Re: [PATCH v2 5/9] mm/compaction: allow to scan nonmovable pageblock when depleted state

[Joonsoo Kim]

On Fri, Sep 25, 2015 at 12:32:02PM +0200, Vlastimil Babka wrote:
> On 08/24/2015 04:19 AM, Joonsoo Kim wrote:
> 
> [...]
> 
> > 
> > Because we just allow freepage scanner to scan non-movable pageblock
> > in very limited situation, more scanning events happen. But, allowing
> > in very limited situation results in a very important benefit that
> > memory isn't fragmented more than before. Fragmentation effect is
> > measured on following patch so please refer it.
> 
> AFAICS it's measured only for the whole series in the cover letter, no? Just 
> to
> be sure I didn't overlook something.

It takes too much time so no measurement is done on every patch.
I will try to measure it on at least this patch in next revision.

> 
> > Signed-off-by: Joonsoo Kim 
> > ---
> >  include/linux/mmzone.h |  1 +
> >  mm/compaction.c| 27 +--
> >  2 files changed, 26 insertions(+), 2 deletions(-)
> > 
> > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> > index e13b732..5cae0ad 100644
> > --- a/include/linux/mmzone.h
> > +++ b/include/linux/mmzone.h
> > @@ -545,6 +545,7 @@ enum zone_flags {
> >  */
> > ZONE_FAIR_DEPLETED, /* fair zone policy batch depleted */
> > ZONE_COMPACTION_DEPLETED,   /* compaction possiblity depleted */
> > +   ZONE_COMPACTION_SCANALLFREE,/* scan all kinds of pageblocks */
> 
> "SCANALLFREE" is hard to read. Otherwise yeah, I agree scanning unmovable
> pageblocks is necessary sometimes, and this seems to make a reasonable 
> tradeoff.

Good! I will think better name.

Thanks.

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Re: [PATCH v2 5/9] mm/compaction: allow to scan nonmovable pageblock when depleted state

[Joonsoo Kim]

On Fri, Sep 25, 2015 at 12:32:02PM +0200, Vlastimil Babka wrote:
> On 08/24/2015 04:19 AM, Joonsoo Kim wrote:
> 
> [...]
> 
> > 
> > Because we just allow freepage scanner to scan non-movable pageblock
> > in very limited situation, more scanning events happen. But, allowing
> > in very limited situation results in a very important benefit that
> > memory isn't fragmented more than before. Fragmentation effect is
> > measured on following patch so please refer it.
> 
> AFAICS it's measured only for the whole series in the cover letter, no? Just 
> to
> be sure I didn't overlook something.

It takes too much time so no measurement is done on every patch.
I will try to measure it on at least this patch in next revision.

> 
> > Signed-off-by: Joonsoo Kim 
> > ---
> >  include/linux/mmzone.h |  1 +
> >  mm/compaction.c| 27 +--
> >  2 files changed, 26 insertions(+), 2 deletions(-)
> > 
> > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> > index e13b732..5cae0ad 100644
> > --- a/include/linux/mmzone.h
> > +++ b/include/linux/mmzone.h
> > @@ -545,6 +545,7 @@ enum zone_flags {
> >  */
> > ZONE_FAIR_DEPLETED, /* fair zone policy batch depleted */
> > ZONE_COMPACTION_DEPLETED,   /* compaction possiblity depleted */
> > +   ZONE_COMPACTION_SCANALLFREE,/* scan all kinds of pageblocks */
> 
> "SCANALLFREE" is hard to read. Otherwise yeah, I agree scanning unmovable
> pageblocks is necessary sometimes, and this seems to make a reasonable 
> tradeoff.

Good! I will think better name.

Thanks.

--
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the body of a message to majord...@vger.kernel.org
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Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH v2 5/9] mm/compaction: allow to scan nonmovable pageblock when depleted state

[Vlastimil Babka]

On 08/24/2015 04:19 AM, Joonsoo Kim wrote:

[...]

> 
> Because we just allow freepage scanner to scan non-movable pageblock
> in very limited situation, more scanning events happen. But, allowing
> in very limited situation results in a very important benefit that
> memory isn't fragmented more than before. Fragmentation effect is
> measured on following patch so please refer it.

AFAICS it's measured only for the whole series in the cover letter, no? Just to
be sure I didn't overlook something.

> Signed-off-by: Joonsoo Kim 
> ---
>  include/linux/mmzone.h |  1 +
>  mm/compaction.c| 27 +--
>  2 files changed, 26 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index e13b732..5cae0ad 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -545,6 +545,7 @@ enum zone_flags {
>*/
>   ZONE_FAIR_DEPLETED, /* fair zone policy batch depleted */
>   ZONE_COMPACTION_DEPLETED,   /* compaction possiblity depleted */
> + ZONE_COMPACTION_SCANALLFREE,/* scan all kinds of pageblocks */

"SCANALLFREE" is hard to read. Otherwise yeah, I agree scanning unmovable
pageblocks is necessary sometimes, and this seems to make a reasonable tradeoff.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH v2 5/9] mm/compaction: allow to scan nonmovable pageblock when depleted state

[Vlastimil Babka]

On 08/24/2015 04:19 AM, Joonsoo Kim wrote:

[...]

> 
> Because we just allow freepage scanner to scan non-movable pageblock
> in very limited situation, more scanning events happen. But, allowing
> in very limited situation results in a very important benefit that
> memory isn't fragmented more than before. Fragmentation effect is
> measured on following patch so please refer it.

AFAICS it's measured only for the whole series in the cover letter, no? Just to
be sure I didn't overlook something.

> Signed-off-by: Joonsoo Kim 
> ---
>  include/linux/mmzone.h |  1 +
>  mm/compaction.c| 27 +--
>  2 files changed, 26 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index e13b732..5cae0ad 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -545,6 +545,7 @@ enum zone_flags {
>*/
>   ZONE_FAIR_DEPLETED, /* fair zone policy batch depleted */
>   ZONE_COMPACTION_DEPLETED,   /* compaction possiblity depleted */
> + ZONE_COMPACTION_SCANALLFREE,/* scan all kinds of pageblocks */

"SCANALLFREE" is hard to read. Otherwise yeah, I agree scanning unmovable
pageblocks is necessary sometimes, and this seems to make a reasonable tradeoff.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/