Bifurcate megapage caches into compact and non-compact variants #47384
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EWS run on previous version of this PR (hash ac8b9b0) |
https://bugs.webkit.org/show_bug.cgi?id=295062 rdar://154434088 Reviewed by NOBODY (OOPS!). Adds new compact megapage caches to basic libpas heaps to support separate heap management for compact pointers. * Source/bmalloc/libpas/src/libpas/pas_basic_heap_page_caches.h: * Source/bmalloc/libpas/src/libpas/pas_create_basic_heap_page_caches_with_reserved_memory.c: (allocate_from_large): (allocate_from_megapages): (pas_create_basic_heap_page_caches_with_reserved_memory): * Source/bmalloc/libpas/src/libpas/pas_heap_config_utils_inlines.h: * Source/bmalloc/libpas/src/libpas/pas_megapage_cache.h:
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EWS run on current version of this PR (hash 2b72d76) |
| pas_megapage_cache_construct( | ||
| &caches->small_compact_exclusive_segregated_megapage_cache, | ||
| allocate_from_large, | ||
| pas_megapage_cache_size_small_compact); | ||
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| pas_megapage_cache_construct( | ||
| &caches->small_compact_other_megapage_cache, | ||
| allocate_from_large, | ||
| pas_megapage_cache_size_small_compact); | ||
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| pas_megapage_cache_construct( | ||
| &caches->medium_compact_megapage_cache, | ||
| allocate_from_large, | ||
| pas_megapage_cache_size_medium_compact); |
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It's unfortunate that we need to allocate 32MiB for each of these (if I'm understanding correctly).
To some extent that doesn't matter since it's all VA, but some amount of that is faulted in -- does this show up at all on memory benchmarks?
| pas_megapage_cache_construct( | ||
| &caches->small_compact_exclusive_segregated_megapage_cache, | ||
| allocate_from_large, | ||
| pas_megapage_cache_size_small_compact); | ||
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| pas_megapage_cache_construct( | ||
| &caches->small_compact_other_megapage_cache, | ||
| allocate_from_large, | ||
| pas_megapage_cache_size_small_compact); |
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Do these strictly need to be separate for functional reasons, or is it just for clarity's sake? I'm OK with "for clarity's sake" I just want to understand if the code would break sans this.
| @@ -37,6 +37,29 @@ | |||
| #include "pas_reserved_memory_provider.h" | |||
| #include "pas_segregated_shared_page_directory.h" | |||
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| static pas_allocation_result allocate_from_large( | |||
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I don't really understand what's going on here. Why does the "allocate_from_megapages" now allocate from the megapage_large_heap, and this function now do what it was doing beforehand?
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