linux

> You cam probably beat an ATMega with a STM32 of some kind. You can run Linux directly on some STM32 MCUs. No emulation required! https://github.com/torvalds/linux/tree/master/arch/arm/mach-... That being said, static operation is really less of an issue than you're implying. Modern MCUs can idle (not sleep!) at under a milliamp; it's not difficult to get them to draw less average current than the leakage current of their battery. The lack of 5V operation is a little annoying in some scenarios, but is easily worked around with a 3.3V LDO -- which is frequently required anyway for interoperability with other components. (A switching converter is hardly necessary for a USB device drawing a couple milliamps.)

The main use case is not forgetting to free resources. It's when you do have resource-freeing code, but it's tricky to make sure you free only the resources you know for sure you have already allocated. This is common in the Linux kernel. A great example is this function I found at random from fork.c: https://github.com/torvalds/linux/blob/master/kernel/fork.c#... Notice that there are five different goto targets, each for a specific case of what has-and-has-not been allocated. The resources are memory, locks, and even TLB flushing. This code would probably be cleaner with defer.

LGTM https://github.com/torvalds/linux/pull/684

The actual code in the kernel is well documented (and different, lines 103-149): https://github.com/torvalds/linux/blob/master/include/linux/...

This is great but here are a few additions that I think are helpful when it comes to gathering information. 1. List all man pages of a specific section (e.g. section 4): `man -k -s 4 . | sort` 2. Output all possible sections: `man man | head -25` 3. Sometimes there is no man page but GNU info can be used: `info ed` `info emacs` 4. A nice website to explain comands and oneliners is explainshell.com. It can also be queried from a terminal quite conveniently. 5. If you're like me, you'll probably often list all the system calls by listing all the pages in section 2. A better way might be to look at the linux source code directly (choose the right architecture): https://github.com/torvalds/linux/blob/master/arch/x86/entry...

Compare this - * Just a few spaces per indent level * To make this work, and yet allow a few indent levels, the code basically have to have small indent-levels, so I prefer to have it set to two spaces per level. To this, courtesy of the "Linux kernel coding style" [1] - 1) Indentation Tabs are 8 characters, and thus indentations are also 8 characters. There are heretic movements that try to make indentations 4 (or even 2!) characters deep, and that is akin to trying to define the value of PI to be 3. Rationale: [snip] Now, some people will claim that having 8- character indentations makes the code move too far to the right, and makes it hard to read on a 80-character terminal screen. The answer to that is that if you need more than 3 levels of indentation, you’re screwed anyway, and

Did you know that the Linux kernel has a bug that makes CPU limits for containers extra costly? https://github.com/kubernetes/kubernetes/issues/67577 https://github.com/torvalds/linux/commit/512ac999d2755d2b710... If I recall correctly you need 4.18+ to get the fix.

A decent chunk of it also comprises definitions of names/addresses/values that are (presumably) automatically translated from some authoritative description. This seems to be optimized for portability and consistent mapping to the input, not optimized for size, so there's a lot of stuff like [1]: typedef enum CRC_SRC_SEL { CRC_SRC_0 = 0x00000000, CRC_SRC_1 = 0x00000001, CRC_SRC_2 = 0x00000002, CRC_SRC_3 = 0x00000003, } CRC_SRC_SEL; This might seem silly and redundant, and there are arguably better ways to express it, but the explicit approach makes a lot more sense if you skim the other definitions and see that some are 1-indexed, some have discontinuities, some have non-obvious reserved or o

https://github.com/iovisor/bcc/blob/master/docs/reference_gu... lists the hook points where BPF code can be attached. Also take a look at https://blogs.oracle.com/linux/notes-on-bpf-1 (there are follow-ups - https://blogs.oracle.com/linux/notes-on-bpf-7 has the links at the bottom) and from the Linux source, https://github.com/torvalds/linux/blob/master/include/uapi/l.... https://docs.cilium.io/en/latest/bpf/ is an extensive reference but with an emphasis on the network-related areas (xdp, tc).

That leaves out the fact that the kernel scheduler does in fact issue timed interrupts to all kernel and userspace code running on a given core, except for "critical sections" (where one or more locks are held). That being said, the scheduler is so reliable and so seamless that one need hardly ever worry about it unless a particular block of code must not be interrupted, usually for parts of parallel/multithreaded code that have shared memory or other resources, or sections within the kernel or scheduler itself. More info on the current Linux scheduler here: https://www.kernel.org/doc/html/latest/scheduler/sched-desig... Check out the code here, if you're brave: https://github.com/torvalds/linux/blob/master/kernel/sched/f...

> I don't think turning issues off is a sign of a serious project that should be used by many people in production > Above all, such behaviour signals to me that there is only 1 person making commits / merging PRs and they are kind of tired of OSS (which is fine, by the way). The linux kernel doesn't have an issue page and PRs receive a polite comment on how to send their PRs as patches outside of github. https://github.com/torvalds/linux

Intersting Linux history - Do you by a chance have a link to the commit ? I picked a file from the patch index mail linked above, mm_inline.h, and went scrolling through its history at https://github.com/torvalds/linux/commits/master/include/lin... but didn't see a corresponding change there. I guess the patches might have gotten refactored before merging or something too but would be nice to have a pointer in the Linux tree history that would work as a reference. edit: tried looking for linux/container.h too but that just brings up a newer acpi container related container.h: https://github.com/torvalds/linux/commits/master/include/lin... edit 2: history for linux/cgroup.c starts in a year later in 2007, with this commit: https://github.com/torvalds/linux/commit/ddbcc7e8e50aefe467c... - it has mentions of people from OpenVZ, IBM and a bu

It's not actually pushed to the DMCA repo, it's pushed to a fork. GitHub will show the commit from the fork as if it's from the main repository if you specify the commit hash in the url. See this comment from yesterday for more details [1], with a proof of concept on the linux kernel repo [2]. [1] https://news.ycombinator.com/item?id=24976138 [2] https://github.com/torvalds/linux/tree/5895e21f3c744ed9829e3...