4fea7b8bb1
The PAL API previously allowed for returning more memory than asked for. This was when the PAL performed the alignment work, now this is done in large alloc, so removing from the PAL.
54 lines
1.2 KiB
C++
54 lines
1.2 KiB
C++
#pragma once
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#include "pal_bsd.h"
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namespace snmalloc
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{
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/**
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* FreeBSD-specific platform abstraction layer.
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*
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* This adds aligned allocation using `MAP_ALIGNED` to the generic BSD
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* implementation. This flag is supported by NetBSD and FreeBSD.
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*/
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template<class OS>
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class PALBSD_Aligned : public PALBSD<OS>
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{
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public:
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/**
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* Bitmap of PalFeatures flags indicating the optional features that this
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* PAL supports.
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*
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* This class adds support for aligned allocation.
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*/
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static constexpr uint64_t pal_features =
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AlignedAllocation | PALBSD<OS>::pal_features;
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/**
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* Reserve memory at a specific alignment.
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*/
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template<bool committed>
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void* reserve(size_t size, size_t align) noexcept
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{
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// Alignment must be a power of 2.
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assert(align == bits::next_pow2(align));
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align = bits::max<size_t>(4096, align);
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size_t log2align = bits::next_pow2_bits(align);
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void* p = mmap(
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nullptr,
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size,
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PROT_READ | PROT_WRITE,
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MAP_PRIVATE | MAP_ANONYMOUS | MAP_ALIGNED(log2align),
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-1,
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0);
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if (p == MAP_FAILED)
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PALBSD<OS>::error("Out of memory");
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return p;
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}
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};
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} // namespace snmalloc
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