35 lines
1.1 KiB
Rust
35 lines
1.1 KiB
Rust
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#![cfg_attr(feature = "alloc_trait", feature(allocator_api))]
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extern crate jemallocator;
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use jemallocator::Jemalloc;
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#[global_allocator]
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static A: Jemalloc = Jemalloc;
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#[test]
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#[cfg(feature = "alloc_trait")]
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fn shrink_in_place() {
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unsafe {
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use std::alloc::{Alloc, Layout};
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// allocate 7 bytes which end up in the 8 byte size-class as long as
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// jemalloc's default size classes are used:
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let orig_sz = 7;
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let orig_l = Layout::from_size_align(orig_sz, 1).unwrap();
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let ptr = Jemalloc.alloc(orig_l).unwrap();
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// try to grow it in place by 1 byte - it should grow without problems:
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let new_sz = orig_sz + 1;
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assert!(Jemalloc.grow_in_place(ptr, orig_l, new_sz).is_ok());
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let new_l = Layout::from_size_align(orig_sz + 1, 1).unwrap();
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// trying to do it again fails because it would require moving the
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// allocation to a different size class which jemalloc's xallocx does not
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// do:
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let new_sz = new_sz + 1;
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assert!(Jemalloc.grow_in_place(ptr, new_l, new_sz).is_err());
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Jemalloc.dealloc(ptr, new_l)
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}
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}
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