[release/7.0] fix lower heap hard limit condition for regions #76588
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
![github-actions[bot]](https://avatars.githubusercontent.com/in/15368?s=60&v=4){kind=small}
|
Tagging subscribers to this area: @dotnet/gc Issue DetailsBackport of #76407 to release/7.0 /cc @mangod9 Customer ImpactTestingRiskIMPORTANT: Is this backport for a servicing release? If so and this change touches code that ships in a NuGet package, please make certain that you have added any necessary package authoring and gotten it explicitly reviewed.
|
jeffschwMSFT
approved these changes
Oct 4, 2022
rbhanda
added
Servicing-approved
oversight from the main PR.
Maoni0
approved these changes
Oct 4, 2022
|
Approved, signed-off, CI is green. Ready to merge. |
ghost
locked as resolved and limited conversation to collaborators
Sign up for free
to subscribe to this conversation on GitHub.
Already have an account?
Sign in.
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Backport of #76407 to release/7.0
/cc @mangod9
Customer Impact
This fixes a customer reported issue here: #76199, where in the docker config specifies a memory limit (something under 512mb) but with unbound cpu, the GC correctly scales down the number of heaps, but each heap still has a minimum size of 4mb (region_size) * 19 (min_regions_per_heap). This causes an initialization failure since the memory reservation size is 2 * heap_hard_limit. We have now increased this to 5x and also dynamically adjust region size to 4, 2 or 1mb. With this change we are now at par with segments and support very low heap_hard_limits (4mb minimum, which is able to run a simple webapi app)
Testing
validated in local experiments that a heap_hard_limit of as low as 4mb can now be specified, which is similar to what it was with segments. We also adjusted the reservation size when per heap hard_limit is specified
Risk
low, only should affect scenarios where memory hard limit is low. It only affects reservation size, but actual committed sizes should be equivalent.
IMPORTANT: Is this backport for a servicing release? If so and this change touches code that ships in a NuGet package, please make certain that you have added any necessary package authoring and gotten it explicitly reviewed.