On Sat, Aug 10, 2013 at 12:20 AM, Oleg Nesterov <[email protected]> wrote: > > Sorry, I didn't read this series yet. Not that I think this needs my > help, but I'll try to do this a later... > > On 08/09, Masami Hiramatsu wrote: > > > > I just concern using kmalloc() in the event handler. > > GFP_KERNEL should be fine for uprobe handler. > > However, iirc this conflicts with the patches from Jovi, > "Support ftrace_event_file base multibuffer" adds rcu_read_lock() > around uprobe_trace_print().
(Sorry about html text rejected by kernel.org, send again with plain text.) Then we might need to call kmalloc before rcu_read_lock, also call kfree after rcu_read_unlock. And it's not needed to call kmalloc for each instances in multi-buffer case, just kmalloc once is enough. I also have same concern about use kmalloc in uprobe handler, use kmalloc in uprobe handler seems have a little overhead, why not pre-allocate one page static memory for temp buffer(perhaps trace_uprobe based)? one page size would be enough for all uprobe args storage, then we don't need to call kmalloc in that "fast path". Thanks. > > > Steven, Jovi, what should we do with that patch? It seems that it > was forgotten. > > I can take these patches into my ubprobes branch and then ask Ingo > to pull. But this will complicate the routing of the new changes > like this. > > Oleg. -- 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/
