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    SubjectRe: [PATCH] Moving spinlock to struct usb_hcd
    Hi,
    Should I go ahead and submit the patch with the usual
    "signed-off" thingie? Or is it totally useless patch that is going to
    be ignored?

    Thanks,
    -Romit


    On Jan 26, 2008 9:06 PM, Romit Dasgupta <romlinux@gmail.com> wrote:
    > >
    > >
    > > Looking at how this lock is used, contention doesn't look likely
    > > to be an issue. It's never held for long ...
    > yes in the general case but in usb_hcd_flush_endpoint routine it seems
    > to be held for longer than other routines. I agree that
    > usb_hcd_flush_endpoint is an infrequently called routine. Normal
    > systems dont have too many HCs. My computer shows 1 EHCI and 3 OHCIs
    > so I guess when I connect high speed devices there are less chances of
    > contention. With more HC this lock might be contended for.
    > Nevertheless, the right place for the lock seems to be inside usb_hcd.
    > What do you think?
    >
    > >
    > >
    > > Do you have any proof that contention is an actual problem?
    > > Because otherwise I see no benefit to such a change.
    > >
    >
    > I will try to see what I can find with /proc/lock_stat.
    >
    > Thanks,
    > -Romit
    >


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