A Brief Introduction to manual release of Linux memory

The release of Linux server memory seems to improve the efficiency of some people, but the actual work is not very satisfactory. Here we will talk about how to do this job, it helps us better understand how the Linux system works.

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1. First use free-m to view the remaining memory

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Linux-8v2i :~ # Free-m

Total used free shared buffers cached

Mem: 3952 2773 178 0 130 1097

-/+ Buffers/cache: 1545 2406

Swap: 2055 0 2055

Linux-8v2i :~ # Free-m

Total used free shared buffers cached

Mem: 3952 2773 178 0 130 1097

-/+ Buffers/cache: 1545 2406

Swap: 2055 0 2055

2. Run the sync command.

Use the sync command to ensure the integrity of the file system. Run the sync command to run the sync subroutine and write all unwritten system buffers to the disk, contains modified I-node, delayed block I/O, and read/write ing files.

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Linux-8v2i :~ # Sync

Linux-8v2i :~ # Sync

3. Modify/proc/sys/vm/drop_caches

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Echo 3>/proc/sys/vm/drop_caches

Echo 3>/proc/sys/vm/drop_caches

Note:

1>./proc is a virtual file system. We can use its read/write operations as a means of communication with the kernel object. In other words, you can modify the file in/proc to adjust the current kernel behavior. In other words, we can adjust/proc/sys/vm/drop_caches to release the memory.

2>. Official descriptions of drop_caches are as follows:

Writing to this file causes the kernel to drop clean caches, dentries and inodes from memory, causing that memory to becomefree.

To free pagecache, use echo 1>/proc/sys/vm/drop_caches;

To free dentries and inodes, use echo 2>/proc/sys/vm/drop_caches;

To free pagecache, dentries and inodes, use echo 3>/proc/sys/vm/drop_caches.

Because this is a non-destructive operation and dirty objects are not freeable, the user shocould run sync first.

3>. the Linux kernel caches the recently accessed file pages in the memory for a period of time. This File Cache is called pagecache.

4. Use free-m to view the remaining memory as follows:

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Linux-8v2i :~ # Free-m

Total used free shared buffers cached

Mem: 3952 1773 2325 0 0 80

-/+ Buffers/cache: 1545 2406

Swap: 2055 0 2055

Linux-8v2i :~ # Free-m

Total used free shared buffers cached

Mem: 3952 1773 2325 0 0 80

-/+ Buffers/cache: 1545 2406

Swap: 2055 0 2055

The release of Linux Server Memory is easy.

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