pt-summary is not showing "shared" memory value

[Daniel Guzmán Burgos]

Memory space used by files inside a partition mounted with the tmpfs filesystem is reported in the "shared" section of the output of the "free" command, as explained in the docs (https://www.kernel.org/doc/Documentation/filesystems/tmpfs.txt):

"Since tmpfs lives completely in the page cache and on swap, all tmpfs
pages will be shown as "Shmem" in /proc/meminfo and "Shared" in
free(1)."

The "parse_free_minus_b" function doesn't take in account that section:

name_val "Total" $(shorten $(awk '/Mem:/{print $2}' "${file}") 1)
   name_val "Free" $(shorten $(awk '/Mem:/{print $4}' "${file}") 1)
   name_val "Used" "physical = $(shorten ${physical} 1), swap allocated = $(shorten ${swap_alloc} 1), swap used = $(shorten ${swap_used} 1), virtual = ${virtual}"
   name_val "Buffers" $(shorten $(awk '/Mem:/{print $6}' "${file}") 1)
   name_val "Caches" $(shorten $(awk '/Mem:/{print $7}' "${file}") 1)
   name_val "Dirty" "$(awk '/Dirty:/ {print $2, $3}' "${file}")"

Which, based on the free output, is the fifth column:

             total used free shared buffers cached
Mem: 2099093504 1454759936 644333568 1036288 37773312 540282880
-/+ buffers/cache: 876703744 1222389760
Swap: 0 0 0

Fix: Add the following line:

 name_val "Shared" $(shorten $(awk '/Mem:/{print $5}' "${file}") 1)

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PT-702