On Mon, May 18, 2015 at 05:46:31AM +0100, Vaneet Narang wrote: > EP-2DAD0AFA905A4ACB804C4F82A001242F > > On Wed, May 13, 2015 at 06:24:06AM +0100, Maninder Singh wrote: > >> EP-2DAD0AFA905A4ACB804C4F82A001242F > >> > >> Subject: [PATCH 1/1] hw_breakpoint.c :cpu hotplug handling > >> > >> This patch adds support for CPU hotplug, It re-installl all installed > >> watchpoints and breakpoints > >> back on H/W in case of cpu-hot plug. > > >Not sure why this is needed -- the scheduler should reinstall the > >breakpoints when the debugged task gets scheduled in via > >arch_install_hw_breakpoint. > > > >Will > > I agree with you this reinstalling has to be either take care by scheduler > or Debug tool.
Which debug tool? If it's a ptrace user, then the scheduler should still manage this, as ptrace will call into perf to create the breakpoints. > In current implementation we clear H/W registers but we don't clear slots > (wp_on_reg / bp_on_reg) for both watchpoint or breakpoint. Ok, so are you saying that when the CPU is hotplugged off, the active breakpoints aren't being uninstalled by perf? I thought this would have happened as a result of the scheduler migrating the current task away from the dying CPU. Will -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
