Would the idea be to fail swap_readpage() on the one that comes last,
simply retrying to lookup the page?
The idea would be that T2's arch_swap_readpage() could potentially not
find tags if it ran after swap_free(), so T2 would produce a page
without restored tags. But that wouldn't matter, because T1 reaching
swap_free() means that T2 will follow the goto at [1] after waiting
for T1 to unlock at [2], and T2's page will be discarded.
Ah, right.
This might be a naive question, but how does MTE play along with shared
anonymous pages?
It should work fine. shmem_writepage() calls swap_writepage() which
calls arch_prepare_to_swap() to write the tags. And
shmem_swapin_folio() has a call to arch_swap_restore() to restore
them.
Sorry, I meant actual anonymous memory pages, not shmem. Like, anonymous
pages that are COW-shared due to fork() or KSM.
How does MTE, in general, interact with that? Assume one process ends up
modifying the tags ... and the page is COW-shared with a different
process that should not observe these tag modifications.
--
Thanks,
David / dhildenb
