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Kernel: Use a raw VM region for sorting ELF symbols instead of a Vector.

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This avoids putting pressure on kmalloc() during backtrace symbolication.
Since we dump backtrace for every process that exits, this is actually a
decent performance improvement for things like GCC that chain a lot of
processes together.
This commit is contained in:
Andreas Kling 2019-06-27 10:49:49 +02:00
parent 7a3f59ae3f
commit f83263a72b
Notes: sideshowbarker 2024-07-19 13:28:43 +09:00
2 changed files with 36 additions and 6 deletions
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30
AK/ELF/ELFLoader.cpp
View file

@ -2,6 +2,10 @@
#include <AK/QuickSort.h>
#include <AK/kstdio.h>
#ifdef KERNEL
#include <Kernel/VM/MemoryManager.h>
#endif
//#define ELFLOADER_DEBUG
ELFLoader::ELFLoader(const byte* buffer)
@ -79,6 +83,24 @@ char* ELFLoader::symbol_ptr(const char* name)
String ELFLoader::symbolicate(dword address) const
{
SortedSymbol* sorted_symbols = nullptr;
#ifdef KERNEL
if (!m_sorted_symbols_region) {
m_sorted_symbols_region = MM.allocate_kernel_region(PAGE_ROUND_UP(m_image.symbol_count() * sizeof(SortedSymbol)), "Sorted symbols");
sorted_symbols = (SortedSymbol*)m_sorted_symbols_region->vaddr().as_ptr();
dbgprintf("sorted_symbols: %p\n", sorted_symbols);
size_t index = 0;
m_image.for_each_symbol([&](auto& symbol) {
sorted_symbols[index++] = { symbol.value(), symbol.name() };
return IterationDecision::Continue;
});
quick_sort(sorted_symbols, sorted_symbols + m_image.symbol_count(), [](auto& a, auto& b) {
return a.address < b.address;
});
} else {
sorted_symbols = (SortedSymbol*)m_sorted_symbols_region->vaddr().as_ptr();
}
#else
if (m_sorted_symbols.is_empty()) {
m_sorted_symbols.ensure_capacity(m_image.symbol_count());
m_image.for_each_symbol([this](auto& symbol) {
@ -89,12 +111,14 @@ String ELFLoader::symbolicate(dword address) const
return a.address < b.address;
});
}
sorted_symbols = m_sorted_symbols.data();
#endif
for (int i = 0; i < m_sorted_symbols.size(); ++i) {
if (m_sorted_symbols[i].address > address) {
for (size_t i = 0; i < m_image.symbol_count(); ++i) {
if (sorted_symbols[i].address > address) {
if (i == 0)
return "!!";
auto& symbol = m_sorted_symbols[i - 1];
auto& symbol = sorted_symbols[i - 1];
return String::format("%s +%u", symbol.name, address - symbol.address);
}
}

12
AK/ELF/ELFLoader.h
View file

@ -4,11 +4,13 @@
#include <AK/HashMap.h>
#include <AK/OwnPtr.h>
#include <AK/Vector.h>
#if defined(KERNEL)
# include <Kernel/VirtualAddress.h>
#endif
#include <AK/ELF/ELFImage.h>
#ifdef KERNEL
#include <Kernel/VirtualAddress.h>
class Region;
#endif
class ELFLoader {
public:
explicit ELFLoader(const byte*);
@ -50,5 +52,9 @@ private:
dword address;
const char* name;
};
#ifdef KERNEL
mutable RefPtr<Region> m_sorted_symbols_region;
#else
mutable Vector<SortedSymbol> m_sorted_symbols;
#endif
};