On Thu, Jun 20, 2024 at 10:36:02AM +0200, Oleg Nesterov wrote: > On 06/20, Liao, Chang wrote: > > > > However, when i asm porting uretprobe trampoline to arm64 > > to explore its benefits on that architecture, i discovered the problem that > > single slot is not large enought for trampoline code. ah ok, makes sense now.. x86_64 has the slot big enough for the trampoline, but arm64 does not > > Ah, but then I'd suggest to make the changelog more clear. It looks as > if the problem was introduced by the patch from Jiri. Note that we was > confused as well ;) > > And, > > + /* Reserve enough slots for the uretprobe trampoline */ > + for (slot_nr = 0; > + slot_nr < max((insns_size / UPROBE_XOL_SLOT_BYTES), 1); > + slot_nr++) > > this doesn't look right. Just suppose that insns_size = UPROBE_XOL_SLOT_BYTES + 1. > I'd suggest DIV_ROUND_UP(insns_size, UPROBE_XOL_SLOT_BYTES). > > And perhaps it would be better to send this change along with > uretprobe_trampoline_for_arm64 ? +1, also I'm curious what's the gain on arm64? thanks, jirka
