[PATCH v2] Make transparent hugepages cpuset aware
From: Alex Thorlton
Date: Tue Jun 11 2013 - 12:14:42 EST
This patch adds the ability to control THPs on a per cpuset basis. Please see
the additions to Documentation/cgroups/cpusets.txt for more information.
Signed-off-by: Alex Thorlton <athorlton@xxxxxxx>
Reviewed-by: Robin Holt <holt@xxxxxxx>
Cc: Li Zefan <lizefan@xxxxxxxxxx>
Cc: Rob Landley <rob@xxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: linux-doc@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
---
Changes since last patch version:
- Modified transparent_hugepage_enable to always check the vma for the
VM_NOHUGEPAGE flag and to always check is_vma_temporary_stack.
- Moved cpuset_update_child_thp_flags above cpuset_update_top_thp_flags
Documentation/cgroups/cpusets.txt | 50 ++++++++++-
include/linux/cpuset.h | 5 ++
include/linux/huge_mm.h | 27 +++++-
kernel/cpuset.c | 181 ++++++++++++++++++++++++++++++++++++++
mm/huge_memory.c | 3 +
5 files changed, 263 insertions(+), 3 deletions(-)
diff --git a/Documentation/cgroups/cpusets.txt b/Documentation/cgroups/cpusets.txt
index 12e01d4..b7b2c83 100644
--- a/Documentation/cgroups/cpusets.txt
+++ b/Documentation/cgroups/cpusets.txt
@@ -22,12 +22,14 @@ CONTENTS:
1.6 What is memory spread ?
1.7 What is sched_load_balance ?
1.8 What is sched_relax_domain_level ?
- 1.9 How do I use cpusets ?
+ 1.9 What is thp_enabled ?
+ 1.10 How do I use cpusets ?
2. Usage Examples and Syntax
2.1 Basic Usage
2.2 Adding/removing cpus
2.3 Setting flags
2.4 Attaching processes
+ 2.5 Setting thp_enabled flags
3. Questions
4. Contact
@@ -581,7 +583,34 @@ If your situation is:
then increasing 'sched_relax_domain_level' would benefit you.
-1.9 How do I use cpusets ?
+1.9 What is thp_enabled ?
+-----------------------
+
+The thp_enabled file contained within each cpuset controls how transparent
+hugepages are handled within that cpuset.
+
+The root cpuset's thp_enabled flags mirror the flags set in
+/sys/kernel/mm/transparent_hugepage/enabled. The flags in the root cpuset can
+only be modified by changing /sys/kernel/mm/transparent_hugepage/enabled. The
+thp_enabled file for the root cpuset is read only. These flags cause the
+root cpuset to behave as one might expect:
+
+- When set to always, THPs are used whenever practical
+- When set to madvise, THPs are used only on chunks of memory that have the
+ MADV_HUGEPAGE flag set
+- When set to never, THPs are never allowed for tasks in this cpuset
+
+The behavior of thp_enabled for children of the root cpuset is where things
+become a bit more interesting. The child cpusets accept the same flags as the
+root, but also have a default flag, which, when set, causes a cpuset to use the
+behavior of its parent. When a child cpuset is created, its default flag is
+always initially set.
+
+Since the flags on child cpusets are allowed to differ from the flags on their
+parents, we are able to enable THPs for tasks in specific cpusets, and disable
+them in others.
+
+1.10 How do I use cpusets ?
--------------------------
In order to minimize the impact of cpusets on critical kernel
@@ -733,6 +762,7 @@ cpuset.cpus cpuset.sched_load_balance
cpuset.mem_exclusive cpuset.sched_relax_domain_level
cpuset.mem_hardwall notify_on_release
cpuset.memory_migrate tasks
+thp_enabled
Reading them will give you information about the state of this cpuset:
the CPUs and Memory Nodes it can use, the processes that are using
@@ -814,6 +844,22 @@ If you have several tasks to attach, you have to do it one after another:
...
# /bin/echo PIDn > tasks
+2.5 Setting thp_enabled flags
+-----------------------------
+
+The syntax for setting these flags is similar to setting thp flags in
+/sys/kernel/mm/transparent_hugepage/enabled. In order to change the flags you
+simply echo the name of the flag you want to set to the thp_enabled file of the
+desired cpuset:
+
+# /bin/echo always > thp_enabled -> always use THPs when practical
+# /bin/echo madvise > thp_enabled -> only use THPs in madvise sections
+# /bin/echo never > thp_enabled -> never use THPs
+# /bin/echo default > thp_enabled -> use parent cpuset's THP flags
+
+Note that the flags on the root cpuset cannot be changed in /dev/cpuset. These
+flags are mirrored from /sys/kernel/mm/transparent_hugepage/enabled and can only
+be modified there.
3. Questions
============
diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index cc1b01c..624aafd 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -19,9 +19,12 @@ extern int number_of_cpusets; /* How many cpusets are defined in system? */
extern int cpuset_init(void);
extern void cpuset_init_smp(void);
+extern void cpuset_update_top_thp_flags(void);
extern void cpuset_update_active_cpus(bool cpu_online);
extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask);
extern void cpuset_cpus_allowed_fallback(struct task_struct *p);
+extern int cpuset_thp_always(struct task_struct *p);
+extern int cpuset_thp_madvise(struct task_struct *p);
extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
#define cpuset_current_mems_allowed (current->mems_allowed)
void cpuset_init_current_mems_allowed(void);
@@ -122,6 +125,8 @@ static inline void set_mems_allowed(nodemask_t nodemask)
static inline int cpuset_init(void) { return 0; }
static inline void cpuset_init_smp(void) {}
+static inline void cpuset_update_top_thp_flags(void) {}
+
static inline void cpuset_update_active_cpus(bool cpu_online)
{
partition_sched_domains(1, NULL, NULL);
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 528454c..d6a8bb3 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -66,7 +66,7 @@ extern pmd_t *page_check_address_pmd(struct page *page,
extern bool is_vma_temporary_stack(struct vm_area_struct *vma);
-#define transparent_hugepage_enabled(__vma) \
+#define _transparent_hugepage_enabled(__vma) \
((transparent_hugepage_flags & \
(1<<TRANSPARENT_HUGEPAGE_FLAG) || \
(transparent_hugepage_flags & \
@@ -177,6 +177,31 @@ static inline struct page *compound_trans_head(struct page *page)
return page;
}
+#ifdef CONFIG_CPUSETS
+extern int cpuset_thp_always(struct task_struct *p);
+extern int cpuset_thp_madvise(struct task_struct *p);
+
+static inline int transparent_hugepage_enabled(struct vm_area_struct *vma)
+{
+ if (cpuset_thp_always(current) &&
+ !((vma)->vm_flags & VM_NOHUGEPAGE) &&
+ !is_vma_temporary_stack(vma))
+ return 1;
+ else if (cpuset_thp_madvise(current) &&
+ ((vma)->vm_flags & VM_HUGEPAGE) &&
+ !((vma)->vm_flags & VM_NOHUGEPAGE) &&
+ !is_vma_temporary_stack(vma))
+ return 1;
+ else
+ return 0;
+}
+#else
+static inline int transparent_hugepage_enabled(struct vm_area_struct *vma)
+{
+ return _transparent_hugepage_enabled(vma);
+}
+#endif
+
extern int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long addr, pmd_t pmd, pmd_t *pmdp);
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 64b3f79..d596e50 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -150,6 +150,9 @@ typedef enum {
CS_SCHED_LOAD_BALANCE,
CS_SPREAD_PAGE,
CS_SPREAD_SLAB,
+ CS_THP_MADVISE,
+ CS_THP_ALWAYS,
+ CS_THP_DEFAULT,
} cpuset_flagbits_t;
/* convenient tests for these bits */
@@ -193,6 +196,56 @@ static inline int is_spread_slab(const struct cpuset *cs)
return test_bit(CS_SPREAD_SLAB, &cs->flags);
}
+static inline int is_thp_always(const struct cpuset *cs)
+{
+ return test_bit(CS_THP_ALWAYS, &cs->flags);
+}
+
+static inline int is_thp_madvise(const struct cpuset *cs)
+{
+ return test_bit(CS_THP_MADVISE, &cs->flags);
+}
+
+static inline int is_thp_default(const struct cpuset *cs)
+{
+ return test_bit(CS_THP_DEFAULT, &cs->flags);
+}
+
+/* convenient sets for thp flags */
+static inline void set_thp_always(struct cpuset *cs)
+{
+ set_bit(CS_THP_ALWAYS, &cs->flags);
+ clear_bit(CS_THP_MADVISE, &cs->flags);
+}
+
+static inline void set_thp_madvise(struct cpuset *cs)
+{
+ set_bit(CS_THP_MADVISE, &cs->flags);
+ clear_bit(CS_THP_ALWAYS, &cs->flags);
+}
+
+static inline void set_thp_never(struct cpuset *cs)
+{
+ clear_bit(CS_THP_ALWAYS, &cs->flags);
+ clear_bit(CS_THP_MADVISE, &cs->flags);
+}
+
+static inline void copy_thp_flags(struct cpuset *source_cs,
+ struct cpuset *dest_cs)
+{
+ /*
+ * The CS_THP_DEFAULT flag isn't copied here because it is
+ * set by default when a new cpuset is created, and after
+ * that point, should only be changed by the user.
+ */
+ if (is_thp_always(source_cs))
+ set_thp_always(dest_cs);
+ else if (is_thp_madvise(source_cs))
+ set_thp_madvise(dest_cs);
+ else
+ set_thp_never(dest_cs);
+}
+
static struct cpuset top_cpuset = {
.flags = ((1 << CS_ONLINE) | (1 << CS_CPU_EXCLUSIVE) |
(1 << CS_MEM_EXCLUSIVE)),
@@ -1496,6 +1549,7 @@ typedef enum {
FILE_MEMORY_PRESSURE,
FILE_SPREAD_PAGE,
FILE_SPREAD_SLAB,
+ FILE_THP_ENABLED,
} cpuset_filetype_t;
static int cpuset_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val)
@@ -1624,6 +1678,71 @@ out_unlock:
return retval;
}
+static void cpuset_update_child_thp_flags(struct cpuset *parent_cs)
+{
+ struct cpuset *child_cs;
+ struct cgroup *pos_cg;
+
+ rcu_read_lock();
+ cpuset_for_each_child(child_cs, pos_cg, parent_cs) {
+ if (test_bit(CS_THP_DEFAULT, &child_cs->flags)) {
+ copy_thp_flags(parent_cs, child_cs);
+ cpuset_update_child_thp_flags(child_cs);
+ }
+ }
+ rcu_read_unlock();
+}
+
+void cpuset_update_top_thp_flags(void)
+{
+ if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) {
+ set_thp_always(&top_cpuset);
+ } else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
+ &transparent_hugepage_flags)) {
+ set_thp_madvise(&top_cpuset);
+ } else {
+ set_thp_never(&top_cpuset);
+ }
+
+ cpuset_update_child_thp_flags(&top_cpuset);
+}
+
+static int cpuset_thp_enabled_write(struct cgroup *cgrp, struct cftype *cft,
+ const char *buf)
+{
+ struct cpuset *cs = cgroup_cs(cgrp);
+ int retval = strlen(buf) + 1;
+
+ if (cs == &top_cpuset) {
+ retval = -EPERM;
+ goto out;
+ }
+
+ if (cft->private == FILE_THP_ENABLED) {
+ if (!memcmp("always", buf, sizeof("always")-1)) {
+ clear_bit(CS_THP_DEFAULT, &cs->flags);
+ set_thp_always(cs);
+ } else if (!memcmp("madvise", buf, sizeof("madvise")-1)) {
+ clear_bit(CS_THP_DEFAULT, &cs->flags);
+ set_thp_madvise(cs);
+ } else if (!memcmp("never", buf, sizeof("never")-1)) {
+ clear_bit(CS_THP_DEFAULT, &cs->flags);
+ set_thp_never(cs);
+ } else if (!memcmp("default", buf, sizeof("default")-1)) {
+ set_bit(CS_THP_DEFAULT, &cs->flags);
+ copy_thp_flags(parent_cs(cs), cs);
+ } else {
+ retval = -EINVAL;
+ goto out;
+ }
+ }
+
+ cpuset_update_child_thp_flags(cs);
+
+out:
+ return retval;
+}
+
/*
* These ascii lists should be read in a single call, by using a user
* buffer large enough to hold the entire map. If read in smaller
@@ -1658,6 +1777,39 @@ static size_t cpuset_sprintf_memlist(char *page, struct cpuset *cs)
return count;
}
+static size_t cpuset_sprintf_thp(char *buf, struct cpuset *cs)
+{
+ if (test_bit(CS_THP_ALWAYS, &cs->flags)) {
+ VM_BUG_ON(test_bit(CS_THP_MADVISE, &cs->flags));
+ return sprintf(buf, "[always] madvise never %s",
+ test_bit(CS_THP_DEFAULT, &cs->flags) ?
+ "(default from parent)" :
+ "(overrides parent)");
+ } else if (test_bit(CS_THP_MADVISE, &cs->flags)) {
+ VM_BUG_ON(test_bit(CS_THP_ALWAYS, &cs->flags));
+ return sprintf(buf, "always [madvise] never %s",
+ test_bit(CS_THP_DEFAULT, &cs->flags) ?
+ "(default from parent)" :
+ "(overrides parent)");
+ } else
+ return sprintf(buf, "always madvise [never] %s",
+ test_bit(CS_THP_DEFAULT, &cs->flags) ?
+ "(default from parent)" :
+ "(overrides parent)");
+}
+
+static size_t cpuset_sprintf_thp_top(char *buf, struct cpuset *cs)
+{
+ if (test_bit(CS_THP_ALWAYS, &cs->flags)) {
+ VM_BUG_ON(test_bit(CS_THP_MADVISE, &cs->flags));
+ return sprintf(buf, "[always] madvise never");
+ } else if (test_bit(CS_THP_MADVISE, &cs->flags)) {
+ VM_BUG_ON(test_bit(CS_THP_ALWAYS, &cs->flags));
+ return sprintf(buf, "always [madvise] never");
+ } else
+ return sprintf(buf, "always madvise [never]");
+}
+
static ssize_t cpuset_common_file_read(struct cgroup *cont,
struct cftype *cft,
struct file *file,
@@ -1682,6 +1834,12 @@ static ssize_t cpuset_common_file_read(struct cgroup *cont,
case FILE_MEMLIST:
s += cpuset_sprintf_memlist(s, cs);
break;
+ case FILE_THP_ENABLED:
+ if (&top_cpuset == cs)
+ s += cpuset_sprintf_thp_top(s, cs);
+ else
+ s += cpuset_sprintf_thp(s, cs);
+ break;
default:
retval = -EINVAL;
goto out;
@@ -1834,6 +1992,13 @@ static struct cftype files[] = {
.private = FILE_MEMORY_PRESSURE_ENABLED,
},
+ {
+ .name = "thp_enabled",
+ .read = cpuset_common_file_read,
+ .write_string = cpuset_thp_enabled_write,
+ .private = FILE_THP_ENABLED,
+ },
+
{ } /* terminate */
};
@@ -1880,11 +2045,14 @@ static int cpuset_css_online(struct cgroup *cgrp)
mutex_lock(&cpuset_mutex);
set_bit(CS_ONLINE, &cs->flags);
+ set_bit(CS_THP_DEFAULT, &cs->flags);
if (is_spread_page(parent))
set_bit(CS_SPREAD_PAGE, &cs->flags);
if (is_spread_slab(parent))
set_bit(CS_SPREAD_SLAB, &cs->flags);
+ copy_thp_flags(parent, cs);
+
number_of_cpusets++;
if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &cgrp->flags))
@@ -1982,6 +2150,9 @@ int __init cpuset_init(void)
fmeter_init(&top_cpuset.fmeter);
set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags);
+
+ cpuset_update_top_thp_flags();
+
top_cpuset.relax_domain_level = -1;
err = register_filesystem(&cpuset_fs_type);
@@ -2276,6 +2447,16 @@ void cpuset_cpus_allowed_fallback(struct task_struct *tsk)
*/
}
+int cpuset_thp_always(struct task_struct *p)
+{
+ return is_thp_always(task_cs(p));
+}
+
+int cpuset_thp_madvise(struct task_struct *p)
+{
+ return is_thp_madvise(task_cs(p));
+}
+
void cpuset_init_current_mems_allowed(void)
{
nodes_setall(current->mems_allowed);
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 03a89a2..d48f0b5 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -21,6 +21,7 @@
#include <linux/pagemap.h>
#include <linux/migrate.h>
#include <linux/hashtable.h>
+#include <linux/cpuset.h>
#include <asm/tlb.h>
#include <asm/pgalloc.h>
@@ -268,6 +269,8 @@ static ssize_t double_flag_store(struct kobject *kobj,
} else
return -EINVAL;
+ cpuset_update_top_thp_flags();
+
return count;
}
--
1.7.12.4
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