Re: [PATCH 3.19-rc2 v15 4/8] sched_clock: Avoid deadlock during read from NMI

2015-01-26 Thread Daniel Thompson
On 24/01/15 22:40, Thomas Gleixner wrote: > On Fri, 23 Jan 2015, Daniel Thompson wrote: >> This patch fixes that problem by providing banked clock data in a >> similar manner to Thomas Gleixner's 4396e058c52e("timekeeping: Provide >> fast and NMI safe access to CLOCK_MONOTONIC"). > > By some defin

Re: [PATCH 3.19-rc2 v15 4/8] sched_clock: Avoid deadlock during read from NMI

2015-01-24 Thread Thomas Gleixner
On Fri, 23 Jan 2015, Daniel Thompson wrote: > This patch fixes that problem by providing banked clock data in a > similar manner to Thomas Gleixner's 4396e058c52e("timekeeping: Provide > fast and NMI safe access to CLOCK_MONOTONIC"). By some definition of similar. > -struct clock_data { > - k

[PATCH 3.19-rc2 v15 4/8] sched_clock: Avoid deadlock during read from NMI

2015-01-23 Thread Daniel Thompson
Currently it is possible for an NMI (or FIQ on ARM) to come in and read sched_clock() whilst update_sched_clock() has locked the seqcount for writing. This results in the NMI handler locking up when it calls raw_read_seqcount_begin(). This patch fixes that problem by providing banked clock data in