* Re: [RFC PATCH v2] page_alloc: allow migration of smaller hugepages during contig_alloc.
2025-10-20 21:08 [RFC PATCH v2] page_alloc: allow migration of smaller hugepages during contig_alloc Gregory Price
@ 2025-10-20 23:02 ` Zi Yan
2025-10-21 1:25 ` Wei Yang
` (2 subsequent siblings)
3 siblings, 0 replies; 12+ messages in thread
From: Zi Yan @ 2025-10-20 23:02 UTC (permalink / raw)
To: Gregory Price
Cc: linux-mm, linux-kernel, kernel-team, akpm, vbabka, surenb, mhocko,
jackmanb, hannes, David Hildenbrand
On 20 Oct 2025, at 17:08, Gregory Price wrote:
> We presently skip regions with hugepages entirely when trying to do
> contiguous page allocation. Instead, if hugepage migration is enabled,
> consider regions with hugepages smaller than the requested allocation.
>
> Compaction `isolate_migrate_pages_block()` already expects requests
> with hugepages to originate from alloc_contig, and hugetlb code also
> does a migratable check when isolating in `folio_isolate_hugetlb()`.
>
> Suggested-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: Gregory Price <gourry@gourry.net>
> ---
> mm/page_alloc.c | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
LGTM. Reviewed-by: Zi Yan <ziy@nvidia.com>
--
Best Regards,
Yan, Zi
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [RFC PATCH v2] page_alloc: allow migration of smaller hugepages during contig_alloc.
2025-10-20 21:08 [RFC PATCH v2] page_alloc: allow migration of smaller hugepages during contig_alloc Gregory Price
2025-10-20 23:02 ` Zi Yan
@ 2025-10-21 1:25 ` Wei Yang
2025-10-21 1:28 ` Zi Yan
2025-10-21 1:29 ` Wei Yang
2025-10-21 9:30 ` David Hildenbrand
2025-10-22 1:40 ` SeongJae Park
3 siblings, 2 replies; 12+ messages in thread
From: Wei Yang @ 2025-10-21 1:25 UTC (permalink / raw)
To: Gregory Price
Cc: linux-mm, linux-kernel, kernel-team, akpm, vbabka, surenb, mhocko,
jackmanb, hannes, ziy, David Hildenbrand
On Mon, Oct 20, 2025 at 05:08:16PM -0400, Gregory Price wrote:
>We presently skip regions with hugepages entirely when trying to do
>contiguous page allocation. Instead, if hugepage migration is enabled,
>consider regions with hugepages smaller than the requested allocation.
>
>Compaction `isolate_migrate_pages_block()` already expects requests
isolate_migratepages_block() ?
>with hugepages to originate from alloc_contig, and hugetlb code also
>does a migratable check when isolating in `folio_isolate_hugetlb()`.
>
>Suggested-by: David Hildenbrand <david@redhat.com>
>Signed-off-by: Gregory Price <gourry@gourry.net>
>---
> mm/page_alloc.c | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
>diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>index 600d9e981c23..da2e65bf63e3 100644
>--- a/mm/page_alloc.c
>+++ b/mm/page_alloc.c
>@@ -7048,8 +7048,19 @@ static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn,
> if (PageReserved(page))
> return false;
>
>- if (PageHuge(page))
>- return false;
>+ if (PageHuge(page)) {
>+ unsigned int order;
>+
>+ if (!IS_ENABLED(CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION))
>+ return false;
>+
>+ /* Don't consider moving same size/larger pages */
>+ page = compound_head(page);
>+ order = compound_order(page);
How about using folio_large_order(page_folio(page)) ?
>+ if ((order >= MAX_PAGE_ORDER) ||
>+ (nr_pages < (1 << order)))
>+ return false;
>+ }
> }
> return true;
> }
>--
>2.51.0
>
Generally LGTM
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
--
Wei Yang
Help you, Help me
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [RFC PATCH v2] page_alloc: allow migration of smaller hugepages during contig_alloc.
2025-10-21 1:25 ` Wei Yang
@ 2025-10-21 1:28 ` Zi Yan
2025-10-21 9:14 ` Wei Yang
2025-10-21 1:29 ` Wei Yang
1 sibling, 1 reply; 12+ messages in thread
From: Zi Yan @ 2025-10-21 1:28 UTC (permalink / raw)
To: Wei Yang
Cc: Gregory Price, linux-mm, linux-kernel, kernel-team, akpm, vbabka,
surenb, mhocko, jackmanb, hannes, David Hildenbrand
On 20 Oct 2025, at 21:25, Wei Yang wrote:
> On Mon, Oct 20, 2025 at 05:08:16PM -0400, Gregory Price wrote:
>> We presently skip regions with hugepages entirely when trying to do
>> contiguous page allocation. Instead, if hugepage migration is enabled,
>> consider regions with hugepages smaller than the requested allocation.
>>
>> Compaction `isolate_migrate_pages_block()` already expects requests
>
> isolate_migratepages_block() ?
>
>> with hugepages to originate from alloc_contig, and hugetlb code also
>> does a migratable check when isolating in `folio_isolate_hugetlb()`.
>>
>> Suggested-by: David Hildenbrand <david@redhat.com>
>> Signed-off-by: Gregory Price <gourry@gourry.net>
>> ---
>> mm/page_alloc.c | 15 +++++++++++++--
>> 1 file changed, 13 insertions(+), 2 deletions(-)
>>
>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>> index 600d9e981c23..da2e65bf63e3 100644
>> --- a/mm/page_alloc.c
>> +++ b/mm/page_alloc.c
>> @@ -7048,8 +7048,19 @@ static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn,
>> if (PageReserved(page))
>> return false;
>>
>> - if (PageHuge(page))
>> - return false;
>> + if (PageHuge(page)) {
>> + unsigned int order;
>> +
>> + if (!IS_ENABLED(CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION))
>> + return false;
>> +
>> + /* Don't consider moving same size/larger pages */
>> + page = compound_head(page);
>> + order = compound_order(page);
>
> How about using folio_large_order(page_folio(page)) ?
See the discussion at https://lore.kernel.org/linux-mm/609E7E01-33A6-4931-AC89-1F4B2944FB64@nvidia.com/ about reading folio order without locking.
>
>> + if ((order >= MAX_PAGE_ORDER) ||
>> + (nr_pages < (1 << order)))
>> + return false;
>> + }
>> }
>> return true;
>> }
>> --
>> 2.51.0
>>
>
> Generally LGTM
>
> Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
>
> --
> Wei Yang
> Help you, Help me
--
Best Regards,
Yan, Zi
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [RFC PATCH v2] page_alloc: allow migration of smaller hugepages during contig_alloc
2025-10-21 1:28 ` Zi Yan
@ 2025-10-21 9:14 ` Wei Yang
2025-10-21 16:03 ` Gregory Price
0 siblings, 1 reply; 12+ messages in thread
From: Wei Yang @ 2025-10-21 9:14 UTC (permalink / raw)
To: Zi Yan
Cc: Wei Yang, Gregory Price, linux-mm, linux-kernel, kernel-team,
akpm, vbabka, surenb, mhocko, jackmanb, hannes, David Hildenbrand
On Mon, Oct 20, 2025 at 09:28:18PM -0400, Zi Yan wrote:
>On 20 Oct 2025, at 21:25, Wei Yang wrote:
>
>> On Mon, Oct 20, 2025 at 05:08:16PM -0400, Gregory Price wrote:
>>> We presently skip regions with hugepages entirely when trying to do
>>> contiguous page allocation. Instead, if hugepage migration is enabled,
>>> consider regions with hugepages smaller than the requested allocation.
>>>
>>> Compaction `isolate_migrate_pages_block()` already expects requests
>>
>> isolate_migratepages_block() ?
>>
>>> with hugepages to originate from alloc_contig, and hugetlb code also
>>> does a migratable check when isolating in `folio_isolate_hugetlb()`.
>>>
>>> Suggested-by: David Hildenbrand <david@redhat.com>
>>> Signed-off-by: Gregory Price <gourry@gourry.net>
>>> ---
>>> mm/page_alloc.c | 15 +++++++++++++--
>>> 1 file changed, 13 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>>> index 600d9e981c23..da2e65bf63e3 100644
>>> --- a/mm/page_alloc.c
>>> +++ b/mm/page_alloc.c
>>> @@ -7048,8 +7048,19 @@ static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn,
>>> if (PageReserved(page))
>>> return false;
>>>
>>> - if (PageHuge(page))
>>> - return false;
>>> + if (PageHuge(page)) {
>>> + unsigned int order;
>>> +
>>> + if (!IS_ENABLED(CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION))
>>> + return false;
>>> +
>>> + /* Don't consider moving same size/larger pages */
>>> + page = compound_head(page);
>>> + order = compound_order(page);
>>
>> How about using folio_large_order(page_folio(page)) ?
>
>See the discussion at https://lore.kernel.org/linux-mm/609E7E01-33A6-4931-AC89-1F4B2944FB64@nvidia.com/ about reading folio order without locking.
>
I took another look at this.
The above code is expanded to:
page = _compound_head(page);
order = compound_order(page);
folio = page;
test_bit(PG_head, &folio->flags.f);
return folio_large_order(folio);
If we use
order = folio_order(page_folio(page))
It is expanded to:
folio = _compound_head(page);
folio_test_large(folio)
folio_test_head(folio)
test_bit(PG_head, &folio->flags.f)
return folio_large_order(folio);
These two seems expanded to the same code.
Maybe we can use folio_order() here?
>>
>>> + if ((order >= MAX_PAGE_ORDER) ||
>>> + (nr_pages < (1 << order)))
>>> + return false;
>>> + }
>>> }
>>> return true;
>>> }
>>> --
>>> 2.51.0
>>>
>>
>> Generally LGTM
>>
>> Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
>>
>> --
>> Wei Yang
>> Help you, Help me
>
>
>--
>Best Regards,
>Yan, Zi
--
Wei Yang
Help you, Help me
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [RFC PATCH v2] page_alloc: allow migration of smaller hugepages during contig_alloc
2025-10-21 9:14 ` Wei Yang
@ 2025-10-21 16:03 ` Gregory Price
2025-10-21 20:15 ` Wei Yang
0 siblings, 1 reply; 12+ messages in thread
From: Gregory Price @ 2025-10-21 16:03 UTC (permalink / raw)
To: Wei Yang
Cc: Zi Yan, linux-mm, linux-kernel, kernel-team, akpm, vbabka, surenb,
mhocko, jackmanb, hannes, David Hildenbrand
On Tue, Oct 21, 2025 at 09:14:43AM +0000, Wei Yang wrote:
>
> The above code is expanded to:
>
> page = _compound_head(page);
> order = compound_order(page);
> folio = page;
> test_bit(PG_head, &folio->flags.f);
> return folio_large_order(folio);
>
> If we use
>
> order = folio_order(page_folio(page))
>
> It is expanded to:
>
> folio = _compound_head(page);
> folio_test_large(folio)
> folio_test_head(folio)
> test_bit(PG_head, &folio->flags.f)
> return folio_large_order(folio);
>
> These two seems expanded to the same code.
>
folio_test_large drops into const_folio_flags which does
a VM_BUG_ON_PGFLAGS, so not the same logic here.
> Maybe we can use folio_order() here?
>
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [RFC PATCH v2] page_alloc: allow migration of smaller hugepages during contig_alloc
2025-10-21 16:03 ` Gregory Price
@ 2025-10-21 20:15 ` Wei Yang
0 siblings, 0 replies; 12+ messages in thread
From: Wei Yang @ 2025-10-21 20:15 UTC (permalink / raw)
To: Gregory Price
Cc: Wei Yang, Zi Yan, linux-mm, linux-kernel, kernel-team, akpm,
vbabka, surenb, mhocko, jackmanb, hannes, David Hildenbrand
On Tue, Oct 21, 2025 at 12:03:39PM -0400, Gregory Price wrote:
>On Tue, Oct 21, 2025 at 09:14:43AM +0000, Wei Yang wrote:
>>
>> The above code is expanded to:
>>
>> page = _compound_head(page);
>> order = compound_order(page);
>> folio = page;
>> test_bit(PG_head, &folio->flags.f);
>> return folio_large_order(folio);
>>
>> If we use
>>
>> order = folio_order(page_folio(page))
>>
>> It is expanded to:
>>
>> folio = _compound_head(page);
>> folio_test_large(folio)
>> folio_test_head(folio)
>> test_bit(PG_head, &folio->flags.f)
>> return folio_large_order(folio);
>>
>> These two seems expanded to the same code.
>>
>
>folio_test_large drops into const_folio_flags which does
>a VM_BUG_ON_PGFLAGS, so not the same logic here.
>
Thanks, you are right.
>> Maybe we can use folio_order() here?
>>
--
Wei Yang
Help you, Help me
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [RFC PATCH v2] page_alloc: allow migration of smaller hugepages during contig_alloc.
2025-10-21 1:25 ` Wei Yang
2025-10-21 1:28 ` Zi Yan
@ 2025-10-21 1:29 ` Wei Yang
1 sibling, 0 replies; 12+ messages in thread
From: Wei Yang @ 2025-10-21 1:29 UTC (permalink / raw)
To: Wei Yang
Cc: Gregory Price, linux-mm, linux-kernel, kernel-team, akpm, vbabka,
surenb, mhocko, jackmanb, hannes, ziy, David Hildenbrand
On Tue, Oct 21, 2025 at 01:25:33AM +0000, Wei Yang wrote:
>On Mon, Oct 20, 2025 at 05:08:16PM -0400, Gregory Price wrote:
>>We presently skip regions with hugepages entirely when trying to do
>>contiguous page allocation. Instead, if hugepage migration is enabled,
>>consider regions with hugepages smaller than the requested allocation.
>>
>>Compaction `isolate_migrate_pages_block()` already expects requests
>
>isolate_migratepages_block() ?
>
>>with hugepages to originate from alloc_contig, and hugetlb code also
>>does a migratable check when isolating in `folio_isolate_hugetlb()`.
>>
>>Suggested-by: David Hildenbrand <david@redhat.com>
>>Signed-off-by: Gregory Price <gourry@gourry.net>
>>---
>> mm/page_alloc.c | 15 +++++++++++++--
>> 1 file changed, 13 insertions(+), 2 deletions(-)
>>
>>diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>>index 600d9e981c23..da2e65bf63e3 100644
>>--- a/mm/page_alloc.c
>>+++ b/mm/page_alloc.c
>>@@ -7048,8 +7048,19 @@ static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn,
>> if (PageReserved(page))
>> return false;
>>
>>- if (PageHuge(page))
>>- return false;
>>+ if (PageHuge(page)) {
>>+ unsigned int order;
>>+
>>+ if (!IS_ENABLED(CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION))
>>+ return false;
>>+
>>+ /* Don't consider moving same size/larger pages */
>>+ page = compound_head(page);
>>+ order = compound_order(page);
>
>How about using folio_large_order(page_folio(page)) ?
>
Hmm... I see the discussion. Forget about it.
>>+ if ((order >= MAX_PAGE_ORDER) ||
>>+ (nr_pages < (1 << order)))
>>+ return false;
>>+ }
>> }
>> return true;
>> }
>>--
>>2.51.0
>>
>
>Generally LGTM
>
>Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
>
>--
>Wei Yang
>Help you, Help me
--
Wei Yang
Help you, Help me
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [RFC PATCH v2] page_alloc: allow migration of smaller hugepages during contig_alloc.
2025-10-20 21:08 [RFC PATCH v2] page_alloc: allow migration of smaller hugepages during contig_alloc Gregory Price
2025-10-20 23:02 ` Zi Yan
2025-10-21 1:25 ` Wei Yang
@ 2025-10-21 9:30 ` David Hildenbrand
2025-10-21 16:05 ` Gregory Price
2025-10-22 1:40 ` SeongJae Park
3 siblings, 1 reply; 12+ messages in thread
From: David Hildenbrand @ 2025-10-21 9:30 UTC (permalink / raw)
To: Gregory Price, linux-mm
Cc: linux-kernel, kernel-team, akpm, vbabka, surenb, mhocko, jackmanb,
hannes, ziy
On 20.10.25 23:08, Gregory Price wrote:
> We presently skip regions with hugepages entirely when trying to do
> contiguous page allocation. Instead, if hugepage migration is enabled,
> consider regions with hugepages smaller than the requested allocation.
>
> Compaction `isolate_migrate_pages_block()` already expects requests
Please, let's not talk about "compaction" here, it's just confusing to
talk about compaction for something that is not compaction but uses some
primitives (because not properly separated yet)
Just say "isolate_migrate_pages_block() already expects ..."
> with hugepages to originate from alloc_contig, and hugetlb code also
> does a migratable check when isolating in `folio_isolate_hugetlb()`.
>
> Suggested-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: Gregory Price <gourry@gourry.net>
> ---
> mm/page_alloc.c | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 600d9e981c23..da2e65bf63e3 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -7048,8 +7048,19 @@ static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn,
> if (PageReserved(page))
> return false;
>
> - if (PageHuge(page))
> - return false;
> + if (PageHuge(page)) {
> + unsigned int order;
> +
> + if (!IS_ENABLED(CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION))
> + return false;
> +
> + /* Don't consider moving same size/larger pages */
> + page = compound_head(page);
> + order = compound_order(page);
> + if ((order >= MAX_PAGE_ORDER) ||
> + (nr_pages < (1 << order)))
> + return false;
This is roughly what we do in pageblock_skip_persistent(), just with a
hardcoded pageblock size.
I'm not sure about the MAX_PAGE_ORDER check, though. If an arch supports
two hugetlb sizes that exceed MAX_PAGE_ORDER, it would not work as expected.
Doesn't arm64 support that with cont-PMD vs. PUD hugetlb folios?
MAX_FOLIO_ORDER would be better.
--
Cheers
David / dhildenb
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [RFC PATCH v2] page_alloc: allow migration of smaller hugepages during contig_alloc.
2025-10-21 9:30 ` David Hildenbrand
@ 2025-10-21 16:05 ` Gregory Price
0 siblings, 0 replies; 12+ messages in thread
From: Gregory Price @ 2025-10-21 16:05 UTC (permalink / raw)
To: David Hildenbrand
Cc: linux-mm, linux-kernel, kernel-team, akpm, vbabka, surenb, mhocko,
jackmanb, hannes, ziy
On Tue, Oct 21, 2025 at 11:30:48AM +0200, David Hildenbrand wrote:
> > Compaction `isolate_migrate_pages_block()` already expects requests
>
> Please, let's not talk about "compaction" here, it's just confusing to talk
> about compaction for something that is not compaction but uses some
> primitives (because not properly separated yet)
>
> Just say "isolate_migrate_pages_block() already expects ..."
>
will do
> > + /* Don't consider moving same size/larger pages */
> > + page = compound_head(page);
> > + order = compound_order(page);
> > + if ((order >= MAX_PAGE_ORDER) ||
> > + (nr_pages < (1 << order)))
> > + return false;
>
> This is roughly what we do in pageblock_skip_persistent(), just with a
> hardcoded pageblock size.
>
> I'm not sure about the MAX_PAGE_ORDER check, though. If an arch supports two
> hugetlb sizes that exceed MAX_PAGE_ORDER, it would not work as expected.
>
> Doesn't arm64 support that with cont-PMD vs. PUD hugetlb folios?
> MAX_FOLIO_ORDER would be better.
Will adjust to MAX_FOLIO_ORDER, makes sense. Missed that. Will take a
look at the pageblock code, I think I was looking at the compaction and
some other code for inspiration here.
~Gregory
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [RFC PATCH v2] page_alloc: allow migration of smaller hugepages during contig_alloc.
2025-10-20 21:08 [RFC PATCH v2] page_alloc: allow migration of smaller hugepages during contig_alloc Gregory Price
` (2 preceding siblings ...)
2025-10-21 9:30 ` David Hildenbrand
@ 2025-10-22 1:40 ` SeongJae Park
2025-10-22 14:53 ` Gregory Price
3 siblings, 1 reply; 12+ messages in thread
From: SeongJae Park @ 2025-10-22 1:40 UTC (permalink / raw)
To: Gregory Price
Cc: SeongJae Park, linux-mm, linux-kernel, kernel-team, akpm, vbabka,
surenb, mhocko, jackmanb, hannes, ziy, David Hildenbrand
On Mon, 20 Oct 2025 17:08:16 -0400 Gregory Price <gourry@gourry.net> wrote:
> We presently skip regions with hugepages entirely when trying to do
> contiguous page allocation. Instead, if hugepage migration is enabled,
> consider regions with hugepages smaller than the requested allocation.
>
> Compaction `isolate_migrate_pages_block()` already expects requests
> with hugepages to originate from alloc_contig, and hugetlb code also
> does a migratable check when isolating in `folio_isolate_hugetlb()`.
>
> Suggested-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: Gregory Price <gourry@gourry.net>
> ---
> mm/page_alloc.c | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 600d9e981c23..da2e65bf63e3 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -7048,8 +7048,19 @@ static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn,
> if (PageReserved(page))
> return false;
>
> - if (PageHuge(page))
> - return false;
> + if (PageHuge(page)) {
> + unsigned int order;
> +
> + if (!IS_ENABLED(CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION))
> + return false;
> +
> + /* Don't consider moving same size/larger pages */
> + page = compound_head(page);
> + order = compound_order(page);
> + if ((order >= MAX_PAGE_ORDER) ||
> + (nr_pages < (1 << order)))
> + return false;
Shouldn't the comparison of 'nr_pages' against '1 << order' use '<=' instead of
'<', to match the commit description?
> + }
> }
> return true;
> }
> --
> 2.51.0
Thanks,
SJ
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [RFC PATCH v2] page_alloc: allow migration of smaller hugepages during contig_alloc.
2025-10-22 1:40 ` SeongJae Park
@ 2025-10-22 14:53 ` Gregory Price
0 siblings, 0 replies; 12+ messages in thread
From: Gregory Price @ 2025-10-22 14:53 UTC (permalink / raw)
To: SeongJae Park
Cc: linux-mm, linux-kernel, kernel-team, akpm, vbabka, surenb, mhocko,
jackmanb, hannes, ziy, David Hildenbrand
On Tue, Oct 21, 2025 at 06:40:57PM -0700, SeongJae Park wrote:
> On Mon, 20 Oct 2025 17:08:16 -0400 Gregory Price <gourry@gourry.net> wrote:
> > +
> > + /* Don't consider moving same size/larger pages */
> > + page = compound_head(page);
> > + order = compound_order(page);
> > + if ((order >= MAX_PAGE_ORDER) ||
> > + (nr_pages < (1 << order)))
> > + return false;
>
> Shouldn't the comparison of 'nr_pages' against '1 << order' use '<=' instead of
> '<', to match the commit description?
>
Good catch, got lost in the shuffle. Thank you!
~Gregory
^ permalink raw reply [flat|nested] 12+ messages in thread