On Tue, 18 Jul 2023 16:36:53 -0500, Dave Hansen <dave.hansen@xxxxxxxxx>
wrote:
On 7/18/23 14:22, Haitao Huang wrote:
I agree this is the race. But for this to happen, that is at #1 you have
only one non-SECS page left so #3 can happen. That means it is already
high pressure
I think our definitions of memory pressure differ.
Pressure is raised by allocations and dropped by reclaim. This
raise->drop cycle is (or should be) time-limited and can't take forever.
The reclaim either works in a short period of time or something dies.
If allocations are transient, pressure is transient.
Let's say a pressure blip (a one-time event) comes along and pages out
that second-to-last page. That's pretty low pressure. Years pass. The
enclave never gets run. Nothing pages the second-to-last page back in.
A second pressure blip comes along. The SECS page gets paged out.
That's two pressure blips in, say 10 years. Is that "high pressure"?
Okay, that explains. I would consider it still triggered by high pressure
blips :-)
But I agree we can drop the mentioning of pressure altogether and just
state the race so no confusions.
Thanks
Haitao
