* + mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch added to mm-unstable branch
@ 2024-01-12 22:33 Andrew Morton
0 siblings, 0 replies; 5+ messages in thread
From: Andrew Morton @ 2024-01-12 22:33 UTC (permalink / raw)
To: mm-commits, ying.huang, sthanneeru.opensrc, ravis.opensrc,
rakie.kim, mhocko, Jonathan.Cameron, hyeongtak.ji, honggyu.kim,
Hasan.Maruf, hannes, gregory.price, fvdl, dan.j.williams, corbet,
ak, gourry.memverge, akpm
The patch titled
Subject: mm/mempolicy: refactor a read-once mechanism into a function for re-use
has been added to the -mm mm-unstable branch. Its filename is
mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Gregory Price <gourry.memverge@gmail.com>
Subject: mm/mempolicy: refactor a read-once mechanism into a function for re-use
Date: Fri, 12 Jan 2024 16:08:33 -0500
Move the use of barrier() to force policy->nodemask onto the stack into a
function `read_once_policy_nodemask` so that it may be re-used.
Link: https://lkml.kernel.org/r/20240112210834.8035-3-gregory.price@memverge.com
Signed-off-by: Gregory Price <gregory.price@memverge.com>
Suggested-by: Huang Ying <ying.huang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Frank van der Linden <fvdl@google.com>
Cc: Hasan Al Maruf <Hasan.Maruf@amd.com>
Cc: Honggyu Kim <honggyu.kim@sk.com>
Cc: Hyeongtak Ji <hyeongtak.ji@sk.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Ravi Jonnalagadda <ravis.opensrc@micron.com>
Cc: Srinivasulu Thanneeru <sthanneeru.opensrc@micron.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/mempolicy.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)
--- a/mm/mempolicy.c~mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use
+++ a/mm/mempolicy.c
@@ -1907,6 +1907,20 @@ unsigned int mempolicy_slab_node(void)
}
}
+static unsigned int read_once_policy_nodemask(struct mempolicy *pol,
+ nodemask_t *mask)
+{
+ /*
+ * barrier stabilizes the nodemask locally so that it can be iterated
+ * over safely without concern for changes. Allocators validate node
+ * selection does not violate mems_allowed, so this is safe.
+ */
+ barrier();
+ __builtin_memcpy(mask, &pol->nodes, sizeof(nodemask_t));
+ barrier();
+ return nodes_weight(*mask);
+}
+
/*
* Do static interleaving for interleave index @ilx. Returns the ilx'th
* node in pol->nodes (starting from ilx=0), wrapping around if ilx
@@ -1914,20 +1928,12 @@ unsigned int mempolicy_slab_node(void)
*/
static unsigned int interleave_nid(struct mempolicy *pol, pgoff_t ilx)
{
- nodemask_t nodemask = pol->nodes;
+ nodemask_t nodemask;
unsigned int target, nnodes;
int i;
int nid;
- /*
- * The barrier will stabilize the nodemask in a register or on
- * the stack so that it will stop changing under the code.
- *
- * Between first_node() and next_node(), pol->nodes could be changed
- * by other threads. So we put pol->nodes in a local stack.
- */
- barrier();
- nnodes = nodes_weight(nodemask);
+ nnodes = read_once_policy_nodemask(pol, &nodemask);
if (!nnodes)
return numa_node_id();
target = ilx % nnodes;
_
Patches currently in -mm which might be from gourry.memverge@gmail.com are
mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch
mm-mempolicy-introduce-mpol_weighted_interleave-for-weighted-interleaving.patch
^ permalink raw reply [flat|nested] 5+ messages in thread
* + mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch added to mm-unstable branch
@ 2024-01-21 22:14 Andrew Morton
0 siblings, 0 replies; 5+ messages in thread
From: Andrew Morton @ 2024-01-21 22:14 UTC (permalink / raw)
To: mm-commits, ying.huang, sthanneeru.opensrc, ravis.opensrc,
rakie.kim, mhocko, Jonathan.Cameron, hyeongtak.ji, honggyu.kim,
Hasan.Maruf, hannes, gregory.price, fvdl, dan.j.williams, corbet,
ak, gourry.memverge, akpm
The patch titled
Subject: mm/mempolicy: refactor a read-once mechanism into a function for re-use
has been added to the -mm mm-unstable branch. Its filename is
mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Gregory Price <gourry.memverge@gmail.com>
Subject: mm/mempolicy: refactor a read-once mechanism into a function for re-use
Date: Fri, 19 Jan 2024 12:57:29 -0500
Move the use of barrier() to force policy->nodemask onto the stack into a
function `read_once_policy_nodemask` so that it may be re-used.
Link: https://lkml.kernel.org/r/20240119175730.15484-3-gregory.price@memverge.com
Signed-off-by: Gregory Price <gregory.price@memverge.com>
Suggested-by: Huang Ying <ying.huang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Frank van der Linden <fvdl@google.com>
Cc: Hasan Al Maruf <Hasan.Maruf@amd.com>
Cc: Honggyu Kim <honggyu.kim@sk.com>
Cc: Hyeongtak Ji <hyeongtak.ji@sk.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Ravi Jonnalagadda <ravis.opensrc@micron.com>
Cc: Srinivasulu Thanneeru <sthanneeru.opensrc@micron.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/mempolicy.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)
--- a/mm/mempolicy.c~mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use
+++ a/mm/mempolicy.c
@@ -1893,6 +1893,20 @@ unsigned int mempolicy_slab_node(void)
}
}
+static unsigned int read_once_policy_nodemask(struct mempolicy *pol,
+ nodemask_t *mask)
+{
+ /*
+ * barrier stabilizes the nodemask locally so that it can be iterated
+ * over safely without concern for changes. Allocators validate node
+ * selection does not violate mems_allowed, so this is safe.
+ */
+ barrier();
+ memcpy(mask, &pol->nodes, sizeof(nodemask_t));
+ barrier();
+ return nodes_weight(*mask);
+}
+
/*
* Do static interleaving for interleave index @ilx. Returns the ilx'th
* node in pol->nodes (starting from ilx=0), wrapping around if ilx
@@ -1900,20 +1914,12 @@ unsigned int mempolicy_slab_node(void)
*/
static unsigned int interleave_nid(struct mempolicy *pol, pgoff_t ilx)
{
- nodemask_t nodemask = pol->nodes;
+ nodemask_t nodemask;
unsigned int target, nnodes;
int i;
int nid;
- /*
- * The barrier will stabilize the nodemask in a register or on
- * the stack so that it will stop changing under the code.
- *
- * Between first_node() and next_node(), pol->nodes could be changed
- * by other threads. So we put pol->nodes in a local stack.
- */
- barrier();
- nnodes = nodes_weight(nodemask);
+ nnodes = read_once_policy_nodemask(pol, &nodemask);
if (!nnodes)
return numa_node_id();
target = ilx % nnodes;
_
Patches currently in -mm which might be from gourry.memverge@gmail.com are
mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch
mm-mempolicy-introduce-mpol_weighted_interleave-for-weighted-interleaving.patch
^ permalink raw reply [flat|nested] 5+ messages in thread
* + mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch added to mm-unstable branch
@ 2024-01-26 2:15 Andrew Morton
0 siblings, 0 replies; 5+ messages in thread
From: Andrew Morton @ 2024-01-26 2:15 UTC (permalink / raw)
To: mm-commits, ying.huang, sthanneeru.opensrc, ravis.opensrc,
rakie.kim, mhocko, mhocko, Jonathan.Cameron, hyeongtak.ji,
honggyu.kim, Hasan.Maruf, hannes, gregory.price, fvdl,
dan.j.williams, corbet, ak, gourry.memverge, akpm
The patch titled
Subject: mm/mempolicy: refactor a read-once mechanism into a function for re-use
has been added to the -mm mm-unstable branch. Its filename is
mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Gregory Price <gourry.memverge@gmail.com>
Subject: mm/mempolicy: refactor a read-once mechanism into a function for re-use
Date: Thu, 25 Jan 2024 13:43:43 -0500
move the use of barrier() to force policy->nodemask onto the stack into
a function `read_once_policy_nodemask` so that it may be re-used.
Link: https://lkml.kernel.org/r/20240125184345.47074-3-gregory.price@memverge.com
Signed-off-by: Gregory Price <gregory.price@memverge.com>
Suggested-by: Huang Ying <ying.huang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Frank van der Linden <fvdl@google.com>
Cc: Hasan Al Maruf <Hasan.Maruf@amd.com>
Cc: Honggyu Kim <honggyu.kim@sk.com>
Cc: Hyeongtak Ji <hyeongtak.ji@sk.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Ravi Jonnalagadda <ravis.opensrc@micron.com>
Cc: Srinivasulu Thanneeru <sthanneeru.opensrc@micron.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/mempolicy.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)
--- a/mm/mempolicy.c~mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use
+++ a/mm/mempolicy.c
@@ -1890,6 +1890,20 @@ unsigned int mempolicy_slab_node(void)
}
}
+static unsigned int read_once_policy_nodemask(struct mempolicy *pol,
+ nodemask_t *mask)
+{
+ /*
+ * barrier stabilizes the nodemask locally so that it can be iterated
+ * over safely without concern for changes. Allocators validate node
+ * selection does not violate mems_allowed, so this is safe.
+ */
+ barrier();
+ memcpy(mask, &pol->nodes, sizeof(nodemask_t));
+ barrier();
+ return nodes_weight(*mask);
+}
+
/*
* Do static interleaving for interleave index @ilx. Returns the ilx'th
* node in pol->nodes (starting from ilx=0), wrapping around if ilx
@@ -1897,20 +1911,12 @@ unsigned int mempolicy_slab_node(void)
*/
static unsigned int interleave_nid(struct mempolicy *pol, pgoff_t ilx)
{
- nodemask_t nodemask = pol->nodes;
+ nodemask_t nodemask;
unsigned int target, nnodes;
int i;
int nid;
- /*
- * The barrier will stabilize the nodemask in a register or on
- * the stack so that it will stop changing under the code.
- *
- * Between first_node() and next_node(), pol->nodes could be changed
- * by other threads. So we put pol->nodes in a local stack.
- */
- barrier();
- nnodes = nodes_weight(nodemask);
+ nnodes = read_once_policy_nodemask(pol, &nodemask);
if (!nnodes)
return numa_node_id();
target = ilx % nnodes;
_
Patches currently in -mm which might be from gourry.memverge@gmail.com are
mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch
mm-mempolicy-introduce-mpol_weighted_interleave-for-weighted-interleaving.patch
mm-mempolicy-change-cur_il_weight-to-atomic-and-carry-the-node-with-it.patch
^ permalink raw reply [flat|nested] 5+ messages in thread
* + mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch added to mm-unstable branch
@ 2024-01-31 6:35 Andrew Morton
0 siblings, 0 replies; 5+ messages in thread
From: Andrew Morton @ 2024-01-31 6:35 UTC (permalink / raw)
To: mm-commits, ying.huang, sthanneeru.opensrc, ravis.opensrc,
rakie.kim, mhocko, mhocko, Jonathan.Cameron, hyeongtak.ji,
honggyu.kim, Hasan.Maruf, hannes, gregory.price, fvdl,
dan.j.williams, corbet, ak, gourry.memverge, akpm
The patch titled
Subject: mm/mempolicy: refactor a read-once mechanism into a function for re-use
has been added to the -mm mm-unstable branch. Its filename is
mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Gregory Price <gourry.memverge@gmail.com>
Subject: mm/mempolicy: refactor a read-once mechanism into a function for re-use
Date: Tue, 30 Jan 2024 13:20:45 -0500
Move the use of barrier() to force policy->nodemask onto the stack into a
function `read_once_policy_nodemask` so that it may be re-used.
Link: https://lkml.kernel.org/r/20240130182046.74278-3-gregory.price@memverge.com
Signed-off-by: Gregory Price <gregory.price@memverge.com>
Suggested-by: Huang Ying <ying.huang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Frank van der Linden <fvdl@google.com>
Cc: Hasan Al Maruf <Hasan.Maruf@amd.com>
Cc: Honggyu Kim <honggyu.kim@sk.com>
Cc: Hyeongtak Ji <hyeongtak.ji@sk.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Ravi Jonnalagadda <ravis.opensrc@micron.com>
Cc: Srinivasulu Thanneeru <sthanneeru.opensrc@micron.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/mempolicy.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)
--- a/mm/mempolicy.c~mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use
+++ a/mm/mempolicy.c
@@ -1905,6 +1905,20 @@ unsigned int mempolicy_slab_node(void)
}
}
+static unsigned int read_once_policy_nodemask(struct mempolicy *pol,
+ nodemask_t *mask)
+{
+ /*
+ * barrier stabilizes the nodemask locally so that it can be iterated
+ * over safely without concern for changes. Allocators validate node
+ * selection does not violate mems_allowed, so this is safe.
+ */
+ barrier();
+ memcpy(mask, &pol->nodes, sizeof(nodemask_t));
+ barrier();
+ return nodes_weight(*mask);
+}
+
/*
* Do static interleaving for interleave index @ilx. Returns the ilx'th
* node in pol->nodes (starting from ilx=0), wrapping around if ilx
@@ -1912,20 +1926,12 @@ unsigned int mempolicy_slab_node(void)
*/
static unsigned int interleave_nid(struct mempolicy *pol, pgoff_t ilx)
{
- nodemask_t nodemask = pol->nodes;
+ nodemask_t nodemask;
unsigned int target, nnodes;
int i;
int nid;
- /*
- * The barrier will stabilize the nodemask in a register or on
- * the stack so that it will stop changing under the code.
- *
- * Between first_node() and next_node(), pol->nodes could be changed
- * by other threads. So we put pol->nodes in a local stack.
- */
- barrier();
- nnodes = nodes_weight(nodemask);
+ nnodes = read_once_policy_nodemask(pol, &nodemask);
if (!nnodes)
return numa_node_id();
target = ilx % nnodes;
_
Patches currently in -mm which might be from gourry.memverge@gmail.com are
mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch
mm-mempolicy-introduce-mpol_weighted_interleave-for-weighted-interleaving.patch
^ permalink raw reply [flat|nested] 5+ messages in thread
* + mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch added to mm-unstable branch
@ 2024-02-04 7:20 Andrew Morton
0 siblings, 0 replies; 5+ messages in thread
From: Andrew Morton @ 2024-02-04 7:20 UTC (permalink / raw)
To: mm-commits, ying.huang, sthanneeru.opensrc, ravis.opensrc,
rakie.kim, mhocko, hyeongtak.ji, honggyu.kim, Hasan.Maruf, hannes,
gregory.price, dan.j.williams, corbet, gourry.memverge, akpm
The patch titled
Subject: mm/mempolicy: refactor a read-once mechanism into a function for re-use
has been added to the -mm mm-unstable branch. Its filename is
mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Gregory Price <gourry.memverge@gmail.com>
Subject: mm/mempolicy: refactor a read-once mechanism into a function for re-use
Date: Fri, 2 Feb 2024 12:02:36 -0500
Move the use of barrier() to force policy->nodemask onto the stack into a
function `read_once_policy_nodemask` so that it may be re-used.
Link: https://lkml.kernel.org/r/20240202170238.90004-3-gregory.price@memverge.com
Signed-off-by: Gregory Price <gregory.price@memverge.com>
Suggested-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Hasan Al Maruf <Hasan.Maruf@amd.com>
Cc: Honggyu Kim <honggyu.kim@sk.com>
Cc: Hyeongtak Ji <hyeongtak.ji@sk.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Ravi Jonnalagadda <ravis.opensrc@micron.com>
Cc: Srinivasulu Thanneeru <sthanneeru.opensrc@micron.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/mempolicy.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)
--- a/mm/mempolicy.c~mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use
+++ a/mm/mempolicy.c
@@ -1905,6 +1905,20 @@ unsigned int mempolicy_slab_node(void)
}
}
+static unsigned int read_once_policy_nodemask(struct mempolicy *pol,
+ nodemask_t *mask)
+{
+ /*
+ * barrier stabilizes the nodemask locally so that it can be iterated
+ * over safely without concern for changes. Allocators validate node
+ * selection does not violate mems_allowed, so this is safe.
+ */
+ barrier();
+ memcpy(mask, &pol->nodes, sizeof(nodemask_t));
+ barrier();
+ return nodes_weight(*mask);
+}
+
/*
* Do static interleaving for interleave index @ilx. Returns the ilx'th
* node in pol->nodes (starting from ilx=0), wrapping around if ilx
@@ -1912,20 +1926,12 @@ unsigned int mempolicy_slab_node(void)
*/
static unsigned int interleave_nid(struct mempolicy *pol, pgoff_t ilx)
{
- nodemask_t nodemask = pol->nodes;
+ nodemask_t nodemask;
unsigned int target, nnodes;
int i;
int nid;
- /*
- * The barrier will stabilize the nodemask in a register or on
- * the stack so that it will stop changing under the code.
- *
- * Between first_node() and next_node(), pol->nodes could be changed
- * by other threads. So we put pol->nodes in a local stack.
- */
- barrier();
- nnodes = nodes_weight(nodemask);
+ nnodes = read_once_policy_nodemask(pol, &nodemask);
if (!nnodes)
return numa_node_id();
target = ilx % nnodes;
_
Patches currently in -mm which might be from gourry.memverge@gmail.com are
mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch
mm-mempolicy-introduce-mpol_weighted_interleave-for-weighted-interleaving.patch
mm-mempolicy-protect-task-interleave-functions-with-tsk-mems_allowed_seq.patch
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2024-01-31 6:35 + mm-mempolicy-refactor-a-read-once-mechanism-into-a-function-for-re-use.patch added to mm-unstable branch Andrew Morton
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