Implementation of the new validator disabling strategy (#2226)

Closes https://github.com/paritytech/polkadot-sdk/issues/1966,
https://github.com/paritytech/polkadot-sdk/issues/1963 and
https://github.com/paritytech/polkadot-sdk/issues/1962.

Disabling strategy specification
[here](https://github.com/paritytech/polkadot-sdk/pull/2955). (Updated
13/02/2024)

Implements:
* validator disabling for a whole era instead of just a session
* no more than 1/3 of the validators in the active set are disabled
Removes:
* `DisableStrategy` enum - now each validator committing an offence is
disabled.
* New era is not forced if too many validators are disabled.

Before this PR not all offenders were disabled. A decision was made
based on [`enum
DisableStrategy`](https://github.com/paritytech/polkadot-sdk/blob/bbb6631641f9adba30c0ee6f4d11023a424dd362/substrate/primitives/staking/src/offence.rs#L54).
Some offenders were disabled for a whole era, some just for a session,
some were not disabled at all.

This PR changes the disabling behaviour. Now a validator committing an
offense is disabled immediately till the end of the current era.

Some implementation notes:
* `OffendingValidators` in pallet session keeps all offenders (this is
not changed). However its type is changed from `Vec<(u32, bool)>` to
`Vec<u32>`. The reason is simple - each offender is getting disabled so
the bool doesn't make sense anymore.
* When a validator is disabled it is first added to
`OffendingValidators` and then to `DisabledValidators`. This is done in
[`add_offending_validator`](https://github.com/paritytech/polkadot-sdk/blob/bbb6631641f9adba30c0ee6f4d11023a424dd362/substrate/frame/staking/src/slashing.rs#L325)
from staking pallet.
* In
[`rotate_session`](https://github.com/paritytech/polkadot-sdk/blob/bdbe98297032e21a553bf191c530690b1d591405/substrate/frame/session/src/lib.rs#L623)
the `end_session` also calls
[`end_era`](https://github.com/paritytech/polkadot-sdk/blob/bbb6631641f9adba30c0ee6f4d11023a424dd362/substrate/frame/staking/src/pallet/impls.rs#L490)
when an era ends. In this case `OffendingValidators` are cleared
**(1)**.
* Then in
[`rotate_session`](https://github.com/paritytech/polkadot-sdk/blob/bdbe98297032e21a553bf191c530690b1d591405/substrate/frame/session/src/lib.rs#L623)
`DisabledValidators` are cleared **(2)**
* And finally (still in `rotate_session`) a call to
[`start_session`](https://github.com/paritytech/polkadot-sdk/blob/bbb6631641f9adba30c0ee6f4d11023a424dd362/substrate/frame/staking/src/pallet/impls.rs#L430)
repopulates the disabled validators **(3)**.
* The reason for this complication is that session pallet knows nothing
abut eras. To overcome this on each new session the disabled list is
repopulated (points 2 and 3). Staking pallet knows when a new era starts
so with point 1 it ensures that the offenders list is cleared.

---------

Co-authored-by: ordian <noreply@reusable.software>
Co-authored-by: ordian <write@reusable.software>
Co-authored-by: Maciej <maciej.zyszkiewicz@parity.io>
Co-authored-by: Gonçalo Pestana <g6pestana@gmail.com>
Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>
Co-authored-by: command-bot <>
Co-authored-by: Ankan <10196091+Ank4n@users.noreply.github.com>
This commit is contained in:
Tsvetomir Dimitrov
2024-04-26 16:28:08 +03:00
committed by GitHub
parent 97f7425338
commit 988e30f102
33 changed files with 775 additions and 700 deletions
+1 -2
View File
@@ -654,7 +654,6 @@ parameter_types! {
pub const SlashDeferDuration: sp_staking::EraIndex = 24 * 7; // 1/4 the bonding duration.
pub const RewardCurve: &'static PiecewiseLinear<'static> = &REWARD_CURVE;
pub const MaxNominators: u32 = 64;
pub const OffendingValidatorsThreshold: Perbill = Perbill::from_percent(17);
pub const MaxControllersInDeprecationBatch: u32 = 5900;
pub OffchainRepeat: BlockNumber = 5;
pub HistoryDepth: u32 = 84;
@@ -690,7 +689,6 @@ impl pallet_staking::Config for Runtime {
type EraPayout = pallet_staking::ConvertCurve<RewardCurve>;
type NextNewSession = Session;
type MaxExposurePageSize = ConstU32<256>;
type OffendingValidatorsThreshold = OffendingValidatorsThreshold;
type ElectionProvider = ElectionProviderMultiPhase;
type GenesisElectionProvider = onchain::OnChainExecution<OnChainSeqPhragmen>;
type VoterList = VoterList;
@@ -703,6 +701,7 @@ impl pallet_staking::Config for Runtime {
type EventListeners = NominationPools;
type WeightInfo = pallet_staking::weights::SubstrateWeight<Runtime>;
type BenchmarkingConfig = StakingBenchmarkingConfig;
type DisablingStrategy = pallet_staking::UpToLimitDisablingStrategy;
}
impl pallet_fast_unstake::Config for Runtime {