Hi there,
With reference to 2.4.20, I have a few questions:
[1] I was looking at mm/memory.c. I noticed that there is a
difference between minor, and major faults. My guess is that
when a major fault occurs, the mm performs a page-in from the
swap to the memory, whilst a minor fault doesn't? No?
[2] I understand that for the handle_pte_fault routine, the
if structure basically handles page-in. I am trying to figure
out where I can find the code for page-out which I understand
it can be involved the swap, etc. Can someone give me some
pointers as to where I can look for:
- what causes page-outs,
- where in the kernel can i look for them?
[3] in mm/memory.c, in do_wp_page, I am not sure what the
portion of code is about:
// If old_page bit is not set, set it, and test.
if (!TryLockPage(old_page) {
// [QN:] I don't understand what can_share_swap_page() do
// I tried tracing, but i still don't quite get it.
int reuse = can_share_swap_page(old_page);
unlock_page(old_page);
if (reuse) {
// flush the old mapping out of the tlb.
fluse_cache_page(vma, address);
// creates a new mapping with entry in the page table
// [QN:] What is pte_mkyoung?
establish_pte(vma, address, page_table, pte_mkyoung(...
spin_unlock(&mm->page_table_lock);
// [QN:] why didn't the mm->rss increased since it is
// a minor fault? hmm, i am not sure what minor
// fault is though.
return 1; /* minor fault */
}
}
Hear from you guys. Thank you so much.
Cheers,
Eugene
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