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| Started by | Vlastimil Babka <vbabka@suse.cz> |
|---|---|
| First post | 2016-06-03 12:30 +0200 |
| Last post | 2016-06-06 17:30 +0200 |
| Articles | 3 — 2 participants |
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Re: [PATCH v2 2/7] mm/page_owner: initialize page owner without holding the zone lock Vlastimil Babka <vbabka@suse.cz> - 2016-06-03 12:30 +0200
Re: [PATCH v2 2/7] mm/page_owner: initialize page owner without holding the zone lock Joonsoo Kim <js1304@gmail.com> - 2016-06-03 14:50 +0200
Re: [PATCH v2 2/7] mm/page_owner: initialize page owner without holding the zone lock Vlastimil Babka <vbabka@suse.cz> - 2016-06-06 17:30 +0200
| From | Vlastimil Babka <vbabka@suse.cz> |
|---|---|
| Date | 2016-06-03 12:30 +0200 |
| Subject | Re: [PATCH v2 2/7] mm/page_owner: initialize page owner without holding the zone lock |
| Message-ID | <rFUwx-1Vl-17@gated-at.bofh.it> |
On 05/26/2016 04:37 AM, js1304@gmail.com wrote:
> From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>
> It's not necessary to initialized page_owner with holding the zone lock.
> It would cause more contention on the zone lock although it's not
> a big problem since it is just debug feature. But, it is better
> than before so do it. This is also preparation step to use stackdepot
> in page owner feature. Stackdepot allocates new pages when there is no
> reserved space and holding the zone lock in this case will cause deadlock.
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> ---
> mm/compaction.c | 3 +++
> mm/page_alloc.c | 2 --
> mm/page_isolation.c | 9 ++++++---
> 3 files changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/mm/compaction.c b/mm/compaction.c
> index 8e013eb..6043ef8 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -20,6 +20,7 @@
> #include <linux/kasan.h>
> #include <linux/kthread.h>
> #include <linux/freezer.h>
> +#include <linux/page_owner.h>
> #include "internal.h"
>
> #ifdef CONFIG_COMPACTION
> @@ -80,6 +81,8 @@ static void map_pages(struct list_head *list)
> arch_alloc_page(page, order);
> kernel_map_pages(page, nr_pages, 1);
> kasan_alloc_pages(page, order);
> +
> + set_page_owner(page, order, __GFP_MOVABLE);
> if (order)
> split_page(page, order);
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 5134f46..1b1ca57 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -2507,8 +2507,6 @@ int __isolate_free_page(struct page *page, unsigned int order)
> zone->free_area[order].nr_free--;
> rmv_page_order(page);
>
> - set_page_owner(page, order, __GFP_MOVABLE);
> -
> /* Set the pageblock if the isolated page is at least a pageblock */
> if (order >= pageblock_order - 1) {
> struct page *endpage = page + (1 << order) - 1;
> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> index 612122b..927f5ee 100644
> --- a/mm/page_isolation.c
> +++ b/mm/page_isolation.c
> @@ -7,6 +7,7 @@
> #include <linux/pageblock-flags.h>
> #include <linux/memory.h>
> #include <linux/hugetlb.h>
> +#include <linux/page_owner.h>
> #include "internal.h"
>
> #define CREATE_TRACE_POINTS
> @@ -108,8 +109,6 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
> if (pfn_valid_within(page_to_pfn(buddy)) &&
> !is_migrate_isolate_page(buddy)) {
> __isolate_free_page(page, order);
> - kernel_map_pages(page, (1 << order), 1);
> - set_page_refcounted(page);
> isolated_page = page;
> }
> }
> @@ -128,8 +127,12 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
> zone->nr_isolate_pageblock--;
> out:
> spin_unlock_irqrestore(&zone->lock, flags);
> - if (isolated_page)
> + if (isolated_page) {
> + kernel_map_pages(page, (1 << order), 1);
So why we don't need the other stuff done by e.g. map_pages()? For example
arch_alloc_page() and kasan_alloc_pages(). Maybe kasan_free_pages() (called
below via __free_pages() I assume) now doesn't check if the allocation part was
done. But maybe it will start doing that?
See how the multiple places doing similar stuff is fragile? :(
> + set_page_refcounted(page);
> + set_page_owner(page, order, __GFP_MOVABLE);
> __free_pages(isolated_page, order);
This mixing of "isolated_page" and "page" is not a bug, but quite ugly. Can't
isolated_page variable just be a bool?
> + }
> }
>
> static inline struct page *
>
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| From | Joonsoo Kim <js1304@gmail.com> |
|---|---|
| Date | 2016-06-03 14:50 +0200 |
| Message-ID | <rFWI1-3dd-21@gated-at.bofh.it> |
| In reply to | #1413034 |
2016-06-03 19:23 GMT+09:00 Vlastimil Babka <vbabka@suse.cz>:
> On 05/26/2016 04:37 AM, js1304@gmail.com wrote:
>>
>> From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>>
>> It's not necessary to initialized page_owner with holding the zone lock.
>> It would cause more contention on the zone lock although it's not
>> a big problem since it is just debug feature. But, it is better
>> than before so do it. This is also preparation step to use stackdepot
>> in page owner feature. Stackdepot allocates new pages when there is no
>> reserved space and holding the zone lock in this case will cause deadlock.
>>
>> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>> ---
>> mm/compaction.c | 3 +++
>> mm/page_alloc.c | 2 --
>> mm/page_isolation.c | 9 ++++++---
>> 3 files changed, 9 insertions(+), 5 deletions(-)
>>
>> diff --git a/mm/compaction.c b/mm/compaction.c
>> index 8e013eb..6043ef8 100644
>> --- a/mm/compaction.c
>> +++ b/mm/compaction.c
>> @@ -20,6 +20,7 @@
>> #include <linux/kasan.h>
>> #include <linux/kthread.h>
>> #include <linux/freezer.h>
>> +#include <linux/page_owner.h>
>> #include "internal.h"
>>
>> #ifdef CONFIG_COMPACTION
>> @@ -80,6 +81,8 @@ static void map_pages(struct list_head *list)
>> arch_alloc_page(page, order);
>> kernel_map_pages(page, nr_pages, 1);
>> kasan_alloc_pages(page, order);
>> +
>> + set_page_owner(page, order, __GFP_MOVABLE);
>> if (order)
>> split_page(page, order);
>>
>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>> index 5134f46..1b1ca57 100644
>> --- a/mm/page_alloc.c
>> +++ b/mm/page_alloc.c
>> @@ -2507,8 +2507,6 @@ int __isolate_free_page(struct page *page, unsigned
>> int order)
>> zone->free_area[order].nr_free--;
>> rmv_page_order(page);
>>
>> - set_page_owner(page, order, __GFP_MOVABLE);
>> -
>> /* Set the pageblock if the isolated page is at least a pageblock
>> */
>> if (order >= pageblock_order - 1) {
>> struct page *endpage = page + (1 << order) - 1;
>> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
>> index 612122b..927f5ee 100644
>> --- a/mm/page_isolation.c
>> +++ b/mm/page_isolation.c
>> @@ -7,6 +7,7 @@
>> #include <linux/pageblock-flags.h>
>> #include <linux/memory.h>
>> #include <linux/hugetlb.h>
>> +#include <linux/page_owner.h>
>> #include "internal.h"
>>
>> #define CREATE_TRACE_POINTS
>> @@ -108,8 +109,6 @@ static void unset_migratetype_isolate(struct page
>> *page, unsigned migratetype)
>> if (pfn_valid_within(page_to_pfn(buddy)) &&
>> !is_migrate_isolate_page(buddy)) {
>> __isolate_free_page(page, order);
>> - kernel_map_pages(page, (1 << order), 1);
>> - set_page_refcounted(page);
>> isolated_page = page;
>> }
>> }
>> @@ -128,8 +127,12 @@ static void unset_migratetype_isolate(struct page
>> *page, unsigned migratetype)
>> zone->nr_isolate_pageblock--;
>> out:
>> spin_unlock_irqrestore(&zone->lock, flags);
>> - if (isolated_page)
>> + if (isolated_page) {
>> + kernel_map_pages(page, (1 << order), 1);
>
>
> So why we don't need the other stuff done by e.g. map_pages()? For example
> arch_alloc_page() and kasan_alloc_pages(). Maybe kasan_free_pages() (called
> below via __free_pages() I assume) now doesn't check if the allocation part
> was done. But maybe it will start doing that?
>
> See how the multiple places doing similar stuff is fragile? :(
I answered it in reply of comment of patch 1.
>> + set_page_refcounted(page);
>> + set_page_owner(page, order, __GFP_MOVABLE);
>> __free_pages(isolated_page, order);
>
>
> This mixing of "isolated_page" and "page" is not a bug, but quite ugly.
> Can't isolated_page variable just be a bool?
>
Looks better. I will do it.
Thanks.
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| From | Vlastimil Babka <vbabka@suse.cz> |
|---|---|
| Date | 2016-06-06 17:30 +0200 |
| Message-ID | <rH4Dw-6Hq-15@gated-at.bofh.it> |
| In reply to | #1413205 |
On 06/03/2016 02:47 PM, Joonsoo Kim wrote:
[...]
>>> @@ -128,8 +127,12 @@ static void unset_migratetype_isolate(struct page
>>> *page, unsigned migratetype)
>>> zone->nr_isolate_pageblock--;
>>> out:
>>> spin_unlock_irqrestore(&zone->lock, flags);
>>> - if (isolated_page)
>>> + if (isolated_page) {
>>> + kernel_map_pages(page, (1 << order), 1);
>>
>>
>> So why we don't need the other stuff done by e.g. map_pages()? For example
>> arch_alloc_page() and kasan_alloc_pages(). Maybe kasan_free_pages() (called
>> below via __free_pages() I assume) now doesn't check if the allocation part
>> was done. But maybe it will start doing that?
>>
>> See how the multiple places doing similar stuff is fragile? :(
>
> I answered it in reply of comment of patch 1.
Right.
Acked-by: Vlastimil Babka <vbabka@suse.cz>
>
>>> + set_page_refcounted(page);
>>> + set_page_owner(page, order, __GFP_MOVABLE);
>>> __free_pages(isolated_page, order);
>>
>>
>> This mixing of "isolated_page" and "page" is not a bug, but quite ugly.
>> Can't isolated_page variable just be a bool?
>>
>
> Looks better. I will do it.
>
> Thanks.
>
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