Linux memory - Revision history

Tony: /* Documentation */

2025-11-07T10:59:03Z

Documentation

← Older revision		Revision as of 10:59, 7 November 2025
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	= Documentation =		= Documentation =

			*[https://www.baeldung.com/linux/buffer-vs-cache-memory Buffer and Cache Memory in Linux]

	==Output of 'free' command==		==Output of 'free' command==

Tony: /* What is using all my memory? */

2025-10-13T12:39:10Z

What is using all my memory?

← Older revision		Revision as of 12:39, 13 October 2025
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	== What is using all my memory? ==		== What is using all my memory? ==
			NOTE: smem has a LOT of dependencies

	smem -r -s swap\| head -n3		smem -r -s swap\| head -n3


	==What is using all my swap? ==		==What is using all my swap? ==

Tony: /* Watch buffer/cache activity */

2025-09-15T15:16:20Z

Watch buffer/cache activity

← Older revision		Revision as of 15:16, 15 September 2025
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	===Cannot open /var/log/sysstat/sa15: No such file or directory===		===Cannot open /var/log/sysstat/sa15: No such file or directory===
	systemctl start sysstat		systemctl start sysstat 2 2

	==What is in buffer/cache?==		==What is in buffer/cache?==

Tony: /* Watch buffer/cache activity */

2025-09-15T15:15:35Z

Watch buffer/cache activity

← Older revision		Revision as of 15:15, 15 September 2025
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	sar -B		sar -B

			===Cannot open /var/log/sysstat/sa15: No such file or directory===
			systemctl start sysstat

	==What is in buffer/cache?==		==What is in buffer/cache?==

Tony: /* Links */

2023-11-15T11:07:19Z

Links

← Older revision		Revision as of 11:07, 15 November 2023
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	= Links =		= Links =

	*[http://www.linuxatemyram.com/ Linux ate my RAM!]		*[http://www.linuxatemyram.com/ Linux ate my RAM!]
	*[https://www.thegeekdiary.com/understanding-proc-meminfo-file-analyzing-memory-utilization-in-linux/ Understanding /proc/meminfo]
	*[https://www.tecmint.com/clear-ram-memory-cache-buffer-and-swap-space-on-linux/ How to Clear RAM Memory Cache, Buffer and Swap Space on Linux]		*[https://www.tecmint.com/clear-ram-memory-cache-buffer-and-swap-space-on-linux/ How to Clear RAM Memory Cache, Buffer and Swap Space on Linux]
	*[http://serverfault.com/questions/377617/how-to-interpret-output-from-linux-top-command How to interpret output from Linux 'top' command?]		*[http://serverfault.com/questions/377617/how-to-interpret-output-from-linux-top-command How to interpret output from Linux 'top' command?]
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	*[https://unix.stackexchange.com/questions/2658/why-use-swap-when-there-is-more-than-enough-free-space-in-ram Why is system using swap when there is enough free space in ram?]		*[https://unix.stackexchange.com/questions/2658/why-use-swap-when-there-is-more-than-enough-free-space-in-ram Why is system using swap when there is enough free space in ram?]
	*[https://www.thomas-krenn.com/en/wiki/Linux_Page_Cache_Basics Linux page cache basics]		*[https://www.thomas-krenn.com/en/wiki/Linux_Page_Cache_Basics Linux page cache basics]

			==/proc/meminfo==
			*[https://www.thegeekdiary.com/understanding-proc-meminfo-file-analyzing-memory-utilization-in-linux/ Understanding /proc/meminfo]
			*[https://www.baeldung.com/linux/proc-meminfo The /proc/meminfo File in Linux]

	= Documentation =		= Documentation =

Tony: /* Documentation */

2023-11-15T11:05:49Z

Documentation

← Older revision		Revision as of 11:05, 15 November 2023
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	= Documentation =		= Documentation =


			==Output of 'free' command==
			===available===
			MemAvailable in /proc/meminfo



	man 5 proc		man 5 proc

Tony: /* What is in buffer/cache? */

2023-11-10T10:06:34Z

What is in buffer/cache?

← Older revision		Revision as of 10:06, 10 November 2023
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	or to just list top 3		or to just list top 3
	for file in /proc/*/status ; do awk '/VmSwap\|Name/{printf $2 " " $3}END{ print ""}' $file; done \| sort -k 2 -n -r \| head -n 3		for file in /proc/*/status ; do awk '/VmSwap\|Name/{printf $2 " " $3}END{ print ""}' $file; done \| sort -k 2 -n -r \| head -n 3


			==Watch buffer/cache activity==
			https://www.heroix.com/blog/linux-memory-use/
			sar -B

Tony: /* What is in buffer/cache? */

2023-11-10T09:33:08Z

What is in buffer/cache?

← Older revision		Revision as of 09:33, 10 November 2023
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	===Tools===		===Tools===
	*[https://github.com/brendangregg/perf-tools perf-tools]		*[https://github.com/brendangregg/perf-tools perf-tools]
			*https://www.brendangregg.com/blog/2014-12-31/linux-page-cache-hit-ratio.html

	== Clear buffer/cache ==		== Clear buffer/cache ==

	sync; echo 3 > /proc/sys/vm/drop_caches		sync; echo 3 > /proc/sys/vm/drop_caches

Tony: /* What is in buffer/cache? */

2023-11-10T09:27:36Z

What is in buffer/cache?

← Older revision		Revision as of 09:27, 10 November 2023
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	==What is in buffer/cache?==		==What is in buffer/cache?==
	~~Bob knows~~		===Tools===
			*[https://github.com/brendangregg/perf-tools perf-tools]

	== Clear buffer/cache ==		== Clear buffer/cache ==

	sync; echo 3 > /proc/sys/vm/drop_caches		sync; echo 3 > /proc/sys/vm/drop_caches

Tony: /* FAQ */

2023-11-09T12:30:41Z

FAQ

← Older revision		Revision as of 12:30, 9 November 2023
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	or to just list top 3		or to just list top 3
	for file in /proc/*/status ; do awk '/VmSwap\|Name/{printf $2 " " $3}END{ print ""}' $file; done \| sort -k 2 -n -r \| head -n 3		for file in /proc/*/status ; do awk '/VmSwap\|Name/{printf $2 " " $3}END{ print ""}' $file; done \| sort -k 2 -n -r \| head -n 3


			==What is in buffer/cache?==
			Bob knows

	== Clear buffer/cache ==		== Clear buffer/cache ==

	sync; echo 3 > /proc/sys/vm/drop_caches		sync; echo 3 > /proc/sys/vm/drop_caches