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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 72C924000B X-Stat-Signature: aggrwcqh5jq6a13cxfiet4j685ydux87 X-Rspam-User: X-HE-Tag: 1745484343-448958 X-HE-Meta: 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 Dj32gaV5 o2ca1eG7NsKnoXbI45V3lVmf2Y/tJ0AXy94Qxd/Lt8yFk7f4gr+xYEc83mysfgTHJeM8+NRfiaKKyV0w0KHv7VrSIcT5z6S3mTs0OZ212WvFJvsIZAbfbgglSQAjziHHn6fhdCZaJlOs4hVH1guOWAZOMp0ZTZUlbZsTabQJOqVmcBFhQqqOGRpYfihqIHDaxqZrJybUAjTpQFFSJFe+FsHj1d6Sl2rIW06xT+/jZdqBYB3uj3w1f1+lEZFkZEDwtuzb0JrkPTvP5GoshvzxSXwnhXFNVc9e4pSCJu5xC4oQelvPyssOS43ZPnCblwOuJNy3fzv1bVydWrZK6CHPgDpGxVGkeb+Q5apeqXjH/DNZSq8SnvQDlzw5VIz6j88aYYiUAq67DwDCkalho3BiLzyFrXMjpDusQ1mL1VzXiy2xNzP1/30i988GSYs54QL26FJjyq1f0jI2oPEs= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: >> Probably the right way of attaching such metadata to a VMA would be >> remembering it alongside the VMA in a very simple way. >> >> For example, when we perform a reservation we would allocate a refcounted >> object and assign it to the VMA (pointer, xarray, whatever). >> >> Duplicating the VMA would increase the refcount. Freeing a VMA would >> decrease the refcount. >> >> Once the refcount goes to zero, we undo the reservation and free the object. >> >> We would not adjust a reservation on partial VMA unmap (split + unmap A or >> B), but I strongly assume that would just be fine as long as we undo the >> reservation once the refcount goes to 0. > > Yeah this is a really good idea actually, almost kinda what refcounts are > for haha... > > The problem is we talk about this idly here, but neither of us wants to > actually write PAT code I'd say, so this may go nowhere. But maybe one of > us will get so frustrated that we do this anyway but still... > > Then again - actually, is this something you are planning to tackle? I hate this much with that much passion that I'll give it a try for a couple of hours, as it might fix the other issues we are seeing. So far it looks like it cleans up stuff *beautifully*. Even VM_PAT can go ... :) ... and I think we still have space in vm_area_struct without increasing it beyond 192 bytes. -- Cheers, David / dhildenb