Re: [RFCv3 2/5] mm/compaction: enable mobile-page migration
@@ -51,6 +54,66 @@ extern void compaction_defer_reset(struct zone *zone, int
order,
bool alloc_success);
extern bool compaction_restarting(struct zone *zone, int order);
+static inline bool mobile_page(struct page *page)
+{
+ return page-mapping page-mapping-a_ops
Dereferncing mapping-a_ops isn't safe without page-lock and isn't required:
all mappings always have -a_ops.
I got it.
+static inline void putback_mobilepage(struct page *page)
+{
+ /*
+* 'lock_page()' stabilizes the page and prevents races against
+* concurrent isolation threads attempting to re-isolate it.
+*/
+ lock_page(page);
+ if (mobile_page(page) page-mapping-a_ops-putbackpage) {
It seems if (page-mapping page-mapping-a_ops-putbackpage)
should be enough: we already seen that page as mobile.
Ditto.
+ page-mapping-a_ops-putbackpage(page);
+ /* drop the extra ref count taken for mobile page isolation */
+ put_page(page);
+ }
+ unlock_page(page);
call put_page() after unlock and do that always -- putback must drop
page reference from caller.
lock_page(page);
if (page-mapping page-mapping-a_ops-putbackpage)
page-mapping-a_ops-putbackpage(page);
unlock_page();
put_page(page);
Ditto.
+}
#else
static inline unsigned long try_to_compact_pages(gfp_t gfp_mask,
unsigned int order, int alloc_flags,
@@ -83,6 +146,19 @@ static inline bool compaction_deferred(struct zone *zone,
int order)
return true;
}
+static inline bool mobile_page(struct page *page)
+{
+ return false;
+}
+
+static inline bool isolate_mobilepage(struct page *page, isolate_mode_t mode)
+{
+ return false;
+}
+
+static inline void putback_mobilepage(struct page *page)
+{
+}
#endif /* CONFIG_COMPACTION */
#if defined(CONFIG_COMPACTION) defined(CONFIG_SYSFS)
defined(CONFIG_NUMA)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 35ec87e..33c9aa5 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -395,6 +395,8 @@ struct address_space_operations {
*/
int (*migratepage) (struct address_space *,
struct page *, struct page *, enum migrate_mode);
+ bool (*isolatepage) (struct page *, isolate_mode_t);
+ void (*putbackpage) (struct page *);
int (*launder_page) (struct page *);
int (*is_partially_uptodate) (struct page *, unsigned long,
unsigned long);
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index f34e040..abef145 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -582,6 +582,25 @@ static inline void __ClearPageBalloon(struct page *page)
atomic_set(page-_mapcount, -1);
}
+#define PAGE_MOBILE_MAPCOUNT_VALUE (-255)
+
+static inline int PageMobile(struct page *page)
+{
+ return atomic_read(page-_mapcount) == PAGE_MOBILE_MAPCOUNT_VALUE;
+}
+
+static inline void __SetPageMobile(struct page *page)
+{
+ VM_BUG_ON_PAGE(atomic_read(page-_mapcount) != -1, page);
+ atomic_set(page-_mapcount, PAGE_MOBILE_MAPCOUNT_VALUE);
+}
+
+static inline void __ClearPageMobile(struct page *page)
+{
+ VM_BUG_ON_PAGE(!PageMobile(page), page);
+ atomic_set(page-_mapcount, -1);
+}
+
/*
* If network-based swap is enabled, sl*b must keep track of whether pages
* were allocated from pfmemalloc reserves.
diff --git a/include/uapi/linux/kernel-page-flags.h
b/include/uapi/linux/kernel-page-flags.h
index a6c4962..d50d9e8 100644
--- a/include/uapi/linux/kernel-page-flags.h
+++ b/include/uapi/linux/kernel-page-flags.h
@@ -33,6 +33,7 @@
#define KPF_THP22
#define KPF_BALLOON23
#define KPF_ZERO_PAGE 24
+#define KPF_MOBILE 25
#endif /* _UAPILINUX_KERNEL_PAGE_FLAGS_H */
--
2.1.4
I fixed the code as your comments and I found patch 3/5 and 4/5 could not be
applied separately.
So I merge them and report new [PATCH].
I appreciate your reviews.
___
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [RFCv3 2/5] mm/compaction: enable mobile-page migration
On Tue, Jul 7, 2015 at 7:36 AM, Gioh Kim gioh@lge.com wrote:
From: Gioh Kim guru...@hanmail.net
Add framework to register callback functions and check page mobility.
There are some modes for page isolation so that isolate interface
has arguments of page address and isolation mode while putback
interface has only page address as argument.
Signed-off-by: Gioh Kim gioh@lge.com
---
fs/proc/page.c | 3 ++
include/linux/compaction.h | 76
++
include/linux/fs.h | 2 +
include/linux/page-flags.h | 19 +
include/uapi/linux/kernel-page-flags.h | 1 +
5 files changed, 101 insertions(+)
diff --git a/fs/proc/page.c b/fs/proc/page.c
index 7eee2d8..a4f5a00 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -146,6 +146,9 @@ u64 stable_page_flags(struct page *page)
if (PageBalloon(page))
u |= 1 KPF_BALLOON;
+ if (PageMobile(page))
+ u |= 1 KPF_MOBILE;
+
u |= kpf_copy_bit(k, KPF_LOCKED,PG_locked);
u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
diff --git a/include/linux/compaction.h b/include/linux/compaction.h
index aa8f61c..c375a89 100644
--- a/include/linux/compaction.h
+++ b/include/linux/compaction.h
@@ -1,6 +1,9 @@
#ifndef _LINUX_COMPACTION_H
#define _LINUX_COMPACTION_H
+#include linux/page-flags.h
+#include linux/pagemap.h
+
/* Return values for compact_zone() and try_to_compact_pages() */
/* compaction didn't start as it was deferred due to past failures */
#define COMPACT_DEFERRED 0
@@ -51,6 +54,66 @@ extern void compaction_defer_reset(struct zone *zone, int
order,
bool alloc_success);
extern bool compaction_restarting(struct zone *zone, int order);
+static inline bool mobile_page(struct page *page)
+{
+ return page-mapping page-mapping-a_ops
Dereferncing mapping-a_ops isn't safe without page-lock and isn't required:
all mappings always have -a_ops.
+ (PageMobile(page) || PageBalloon(page));
+}
+
+static inline bool isolate_mobilepage(struct page *page, isolate_mode_t mode)
+{
+ bool ret;
+
+ /*
+* Avoid burning cycles with pages that are yet under __free_pages(),
+* or just got freed under us.
+*
+* In case we 'win' a race for a mobile page being freed under us and
+* raise its refcount preventing __free_pages() from doing its job
+* the put_page() at the end of this block will take care of
+* release this page, thus avoiding a nasty leakage.
+*/
+ if (likely(get_page_unless_zero(page))) {
+ /*
+* As mobile pages are not isolated from LRU lists, concurrent
+* compaction threads can race against page migration
functions
+* as well as race against the releasing a page.
+*
+* In order to avoid having an already isolated mobile page
+* being (wrongly) re-isolated while it is under migration,
+* or to avoid attempting to isolate pages being released,
+* lets be sure we have the page lock
+* before proceeding with the mobile page isolation steps.
+*/
+ if (likely(trylock_page(page))) {
+ if (mobile_page(page)
+ page-mapping-a_ops-isolatepage) {
+ ret = page-mapping-a_ops-isolatepage(page,
+ mode);
+ unlock_page(page);
+ return ret;
+ }
+ unlock_page(page);
+ }
+ put_page(page);
+ }
+ return false;
+}
+
+static inline void putback_mobilepage(struct page *page)
+{
+ /*
+* 'lock_page()' stabilizes the page and prevents races against
+* concurrent isolation threads attempting to re-isolate it.
+*/
+ lock_page(page);
+ if (mobile_page(page) page-mapping-a_ops-putbackpage) {
It seems if (page-mapping page-mapping-a_ops-putbackpage)
should be enough: we already seen that page as mobile.
+ page-mapping-a_ops-putbackpage(page);
+ /* drop the extra ref count taken for mobile page isolation */
+ put_page(page);
+ }
+ unlock_page(page);
call put_page() after unlock and do that always -- putback must drop
page reference from caller.
lock_page(page);
if (page-mapping page-mapping-a_ops-putbackpage)
page-mapping-a_ops-putbackpage(page);
unlock_page();
put_page(page);
+}
#else
static inline unsigned long try_to_compact_pages(gfp_t gfp_mask,
unsigned int order, int alloc_flags,
Re: [RFCv3 2/5] mm/compaction: enable mobile-page migration
One more note below.
On Tue, Jul 7, 2015 at 7:36 AM, Gioh Kim gioh@lge.com wrote:
From: Gioh Kim guru...@hanmail.net
Add framework to register callback functions and check page mobility.
There are some modes for page isolation so that isolate interface
has arguments of page address and isolation mode while putback
interface has only page address as argument.
Signed-off-by: Gioh Kim gioh@lge.com
---
fs/proc/page.c | 3 ++
include/linux/compaction.h | 76
++
include/linux/fs.h | 2 +
include/linux/page-flags.h | 19 +
include/uapi/linux/kernel-page-flags.h | 1 +
5 files changed, 101 insertions(+)
diff --git a/fs/proc/page.c b/fs/proc/page.c
index 7eee2d8..a4f5a00 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -146,6 +146,9 @@ u64 stable_page_flags(struct page *page)
if (PageBalloon(page))
u |= 1 KPF_BALLOON;
+ if (PageMobile(page))
+ u |= 1 KPF_MOBILE;
+
u |= kpf_copy_bit(k, KPF_LOCKED,PG_locked);
u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
diff --git a/include/linux/compaction.h b/include/linux/compaction.h
index aa8f61c..c375a89 100644
--- a/include/linux/compaction.h
+++ b/include/linux/compaction.h
@@ -1,6 +1,9 @@
#ifndef _LINUX_COMPACTION_H
#define _LINUX_COMPACTION_H
+#include linux/page-flags.h
+#include linux/pagemap.h
+
/* Return values for compact_zone() and try_to_compact_pages() */
/* compaction didn't start as it was deferred due to past failures */
#define COMPACT_DEFERRED 0
@@ -51,6 +54,66 @@ extern void compaction_defer_reset(struct zone *zone, int
order,
bool alloc_success);
extern bool compaction_restarting(struct zone *zone, int order);
+static inline bool mobile_page(struct page *page)
+{
+ return page-mapping page-mapping-a_ops
+ (PageMobile(page) || PageBalloon(page));
+}
+
+static inline bool isolate_mobilepage(struct page *page, isolate_mode_t mode)
+{
+ bool ret;
+
+ /*
+* Avoid burning cycles with pages that are yet under __free_pages(),
+* or just got freed under us.
+*
+* In case we 'win' a race for a mobile page being freed under us and
+* raise its refcount preventing __free_pages() from doing its job
+* the put_page() at the end of this block will take care of
+* release this page, thus avoiding a nasty leakage.
+*/
+ if (likely(get_page_unless_zero(page))) {
+ /*
+* As mobile pages are not isolated from LRU lists, concurrent
+* compaction threads can race against page migration
functions
+* as well as race against the releasing a page.
+*
+* In order to avoid having an already isolated mobile page
+* being (wrongly) re-isolated while it is under migration,
+* or to avoid attempting to isolate pages being released,
+* lets be sure we have the page lock
+* before proceeding with the mobile page isolation steps.
+*/
+ if (likely(trylock_page(page))) {
+ if (mobile_page(page)
+ page-mapping-a_ops-isolatepage) {
+ ret = page-mapping-a_ops-isolatepage(page,
+ mode);
+ unlock_page(page);
Here you leak page reference if isolatepage() fails.
+ return ret;
+ }
+ unlock_page(page);
+ }
+ put_page(page);
+ }
+ return false;
+}
+
+static inline void putback_mobilepage(struct page *page)
+{
+ /*
+* 'lock_page()' stabilizes the page and prevents races against
+* concurrent isolation threads attempting to re-isolate it.
+*/
+ lock_page(page);
+ if (mobile_page(page) page-mapping-a_ops-putbackpage) {
+ page-mapping-a_ops-putbackpage(page);
+ /* drop the extra ref count taken for mobile page isolation */
+ put_page(page);
+ }
+ unlock_page(page);
+}
#else
static inline unsigned long try_to_compact_pages(gfp_t gfp_mask,
unsigned int order, int alloc_flags,
@@ -83,6 +146,19 @@ static inline bool compaction_deferred(struct zone *zone,
int order)
return true;
}
+static inline bool mobile_page(struct page *page)
+{
+ return false;
+}
+
+static inline bool isolate_mobilepage(struct page *page, isolate_mode_t mode)
+{
+ return false;
+}
+
+static inline void putback_mobilepage(struct page *page)
+{
+}
[RFCv3 2/5] mm/compaction: enable mobile-page migration
From: Gioh Kim guru...@hanmail.net
Add framework to register callback functions and check page mobility.
There are some modes for page isolation so that isolate interface
has arguments of page address and isolation mode while putback
interface has only page address as argument.
Signed-off-by: Gioh Kim gioh@lge.com
---
fs/proc/page.c | 3 ++
include/linux/compaction.h | 76 ++
include/linux/fs.h | 2 +
include/linux/page-flags.h | 19 +
include/uapi/linux/kernel-page-flags.h | 1 +
5 files changed, 101 insertions(+)
diff --git a/fs/proc/page.c b/fs/proc/page.c
index 7eee2d8..a4f5a00 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -146,6 +146,9 @@ u64 stable_page_flags(struct page *page)
if (PageBalloon(page))
u |= 1 KPF_BALLOON;
+ if (PageMobile(page))
+ u |= 1 KPF_MOBILE;
+
u |= kpf_copy_bit(k, KPF_LOCKED,PG_locked);
u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
diff --git a/include/linux/compaction.h b/include/linux/compaction.h
index aa8f61c..c375a89 100644
--- a/include/linux/compaction.h
+++ b/include/linux/compaction.h
@@ -1,6 +1,9 @@
#ifndef _LINUX_COMPACTION_H
#define _LINUX_COMPACTION_H
+#include linux/page-flags.h
+#include linux/pagemap.h
+
/* Return values for compact_zone() and try_to_compact_pages() */
/* compaction didn't start as it was deferred due to past failures */
#define COMPACT_DEFERRED 0
@@ -51,6 +54,66 @@ extern void compaction_defer_reset(struct zone *zone, int
order,
bool alloc_success);
extern bool compaction_restarting(struct zone *zone, int order);
+static inline bool mobile_page(struct page *page)
+{
+ return page-mapping page-mapping-a_ops
+ (PageMobile(page) || PageBalloon(page));
+}
+
+static inline bool isolate_mobilepage(struct page *page, isolate_mode_t mode)
+{
+ bool ret;
+
+ /*
+* Avoid burning cycles with pages that are yet under __free_pages(),
+* or just got freed under us.
+*
+* In case we 'win' a race for a mobile page being freed under us and
+* raise its refcount preventing __free_pages() from doing its job
+* the put_page() at the end of this block will take care of
+* release this page, thus avoiding a nasty leakage.
+*/
+ if (likely(get_page_unless_zero(page))) {
+ /*
+* As mobile pages are not isolated from LRU lists, concurrent
+* compaction threads can race against page migration functions
+* as well as race against the releasing a page.
+*
+* In order to avoid having an already isolated mobile page
+* being (wrongly) re-isolated while it is under migration,
+* or to avoid attempting to isolate pages being released,
+* lets be sure we have the page lock
+* before proceeding with the mobile page isolation steps.
+*/
+ if (likely(trylock_page(page))) {
+ if (mobile_page(page)
+ page-mapping-a_ops-isolatepage) {
+ ret = page-mapping-a_ops-isolatepage(page,
+ mode);
+ unlock_page(page);
+ return ret;
+ }
+ unlock_page(page);
+ }
+ put_page(page);
+ }
+ return false;
+}
+
+static inline void putback_mobilepage(struct page *page)
+{
+ /*
+* 'lock_page()' stabilizes the page and prevents races against
+* concurrent isolation threads attempting to re-isolate it.
+*/
+ lock_page(page);
+ if (mobile_page(page) page-mapping-a_ops-putbackpage) {
+ page-mapping-a_ops-putbackpage(page);
+ /* drop the extra ref count taken for mobile page isolation */
+ put_page(page);
+ }
+ unlock_page(page);
+}
#else
static inline unsigned long try_to_compact_pages(gfp_t gfp_mask,
unsigned int order, int alloc_flags,
@@ -83,6 +146,19 @@ static inline bool compaction_deferred(struct zone *zone,
int order)
return true;
}
+static inline bool mobile_page(struct page *page)
+{
+ return false;
+}
+
+static inline bool isolate_mobilepage(struct page *page, isolate_mode_t mode)
+{
+ return false;
+}
+
+static inline void putback_mobilepage(struct page *page)
+{
+}
#endif /* CONFIG_COMPACTION */
#if defined(CONFIG_COMPACTION) defined(CONFIG_SYSFS) defined(CONFIG_NUMA)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 35ec87e..33c9aa5 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -395,6 +395,8 @@
