Lei Yang wrote:
Could anyone pls tell me what exactly happens when an executable sitting in hard disk is running?
I understand that the file will be "memory-mapped". Since the requested data is not in RAM when it is read, kernel would try to read from the file region that does not exist in physical memory. A page fault is generated, which traps into the virtual memory management system. This system then allocates physical memory, then schedules a file read to bring the data into memory.
I am a little bit confused here, is that when the page fault is generated, kernel will load pages of data of executable file from hard disk to a certain buffer area in memory and then map this area to process address space; or is the file itself on hard disk mapped to address space?
When the page fault happens, the kernel reads a whole page of data from
disk to a 'struct page' and sets the process' page table to point to
this page.
Thank you in advance!
Lei
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