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// This file is part of dpdk. It is subject to the license terms in the COPYRIGHT file found in the top-level directory of this distribution and at https://raw.githubusercontent.com/lemonrock/dpdk/master/COPYRIGHT. No part of dpdk, including this file, may be copied, modified, propagated, or distributed except according to the terms contained in the COPYRIGHT file.
// Copyright © 2016-2017 The developers of dpdk. See the COPYRIGHT file in the top-level directory of this distribution and at https://raw.githubusercontent.com/lemonrock/dpdk/master/COPYRIGHT.
/// Strategies for allocating memory from NUMA nodes.
///
/// These all round memory requests down to a size that fits the largest huge page size for the processor.
#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[derive(Serialize, Deserialize)]
pub enum HugePageAllocationStrategy
{
/// As a per-myriad `ratio` ('percentage') of total free memory.
TotalFreeRatio
{
/// Ratio in per myriads (‱), also known as basis points (bp).
ratio: PerMyriad
},
/// As total free memory less a `reserve`).
TotalFreeLessReserve
{
/// Reserve.
reserve: KiloBytes,
},
/// A `fixed_amount` allocation, otherwise panic.
FixedOrFail
{
/// Fixed amount.
fixed_amount: KiloBytes,
},
}
impl Default for HugePageAllocationStrategy
{
#[inline(always)]
fn default() -> Self
{
HugePageAllocationStrategy::TotalFreeRatio
{
ratio: PerMyriad::NinetyFivePercent,
}
}
}
impl HugePageAllocationStrategy
{
#[inline(always)]
pub(crate) fn calculate_number_of_huge_pages(&self, huge_page_size: HugePageSize, total_free: KiloBytes) -> u64
{
use self::HugePageAllocationStrategy::*;
let allocation = match *self
{
TotalFreeRatio { ratio } => total_free.scale_by(ratio),
TotalFreeLessReserve { reserve } => total_free.subtract_with_zero_floor(reserve),
FixedOrFail { fixed_amount } =>
{
assert!(fixed_amount >= total_free, "total_free '{}' is less than the fixed amount of fixed_amount '{}'", total_free, fixed_amount);
fixed_amount
}
};
huge_page_size.calculate_number_of_huge_pages(allocation.0)
}
}