On Wed, Jun 02, 2021 at 07:26:03PM +0800, Xu, Yanfei wrote: > > > On 6/2/21 1:41 AM, Will Deacon wrote: > > [Please note: This e-mail is from an EXTERNAL e-mail address] > > > > On Tue, Jun 01, 2021 at 07:20:04PM +0200, Daniel Borkmann wrote: > > > On 6/1/21 5:06 PM, Yanfei Xu wrote: > > > > It's no need to trigger IPI for keeping pipeline fresh in bpf case. > > > > > > This needs a more concrete explanation/analysis on "why it is safe" to do so > > > rather than just saying that it is not needed. > > > > Agreed. You need to show how the executing thread ends up going through a > > context synchronizing operation before jumping to the generated code if > > the IPI here is removed. > > This patch came out with I looked through ftrace codes. Ftrace modify > the text code and don't send IPI in aarch64_insn_patch_text_nosync(). I > mistakenly thought the bpf is same with ftrace. > > But now I'm still not sure why the ftrace don't need the IPI to go > through context synchronizing, maybe the worst situation is omit a > tracing event? I think ftrace handles this itself via ftrace_sync_ipi, no? Will
