On Tue, 3 Dec 2024 11:08:44 +0200 Mike Rapoport <[email protected]> wrote:
> Gentle ping I'll take this if nobody else will. -- Steve > > On Sun, Nov 24, 2024 at 04:07:05PM +0200, Mike Rapoport wrote: > > From: "Mike Rapoport (Microsoft)" <[email protected]> > > > > Steven Rostedt reported slowdown by over 30ms caused by commit 9bfc4824fd48 > > ("x86/module: prepare module loading for ROX allocations of text") > > > > Before: > > > > # cat /sys/kernel/tracing/dyn_ftrace_total_info > > 57695 pages:231 groups: 9 > > ftrace boot update time = 14733459 (ns) > > ftrace module total update time = 449016 (ns) > > > > After: > > > > # cat /sys/kernel/tracing/dyn_ftrace_total_info > > 57708 pages:231 groups: 9 > > ftrace boot update time = 47195374 (ns) > > ftrace module total update time = 592080 (ns) > > > > The slowdown happened because initial patching of kernel code for ftrace > > was switched from text_poke_early() to text_poke() to accommodate ftrace > > updates of module text allocated as ROX. > > > > Restore the use of text_poke_early() for boot time patching of the kernel > > code. > > > > Reported-by: Steven Rostedt <[email protected]> > > Closes: > > https://lore.kernel.org/all/[email protected] > > Fixes: 9bfc4824fd48 ("x86/module: prepare module loading for ROX > > allocations of text") > > Signed-off-by: Mike Rapoport (Microsoft) <[email protected]> > > --- > > arch/x86/kernel/ftrace.c | 8 +++++--- > > 1 file changed, 5 insertions(+), 3 deletions(-) > > > > diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c > > index 4dd0ad6c94d6..9e50288abbaa 100644 > > --- a/arch/x86/kernel/ftrace.c > > +++ b/arch/x86/kernel/ftrace.c > > @@ -111,7 +111,7 @@ static int ftrace_verify_code(unsigned long ip, const > > char *old_code) > > */ > > static int __ref > > ftrace_modify_code_direct(unsigned long ip, const char *old_code, > > - const char *new_code) > > + const char *new_code, struct module *mod) > > { > > int ret = ftrace_verify_code(ip, old_code); > > if (ret) > > @@ -120,6 +120,8 @@ ftrace_modify_code_direct(unsigned long ip, const char > > *old_code, > > /* replace the text with the new text */ > > if (ftrace_poke_late) { > > text_poke_queue((void *)ip, new_code, MCOUNT_INSN_SIZE, NULL); > > + } else if (!mod) { > > + text_poke_early((void *)ip, new_code, MCOUNT_INSN_SIZE); > > } else { > > mutex_lock(&text_mutex); > > text_poke((void *)ip, new_code, MCOUNT_INSN_SIZE); > > @@ -145,7 +147,7 @@ int ftrace_make_nop(struct module *mod, struct > > dyn_ftrace *rec, unsigned long ad > > * just modify the code directly. > > */ > > if (addr == MCOUNT_ADDR) > > - return ftrace_modify_code_direct(ip, old, new); > > + return ftrace_modify_code_direct(ip, old, new, mod); > > > > /* > > * x86 overrides ftrace_replace_code -- this function will never be used > > @@ -164,7 +166,7 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned > > long addr) > > new = ftrace_call_replace(ip, addr); > > > > /* Should only be called when module is loaded */ > > - return ftrace_modify_code_direct(rec->ip, old, new); > > + return ftrace_modify_code_direct(rec->ip, old, new, NULL); > > } > > > > /* > > > > base-commit: 9f16d5e6f220661f73b36a4be1b21575651d8833 > > -- > > 2.45.2 > > >
