| Message ID | 20241024034120.3814224-1-liaochang1@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] arm64: Return early when break handler is found on linked-list | expand |
On Thu, Oct 24, 2024 at 03:41:20AM +0000, Liao Chang wrote: > The search for breakpoint handlers iterate through the entire > linked list. Given that all registered hook has a valid fn field, and no > registered hooks share the same mask and imm. This commit optimize the > efficiency slightly by returning early as a matching handler is found. > > v2->v1: > Remove all WARN_ON(!hook->fn) in v1 as Will suggested. nit: Changelogs like ^^^ should go after the '---' line, otherwise they end up in the git history. > Signed-off-by: Liao Chang <liaochang1@huawei.com> > --- > arch/arm64/kernel/debug-monitors.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c > index c60a4a90c6a5..58f047de3e1c 100644 > --- a/arch/arm64/kernel/debug-monitors.c > +++ b/arch/arm64/kernel/debug-monitors.c > @@ -303,7 +303,6 @@ static int call_break_hook(struct pt_regs *regs, unsigned long esr) > { > struct break_hook *hook; > struct list_head *list; > - int (*fn)(struct pt_regs *regs, unsigned long esr) = NULL; > > list = user_mode(regs) ? &user_break_hook : &kernel_break_hook; > > @@ -313,10 +312,10 @@ static int call_break_hook(struct pt_regs *regs, unsigned long esr) > */ > list_for_each_entry_rcu(hook, list, node) { > if ((esr_brk_comment(esr) & ~hook->mask) == hook->imm) > - fn = hook->fn; > + return hook->fn(regs, esr); > } > > - return fn ? fn(regs, esr) : DBG_HOOK_ERROR; > + return DBG_HOOK_ERROR; > } > NOKPROBE_SYMBOL(call_break_hook); Acked-by: Will Deacon <will@kernel.org> I assume Catalin will pick this one up (but he'll need to tweak the commit message as per my comment above). Will
在 2024/10/24 22:50, Will Deacon 写道: > On Thu, Oct 24, 2024 at 03:41:20AM +0000, Liao Chang wrote: >> The search for breakpoint handlers iterate through the entire >> linked list. Given that all registered hook has a valid fn field, and no >> registered hooks share the same mask and imm. This commit optimize the >> efficiency slightly by returning early as a matching handler is found. >> >> v2->v1: >> Remove all WARN_ON(!hook->fn) in v1 as Will suggested. > > nit: Changelogs like ^^^ should go after the '---' line, otherwise they > end up in the git history. Will Thanks for pointing out. > >> Signed-off-by: Liao Chang <liaochang1@huawei.com> >> --- >> arch/arm64/kernel/debug-monitors.c | 5 ++--- >> 1 file changed, 2 insertions(+), 3 deletions(-) >> >> diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c >> index c60a4a90c6a5..58f047de3e1c 100644 >> --- a/arch/arm64/kernel/debug-monitors.c >> +++ b/arch/arm64/kernel/debug-monitors.c >> @@ -303,7 +303,6 @@ static int call_break_hook(struct pt_regs *regs, unsigned long esr) >> { >> struct break_hook *hook; >> struct list_head *list; >> - int (*fn)(struct pt_regs *regs, unsigned long esr) = NULL; >> >> list = user_mode(regs) ? &user_break_hook : &kernel_break_hook; >> >> @@ -313,10 +312,10 @@ static int call_break_hook(struct pt_regs *regs, unsigned long esr) >> */ >> list_for_each_entry_rcu(hook, list, node) { >> if ((esr_brk_comment(esr) & ~hook->mask) == hook->imm) >> - fn = hook->fn; >> + return hook->fn(regs, esr); >> } >> >> - return fn ? fn(regs, esr) : DBG_HOOK_ERROR; >> + return DBG_HOOK_ERROR; >> } >> NOKPROBE_SYMBOL(call_break_hook); > > Acked-by: Will Deacon <will@kernel.org> > > I assume Catalin will pick this one up (but he'll need to tweak the > commit message as per my comment above). > > Will
On Thu, 24 Oct 2024 03:41:20 +0000, Liao Chang wrote: > The search for breakpoint handlers iterate through the entire > linked list. Given that all registered hook has a valid fn field, and no > registered hooks share the same mask and imm. This commit optimize the > efficiency slightly by returning early as a matching handler is found. > > v2->v1: > Remove all WARN_ON(!hook->fn) in v1 as Will suggested. > > [...] Applied to arm64 (for-next/misc), thanks! [1/1] arm64: Return early when break handler is found on linked-list https://git.kernel.org/arm64/c/9a0e3b92b02e
diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c index c60a4a90c6a5..58f047de3e1c 100644 --- a/arch/arm64/kernel/debug-monitors.c +++ b/arch/arm64/kernel/debug-monitors.c @@ -303,7 +303,6 @@ static int call_break_hook(struct pt_regs *regs, unsigned long esr) { struct break_hook *hook; struct list_head *list; - int (*fn)(struct pt_regs *regs, unsigned long esr) = NULL; list = user_mode(regs) ? &user_break_hook : &kernel_break_hook; @@ -313,10 +312,10 @@ static int call_break_hook(struct pt_regs *regs, unsigned long esr) */ list_for_each_entry_rcu(hook, list, node) { if ((esr_brk_comment(esr) & ~hook->mask) == hook->imm) - fn = hook->fn; + return hook->fn(regs, esr); } - return fn ? fn(regs, esr) : DBG_HOOK_ERROR; + return DBG_HOOK_ERROR; } NOKPROBE_SYMBOL(call_break_hook);
The search for breakpoint handlers iterate through the entire linked list. Given that all registered hook has a valid fn field, and no registered hooks share the same mask and imm. This commit optimize the efficiency slightly by returning early as a matching handler is found. v2->v1: Remove all WARN_ON(!hook->fn) in v1 as Will suggested. Signed-off-by: Liao Chang <liaochang1@huawei.com> --- arch/arm64/kernel/debug-monitors.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)