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[wasm] Grow reserved code space exponentially

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If a new code allocation request cannot be fulfilled, do not just
reserve enough to fulfill this one request, but request at least 20
percent of the total reserved code space so far. This ensures that
the reserved space grows exponentially instead of linearly.

R=mstarzinger@chromium.org

Bug: chromium:987560
Change-Id: I3fc4dd0f7acee2a380495a87c0425c58058551bc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1718144
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62910}
This commit is contained in:
Clemens Hammacher 2019-07-25 12:02:34 +02:00 committed by Commit Bot
parent 7f1304755b
commit 9afbef1ebe
1 changed files with 7 additions and 1 deletions
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8
src/wasm/wasm-code-manager.cc
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@ -480,8 +480,14 @@ Vector<byte> WasmCodeAllocator::AllocateForCode(NativeModule* native_module,
Address hint = owned_code_space_.empty() ? kNullAddress
: owned_code_space_.back().end();
// Reserve at least 20% of the total generated code size so far, and of
// course at least {size}. Round up to the next power of two.
size_t total_reserved = 0;
for (auto& vmem : owned_code_space_) total_reserved += vmem.size();
size_t reserve_size =
base::bits::RoundUpToPowerOfTwo(std::max(size, total_reserved / 5));
VirtualMemory new_mem =
code_manager_->TryAllocate(size, reinterpret_cast<void*>(hint));
code_manager_->TryAllocate(reserve_size, reinterpret_cast<void*>(hint));
if (!new_mem.IsReserved()) {
V8::FatalProcessOutOfMemory(nullptr, "wasm code reservation");
UNREACHABLE();