HUGE memory copy

This is from mm/memory.c: copy_huge_page_from_user(), which is to copy memory from userspace to kernel, where the kernel is setup with HUGE page as the page table.

Look at the cond_resched() in the last few lines.

What does that mean? It means the the kernel has voluntarily schedule itself out, and if there are other more urgent process that need to be executed, it will take over the ownership of the CPU to continue execution.

In general, any long or large operation: always introduce cond_resched() to ensure the kernel will not be hijacked by these long running process.

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