fix: it is so slow to create a Pod requiring IP from a super big CIDR

[lou-lan]

git-cherry-pick #3583

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 74.60317% with 16 lines in your changes missing coverage. Please review.

Project coverage is 81.05%. Comparing base (1c0cd94) to head (9b1e15c).

Additional details and impacted files

[](https://app.codecov.io/gh/spidernet-io/spiderpool/pull/3629?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=spidernet-io) ```diff @@ Coverage Diff @@ ## release-v0.9 #3629 +/- ## ================================================ - Coverage 81.12% 81.05% -0.08% ================================================ Files 50 50 Lines 5373 5415 +42 ================================================ + Hits 4359 4389 +30 - Misses 856 864 +8 - Partials 158 162 +4 ``` | [Flag](https://app.codecov.io/gh/spidernet-io/spiderpool/pull/3629/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=spidernet-io) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/spidernet-io/spiderpool/pull/3629/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=spidernet-io) | `81.05% <74.60%> (-0.08%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=spidernet-io#carryforward-flags-in-the-pull-request-comment) to find out more. | [Files](https://app.codecov.io/gh/spidernet-io/spiderpool/pull/3629?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=spidernet-io) | Coverage Δ | | |---|---|---| | [pkg/ippoolmanager/ippool\_manager.go](https://app.codecov.io/gh/spidernet-io/spiderpool/pull/3629?src=pr&el=tree&filepath=pkg%2Fippoolmanager%2Fippool_manager.go&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=spidernet-io#diff-cGtnL2lwcG9vbG1hbmFnZXIvaXBwb29sX21hbmFnZXIuZ28=) | `85.88% <100.00%> (ø)` | | | [pkg/subnetmanager/subnet\_validate.go](https://app.codecov.io/gh/spidernet-io/spiderpool/pull/3629?src=pr&el=tree&filepath=pkg%2Fsubnetmanager%2Fsubnet_validate.go&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=spidernet-io#diff-cGtnL3N1Ym5ldG1hbmFnZXIvc3VibmV0X3ZhbGlkYXRlLmdv) | `91.86% <100.00%> (-0.04%)` | :arrow_down: | | [pkg/subnetmanager/subnet\_manager.go](https://app.codecov.io/gh/spidernet-io/spiderpool/pull/3629?src=pr&el=tree&filepath=pkg%2Fsubnetmanager%2Fsubnet_manager.go&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=spidernet-io#diff-cGtnL3N1Ym5ldG1hbmFnZXIvc3VibmV0X21hbmFnZXIuZ28=) | `41.48% <0.00%> (ø)` | | | [pkg/ip/ip.go](https://app.codecov.io/gh/spidernet-io/spiderpool/pull/3629?src=pr&el=tree&filepath=pkg%2Fip%2Fip.go&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=spidernet-io#diff-cGtnL2lwL2lwLmdv) | `87.64% <74.57%> (-5.27%)` | :arrow_down: |