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the linux kernel buffer mechanism is an important part of the Linux operating system, which is responsible for caching data, caching earlier used data and other related operations, making the operating system more efficient in the subsequent use of data. Therefore, to improve the performance of the system, we must fully understand the details of the Linux kernel BUFfer mechanism. Let’s take a deeper look at it.
Under the Linux system, the memory format and layout settings of the kernel buffer are determined by the corresponding architecture. The Linux kernel buffer mechanism studies the relationship between the physical buffer and the process, and optimizes the data interaction between them. The kernel buffer itself does not occupy system RAM or disk storage space, but it forces the user space to occupy additional system RAM or disk storage space.
In addition, the Linux kernel buffer mechanism works in the kernel, which means that during memory allocation, the kernel must make judgments according to the considering area, such as occupied/free/remaining size, whether the allocation succeeds/fails/wait, etc. It is a process of continuous change and optimization.
Linux also provides some common APIs to manage the memory buffer, such as dma_buf_map(), dma_buf_unmap(), dma_buf_alloc(), dma_buf_free(), etc. These APIs are used to control the buffer and facilitate users to control the kernel buffer efficiently.
Finally, let’s look at a sample code example:
int dma_buf_map(struct dma_buf *dmabuf)
{
struct dma_buf_attachment *attach;
mutex_lock(&dmabuf->lock);
list_for_each_entry(attach, &dmabuf->attachments, node)
dma_buf_begin_cpu_access(dmabuf, attach, 0, attach->dmabuf->size,
DMA_FROM_DEVICE);
mutex_unlock(&dmabuf->lock);
return 0;
}
EXPORT_SYMBOL_GPL(dma_buf_map);
This is a sample code example of the dma_buf_map() API in the Linux kernel buffer mechanism. This code is used to map the physical memory address of the buffer to the user process. In the code, we can see the usage of the mutex in the Linux system to lock the buffer and the usage of the list to find the corresponding physical address.
In conclusion, Linux kernel buffer mechanism plays an important role in improving system performance. Through understanding the specific details and applying related APIs, we can make our system run more efficiently and stably.
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網(wǎng)站欄目：深入探究Linux內(nèi)核緩沖機(jī)制：提升系統(tǒng)性能的必要步驟（linux內(nèi)核緩沖）
轉(zhuǎn)載源于：http://fisionsoft.com.cn/article/dhoogci.html
