Date: Fri, 2 Sep 2022 16:11:40 +0200 From: Mateusz Guzik <mjguzik@gmail.com> To: Konstantin Belousov <kostikbel@gmail.com> Cc: freebsd-current@freebsd.org Subject: Re: kernel-side thread stack swapping Message-ID: <CAGudoHGbomDGPNsYa_RHGS7NkWU4iOBHnxr9bCnvfn8BYMjEJQ@mail.gmail.com> In-Reply-To: <YxINyjnFDt8kU41j@kib.kiev.ua> References: <CAGudoHFh5H721kcQT0zDdErD%2Bj%2B0YA6Hz=%2Bjarg9R1jdttfx-A@mail.gmail.com> <YxINyjnFDt8kU41j@kib.kiev.ua>
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On 9/2/22, Konstantin Belousov <kostikbel@gmail.com> wrote: > On Fri, Sep 02, 2022 at 02:05:37PM +0200, Mateusz Guzik wrote: >> Is this really of practical use today? >> >> I have a WIP patch which needs to temporarily store something on the >> stack and should things go wrong enough it will be accessed by UMA, >> which can't handle the fault nor decide to skip the access. >> >> I can add something like td_pinstack or whatever to keep it around, >> but perhaps the entire machinery can be just whacked? > p_hold already does that. > I only need to protect the one stack and more importantly don't want to take the proc lock to bump p_hold (nor convert it to atomics), it's all thread-local so to speak. -- Mateusz Guzik <mjguzik gmail.com>
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