[withdrawn] zsmalloc-remove-extra-cond_resched-in-__zs_compact.patch removed from -mm tree

[withdrawn] zsmalloc-remove-extra-cond_resched-in-__zs_compact.patch removed from -mm tree

[akpm]

The patch titled
     Subject: zsmalloc: remove extra cond_resched() in __zs_compact
has been removed from the -mm tree.  Its filename was
     zsmalloc-remove-extra-cond_resched-in-__zs_compact.patch

This patch was dropped because it was withdrawn

------------------------------------------------------
From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Subject: zsmalloc: remove extra cond_resched() in __zs_compact

Do not perform cond_resched() before the busy compaction loop in
__zs_compact(), because this loop does it when needed.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/zsmalloc.c |    2 --
 1 file changed, 2 deletions(-)

diff -puN mm/zsmalloc.c~zsmalloc-remove-extra-cond_resched-in-__zs_compact mm/zsmalloc.c
--- a/mm/zsmalloc.c~zsmalloc-remove-extra-cond_resched-in-__zs_compact
+++ a/mm/zsmalloc.c
@@ -1717,8 +1717,6 @@ static unsigned long __zs_compact(struct
 	struct page *dst_page = NULL;
 	unsigned long nr_total_migrated = 0;
 
-	cond_resched();
-
 	spin_lock(&class->lock);
 	while ((src_page = isolate_source_page(class))) {
 
_

Patches currently in -mm which might be from sergey.senozhatsky@gmail.com are

zram-cosmetic-zram_attr_ro-code-formatting-tweak.patch
zram-use-idr-instead-of-zram_devices-array.patch
zram-factor-out-device-reset-from-reset_store.patch
zram-reorganize-code-layout.patch
zram-add-dynamic-device-add-remove-functionality.patch
zram-add-dynamic-device-add-remove-functionality-fix.patch
zram-remove-max_num_devices-limitation.patch
zram-report-every-added-and-removed-device.patch
zram-trivial-correct-flag-operations-comment.patch
zram-return-zram-device_id-value-from-zram_add.patch
zram-introduce-automatic-device_id-generation.patch
zram-introduce-automatic-device_id-generation-fix.patch
zram-do-not-let-user-enforce-new-device-dev_id.patch
zsmalloc-decouple-handle-and-object.patch
zsmalloc-factor-out-obj_.patch
zsmalloc-support-compaction.patch
zsmalloc-adjust-zs_almost_full.patch
zram-support-compaction.patch
zsmalloc-record-handle-in-page-private-for-huge-object.patch
zsmalloc-add-fullness-into-stat.patch
zsmalloc-zsmalloc-documentation.patch
zram-remove-num_migrated-device-attr.patch
zram-move-compact_store-to-sysfs-functions-area.patch
zram-use-generic-start-end-io-accounting.patch
zram-describe-device-attrs-in-documentation.patch
zram-export-new-io_stat-sysfs-attrs.patch
zram-export-new-mm_stat-sysfs-attrs.patch
zram-deprecate-zram-attrs-sysfs-nodes.patch
zsmalloc-remove-synchronize_rcu-from-zs_compact.patch
zsmalloc-do-not-remap-dst-page-while-prepare-next-src-page.patch
zsmalloc-micro-optimize-zs_object_copy.patch
cpumask-dont-perform-while-loop-in-cpumask_next_and.patch
lib-lz4-pull-out-constant-tables.patch

Re: [withdrawn] zsmalloc-remove-extra-cond_resched-in-__zs_compact.patch removed from -mm tree

[Sergey Senozhatsky]

On (03/25/15 13:25), akpm@linux-foundation.org wrote:
> The patch titled
>      Subject: zsmalloc: remove extra cond_resched() in __zs_compact
> has been removed from the -mm tree.  Its filename was
>      zsmalloc-remove-extra-cond_resched-in-__zs_compact.patch
> 
> This patch was dropped because it was withdrawn
> 
> ------------------------------------------------------
> From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Subject: zsmalloc: remove extra cond_resched() in __zs_compact
> 
> Do not perform cond_resched() before the busy compaction loop in
> __zs_compact(), because this loop does it when needed.
> 
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Cc: Minchan Kim <minchan@kernel.org>
> Cc: Nitin Gupta <ngupta@vflare.org>
> Cc: Stephen Rothwell <sfr@canb.auug.org.au>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
> 
>  mm/zsmalloc.c |    2 --
>  1 file changed, 2 deletions(-)
> 
> diff -puN mm/zsmalloc.c~zsmalloc-remove-extra-cond_resched-in-__zs_compact mm/zsmalloc.c
> --- a/mm/zsmalloc.c~zsmalloc-remove-extra-cond_resched-in-__zs_compact
> +++ a/mm/zsmalloc.c
> @@ -1717,8 +1717,6 @@ static unsigned long __zs_compact(struct
>  	struct page *dst_page = NULL;
>  	unsigned long nr_total_migrated = 0;
>  
> -	cond_resched();
> -
>  	spin_lock(&class->lock);
>  	while ((src_page = isolate_source_page(class))) {
>  

Hello,

Minchan, did I miss your NACK on this patch? or could you please ACK it?

	-ss

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Re: [withdrawn] zsmalloc-remove-extra-cond_resched-in-__zs_compact.patch removed from -mm tree

[Sergey Senozhatsky]

On (03/25/15 13:25), akpm@linux-foundation.org wrote:
> The patch titled
>      Subject: zsmalloc: remove extra cond_resched() in __zs_compact
> has been removed from the -mm tree.  Its filename was
>      zsmalloc-remove-extra-cond_resched-in-__zs_compact.patch
> 
> This patch was dropped because it was withdrawn
> 
> ------------------------------------------------------
> From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Subject: zsmalloc: remove extra cond_resched() in __zs_compact
> 
> Do not perform cond_resched() before the busy compaction loop in
> __zs_compact(), because this loop does it when needed.
> 
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Cc: Minchan Kim <minchan@kernel.org>
> Cc: Nitin Gupta <ngupta@vflare.org>
> Cc: Stephen Rothwell <sfr@canb.auug.org.au>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
> 
>  mm/zsmalloc.c |    2 --
>  1 file changed, 2 deletions(-)
> 
> diff -puN mm/zsmalloc.c~zsmalloc-remove-extra-cond_resched-in-__zs_compact mm/zsmalloc.c
> --- a/mm/zsmalloc.c~zsmalloc-remove-extra-cond_resched-in-__zs_compact
> +++ a/mm/zsmalloc.c
> @@ -1717,8 +1717,6 @@ static unsigned long __zs_compact(struct
>  	struct page *dst_page = NULL;
>  	unsigned long nr_total_migrated = 0;
>  
> -	cond_resched();
> -
>  	spin_lock(&class->lock);
>  	while ((src_page = isolate_source_page(class))) {
>  

Hello,

Minchan, did I miss your NACK on this patch? or could you please ACK it?

	-ss

Re: [withdrawn] zsmalloc-remove-extra-cond_resched-in-__zs_compact.patch removed from -mm tree

[Minchan Kim]

Hello Sergey,

Sorry for slow response.
I am overwhelmed with too much to do. :(

On Thu, Mar 26, 2015 at 09:27:17AM +0900, Sergey Senozhatsky wrote:
> On (03/25/15 13:25), akpm@linux-foundation.org wrote:
> > The patch titled
> >      Subject: zsmalloc: remove extra cond_resched() in __zs_compact
> > has been removed from the -mm tree.  Its filename was
> >      zsmalloc-remove-extra-cond_resched-in-__zs_compact.patch
> > 
> > This patch was dropped because it was withdrawn
> > 
> > ------------------------------------------------------
> > From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> > Subject: zsmalloc: remove extra cond_resched() in __zs_compact
> > 
> > Do not perform cond_resched() before the busy compaction loop in
> > __zs_compact(), because this loop does it when needed.
> > 
> > Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> > Cc: Minchan Kim <minchan@kernel.org>
> > Cc: Nitin Gupta <ngupta@vflare.org>
> > Cc: Stephen Rothwell <sfr@canb.auug.org.au>
> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> > ---
> > 
> >  mm/zsmalloc.c |    2 --
> >  1 file changed, 2 deletions(-)
> > 
> > diff -puN mm/zsmalloc.c~zsmalloc-remove-extra-cond_resched-in-__zs_compact mm/zsmalloc.c
> > --- a/mm/zsmalloc.c~zsmalloc-remove-extra-cond_resched-in-__zs_compact
> > +++ a/mm/zsmalloc.c
> > @@ -1717,8 +1717,6 @@ static unsigned long __zs_compact(struct
> >  	struct page *dst_page = NULL;
> >  	unsigned long nr_total_migrated = 0;
> >  
> > -	cond_resched();
> > -
> >  	spin_lock(&class->lock);
> >  	while ((src_page = isolate_source_page(class))) {
> >  
> 
> Hello,
> 
> Minchan, did I miss your NACK on this patch? or could you please ACK it?

I saw this patch yesterday night but didn't acked intentionally because
I was not sure and too tired to see the code so I postpone.

If we removed cond_resched out of outer loop(ie, your patch), we lose
the chance to reschedule if alloc_target_page fails(ie, there is no
zspage in ZS_ALMOST_FULL and ZS_ALMOST_EMPTY).
It might be not rare event if we does compation successfully for a
size_class. However, with next coming higher size_class for __zs_compact,
we will encounter cond_resched during compaction.
So, I am happy to ack. :)

Acked-by: Minchan Kim <minchan@kernel.org>

> 
> 	-ss

-- 
Kind regards,
Minchan Kim

--
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Re: [withdrawn] zsmalloc-remove-extra-cond_resched-in-__zs_compact.patch removed from -mm tree

[Minchan Kim]

Hello Sergey,

Sorry for slow response.
I am overwhelmed with too much to do. :(

On Thu, Mar 26, 2015 at 09:27:17AM +0900, Sergey Senozhatsky wrote:
> On (03/25/15 13:25), akpm@linux-foundation.org wrote:
> > The patch titled
> >      Subject: zsmalloc: remove extra cond_resched() in __zs_compact
> > has been removed from the -mm tree.  Its filename was
> >      zsmalloc-remove-extra-cond_resched-in-__zs_compact.patch
> > 
> > This patch was dropped because it was withdrawn
> > 
> > ------------------------------------------------------
> > From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> > Subject: zsmalloc: remove extra cond_resched() in __zs_compact
> > 
> > Do not perform cond_resched() before the busy compaction loop in
> > __zs_compact(), because this loop does it when needed.
> > 
> > Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> > Cc: Minchan Kim <minchan@kernel.org>
> > Cc: Nitin Gupta <ngupta@vflare.org>
> > Cc: Stephen Rothwell <sfr@canb.auug.org.au>
> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> > ---
> > 
> >  mm/zsmalloc.c |    2 --
> >  1 file changed, 2 deletions(-)
> > 
> > diff -puN mm/zsmalloc.c~zsmalloc-remove-extra-cond_resched-in-__zs_compact mm/zsmalloc.c
> > --- a/mm/zsmalloc.c~zsmalloc-remove-extra-cond_resched-in-__zs_compact
> > +++ a/mm/zsmalloc.c
> > @@ -1717,8 +1717,6 @@ static unsigned long __zs_compact(struct
> >  	struct page *dst_page = NULL;
> >  	unsigned long nr_total_migrated = 0;
> >  
> > -	cond_resched();
> > -
> >  	spin_lock(&class->lock);
> >  	while ((src_page = isolate_source_page(class))) {
> >  
> 
> Hello,
> 
> Minchan, did I miss your NACK on this patch? or could you please ACK it?

I saw this patch yesterday night but didn't acked intentionally because
I was not sure and too tired to see the code so I postpone.

If we removed cond_resched out of outer loop(ie, your patch), we lose
the chance to reschedule if alloc_target_page fails(ie, there is no
zspage in ZS_ALMOST_FULL and ZS_ALMOST_EMPTY).
It might be not rare event if we does compation successfully for a
size_class. However, with next coming higher size_class for __zs_compact,
we will encounter cond_resched during compaction.
So, I am happy to ack. :)

Acked-by: Minchan Kim <minchan@kernel.org>

> 
> 	-ss

-- 
Kind regards,
Minchan Kim

Re: [withdrawn] zsmalloc-remove-extra-cond_resched-in-__zs_compact.patch removed from -mm tree

[Sergey Senozhatsky]

On (03/26/15 16:39), Minchan Kim wrote:
> Hello Sergey,
> 
> Sorry for slow response.
> I am overwhelmed with too much to do. :(
> 

Hello,
sure, no problem.

> > > diff -puN mm/zsmalloc.c~zsmalloc-remove-extra-cond_resched-in-__zs_compact mm/zsmalloc.c
> > > --- a/mm/zsmalloc.c~zsmalloc-remove-extra-cond_resched-in-__zs_compact
> > > +++ a/mm/zsmalloc.c
> > > @@ -1717,8 +1717,6 @@ static unsigned long __zs_compact(struct
> > >  	struct page *dst_page = NULL;
> > >  	unsigned long nr_total_migrated = 0;
> > >  
> > > -	cond_resched();
> > > -
> > >  	spin_lock(&class->lock);
> > >  	while ((src_page = isolate_source_page(class))) {

> 
> If we removed cond_resched out of outer loop(ie, your patch), we lose
> the chance to reschedule if alloc_target_page fails(ie, there is no
> zspage in ZS_ALMOST_FULL and ZS_ALMOST_EMPTY).


in outer loop we have preemption enabled and unlocked class. wouldn't that help?
(hm, UP system?)

> It might be not rare event if we does compation successfully for a
> size_class. However, with next coming higher size_class for __zs_compact,
> we will encounter cond_resched during compaction.
> So, I am happy to ack. :)
> 
> Acked-by: Minchan Kim <minchan@kernel.org>

thanks!

	-ss

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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Re: [withdrawn] zsmalloc-remove-extra-cond_resched-in-__zs_compact.patch removed from -mm tree

[Sergey Senozhatsky]

On (03/26/15 16:39), Minchan Kim wrote:
> Hello Sergey,
> 
> Sorry for slow response.
> I am overwhelmed with too much to do. :(
> 

Hello,
sure, no problem.

> > > diff -puN mm/zsmalloc.c~zsmalloc-remove-extra-cond_resched-in-__zs_compact mm/zsmalloc.c
> > > --- a/mm/zsmalloc.c~zsmalloc-remove-extra-cond_resched-in-__zs_compact
> > > +++ a/mm/zsmalloc.c
> > > @@ -1717,8 +1717,6 @@ static unsigned long __zs_compact(struct
> > >  	struct page *dst_page = NULL;
> > >  	unsigned long nr_total_migrated = 0;
> > >  
> > > -	cond_resched();
> > > -
> > >  	spin_lock(&class->lock);
> > >  	while ((src_page = isolate_source_page(class))) {

> 
> If we removed cond_resched out of outer loop(ie, your patch), we lose
> the chance to reschedule if alloc_target_page fails(ie, there is no
> zspage in ZS_ALMOST_FULL and ZS_ALMOST_EMPTY).


in outer loop we have preemption enabled and unlocked class. wouldn't that help?
(hm, UP system?)

> It might be not rare event if we does compation successfully for a
> size_class. However, with next coming higher size_class for __zs_compact,
> we will encounter cond_resched during compaction.
> So, I am happy to ack. :)
> 
> Acked-by: Minchan Kim <minchan@kernel.org>

thanks!

	-ss

Re: [withdrawn] zsmalloc-remove-extra-cond_resched-in-__zs_compact.patch removed from -mm tree

[Minchan Kim]

On Thu, Mar 26, 2015 at 05:13:13PM +0900, Sergey Senozhatsky wrote:
> On (03/26/15 16:39), Minchan Kim wrote:
> > Hello Sergey,
> > 
> > Sorry for slow response.
> > I am overwhelmed with too much to do. :(
> > 
> 
> Hello,
> sure, no problem.
> 
> > > > diff -puN mm/zsmalloc.c~zsmalloc-remove-extra-cond_resched-in-__zs_compact mm/zsmalloc.c
> > > > --- a/mm/zsmalloc.c~zsmalloc-remove-extra-cond_resched-in-__zs_compact
> > > > +++ a/mm/zsmalloc.c
> > > > @@ -1717,8 +1717,6 @@ static unsigned long __zs_compact(struct
> > > >  	struct page *dst_page = NULL;
> > > >  	unsigned long nr_total_migrated = 0;
> > > >  
> > > > -	cond_resched();
> > > > -
> > > >  	spin_lock(&class->lock);
> > > >  	while ((src_page = isolate_source_page(class))) {
> 
> > 
> > If we removed cond_resched out of outer loop(ie, your patch), we lose
> > the chance to reschedule if alloc_target_page fails(ie, there is no
> > zspage in ZS_ALMOST_FULL and ZS_ALMOST_EMPTY).
> 
> 
> in outer loop we have preemption enabled and unlocked class. wouldn't that help?
> (hm, UP system?)

It depends on preemption model. If you enable full preemption, you are right
but if you enable just voluntary preemption, cond_resched will help latency.

Thanks.

-- 
Kind regards,
Minchan Kim

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
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Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [withdrawn] zsmalloc-remove-extra-cond_resched-in-__zs_compact.patch removed from -mm tree

[Minchan Kim]

On Thu, Mar 26, 2015 at 05:13:13PM +0900, Sergey Senozhatsky wrote:
> On (03/26/15 16:39), Minchan Kim wrote:
> > Hello Sergey,
> > 
> > Sorry for slow response.
> > I am overwhelmed with too much to do. :(
> > 
> 
> Hello,
> sure, no problem.
> 
> > > > diff -puN mm/zsmalloc.c~zsmalloc-remove-extra-cond_resched-in-__zs_compact mm/zsmalloc.c
> > > > --- a/mm/zsmalloc.c~zsmalloc-remove-extra-cond_resched-in-__zs_compact
> > > > +++ a/mm/zsmalloc.c
> > > > @@ -1717,8 +1717,6 @@ static unsigned long __zs_compact(struct
> > > >  	struct page *dst_page = NULL;
> > > >  	unsigned long nr_total_migrated = 0;
> > > >  
> > > > -	cond_resched();
> > > > -
> > > >  	spin_lock(&class->lock);
> > > >  	while ((src_page = isolate_source_page(class))) {
> 
> > 
> > If we removed cond_resched out of outer loop(ie, your patch), we lose
> > the chance to reschedule if alloc_target_page fails(ie, there is no
> > zspage in ZS_ALMOST_FULL and ZS_ALMOST_EMPTY).
> 
> 
> in outer loop we have preemption enabled and unlocked class. wouldn't that help?
> (hm, UP system?)

It depends on preemption model. If you enable full preemption, you are right
but if you enable just voluntary preemption, cond_resched will help latency.

Thanks.

-- 
Kind regards,
Minchan Kim