Messages in this thread | | | Subject | Re: [PATCH] Add a text_poke syscall v2 | From | "H. Peter Anvin" <> | Date | Wed, 27 Nov 2013 18:10:22 -0800 |
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ftrace is the flagship example.
And yes, agreed about timeouts.
Linus Torvalds <torvalds@linux-foundation.org> wrote: >On Wed, Nov 27, 2013 at 3:28 PM, H. Peter Anvin <hpa@zytor.com> wrote: >> >> The timeout bit was an acknowledgment that some kind of batching >> interface is necessary. > >That's just moronic. People would make up totally random timeouts, so >from an interface standpoint it's just horrid, horrid. > >Giving user space random knobs that you don't understand yourself, and >the monkeys in user space are guaranteed to mis-use is just entirely >the wrong thing to do. > >Much better to then just making the interface itself be about >batching, which isn't as hard as you make it out to be. Make it an >array of those addr/replace/len things. And we have that >"restart_block" for system calls, and we'd limit batching to some >random smallish number ("128 instructions, just because"), while still >being easily interruptible in between those blocks. That limits you to >two IPI's per 128 instructions replaced - and at that point even >*that* is just an internal kernel random tuning thing, not some insane >user interface. > >But is such batching really even worth it? If' it's not *that* much >more effort, maybe it's worth it, but do we have known users that >really would have thousands and thousands of cases all at once? > > Linus
-- Sent from my mobile phone. Please pardon brevity and lack of formatting.
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