> - Quickly identify all user processes mapping a given page.
Can be done with /proc/*/pagemap today. Maybe it's not "quick"
because it won't use the rmap chains, but is that a serious
issue?
> - Determine if and where the kernel maps the page, which is also
> important given the opportunity to r
On Mon, Nov 18, 2024 at 02:25:40PM -0800, Yabin Cui wrote:
> Select ARCH_SUPPORTS_AUTOFDO_CLANG to allow AUTOFDO_CLANG to be
> selected.
>
> On ARM64, ETM traces can be recorded and converted to AutoFDO profiles.
> Experiments on Android show 4% improvement in cold app startup time
> and 13% impro
On Wed, Nov 20, 2024 at 8:14 AM Pasha Tatashin
wrote:
>
> On Tue, Nov 19, 2024 at 2:36 PM Yosry Ahmed wrote:
> >
> > On Tue, Nov 19, 2024 at 11:30 AM Pasha Tatashin
> > wrote:
> > >
> > > On Tue, Nov 19, 2024 at 1:23 PM Roman Gushchin
> > > wrote:
> > > >
> > > > On Tue, Nov 19, 2024 at 10:08:
Le Wed, Nov 20, 2024 at 06:10:43PM +0100, Valentin Schneider a écrit :
> On 20/11/24 15:23, Frederic Weisbecker wrote:
>
> > Ah but there is CT_STATE_GUEST and I see the last patch also applies that to
> > CT_STATE_IDLE.
> >
> > So that could be:
> >
> > bool ct_set_cpu_work(unsigned int cpu, unsi
> > /* Use static buffer, for the caller is holding oom_lock. */
> > static char buf[PAGE_SIZE];
> >
> > seq_buf_init(&s, buf, sizeof(buf));
> > memory_stat_format(memcg, &s);
> > seq_buf_do_printk(&s, KERN_INFO);
> > }
> >
> > This is a callosal
On 20/11/24 16:32, Peter Zijlstra wrote:
> On Wed, Nov 20, 2024 at 04:22:16PM +0100, Peter Zijlstra wrote:
>> On Tue, Nov 19, 2024 at 04:35:00PM +0100, Valentin Schneider wrote:
>>
>> > +void noinstr __flush_tlb_all_noinstr(void)
>> > +{
>> > + /*
>> > + * This is for invocation in early entry
On Wed, Nov 20, 2024 at 10:29 AM Andi Kleen wrote:
>
> Pasha Tatashin writes:
>
> > Page Detective is a new kernel debugging tool that provides detailed
> > information about the usage and mapping of physical memory pages.
> >
> > It is often known that a particular page is corrupted, but it is h
On Tue, Nov 19, 2024 at 04:34:56PM +0100, Valentin Schneider wrote:
> Later commits will disallow runtime-mutable text in .noinstr sections in
> order to safely defer instruction patching IPIs.
>
> All static keys used in .noinstr sections have now been checked as being
> either flagged as __ro_af
On 20/11/24 15:23, Frederic Weisbecker wrote:
> Ah but there is CT_STATE_GUEST and I see the last patch also applies that to
> CT_STATE_IDLE.
>
> So that could be:
>
> bool ct_set_cpu_work(unsigned int cpu, unsigned int work)
> {
> struct context_tracking *ct = per_cpu_ptr(&context_tracking,
On Tue, Nov 19, 2024 at 2:36 PM Yosry Ahmed wrote:
>
> On Tue, Nov 19, 2024 at 11:30 AM Pasha Tatashin
> wrote:
> >
> > On Tue, Nov 19, 2024 at 1:23 PM Roman Gushchin
> > wrote:
> > >
> > > On Tue, Nov 19, 2024 at 10:08:36AM -0500, Pasha Tatashin wrote:
> > > > On Mon, Nov 18, 2024 at 8:09 PM G
On Wed, Nov 20, 2024 at 03:57:46PM +0100, Peter Zijlstra wrote:
> On Wed, Nov 20, 2024 at 03:56:49PM +0100, Peter Zijlstra wrote:
>
> > But I think we can make the fall-back safer, we can simply force the IPI
> > when we poke at noinstr code -- then NOHZ_FULL gets to keep the pieces,
> > but at le
We've used ETM in ChromeOS for a while now. Hardware
requirements make it unfortunately less ubiquitous than LBR, but:
- we first launched it on 5.15,
- it's still humming along nicely today on 6.6, so:
Tested-by: George Burgess IV
IIRC, with a baseline of "using x86_64 AFDO profiles on ARM kern
On 20/11/24 15:59, Peter Zijlstra wrote:
> On Tue, Nov 19, 2024 at 04:34:55PM +0100, Valentin Schneider wrote:
>> Later commits will cause objtool to warn about non __ro_after_init static
>> keys being used in .noinstr sections in order to safely defer instruction
>> patching IPIs targeted at NOHZ_
On 19/11/24 15:39, Josh Poimboeuf wrote:
> On Tue, Nov 19, 2024 at 04:34:53PM +0100, Valentin Schneider wrote:
>> Later commits will cause objtool to warn about non __ro_after_init static
>> keys being used in .noinstr sections in order to safely defer instruction
>> patching IPIs targeted at NOHZ_
On 20/11/24 15:50, Peter Zijlstra wrote:
> On Tue, Nov 19, 2024 at 04:34:51PM +0100, Valentin Schneider wrote:
>> A later commit will reduce the size of the RCU watching counter to free up
>> some bits for another purpose. Paul suggested adding a config option to
>> test the extreme case where the
On Tue, Nov 19, 2024 at 04:35:00PM +0100, Valentin Schneider wrote:
> +void noinstr __flush_tlb_all_noinstr(void)
> +{
> + /*
> + * This is for invocation in early entry code that cannot be
> + * instrumented. A RMW to CR4 works for most cases, but relies on
> + * being able to
On Wed, Nov 20, 2024 at 04:22:16PM +0100, Peter Zijlstra wrote:
> On Tue, Nov 19, 2024 at 04:35:00PM +0100, Valentin Schneider wrote:
>
> > +void noinstr __flush_tlb_all_noinstr(void)
> > +{
> > + /*
> > +* This is for invocation in early entry code that cannot be
> > +* instrumented. A
On Tue, Nov 19, 2024 at 04:34:51PM +0100, Valentin Schneider wrote:
> A later commit will reduce the size of the RCU watching counter to free up
> some bits for another purpose. Paul suggested adding a config option to
> test the extreme case where the counter is reduced to its minimum usable
> wid
Pasha Tatashin writes:
> Page Detective is a new kernel debugging tool that provides detailed
> information about the usage and mapping of physical memory pages.
>
> It is often known that a particular page is corrupted, but it is hard to
> extract more information about such a page from live sys
On Tue, Nov 19, 2024 at 04:34:59PM +0100, Valentin Schneider wrote:
> +static void __text_poke_sync(smp_cond_func_t cond_func)
> +{
> + on_each_cpu_cond(cond_func, do_sync_core, NULL, 1);
> +}
> +
> void text_poke_sync(void)
> {
> - on_each_cpu(do_sync_core, NULL, 1);
> + __text_poke
On Tue, Nov 19, 2024 at 04:34:55PM +0100, Valentin Schneider wrote:
> Later commits will cause objtool to warn about non __ro_after_init static
> keys being used in .noinstr sections in order to safely defer instruction
> patching IPIs targeted at NOHZ_FULL CPUs.
>
> __sched_clock_stable is used i
On Wed, Nov 20, 2024 at 03:56:49PM +0100, Peter Zijlstra wrote:
> But I think we can make the fall-back safer, we can simply force the IPI
> when we poke at noinstr code -- then NOHZ_FULL gets to keep the pieces,
> but at least we don't violate any correctness constraints.
I should have read more
On Tue, Nov 19, 2024 at 03:39:02PM -0800, Josh Poimboeuf wrote:
> On Tue, Nov 19, 2024 at 04:34:53PM +0100, Valentin Schneider wrote:
> > Later commits will cause objtool to warn about non __ro_after_init static
> > keys being used in .noinstr sections in order to safely defer instruction
> > patch
Le Wed, Nov 20, 2024 at 11:54:36AM +0100, Frederic Weisbecker a écrit :
> Le Tue, Nov 19, 2024 at 04:34:58PM +0100, Valentin Schneider a écrit :
> > +bool ct_set_cpu_work(unsigned int cpu, unsigned int work)
> > +{
> > + struct context_tracking *ct = per_cpu_ptr(&context_tracking, cpu);
> > + u
Le Tue, Nov 19, 2024 at 04:34:58PM +0100, Valentin Schneider a écrit :
> +bool ct_set_cpu_work(unsigned int cpu, unsigned int work)
> +{
> + struct context_tracking *ct = per_cpu_ptr(&context_tracking, cpu);
> + unsigned int old;
> + bool ret = false;
> +
> + preempt_disable();
> +
On Tue, Nov 19, 2024 at 04:05:32PM -0800, Josh Poimboeuf wrote:
> On Tue, Nov 19, 2024 at 04:34:53PM +0100, Valentin Schneider wrote:
> > +++ b/include/linux/jump_label.h
> > @@ -200,7 +200,8 @@ struct module;
> > #define JUMP_TYPE_FALSE0UL
> > #define JUMP_TYPE_TRUE 1UL
>
On Wed, 2024-11-20 at 10:16 +0100, Roberto Sassu wrote:
> On Tue, 2024-11-19 at 12:10 -0800, Luis Chamberlain wrote:
> > On Tue, Nov 19, 2024 at 01:14:02PM +0100, Christoph Hellwig wrote:
> > > On Tue, Nov 19, 2024 at 11:49:09AM +0100, Roberto Sassu wrote:
> > > > From: Roberto Sassu
> > > >
> >
On Tue, 2024-11-19 at 12:10 -0800, Luis Chamberlain wrote:
> On Tue, Nov 19, 2024 at 01:14:02PM +0100, Christoph Hellwig wrote:
> > On Tue, Nov 19, 2024 at 11:49:09AM +0100, Roberto Sassu wrote:
> > > From: Roberto Sassu
> > >
> > > Introduce ksys_finit_module() to let kernel components request a
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