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Date:      Fri, 24 Sep 2004 07:27:18 +1200
From:      Juha Saarinen <juhasaarinen@gmail.com>
To:        "David G. Lawrence" <dg@dglawrence.com>
Cc:        freebsd-current@freebsd.org
Subject:   Re: Could ARG_MAX be increased?
Message-ID:  <b34be8420409231227575cc793@mail.gmail.com>
In-Reply-To: <20040923122620.GW16205@nexus.dglawrence.com>
References:  <b34be84204092304456066b0a0@mail.gmail.com> <20040923122620.GW16205@nexus.dglawrence.com>

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On Thu, 23 Sep 2004 05:26:20 -0700, David G. Lawrence <dg@dglawrence.com> wrote:
>    I feel compelled to respond since you mentioned me above and since I
> wrote most of the code involved... :-)
>    The main issue with increasing the size of ARG_MAX is that it will result
> in more kernel virtual memory being reserved for temporary storage of the
> args. This used to be a much larger problem when KVM was scarce, but less
> of a problem now with 1GB or more of KVM. The args temporary space is
> allocated out of exec_map (a submap of kernel_map), which is sized to be
> about 16 * ARG_MAX. The '16' is to allow up to 16 processes to simultaneously
> exec until additional execs are blocked waiting for KVM to become
> available. Anyway, increasing ARG_MAX to 256K (roughly 4MB of KVM) should
> be okay on most systems.

Very good and thorough response there :-)

Is it worth putting in a PR on this?

-- 

Juha



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