Messages in this thread | | | Date | Wed, 9 May 2001 14:52:28 -0300 (BRT) | From | Marcelo Tosatti <> | Subject | Race between try_to_swap_out() and swapin_readahead() |
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Ok, what prevents this from happening:
CPU0 CPU1
try_to_swap_out() ...
entry = get_swap_page(); if (!entry.val) goto out_unlock_restore;
swapin_readahead() finds valid swap entry just allocated by try_to_swap_out() lookup_swap_cache() fails... new_page = alloc_page(); lock_page(new_page); add_to_swap_cache(new_page, entry); rw_swap_page(READ, new_page); return new_page;
/* Add it to the swap cache and mark it dirty */ add_to_swap_cache(page, entry); set_page_dirty(page);
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We'll end up with two pages with the same index in the hash tables, and one of them has crap read from swap.
I know the window is really really small, but anyway...
Comments?
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