On Wed, May 06, 2015 at 02:31:58PM +0200, Michael Kerrisk (man-pages) wrote: > Hi Andi, > > Brice's patch seems broadly okay to me, but you originally wrote the > pages, so I'd be happy if you could comment. Could you take a look please? Just s/process/thread/g ? The distinction between process and thread is fuzzy in Linux of course, but i suppose it matches the user's terms better. Fine for me. -Andi > > Cheers, > > Michael > > > On 04/30/2015 12:31 PM, Brice Goglin wrote: > > Hello, > > > > set/get_mempolicy manpages say that the memory allocation policy is > > per process while reading the code and testing shows that it's actually > > per thread. > > Here's a quick fix, which may need to be improved to better explain that we're > > allocating in the context of a thread within a process address space. > > > > Brice > > > > > > > > > > > > > > set/get_mempolicy.2: policy is per thread, not per process > > > > Signed-off-by: Brice Goglin <Brice.Goglin@xxxxxxxx> > > > > diff --git a/man2/get_mempolicy.2 b/man2/get_mempolicy.2 > > index a17c0f3..c0e9639 100644 > > --- a/man2/get_mempolicy.2 > > +++ b/man2/get_mempolicy.2 > > @@ -26,7 +26,7 @@ > > .\" > > .TH GET_MEMPOLICY 2 2008-08-15 Linux "Linux Programmer's Manual" > > .SH NAME > > -get_mempolicy \- retrieve NUMA memory policy for a process > > +get_mempolicy \- retrieve NUMA memory policy for a thread > > .SH SYNOPSIS > > .B "#include <numaif.h>" > > .nf > > @@ -39,19 +39,19 @@ Link with \fI\-lnuma\fP. > > .fi > > .SH DESCRIPTION > > .BR get_mempolicy () > > -retrieves the NUMA policy of the calling process or of a memory address, > > +retrieves the NUMA policy of the calling thread or of a memory address, > > depending on the setting of > > .IR flags . > > > > A NUMA machine has different > > memory controllers with different distances to specific CPUs. > > The memory policy defines from which node memory is allocated for > > -the process. > > +the thread. > > > > If > > .I flags > > is specified as 0, > > -then information about the calling process's default policy > > +then information about the calling thread's default policy > > (as set by > > .BR set_mempolicy (2)) > > is returned. > > @@ -59,7 +59,7 @@ The policy returned > > .RI [ mode > > and > > .IR nodemask ] > > -may be used to restore the process's policy to its state at > > +may be used to restore the thread's policy to its state at > > the time of the call to > > .BR get_mempolicy () > > using > > @@ -72,7 +72,7 @@ specifies > > (available since Linux 2.6.24), the > > .I mode > > argument is ignored and the set of nodes [memories] that the > > -process is allowed to specify in subsequent calls to > > +thread is allowed to specify in subsequent calls to > > .BR mbind (2) > > or > > .BR set_mempolicy (2) > > @@ -94,7 +94,7 @@ specifies > > then information is returned about the policy governing the memory > > address given in > > .IR addr . > > -This policy may be different from the process's default policy if > > +This policy may be different from the thread's default policy if > > .BR mbind (2) > > or one of the helper functions described in > > .BR numa (3) > > @@ -135,7 +135,7 @@ is allocated into the location pointed to by > > .IR mode . > > If no page has yet been allocated for the specified address, > > .BR get_mempolicy () > > -will allocate a page as if the process had performed a read > > +will allocate a page as if the thread had performed a read > > [load] access to that address, and return the ID of the node > > where that page was allocated. > > > > @@ -145,7 +145,7 @@ specifies > > .BR MPOL_F_NODE , > > but not > > .BR MPOL_F_ADDR , > > -and the process's current policy is > > +and the thread's current policy is > > .BR MPOL_INTERLEAVE , > > then > > .BR get_mempolicy () > > @@ -153,7 +153,7 @@ will return in the location pointed to by a non-NULL > > .I mode > > argument, > > the node ID of the next node that will be used for > > -interleaving of internal kernel pages allocated on behalf of the process. > > +interleaving of internal kernel pages allocated on behalf of the thread. > > .\" Note: code returns next interleave node via 'mode' argument -Lee Schermerhorn > > These allocations include pages for memory-mapped files in > > process memory ranges mapped using the > > @@ -214,7 +214,7 @@ specified > > .B MPOL_F_NODE > > but not > > .B MPOL_F_ADDR > > -and the current process policy is not > > +and the current thread policy is not > > .BR MPOL_INTERLEAVE . > > Or, > > .I flags > > diff --git a/man2/set_mempolicy.2 b/man2/set_mempolicy.2 > > index 9d7d1de..f5169da 100644 > > --- a/man2/set_mempolicy.2 > > +++ b/man2/set_mempolicy.2 > > @@ -26,7 +26,7 @@ > > .\" > > .TH SET_MEMPOLICY 2 2014-05-28 Linux "Linux Programmer's Manual" > > .SH NAME > > -set_mempolicy \- set default NUMA memory policy for a process and its children > > +set_mempolicy \- set default NUMA memory policy for a thread and its children > > .SH SYNOPSIS > > .nf > > .B "#include <numaif.h>" > > @@ -38,7 +38,7 @@ Link with \fI\-lnuma\fP. > > .fi > > .SH DESCRIPTION > > .BR set_mempolicy () > > -sets the NUMA memory policy of the calling process, > > +sets the NUMA memory policy of the calling thread, > > which consists of a policy mode and zero or more nodes, > > to the values specified by the > > .IR mode , > > @@ -50,28 +50,28 @@ arguments. > > A NUMA machine has different > > memory controllers with different distances to specific CPUs. > > The memory policy defines from which node memory is allocated for > > -the process. > > +the thread. > > > > -This system call defines the default policy for the process. > > -The process policy governs allocation of pages in the process's > > +This system call defines the default policy for the thread. > > +The thread policy governs allocation of pages in the process's > > address space outside of memory ranges > > controlled by a more specific policy set by > > .BR mbind (2). > > -The process default policy also controls allocation of any pages for > > +The thread default policy also controls allocation of any pages for > > memory-mapped files mapped using the > > .BR mmap (2) > > call with the > > .B MAP_PRIVATE > > -flag and that are only read [loaded] from by the process > > +flag and that are only read [loaded] from by the thread > > and of memory-mapped files mapped using the > > .BR mmap (2) > > call with the > > .B MAP_SHARED > > flag, regardless of the access type. > > The policy is applied only when a new page is allocated > > -for the process. > > +for the thread. > > For anonymous memory this is when the page is first > > -touched by the application. > > +touched by the thread. > > > > The > > .I mode > > @@ -154,7 +154,7 @@ cpuset context includes one or more of the nodes specified by > > > > The > > .B MPOL_DEFAULT > > -mode specifies that any nondefault process memory policy be removed, > > +mode specifies that any nondefault thread memory policy be removed, > > so that the memory policy "falls back" to the system default policy. > > The system default policy is "local allocation"\(emthat is, > > allocate memory on the node of the CPU that triggered the allocation. > > @@ -211,9 +211,9 @@ arguments specify the empty set, then the policy > > specifies "local allocation" > > (like the system default policy discussed above). > > > > -The process memory policy is preserved across an > > +The thread memory policy is preserved across an > > .BR execve (2), > > -and is inherited by child processes created using > > +and is inherited by child threads created using > > .BR fork (2) > > or > > .BR clone (2). > > @@ -279,9 +279,9 @@ system call was added to the Linux kernel in version 2.6.7. > > .SH CONFORMING TO > > This system call is Linux-specific. > > .SH NOTES > > -Process policy is not remembered if the page is swapped out. > > +Memory policy is not remembered if the page is swapped out. > > When such a page is paged back in, it will use the policy of > > -the process or memory range that is in effect at the time the > > +the thread or memory range that is in effect at the time the > > page is allocated. > > > > For information on library support, see > > > > > > > -- > Michael Kerrisk > Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ > Linux/UNIX System Programming Training: http://man7.org/training/ > -- ak@xxxxxxxxxxxxxxx -- Speaking for myself 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