From 860f697f0e6560227677a7543ef8eb1eeb258ca8 Mon Sep 17 00:00:00 2001 From: catherinegreen Date: Sat, 13 Sep 2025 21:43:05 +0800 Subject: [PATCH] =?UTF-8?q?Add=20'Chapter=C2=A013=C2=A0=C2=A0Out=20Of=20Me?= =?UTF-8?q?mory=20Management'?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- Chapter%C2%A013%C2%A0%C2%A0Out-Of-Memory-Management.md | 9 +++++++++ 1 file changed, 9 insertions(+) create mode 100644 Chapter%C2%A013%C2%A0%C2%A0Out-Of-Memory-Management.md diff --git a/Chapter%C2%A013%C2%A0%C2%A0Out-Of-Memory-Management.md b/Chapter%C2%A013%C2%A0%C2%A0Out-Of-Memory-Management.md new file mode 100644 index 0000000..a949283 --- /dev/null +++ b/Chapter%C2%A013%C2%A0%C2%A0Out-Of-Memory-Management.md @@ -0,0 +1,9 @@ +
Sadly, it is feasible that the system is not out memory and simply must anticipate IO to complete or for pages to be swapped to backing storage. This is unfortunate, not because the system has memory, however as a result of the perform is being referred to as unnecessarily opening the possibly of processes being unnecessarily killed. Earlier than deciding to kill a process, it goes through the next checklist. It decides by stepping by means of each operating activity and calculating how suitable it is for killing with the [perform](https://imgur.com/hot?q=perform) badness(). This has been chosen to pick a course of that's using a large amount of memory however just isn't that lengthy lived. Processes which have been working a very long time are unlikely to be the reason for memory scarcity so this calculation is probably going to pick a course of that makes use of a lot of memory however has not been working lengthy. ADMIN capabilities, the factors are divided by 4 as it is assumed that root privilege [processes](https://wideinfo.org/?s=processes) are nicely behaved.
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RAWIO capabilities (access to uncooked gadgets) privileges, the factors are additional divided by 4 as it is undesirable to kill a process that has direct access to hardware. RAWIO capabilities, [MemoryWave Guide](http://ww.enhasusg.co.kr/bbs/board.php?bo_table=free&wr_id=1840805) a SIGTERM is sent to offer the method a chance of exiting cleanly, Memory Wave in any other case a SIGKILL is distributed. Yes, thats it, out of memory administration touches a number of subsystems otherwise, there is not much to it. The majority of OOM administration remains basically the identical for 2.6 aside from the introduction of VM accounted objects. ACCOUNT flag, first talked about in Part 4.8. Extra checks might be made to ensure there is memory out there when performing operations on VMAs with this flag set. The principal incentive for this complexity is to avoid the necessity of an OOM killer. SHARED, non-public regions which can be writable and areas arrange shmget(). This is a reasonably easy mechanism, however it permits Linux to remember how a lot memory it has already dedicated to userspace when deciding if it should commit more. 2.6 has a characteristic out there which allows security related kernel modules to override certain kernel functions. There are quite a lot of dummy, or default, functions which may be used which are all listed in safety/dummy.c but the majority do nothing besides return. These pages, minus a 3% reserve for root processes, is the entire amount of memory that is on the market for the request. If the memory is out there, it makes a examine to make sure the entire amount of dedicated memory does not exceed the allowed threshold. TotalSwapPage, where OverCommitRatio is ready by the system administrator. If the whole quantity of committed space shouldn't be too high, 1 shall be returned in order that the allocation can proceed.
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Microcontrollers are hidden inside a surprising variety of merchandise lately. In case your microwave oven has an LED or LCD display screen and a keypad, it contains a microcontroller. All trendy cars comprise at the least one microcontroller, Memory Wave and may have as many as six or seven: The engine is managed by a microcontroller, as are the anti-lock brakes, the cruise control and so forth. Any device that has a distant control virtually actually contains a microcontroller: TVs, VCRs and excessive-finish stereo techniques all fall into this class. You get the thought. Mainly, any product or device that interacts with its consumer has a microcontroller buried inside. In this article, we'll look at microcontrollers so as to understand what they're and the way they work. Then we'll go one step further and talk about how you can start working with microcontrollers your self -- we'll create a digital clock with a microcontroller! We will even build a digital thermometer.
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In the process, you'll study an awful lot about how microcontrollers are utilized in industrial merchandise. What is a Microcontroller? A microcontroller is a pc. All computer systems have a CPU (central processing unit) that executes packages. If you are sitting at a desktop laptop right now reading this article, the CPU in that machine is executing a program that implements the online browser that's displaying this page. The CPU loads this system from someplace. On your desktop machine, the browser program is loaded from the arduous disk. And the computer has some input and output units so it will possibly discuss to individuals. In your desktop machine, [MemoryWave Guide](https://openbimbar.com/index.php?title=Lenovo_OEM_Memory_Reliability._Lower_Costs) the keyboard and mouse are input devices and the monitor and printer are output units. A hard disk is an I/O gadget -- it handles each input and output. The desktop computer you are using is a "general purpose laptop" that can run any of hundreds of applications.
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Microcontrollers are "special objective computers." Microcontrollers do one factor effectively. There are a variety of other widespread traits that define microcontrollers. Microcontrollers are devoted to one activity and run one specific program. The program is saved in ROM (read-only memory) and usually does not change. Microcontrollers are often low-energy gadgets. A desktop laptop is nearly always plugged into a wall socket and might eat 50 watts of electricity. A battery-operated microcontroller would possibly devour 50 milliwatts. A microcontroller has a devoted enter gadget and infrequently (however not at all times) has a small LED or LCD show for output. A microcontroller also takes input from the machine it is controlling and controls the device by sending alerts to different parts in the machine. For example, the microcontroller inside a Television takes input from the remote management and shows output on the Television display screen. The controller controls the channel selector, the speaker system and sure adjustments on the image tube electronics such as tint and brightness.
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