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Replace mark_(un)blocked with (un)park#155997

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zetanumbers wants to merge 2 commits intorust-lang:mainfrom
zetanumbers:waiter_thread_index
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Replace mark_(un)blocked with (un)park#155997
zetanumbers wants to merge 2 commits intorust-lang:mainfrom
zetanumbers:waiter_thread_index

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@zetanumbers zetanumbers commented Apr 30, 2026

So here's the thing. We can store condvar within rustc_thread_pool and do all of bookkeeping stuff there. I thought about making a QueryLatch a simple AtomicU64 of which each bit represents a waiting thread ordered by its worker thread index. It's not as simple as that in this PR, but by moving query waiter's condvar we are finally able to use Arc::get_mut for the cycle smart pointer.

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rustbot commented Apr 30, 2026

These commits modify the Cargo.lock file. Unintentional changes to Cargo.lock can be introduced when switching branches and rebasing PRs.

If this was unintentional then you should revert the changes before this PR is merged.
Otherwise, you can ignore this comment.

@rustbot rustbot added A-query-system Area: The rustc query system (https://rustc-dev-guide.rust-lang.org/query.html) S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Apr 30, 2026
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rustbot commented Apr 30, 2026

r? @mu001999

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zetanumbers commented Apr 30, 2026

r? @nnethercote

@rustbot rustbot assigned nnethercote and unassigned mu001999 Apr 30, 2026
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bjorn3 commented Apr 30, 2026

Do I understand correctly that blocking no longer releases jobserver tokens?

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zetanumbers commented Apr 30, 2026

Do I understand correctly that blocking no longer releases jobserver tokens?

No, it does.

https://github.com/rust-lang/rust/pull/155997/changes#diff-d53039531e1e9671c009133110e61e29aa96031b55b1f69d4f2a71e89860911eR627-R631

Or am I missing something?

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bjorn3 commented Apr 30, 2026

Missed those calls.

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nnethercote reviewed May 1, 2026
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@nnethercote nnethercote left a comment •
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Seems ok to me, though once again this is code I don't understand well.

@Zoxc: any thoughts before I approve?

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Comment thread compiler/rustc_middle/src/query/job.rs
pub struct QueryWaiter<'tcx> {
pub parent: Option<QueryJobId>,
pub condvar: Condvar,
// FIXME: could be made u16 due to rustc_thread_pool limiting number of threads
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I don't think shrinking this field will change the struct size because the other fields are all 64-bits (on 64-bit platforms). I suggest just removing the comment.

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nnethercote commented May 1, 2026

Let's check perf:

@bors try @rust-timer queue

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rust-timer commented May 1, 2026

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

@rustbot rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label May 1, 2026
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rust-bors Bot commented May 1, 2026 •
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⌛ Trying commit 0d8d68d with merge 03472e2…

To cancel the try build, run the command @bors try cancel.

Workflow: https://github.com/rust-lang/rust/actions/runs/25202610893

rust-bors Bot pushed a commit that referenced this pull request May 1, 2026
@bors
Auto merge of #155997 - zetanumbers:waiter_thread_index, r=<try>
03472e2 
Replace `mark_(un)blocked` with `(un)park`
@rust-bors rust-bors Bot added the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label May 1, 2026
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rust-bors Bot commented May 1, 2026

💥 Test timed out after 21600s

@rust-bors rust-bors Bot removed the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label May 1, 2026
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Zoxc commented May 1, 2026

It looks good to me.

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A-query-system Area: The rustc query system (https://rustc-dev-guide.rust-lang.org/query.html) S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. S-waiting-on-perf Status: Waiting on a perf run to be completed. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.

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