refactor: remove atomic op in #591

[MrCroxx]

What's changed and what's your intention?

Please explain IN DETAIL what the changes are in this PR and why they are needed. :D

As title.

Checklist

• I have written the necessary rustdoc comments
• I have added the necessary unit tests and integration tests
• I have passed make all (or make fast instead if the old tests are not modified) in my local environment.

Related issues or PRs (optional)

#591

[codecov]

Codecov Report

Attention: Patch coverage is 87.95181% with 10 lines in your changes missing coverage. Please review.

Project coverage is 86.06%. Comparing base (ef3f139) to head (c30902e).

Files	Patch %	Lines
foyer-memory/src/generic.rs	89.65%	6 Missing ⚠️
foyer-memory/src/cache.rs	78.94%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #593      +/-   ##
==========================================
+ Coverage   86.02%   86.06%   +0.03%     
==========================================
  Files          59       59              
  Lines        7643     7683      +40     
==========================================
+ Hits         6575     6612      +37     
- Misses       1068     1071       +3     

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[MrCroxx]

Benchmark

rm -rf /6536/foyer && cargo build --release && RUST_BACKTRACE=1 RUST_LOG=info ./target/release/foyer-bench --dir /6536/foyer --mem 64 --disk 102400 --file-size 64 --get-range 10000 --flushers 4 --reclaimers 4 --time 10 --writers 256 --w-rate 4 --admission-rate-limit 500 --readers 1024 --r-rate 1 --runtime --compression none --distribution zipf --distribution-zipf-s 0.8 --metrics

main

Total:
disk total iops: 3546.3
disk total throughput: 583.6 MiB/s
disk read iops: 1249.5
disk read throughput: 83.0 MiB/s
disk write iops: 2296.9
disk write throughput: 500.6 MiB/s
insert iops: 14259.3/s
insert throughput: 891.3 MiB/s
insert lat p50: 4us
insert lat p90: 7us
insert lat p99: 18us
insert lat p999: 50us
insert lat p9999: 181us
insert lat p99999: 353us
insert lat pmax: 699us
get iops: 17300.1/s
get miss: 8.43% 
get throughput: 1.0 GiB/s
get hit lat p50: 4us
get hit lat p90: 947us
get hit lat p99: 2863us
get hit lat p999: 4447us
get hit lat p9999: 5503us
get hit lat p99999: 6495us
get hit lat pmax: 8031us
get miss lat p50: 98us
get miss lat p90: 955us
get miss lat p99: 2639us
get miss lat p999: 3999us
get miss lat p9999: 4927us
get miss lat p99999: 5599us
get miss lat pmax: 5599us

PR

Total:
disk total iops: 3506.5
disk total throughput: 582.9 MiB/s
disk read iops: 1240.7
disk read throughput: 82.4 MiB/s
disk write iops: 2265.8
disk write throughput: 500.5 MiB/s
insert iops: 14248.6/s
insert throughput: 890.6 MiB/s
insert lat p50: 4us
insert lat p90: 7us
insert lat p99: 16us
insert lat p999: 36us
insert lat p9999: 157us
insert lat p99999: 385us
insert lat pmax: 783us
get iops: 17299.2/s
get miss: 8.43% 
get throughput: 1.0 GiB/s
get hit lat p50: 4us
get hit lat p90: 863us
get hit lat p99: 2815us
get hit lat p999: 4383us
get hit lat p9999: 5983us
get hit lat p99999: 6879us
get hit lat pmax: 7423us
get miss lat p50: 49us
get miss lat p90: 1023us
get miss lat p99: 2751us
get miss lat p999: 4063us
get miss lat p9999: 5183us
get miss lat p99999: 5727us
get miss lat pmax: 5727us

[MrCroxx]

Duplicated with #594