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Merge pull request #483 from phantez/memory

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Corrected typos in section: memory
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0xAX 2017-05-30 00:34:52 +06:00 committed by GitHub
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mm/linux-mm-3.md
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@ -61,7 +61,7 @@ $ sudo cat /proc/ioports
...
```
can show us lists of currently registered port regions used for input or output communication with a device. All memory-mapped I/O addresses are not used by the kernel directly. So, before the Linux kernel can use such memory, it must to map it to the virtual memory space which is the main purpose of the `ioremap` mechanism. Note that we saw only early `ioremap` in the previous [part](https://0xax.gitbooks.io/linux-insides/content/mm/linux-mm-2.html). Soon we will look at the implementation of the non-early `ioremap` function. But before this we must learn other things, like a different types of memory allocators and etc., because in other way it will be very difficult to understand it.
can show us lists of currently registered port regions used for input or output communication with a device. All memory-mapped I/O addresses are not used by the kernel directly. So, before the Linux kernel can use such memory, it must map it to the virtual memory space which is the main purpose of the `ioremap` mechanism. Note that we saw only early `ioremap` in the previous [part](https://0xax.gitbooks.io/linux-insides/content/mm/linux-mm-2.html). Soon we will look at the implementation of the non-early `ioremap` function. But before this we must learn other things, like a different types of memory allocators and etc., because in other way it will be very difficult to understand it.
So, before we will move on to the non-early [memory management](https://en.wikipedia.org/wiki/Memory_management) of the Linux kernel, we will see some mechanisms which provide special abilities for [debugging](https://en.wikipedia.org/wiki/Debugging), check of [memory leaks](https://en.wikipedia.org/wiki/Memory_leak), memory control and etc. It will be easier to understand how memory management arranged in the Linux kernel after learning of all of these things.
@ -307,7 +307,7 @@ bool kmemcheck_active(struct pt_regs *regs)
}
```
The `kmemcheck_context` is structure which describes current state of the `kmemcheck` mechanism. It stored unitialized addresses, number of such addresses and etc. The `balance` field of this structure represents current state of the `kmemcheck` or in other words it can tell us did `kmemcheck` already hid pages or not yet. If the `data->balance` is greater than zero, the `kmemcheck_hide` function will be called. This means than `kmemecheck` already set `present` bit for given pages and now we need to hide pages again to to cause nest step page fault. This function will hide addresses of pages again by unsetting of `present` bit. This means that one session of `kmemcheck` already finished and new page fault occured. At the first step the `kmemcheck_active` will return false as the `data->balance` is zero for the start and the `kmemcheck_hide` will not be called. Next, we may see following line of code in the `do_page_fault`:
The `kmemcheck_context` is structure which describes current state of the `kmemcheck` mechanism. It stored unitialized addresses, number of such addresses and etc. The `balance` field of this structure represents current state of the `kmemcheck` or in other words it can tell us did `kmemcheck` already hid pages or not yet. If the `data->balance` is greater than zero, the `kmemcheck_hide` function will be called. This means than `kmemecheck` already set `present` bit for given pages and now we need to hide pages again to cause next step to page fault. This function will hide addresses of pages again by unsetting of `present` bit. This means that one session of `kmemcheck` already finished and new page fault occured. At the first step the `kmemcheck_active` will return false as the `data->balance` is zero for the start and the `kmemcheck_hide` will not be called. Next, we may see following line of code in the `do_page_fault`:
```C
if (kmemcheck_fault(regs, address, error_code))