fix(mm/pagecache): track vma on filemap prefault #1677
Merged
Conversation
This file contains hidden or 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
- Mark filemap prefaulted pages with insert_vma to keep map_count consistent with mappings. - Avoid redundant mapping in filemap_map_pages when a PTE already exists. - Ensure page-cache created pages are fully initialized and UPTODATE. **Motivation** Setting PG_UPTODATE enables prefault mapping via filemap_map_pages. Those pages were mapped without updating vma_set, causing map_count to stay at 0 and enabling reclaim/writeback paths to treat mapped pages as unmapped, leading to mmap hangs. The fix aligns VMA tracking with prefault mappings and adds diagnostics to validate mapping correctness. Signed-off-by: longjin <longjin@DragonOS.org>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
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Outdated suggestions cannot be applied.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.
Motivation
Setting PG_UPTODATE enables prefault mapping via filemap_map_pages. Those pages were mapped without updating vma_set, causing map_count to stay at 0 and enabling reclaim/writeback paths to treat mapped pages as unmapped, leading to mmap hangs. The fix aligns VMA tracking with prefault mappings and adds diagnostics to validate mapping correctness.