How to use Linux for memory management and optimization

How to use Linux for memory management and optimization

[Introduction]
In the Linux system, memory management and optimization is a very important topic. Properly managing memory can improve system performance and stability, while memory optimization can maximize the use of system memory resources. This article will introduce how to use Linux for memory management and optimization, and provide some practical code examples.

[1. Memory Management]
1.1 View memory information
In Linux systems, you can use the command "free" to view the system's memory information, including total memory, used memory, and available memory. , cache and swap partitions. The sample code is as follows:

$ free -h

The output is similar to the following:

              total        used        free      shared  buff/cache   available
Mem:           7.7G        1.9G        706M        512M        5.1G        5.1G
Swap:          2.0G        0B          2.0G

1.2 Clean cache
Sometimes the system caches some data into memory to speed up access. But if memory is tight, you can free up valuable memory space by freeing the cache. The sample code is as follows:

$ sync; echo 1 > /proc/sys/vm/drop_caches

1.3 Release unnecessary memory
Sometimes a process takes up a lot of memory, but it actually does not use the memory. At this time, unnecessary memory can be released through the "malloc_trim" function. The sample code is as follows:

#include <malloc.h>

...

void trim_memory() {
    malloc_trim(0);
}

[2. Memory Optimization]
2.1 Using large page memory
In some applications that require large memory continuous space, using large page memory can improve performance and reduce memory fragmentation . Hugepages can be enabled by following these steps. The sample code is as follows:

$ echo "vm.nr_hugepages=128" >> /etc/sysctl.conf
$ sysctl -p

2.2 Transparent Huge Pages
Transparent Huge Pages is a kernel feature that can automatically convert small page memory into large page memory to reduce memory overhead. You can enable transparent hugepages by following these steps. The sample code is as follows:

$ echo "always" > /sys/kernel/mm/transparent_hugepage/enabled

2.3 Memory recycling strategy
There are a variety of memory recycling strategies to choose from in the Linux system, which can be adjusted according to specific needs. Common memory recovery strategies include "Lru", "Generally FIFO" and "Buddy". The sample code is as follows:

$ echo "lru" > /sys/kernel/mm/allocstool/lru
$ echo "generallyfifo" > /sys/kernel/mm/allocstool/lru
$ echo "buddy" > /sys/kernel/mm/allocstool/lru

[Summary]
This article introduces how to use Linux for memory management and optimization, and provides some practical code examples. Properly managing memory and optimizing memory can improve system performance and stability. Hope this article is helpful to you.

The above is the detailed content of How to use Linux for memory management and optimization. For more information, please follow other related articles on the PHP Chinese website!