*: fix memory leak introduced by timer.After

[lhy1024]

What problem does this PR solve?

Issue Number: Close #6719

What is changed and how does it work?

1. use sync.Pool to maintain TSDeadline

2. replace time.After with NewTimer and timer.Stop, or ticker

• for loop retry use ticker, if the loop is broken, we will stop it by deferring or checking each branch

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)

only bench with forward c.serviceModeUpdateCb(pdpb.ServiceMode_PD_SVC_MODE)

~/pingcap/tiup/bin/tiup-playground v6.6.0 --pd.micro '[{"api":true, "amount":3},{"tso":true,"amount":3}]' --pd.binpath ~/pd-cse/bin/pd-server --db.binpath ~/tidb-cse/bin/tidb-server --kv 3 --db 1 --tiflash 0 --db.port 14000 --host 192.168.8.88

./pd-tso-bench -v -duration 250000s -client 10 -c 1 -interval 3s -pd 192.168.8.88:2379

Before this pr

After this pr

Release note

None.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• binshi-bing
• rleungx

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[codecov]

Codecov Report

Patch coverage: 75.65% and project coverage change: +0.30 🎉

Comparison is base (05f71e0) 74.27% compared to head (a40b03a) 74.58%.

❗ Current head a40b03a differs from pull request most recent head ac7bb65. Consider uploading reports for the commit ac7bb65 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6720      +/-   ##
==========================================
+ Coverage   74.27%   74.58%   +0.30%     
==========================================
  Files         410      418       +8     
  Lines       42871    43706     +835     
==========================================
+ Hits        31844    32599     +755     
- Misses       8169     8215      +46     
- Partials     2858     2892      +34     

Flag	Coverage Δ
unittests	74.58% <75.65%> (+0.30%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pkg/keyspace/keyspace.go	62.32% <0.00%> (+0.11%)	⬆️
pkg/mcs/discovery/register.go	61.53% <33.33%> (-13.98%)	⬇️
server/grpc_service.go	52.87% <33.33%> (+0.52%)	⬆️
pkg/election/lease.go	85.88% <50.00%> (-3.87%)	⬇️
client/timerpool/pool.go	60.00% <60.00%> (ø)
client/client.go	62.66% <66.66%> (-0.30%)	⬇️
client/resource_manager_client.go	70.69% <66.66%> (+1.68%)	⬆️
client/tso_stream.go	74.46% <66.66%> (-1.62%)	⬇️
pkg/mcs/resourcemanager/server/server.go	53.38% <66.66%> (+0.39%)	⬆️
pkg/mcs/utils/util.go	61.53% <66.66%> (+6.99%)	⬆️
... and 9 more

... and 38 files with indirect coverage changes

☔ View full report in Codecov by Sentry.
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[binshi-bing]

left one comment. The reset LGTM

[binshi-bing]

How about we use sync.Pool for TSDeadline and a timer is always attached to a TSDeadline and can be reused and reset every time? In this way, we use sync.Pool for both TSDeadline and Timer in fact.

[lhy1024]

It will make code complex and test show that done and cancel don't cost some memory.

[binshi-bing]

You're right. Timer is the main issue and we can keep smaller change.

[binshi-bing]

LGTM

[binshi-bing]

You're right. Timer is the main issue and we can keep smaller change.

[binshi-bing]

LGTM

[JmPotato]

/merge

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[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: a40b03a

[ti-chi-bot]

@lhy1024: Your PR was out of date, I have automatically updated it for you.

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