util.h
> +++ b/util.h
> @@ -1,5 +1,6 @@
> /* See LICENSE file for copyright and license details. */
> #include <stdint.h>
> +#include <stdio.h>
>
> extern char buf[1024];
>
> @@ -14,3 +15,4 @@ int esnprintf(char *str, size_t size, const char *fmt, ..);
> const char *bprintf(const char *fmt, ...);
> const char *fmt_human(uintmax_t num, int base);
> int pscanf(const char *path, const char *fmt, ...);
> +int lscanf(FILE *fp, const char *key, const char *fmt, void *res);
>
Linux free(1) calculates used memory as MemTotal minus MemAvailable.
https://gitlab.com/procps-ng/procps/-/commit/2184e90d2e7cdb582f9a5b706b47015e56707e4d
