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wmmemload: Use MemAvailable from kernel > v3.14 to display memory usage 

After the introduction of MemAvailable in the kernel v3.14 one can
estimate how much RAM memory is being "used" by how much it is left
before the system starts swapping.

That is the reason why I want to monitor memory usage, to know
how close the system is to swapping. Therefore I propose to
use MemAvailable to compute the percentage of "used" memory.
Theoretically, after this patch a 100% memory usage is a more
accurate description of "yeah, we need to swap from now on".

See https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=34e431b0ae398fc54ea69ff85ec700722c9da773
This commit is contained in:
Carlos R. Mafra 2019-01-12 21:55:02 +00:00
parent 774e4f769f
commit bd0d7d1f67
1 changed files with 7 additions and 3 deletions
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10
wmmemload/src/mem_linux.c
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@ -94,7 +94,7 @@ void mem_getusage(int *per_mem, int *per_swap, const struct mem_options *opts)
{
char buffer[BUFSIZ], *p;
int fd, len, i;
u_int64_t mtotal, mused, mfree, mbuffer, mcached;
u_int64_t mtotal, mused, mfree, mbuffer, mcached, mavail;
u_int64_t stotal, sused, sfree, scached = 0;
/* read /proc/meminfo */
@ -141,8 +141,8 @@ void mem_getusage(int *per_mem, int *per_swap, const struct mem_options *opts)
p = skip_token(p);
/* examine each line of file */
mtotal = strtoul(p, &p, 0); p = skip_multiple_token(p, 2);
mfree = strtoul(p, &p, 0);
p = skip_multiple_token(p, 5); /* skip MemAvailable line */
mfree = strtoul(p, &p, 0); p = skip_multiple_token(p, 2);
mavail = strtoul(p, &p, 0); p = skip_multiple_token(p, 2);
mbuffer = strtoul(p, &p, 0); p = skip_multiple_token(p, 2);
mcached = strtoul(p, &p, 0); p = skip_multiple_token(p, 2);
scached = strtoul(p, &p, 0);
@ -162,6 +162,9 @@ void mem_getusage(int *per_mem, int *per_swap, const struct mem_options *opts)
stotal = strtoul(p, &p, 0); p = skip_multiple_token(p, 2);
sfree = strtoul(p, &p, 0);
if (format == AFTER_3_14) {
*per_mem = 100 * (double) (mtotal - mavail) / (double) mtotal;
} else {
/* calculate memory usage in percent */
mused = mtotal - mfree;
if (opts->ignore_buffers)
@ -169,6 +172,7 @@ void mem_getusage(int *per_mem, int *per_swap, const struct mem_options *opts)
if (opts->ignore_cached)
mused -= mcached;
*per_mem = 100 * (double) mused / (double) mtotal;
}
/* calculate swap usage in percent */
sused = stotal - sfree;