[PATCH 1/2] swapon.2: Adjust decreased value under CONFIG_MIGRATION

[PATCH 1/2] swapon.2: Adjust decreased value under CONFIG_MIGRATION

[Yang Xu]

After kernel 5.19[1], the limit is decreased by 3.

[1]https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/include/linux/swap.h?id=6c287605f

Signed-off-by: Yang Xu <xuyang2018.jy@fujitsu.com>
---
 man2/swapon.2 | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/man2/swapon.2 b/man2/swapon.2
index c0e61cbc6..ee270cea1 100644
--- a/man2/swapon.2
+++ b/man2/swapon.2
@@ -164,7 +164,8 @@ Before Linux 2.4.10,
 .B MAX_SWAPFILES
 has the value 8;
 since Linux 2.4.10, it has the value 32.
-Since Linux 2.6.18, the limit is decreased by 2 (thus: 30)
+Since Linux 2.6.18, the limit is decreased by 2 (Since Linux 5.19.0,
+the limit is decreased by 3)
 if the kernel is built with the
 .B CONFIG_MIGRATION
 option
@@ -172,6 +173,7 @@ option
 .BR mbind (2)
 and
 .BR migrate_pages (2)).
+
 Since Linux 2.6.32, the limit is further decreased by 1
 if the kernel is built with the
 .B CONFIG_MEMORY_FAILURE
-- 
2.27.0

[PATCH 2/2] swapon.2: Adjust decreased value under CONFIG_PTE_MARKER

[Yang Xu]

Since linux 5.19[1], MAX_SWAPFILES will be futher decreased
1 if kernel built with CONFIG_PTE_MARKER.

[1]https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/include/linux/swap.h?id=679d10331

Signed-off-by: Yang Xu <xuyang2018.jy@fujitsu.com>
---
 man2/swapon.2 | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/man2/swapon.2 b/man2/swapon.2
index ee270cea1..0bd62a512 100644
--- a/man2/swapon.2
+++ b/man2/swapon.2
@@ -182,6 +182,10 @@ Since Linux 5.14, the limit is further decreased by 4
 if the kernel is built with the
 .B CONFIG_DEVICE_PRIVATE
 option.
+Since Linux 5.19, the limit is further decreased by 1
+if the kernel is built with the
+.B CONFIG_PTE_MARKER
+option.
 .P
 Discard of swap pages was introduced in Linux 2.6.29,
 then made conditional
-- 
2.27.0

Re: [PATCH 1/2] swapon.2: Adjust decreased value under CONFIG_MIGRATION

[Alejandro Colomar]

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Hi Yang,

On Mon, Dec 04, 2023 at 07:24:30AM -0500, Yang Xu wrote:
> After kernel 5.19[1], the limit is decreased by 3.
> 
> [1]https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/include/linux/swap.h?id=6c287605f
> 
> Signed-off-by: Yang Xu <xuyang2018.jy@fujitsu.com>
> ---
>  man2/swapon.2 | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/man2/swapon.2 b/man2/swapon.2
> index c0e61cbc6..ee270cea1 100644
> --- a/man2/swapon.2
> +++ b/man2/swapon.2
> @@ -164,7 +164,8 @@ Before Linux 2.4.10,
>  .B MAX_SWAPFILES
>  has the value 8;
>  since Linux 2.4.10, it has the value 32.
> -Since Linux 2.6.18, the limit is decreased by 2 (thus: 30)
> +Since Linux 2.6.18, the limit is decreased by 2 (Since Linux 5.19.0,
> +the limit is decreased by 3)
>  if the kernel is built with the
>  .B CONFIG_MIGRATION
>  option
> @@ -172,6 +173,7 @@ option
>  .BR mbind (2)
>  and
>  .BR migrate_pages (2)).
> +

There should be no blank lines in man(7) source.  That would trigger a
warning.  See man-pages(7):

   Formatting conventions (general)
     Paragraphs  should  be separated by suitable markers (usually ei‐
     ther .P or .IP).  Do not separate paragraphs using  blank  lines,
     as this results in poor rendering in some output formats (such as
     PostScript and PDF).

Thanks,
Alex

>  Since Linux 2.6.32, the limit is further decreased by 1
>  if the kernel is built with the
>  .B CONFIG_MEMORY_FAILURE
> -- 
> 2.27.0
> 
> 

-- 
<https://www.alejandro-colomar.es/>

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