[PATCH] futex.2: clarify address mapping

[PATCH] futex.2: clarify address mapping

[Heinrich Schuchardt]

Using the word "physical" address should make the text easier to
make.

Avoid negations like "may not be equal".

Signed-off-by: Heinrich Schuchardt <xypron.glpk-Mmb7MZpHnFY@public.gmane.org>
---
 man2/futex.2 | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/man2/futex.2 b/man2/futex.2
index b4a52b1..0644fc6 100644
--- a/man2/futex.2
+++ b/man2/futex.2
@@ -54,12 +54,10 @@ The condition is represented by the futex word, which is an address
 in memory supplied to the
 .BR futex ()
 system call, and the value at this memory location.
-(While the virtual addresses for the same memory in separate
-processes may not be equal,
-the kernel maps them internally so that the same memory mapped
-in different locations will correspond for
-.BR futex ()
-calls.)
+(While the virtual addresses for the same physical memory address
+in separate processes may be different,
+the same physical address may be shared by the processes using
+.BR mmap (2).)
 
 When executing a futex operation that requests to block a thread,
 the kernel will only block if the futex word has the value that the
-- 
2.1.4

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Re: [PATCH] futex.2: clarify address mapping

[Michael Kerrisk (man-pages)]

On 03/29/2015 08:38 PM, Heinrich Schuchardt wrote:
> Using the word "physical" address should make the text easier to
> make.
> 
> Avoid negations like "may not be equal".


Thanks, Heinrich. Applied.

Cheers,

Michael


> Signed-off-by: Heinrich Schuchardt <xypron.glpk-Mmb7MZpHnFY@public.gmane.org>
> ---
>  man2/futex.2 | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/man2/futex.2 b/man2/futex.2
> index b4a52b1..0644fc6 100644
> --- a/man2/futex.2
> +++ b/man2/futex.2
> @@ -54,12 +54,10 @@ The condition is represented by the futex word, which is an address
>  in memory supplied to the
>  .BR futex ()
>  system call, and the value at this memory location.
> -(While the virtual addresses for the same memory in separate
> -processes may not be equal,
> -the kernel maps them internally so that the same memory mapped
> -in different locations will correspond for
> -.BR futex ()
> -calls.)
> +(While the virtual addresses for the same physical memory address
> +in separate processes may be different,
> +the same physical address may be shared by the processes using
> +.BR mmap (2).)
>  
>  When executing a futex operation that requests to block a thread,
>  the kernel will only block if the futex word has the value that the
> 


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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