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Plack::Middleware::SizeLimit - Terminate processes if they grow too large


use Plack::Builder;

builder {
    enable SizeLimit => (
        max_unshared_size_in_kb => '4096', # 4MB
        # min_shared_size_in_kb => '8192', # 8MB
        # max_process_size_in_kb => '16384', # 16MB
        check_every_n_requests => 2


This middleware is a port of the excellent Apache::SizeLimit module for multi-process Plack servers, such as Starman, Starlet and uWSGI.

This middleware only works when the environment psgix.harakiri is set to a true value by the Plack server. If it's set to false, then this middleware simply does nothing.


  • max_unshared_size_in_kb

The maximum amount of unshared memory the process can use; usually this option is all one needs.

Experience on one heavily trafficked mod_perl site showed that setting this option and leaving the others unset is the most effective policy.

This is because it only kills off processes that are truly using too much physical RAM, allowing most processes to live longer and reducing the process churn rate.

  • min_shared_size_in_kb

Sets the minimum amount of shared memory the process must have.

  • max_process_size_in_kb

The maximum size of the process, including both shared and unshared memory.

  • check_every_n_requests

Since checking the process size can take a few system calls on some platforms (e.g. linux), you may specify this option to check the process size every N requests.


Starman, Starlet



CC0 1.0 Universal

To the extent possible under law, 唐鳳 has waived all copyright and related or neighboring rights to Plack::Middleware::SizeLimit.

This work is published from Taiwan.

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