Harry (Hyeonggon) Yoo
Posts
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112- Linux Kernel Developer @ Oracle (Linux Kernel MM) (2025.02 ~ Present)
- Reviewer for the Linux Slab subsystem
- Former Intern @ NVIDIA, SK Hynix, Panmnesia (Security, MM and CXL)
- B.Sc. in Computer Science & Engineering, Chungnam National University (Class of 2025)
Opinions are my own.
My interests are:
Memory Management,
Computer Architecture,
Circuit Design,
Virtualization
Harry (Hyeonggon) Yoo
hyeyoo
Edited 8 months ago
Reviewing what I learned about Linux context switching years ago because I forgot how it works.
A note for the next time I forget:
Context is switched from one kernel context to another. When a user process is going to be rescheduled, it first switches from user context to its kernel context after storing the registers on the kernel stack (pt_regs) due to a scheduler tick.
When switching between kernel contexts, only callee-saved registers are restored (from cpu_context in thread_struct), as the other registers should have been stored on the kernel stack (by the calling convention) before calling __switch_to()->cpu_switch_to() (on ARM64).
A note for the next time I forget:
Context is switched from one kernel context to another. When a user process is going to be rescheduled, it first switches from user context to its kernel context after storing the registers on the kernel stack (pt_regs) due to a scheduler tick.
When switching between kernel contexts, only callee-saved registers are restored (from cpu_context in thread_struct), as the other registers should have been stored on the kernel stack (by the calling convention) before calling __switch_to()->cpu_switch_to() (on ARM64).
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Harry (Hyeonggon) Yoo
hyeyoo
Edited 8 months ago
init_task is not the task_struct of the init process but of the swapper process.
It confuses me every time.
It confuses me every time.
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LWN.net is now @LWN@lwn.net
LWN@fosstodon.orgSeveral Russian developers lose kernel maintainership status
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@ljs @vbabka @lkundrak
It has gotten long as it has a bit of history :P
- Someone fixed a memory leak but introduced a double-free.
- Another person fixed the double-free, reintroducing the leak.
- A third person then fixed the leak, but reverted it after noticing it introduced another double-free.
It's been there because handling all error cases properly is complicated. Luckily, it's a kind of bug that someone is very unlikely to encounter, and it only leaks 32 bytes of memory.
It has gotten long as it has a bit of history :P
- Someone fixed a memory leak but introduced a double-free.
- Another person fixed the double-free, reintroducing the leak.
- A third person then fixed the leak, but reverted it after noticing it introduced another double-free.
It's been there because handling all error cases properly is complicated. Luckily, it's a kind of bug that someone is very unlikely to encounter, and it only leaks 32 bytes of memory.
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printf of persia 🇺🇦🇨🇿✌️🌻
lkundrak@metalhead.club
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Harry (Hyeonggon) Yoo
hyeyoo
Submitting my school assignment for “Contributing to Open Source Projects” class to linux-mm
https://lore.kernel.org/linux-mm/20241021091413.154775-1-42.hyeyoo@gmail.com/T
https://lore.kernel.org/linux-mm/20241021091413.154775-1-42.hyeyoo@gmail.com/T
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hyeyoo
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Harry (Hyeonggon) Yoo
hyeyoo
@lkundrak @vbabka
It reminds me of Vlasta's old LWN articles named "Patching until the COWs come home"
part 1 - https://lwn.net/Articles/849638/
part 2 - https://lwn.net/Articles/849876/
It reminds me of Vlasta's old LWN articles named "Patching until the COWs come home"
part 1 - https://lwn.net/Articles/849638/
part 2 - https://lwn.net/Articles/849876/
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