2022-05-27 21:27:46

by Anshuman Khandual

Subject: [PATCH V2] mm/memory_hotplug: Drop 'reason' argument from check_pfn_span()

In check_pfn_span(), a 'reason' string is being used to recreate the caller
function name, while printing the warning message. It is really unnecessary
as the warning message could just be printed inside the caller depending on
the return code. Currently there are just two callers for check_pfn_span()
i.e __add_pages() and __remove_pages(). Let's clean this up.

Cc: Oscar Salvador <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Anshuman Khandual <[email protected]>
---
Changes in V2:

- Fixed typo in commit message
- Dropped using 'ret' to capture check_pfn_span() return value in __add_pages()

Changes in V1:

https://lore.kernel.org/all/[email protected]/

mm/memory_hotplug.c | 20 +++++++++-----------
1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 416b38ca8def..3b24386e9276 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -220,8 +220,7 @@ static void release_memory_resource(struct resource *res)
kfree(res);
}

-static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
- const char *reason)
+static int check_pfn_span(unsigned long pfn, unsigned long nr_pages)
{
/*
* Disallow all operations smaller than a sub-section and only
@@ -238,12 +237,8 @@ static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
min_align = PAGES_PER_SUBSECTION;
else
min_align = PAGES_PER_SECTION;
- if (!IS_ALIGNED(pfn, min_align)
- || !IS_ALIGNED(nr_pages, min_align)) {
- WARN(1, "Misaligned __%s_pages start: %#lx end: #%lx\n",
- reason, pfn, pfn + nr_pages - 1);
+ if (!IS_ALIGNED(pfn, min_align) || !IS_ALIGNED(nr_pages, min_align))
return -EINVAL;
- }
return 0;
}

@@ -320,9 +315,10 @@ int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
altmap->alloc = 0;
}

- err = check_pfn_span(pfn, nr_pages, "add");
- if (err)
- return err;
+ if (check_pfn_span(pfn, nr_pages)) {
+ WARN(1, "Misaligned %s start: %#lx end: #%lx\n", __func__, pfn, pfn + nr_pages - 1);
+ return -EINVAL;
+ }

for (; pfn < end_pfn; pfn += cur_nr_pages) {
/* Select all remaining pages up to the next section boundary */
@@ -518,8 +514,10 @@ void __remove_pages(unsigned long pfn, unsigned long nr_pages,

map_offset = vmem_altmap_offset(altmap);

- if (check_pfn_span(pfn, nr_pages, "remove"))
+ if (check_pfn_span(pfn, nr_pages)) {
+ WARN(1, "Misaligned %s start: %#lx end: #%lx\n", __func__, pfn, pfn + nr_pages - 1);
return;
+ }

for (; pfn < end_pfn; pfn += cur_nr_pages) {
cond_resched();
--
2.20.1

2022-05-30 06:23:54

by Oscar Salvador

Subject: Re: [PATCH V2] mm/memory_hotplug: Drop 'reason' argument from check_pfn_span()

On Thu, May 26, 2022 at 07:42:58AM +0530, Anshuman Khandual wrote:
> In check_pfn_span(), a 'reason' string is being used to recreate the caller
> function name, while printing the warning message. It is really unnecessary
> as the warning message could just be printed inside the caller depending on
> the return code. Currently there are just two callers for check_pfn_span()
> i.e __add_pages() and __remove_pages(). Let's clean this up.
>
> Cc: Oscar Salvador <[email protected]>
> Cc: David Hildenbrand <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Anshuman Khandual <[email protected]>

Acked-by: Oscar Salvador <[email protected]>

> ---
> Changes in V2:
>
> - Fixed typo in commit message
> - Dropped using 'ret' to capture check_pfn_span() return value in __add_pages()
>
> Changes in V1:
>
> https://lore.kernel.org/all/[email protected]/
>
> mm/memory_hotplug.c | 20 +++++++++-----------
> 1 file changed, 9 insertions(+), 11 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 416b38ca8def..3b24386e9276 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -220,8 +220,7 @@ static void release_memory_resource(struct resource *res)
> kfree(res);
> }
>
> -static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
> - const char *reason)
> +static int check_pfn_span(unsigned long pfn, unsigned long nr_pages)
> {
> /*
> * Disallow all operations smaller than a sub-section and only
> @@ -238,12 +237,8 @@ static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
> min_align = PAGES_PER_SUBSECTION;
> else
> min_align = PAGES_PER_SECTION;
> - if (!IS_ALIGNED(pfn, min_align)
> - || !IS_ALIGNED(nr_pages, min_align)) {
> - WARN(1, "Misaligned __%s_pages start: %#lx end: #%lx\n",
> - reason, pfn, pfn + nr_pages - 1);
> + if (!IS_ALIGNED(pfn, min_align) || !IS_ALIGNED(nr_pages, min_align))
> return -EINVAL;
> - }
> return 0;
> }
>
> @@ -320,9 +315,10 @@ int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
> altmap->alloc = 0;
> }
>
> - err = check_pfn_span(pfn, nr_pages, "add");
> - if (err)
> - return err;
> + if (check_pfn_span(pfn, nr_pages)) {
> + WARN(1, "Misaligned %s start: %#lx end: #%lx\n", __func__, pfn, pfn + nr_pages - 1);
> + return -EINVAL;
> + }
>
> for (; pfn < end_pfn; pfn += cur_nr_pages) {
> /* Select all remaining pages up to the next section boundary */
> @@ -518,8 +514,10 @@ void __remove_pages(unsigned long pfn, unsigned long nr_pages,
>
> map_offset = vmem_altmap_offset(altmap);
>
> - if (check_pfn_span(pfn, nr_pages, "remove"))
> + if (check_pfn_span(pfn, nr_pages)) {
> + WARN(1, "Misaligned %s start: %#lx end: #%lx\n", __func__, pfn, pfn + nr_pages - 1);
> return;
> + }
>
> for (; pfn < end_pfn; pfn += cur_nr_pages) {
> cond_resched();
> --
> 2.20.1
>

--
Oscar Salvador
SUSE Labs

2022-05-30 07:38:44

by David Hildenbrand

Subject: Re: [PATCH V2] mm/memory_hotplug: Drop 'reason' argument from check_pfn_span()

On 26.05.22 04:12, Anshuman Khandual wrote:
> In check_pfn_span(), a 'reason' string is being used to recreate the caller
> function name, while printing the warning message. It is really unnecessary
> as the warning message could just be printed inside the caller depending on
> the return code. Currently there are just two callers for check_pfn_span()
> i.e __add_pages() and __remove_pages(). Let's clean this up.
>
> Cc: Oscar Salvador <[email protected]>
> Cc: David Hildenbrand <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Anshuman Khandual <[email protected]>
> ---
> Changes in V2:
>
> - Fixed typo in commit message
> - Dropped using 'ret' to capture check_pfn_span() return value in __add_pages()
>
> Changes in V1:
>
> https://lore.kernel.org/all/[email protected]/
>
> mm/memory_hotplug.c | 20 +++++++++-----------
> 1 file changed, 9 insertions(+), 11 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 416b38ca8def..3b24386e9276 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -220,8 +220,7 @@ static void release_memory_resource(struct resource *res)
> kfree(res);
> }
>
> -static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
> - const char *reason)
> +static int check_pfn_span(unsigned long pfn, unsigned long nr_pages)
> {
> /*
> * Disallow all operations smaller than a sub-section and only
> @@ -238,12 +237,8 @@ static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
> min_align = PAGES_PER_SUBSECTION;
> else
> min_align = PAGES_PER_SECTION;
> - if (!IS_ALIGNED(pfn, min_align)
> - || !IS_ALIGNED(nr_pages, min_align)) {
> - WARN(1, "Misaligned __%s_pages start: %#lx end: #%lx\n",
> - reason, pfn, pfn + nr_pages - 1);
> + if (!IS_ALIGNED(pfn, min_align) || !IS_ALIGNED(nr_pages, min_align))

We could do

if (!IS_ALIGNED(pfn | nr_pages, min_align))


Reviewed-by: David Hildenbrand <[email protected]>

--
Thanks,

David / dhildenb

2022-06-01 21:28:19

by Anshuman Khandual

Subject: Re: [PATCH V2] mm/memory_hotplug: Drop 'reason' argument from check_pfn_span()

On 5/30/22 12:24, David Hildenbrand wrote:
> On 26.05.22 04:12, Anshuman Khandual wrote:
>> In check_pfn_span(), a 'reason' string is being used to recreate the caller
>> function name, while printing the warning message. It is really unnecessary
>> as the warning message could just be printed inside the caller depending on
>> the return code. Currently there are just two callers for check_pfn_span()
>> i.e __add_pages() and __remove_pages(). Let's clean this up.
>>
>> Cc: Oscar Salvador <[email protected]>
>> Cc: David Hildenbrand <[email protected]>
>> Cc: Andrew Morton <[email protected]>
>> Cc: [email protected]
>> Cc: [email protected]
>> Signed-off-by: Anshuman Khandual <[email protected]>
>> ---
>> Changes in V2:
>>
>> - Fixed typo in commit message
>> - Dropped using 'ret' to capture check_pfn_span() return value in __add_pages()
>>
>> Changes in V1:
>>
>> https://lore.kernel.org/all/[email protected]/
>>
>> mm/memory_hotplug.c | 20 +++++++++-----------
>> 1 file changed, 9 insertions(+), 11 deletions(-)
>>
>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>> index 416b38ca8def..3b24386e9276 100644
>> --- a/mm/memory_hotplug.c
>> +++ b/mm/memory_hotplug.c
>> @@ -220,8 +220,7 @@ static void release_memory_resource(struct resource *res)
>> kfree(res);
>> }
>>
>> -static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
>> - const char *reason)
>> +static int check_pfn_span(unsigned long pfn, unsigned long nr_pages)
>> {
>> /*
>> * Disallow all operations smaller than a sub-section and only
>> @@ -238,12 +237,8 @@ static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
>> min_align = PAGES_PER_SUBSECTION;
>> else
>> min_align = PAGES_PER_SECTION;
>> - if (!IS_ALIGNED(pfn, min_align)
>> - || !IS_ALIGNED(nr_pages, min_align)) {
>> - WARN(1, "Misaligned __%s_pages start: %#lx end: #%lx\n",
>> - reason, pfn, pfn + nr_pages - 1);
>> + if (!IS_ALIGNED(pfn, min_align) || !IS_ALIGNED(nr_pages, min_align))
> We could do
>
> if (!IS_ALIGNED(pfn | nr_pages, min_align))


Sure, will change it.