在取每个rq前,会判断low-level drive是否busy(不能再处理更多的请求了),如果busy那么scsi_request_fn退出循环。这个过程见图中1如果request_queue为空,并且low-leveldirve可以继续处理请求,那么会找到当前request_queue对应的cfq_data,这个结构中维护了一些rbtree,从而可以找到下一次待处理的rq,并把这个rq添加到reque...
1年前 README GPL-2.0 kernel_linux_common_modules 介绍 仓用途:为Linux内核通用模块放置仓,为各内核领域公共仓。该仓不提供任何特性或能力,仅为集中容纳各内核独立模块,方便内核仓管理。 适用模块:通用内核模块,可在OpenHarmony支持的任何Linux内核版本上使用。对特定平台或硬件等依赖的模块不适合合入该仓。
关于list中的WRITE_ONCE使用,over stackflow上也有讨论:WRITE_ONCE in linux kernel lists 对此我的理解是:list模块是无锁化设计(不是说不需要锁,而是API里不使用锁,需要调用者根据实际情况加锁),且API都是内联函数,对 head->next 使用WRITE_ONCE,主要是为了保证原子化操作(这是volatile的又一特性,避免超16位...
Downgrading to kernels prior tokernel-4.18.0-240.el8causes performance to resume to previous levels. Resolution Red Hat Enterprise Linux 8 Update packagenfs-utilsto2.3.3-57.el8(released withRHBA-2022:7768) or later, which introduces thenfsraheadtool, which you can use it to modify thereadahead...
使用Source Insight阅读Linux内核代码是很方便的,面对那么多的代码文件,也可以做到很快的响应。但同时也存在一些小的痛点,比如本文将要介绍的__read_mostly的误解析问题,就导致代码跟踪中断。 1. __read_mostly误解析 在跟踪数据帧接收流程的过程中,驱动接收完数据包之后,会调用netif_receive_skb把帧交给协议栈处理,...
Having worked pretty much exclusively in a Unix world for the past two decades, my experience with Windows development is rather limited and I'd expect there to definitely be bugs and rough edges in the Windows code. The Windows version of the DwarFS filesystem driver relies on the awesome ...
Merge tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/lin… Sep 1, 2023 kernel Merge tag 'xilinx-v2024.1' of https://github.com/Xilinx/linux-xlnx.git Dec 3, 2024 lib maple_tree: add GFP_KERNEL to allocations in mas_expected_entries() Oct 19, 2023 mm Merge tag ...
Issue Kernel logged Voluntary context switch within RCU read-side critical section! message followed by WARNING: CPU: 2 PID: 374862 at kernel/rcu/tree_plugin.h:316 rcu_note_context_switch+0x247/0x260 warning.Environment Red Hat Enterprise Linux 9 be2net module ...
- I tried read UVC header via v4l2(https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/pixfmt-meta-uvc.html) - The procedure is something like that in librealsense(https://github.com/IntelRealSense/librealsense/blob/master/src/linux/backend-v4l2.h). Open the video captu...
When you attempt to delete or modify a file on a Linux ECS, the message Read-only file system is displayed. Possible Cause The possible causes are as follows: A file system error caused the file system to be read-only. The file system is mounted as read-only. The hardware is faulty,...