Fix some cases of swap setting#2426
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@lifubang @cyphar @AkihiroSuda PTAL |
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rebased |
Commit 18ebc51b3cc3 "Reset Swap when memory is set to unlimited (-1)" added handling of the case when a user updates the container limits to set memory to unlimited (-1) but do not set any other limits. Apparently, in this case, if swap limit was previously set, kernel fails to set memory.limit_in_bytes to -1 if memory.memsw.limit_in_bytes is not set to -1. What the above commit fails to handle correctly is the request when Memory is set to -1 and MemorySwap is set to some specific limit N (where N > 0). In this case, the value of N is silently discarded and MemorySwap is set to -1 instead. This is wrong thing to do, as the limit set, even if incorrectly, should not be ignored. Fix this by only assigning MemorySwap == -1 in case it was not explicitly set. Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
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ah, got a typo while rebasing... fixed now |
... and mem+swap is not explicitly set otherwise. This ensures compatibility with cgroupv1 controller which interprets things this way. With this fixed, we can finally enable swap tests for cgroupv2. Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
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LGTM |
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LGTM |
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This fixes two nuances in memory+swap update handling, and finally enables cgroupv2 swap checks in
tests/integration/update.bats.cgroupv1: don't ignore MemorySwap if Memory==-1
Commit 18ebc51b3cc3 "Reset Swap when memory is set to unlimited (-1)"
(see PR #1127) added handling of the case when a user updates the container
limits to set memory to unlimited (-1) but do not set any other limits.
Apparently, in this case, if swap limit was previously set, kernel fails
to set
memory.limit_in_bytesto -1 ifmemory.memsw.limit_in_bytesisnot set to -1.
What the above commit fails to handle correctly is the request when
Memory is set to -1 and MemorySwap is set to some specific limit N
(where N > 0). In this case, the value of N is silently discarded
and MemorySwap is set to -1 instead.
This is wrong thing to do, as the limit set, even if incorrectly,
should not be ignored.
Fix this by only assigning MemorySwap == -1 in case it was not
explicitly set.
cgroupv2: set mem+swap to max if mem set to max
... and mem+swap is not explicitly set otherwise.
This ensures compatibility with cgroupv1 controller which interprets
things this way. Previous attempts to fix this: #2285, #2405.
With this fixed, we can finally enable swap tests for cgroupv2.