CODEWITHSUNDEEP
linuxmemoryrustmemory-leaksmalloc
Pure White
Pure White

Reputation: 125

How to set a free strategy?

I've encountered high memory usage (looks like a memory leak) in production environment (container in k8s), and want to check if it's because of the "MADV_FREE" behaviour.

Is there a way to change to use MADV_DONTNEED instead of MADV_FREE in rust?

Upvotes: 2

Views: 104

Answers (1)

pigeonhands
pigeonhands

Reputation: 3424

Rust allows overriding the default allocator with the #[global_allocator] attribute

struct MyAllocator;

unsafe impl GlobalAlloc for MyAllocator {
    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
        System.alloc(layout)
    }

    unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
        System.dealloc(ptr, layout)
    }
}

#[global_allocator]
static GLOBAL: MyAllocator = MyAllocator;

You could use this to change the behavior of the deallocation to your needs.

Or possibly use an existing crate that implements allocators that logs the allocations/deallocations such as tracing-allocator or logging-allocator.

#[global_allocator]
static GLOBAL: tracing_allocator::Allocator = tracing_allocator::Allocator{};

fn main() {
  let f = File::create("trace.txt").unwrap();
  tracing_allocator::Allocator::initialize(&f);
  tracing_allocator::Allocator::activate();
}

(I have no experience with these crates so I have no idea what they uses for allocations)

Upvotes: 3

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