[PATCH v2 1/4] Make place for common balloon code

[PATCH v2 1/4] Make place for common balloon code

[Alexander Atanasov]

File already contains code that is common along balloon
drivers so rename it to reflect its contents.
mm/balloon_compaction.c -> mm/balloon_common.c

Signed-off-by: Alexander Atanasov <alexander.atanasov@virtuozzo.com>
---
 MAINTAINERS                                              | 4 ++--
 arch/powerpc/platforms/pseries/cmm.c                     | 2 +-
 drivers/misc/vmw_balloon.c                               | 2 +-
 drivers/virtio/virtio_balloon.c                          | 2 +-
 include/linux/{balloon_compaction.h => balloon_common.h} | 2 +-
 mm/Makefile                                              | 2 +-
 mm/{balloon_compaction.c => balloon_common.c}            | 4 ++--
 mm/migrate.c                                             | 2 +-
 mm/vmscan.c                                              | 2 +-
 9 files changed, 11 insertions(+), 11 deletions(-)
 rename include/linux/{balloon_compaction.h => balloon_common.h} (99%)
 rename mm/{balloon_compaction.c => balloon_common.c} (99%)

diff --git a/MAINTAINERS b/MAINTAINERS
index 8a5012ba6ff9..1b94bf3eb95d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -21493,8 +21493,8 @@ L:	virtualization@lists.linux-foundation.org
 S:	Maintained
 F:	drivers/virtio/virtio_balloon.c
 F:	include/uapi/linux/virtio_balloon.h
-F:	include/linux/balloon_compaction.h
-F:	mm/balloon_compaction.c
+F:	include/linux/balloon_common.h
+F:	mm/balloon_common.c
 
 VIRTIO CRYPTO DRIVER
 M:	Gonglei <arei.gonglei@huawei.com>
diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c
index 5f4037c1d7fe..3beb109c7e44 100644
--- a/arch/powerpc/platforms/pseries/cmm.c
+++ b/arch/powerpc/platforms/pseries/cmm.c
@@ -19,7 +19,7 @@
 #include <linux/stringify.h>
 #include <linux/swap.h>
 #include <linux/device.h>
-#include <linux/balloon_compaction.h>
+#include <linux/balloon_common.h>
 #include <asm/firmware.h>
 #include <asm/hvcall.h>
 #include <asm/mmu.h>
diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index 61a2be712bf7..6c6d24783548 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -29,7 +29,7 @@
 #include <linux/rwsem.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
-#include <linux/balloon_compaction.h>
+#include <linux/balloon_common.h>
 #include <linux/vmw_vmci_defs.h>
 #include <linux/vmw_vmci_api.h>
 #include <asm/hypervisor.h>
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 3f78a3a1eb75..6f69e483d98a 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -13,7 +13,7 @@
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/module.h>
-#include <linux/balloon_compaction.h>
+#include <linux/balloon_common.h>
 #include <linux/oom.h>
 #include <linux/wait.h>
 #include <linux/mm.h>
diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_common.h
similarity index 99%
rename from include/linux/balloon_compaction.h
rename to include/linux/balloon_common.h
index 5ca2d5699620..a45e9fd76235 100644
--- a/include/linux/balloon_compaction.h
+++ b/include/linux/balloon_common.h
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 /*
- * include/linux/balloon_compaction.h
+ * include/linux/balloon_common.h
  *
  * Common interface definitions for making balloon pages movable by compaction.
  *
diff --git a/mm/Makefile b/mm/Makefile
index 9a564f836403..a3390f255b82 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -112,7 +112,7 @@ obj-$(CONFIG_ZSMALLOC)	+= zsmalloc.o
 obj-$(CONFIG_Z3FOLD)	+= z3fold.o
 obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
 obj-$(CONFIG_CMA)	+= cma.o
-obj-$(CONFIG_MEMORY_BALLOON) += balloon_compaction.o
+obj-$(CONFIG_MEMORY_BALLOON) += balloon_common.o
 obj-$(CONFIG_PAGE_EXTENSION) += page_ext.o
 obj-$(CONFIG_PAGE_TABLE_CHECK) += page_table_check.o
 obj-$(CONFIG_CMA_DEBUGFS) += cma_debug.o
diff --git a/mm/balloon_compaction.c b/mm/balloon_common.c
similarity index 99%
rename from mm/balloon_compaction.c
rename to mm/balloon_common.c
index 22c96fed70b5..54ed98653c78 100644
--- a/mm/balloon_compaction.c
+++ b/mm/balloon_common.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * mm/balloon_compaction.c
+ * mm/balloon_common.c
  *
  * Common interface for making balloon pages movable by compaction.
  *
@@ -9,7 +9,7 @@
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/export.h>
-#include <linux/balloon_compaction.h>
+#include <linux/balloon_common.h>
 
 static void balloon_page_enqueue_one(struct balloon_dev_info *b_dev_info,
 				     struct page *page)
diff --git a/mm/migrate.c b/mm/migrate.c
index 6a1597c92261..a6df467a250a 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -41,7 +41,7 @@
 #include <linux/pfn_t.h>
 #include <linux/memremap.h>
 #include <linux/userfaultfd_k.h>
-#include <linux/balloon_compaction.h>
+#include <linux/balloon_common.h>
 #include <linux/page_idle.h>
 #include <linux/page_owner.h>
 #include <linux/sched/mm.h>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index b2b1431352dc..4732f8c24264 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -54,7 +54,7 @@
 #include <asm/div64.h>
 
 #include <linux/swapops.h>
-#include <linux/balloon_compaction.h>
+#include <linux/balloon_common.h>
 #include <linux/sched/sysctl.h>
 
 #include "internal.h"
-- 
2.31.1

[PATCH v2 2/4] Enable balloon drivers to report inflated memory

[Alexander Atanasov]

Add counters to be updated by the balloon drivers.
Create balloon notifier to propagate changes.

Signed-off-by: Alexander Atanasov <alexander.atanasov@virtuozzo.com>
---
 include/linux/balloon_common.h | 18 ++++++++++++++++++
 mm/balloon_common.c            | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)

diff --git a/include/linux/balloon_common.h b/include/linux/balloon_common.h
index a45e9fd76235..e707f57f58da 100644
--- a/include/linux/balloon_common.h
+++ b/include/linux/balloon_common.h
@@ -59,6 +59,24 @@ struct balloon_dev_info {
 			struct page *page, enum migrate_mode mode);
 };
 
+extern atomic_long_t mem_balloon_inflated_total_kb;
+extern atomic_long_t mem_balloon_inflated_free_kb;
+
+void balloon_set_inflated_total(long inflated_kb);
+void balloon_set_inflated_free(long inflated_kb);
+
+#define BALLOON_CHANGED_TOTAL 0
+#define BALLOON_CHANGED_FREE  1
+
+extern int register_balloon_notifier(struct notifier_block *nb);
+extern void unregister_balloon_notifier(struct notifier_block *nb);
+
+#define balloon_notifier(fn, pri) ({						\
+	static struct notifier_block fn##_mem_nb __meminitdata =\
+		{ .notifier_call = fn, .priority = pri };			\
+	register_balloon_notifier(&fn##_mem_nb);				\
+})
+
 extern struct page *balloon_page_alloc(void);
 extern void balloon_page_enqueue(struct balloon_dev_info *b_dev_info,
 				 struct page *page);
diff --git a/mm/balloon_common.c b/mm/balloon_common.c
index 54ed98653c78..abeee6882649 100644
--- a/mm/balloon_common.c
+++ b/mm/balloon_common.c
@@ -9,8 +9,42 @@
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/export.h>
+#include <linux/notifier.h>
 #include <linux/balloon_common.h>
 
+atomic_long_t mem_balloon_inflated_total_kb = ATOMIC_LONG_INIT(0);
+atomic_long_t mem_balloon_inflated_free_kb = ATOMIC_LONG_INIT(0);
+SRCU_NOTIFIER_HEAD_STATIC(balloon_chain);
+
+int register_balloon_notifier(struct notifier_block *nb)
+{
+	return srcu_notifier_chain_register(&balloon_chain, nb);
+}
+EXPORT_SYMBOL(register_balloon_notifier);
+
+void unregister_balloon_notifier(struct notifier_block *nb)
+{
+	srcu_notifier_chain_unregister(&balloon_chain, nb);
+}
+EXPORT_SYMBOL(unregister_balloon_notifier);
+
+static int balloon_notify(unsigned long val)
+{
+	return srcu_notifier_call_chain(&balloon_chain, val, NULL);
+}
+
+void balloon_set_inflated_total(long inflated_kb)
+{
+	atomic_long_set(&mem_balloon_inflated_total_kb, inflated_kb);
+	balloon_notify(BALLOON_CHANGED_TOTAL);
+}
+
+void balloon_set_inflated_free(long inflated_kb)
+{
+	atomic_long_set(&mem_balloon_inflated_free_kb, inflated_kb);
+	balloon_notify(BALLOON_CHANGED_FREE);
+}
+
 static void balloon_page_enqueue_one(struct balloon_dev_info *b_dev_info,
 				     struct page *page)
 {
-- 
2.31.1

Re: [PATCH v2 1/4] Make place for common balloon code

[Greg Kroah-Hartman]

On Tue, Aug 16, 2022 at 12:41:14PM +0300, Alexander Atanasov wrote:
> File already contains code that is common along balloon
> drivers so rename it to reflect its contents.
> mm/balloon_compaction.c -> mm/balloon_common.c
> 
> Signed-off-by: Alexander Atanasov <alexander.atanasov@virtuozzo.com>
> ---
>  MAINTAINERS                                              | 4 ++--
>  arch/powerpc/platforms/pseries/cmm.c                     | 2 +-
>  drivers/misc/vmw_balloon.c                               | 2 +-
>  drivers/virtio/virtio_balloon.c                          | 2 +-
>  include/linux/{balloon_compaction.h => balloon_common.h} | 2 +-
>  mm/Makefile                                              | 2 +-
>  mm/{balloon_compaction.c => balloon_common.c}            | 4 ++--
>  mm/migrate.c                                             | 2 +-
>  mm/vmscan.c                                              | 2 +-
>  9 files changed, 11 insertions(+), 11 deletions(-)
>  rename include/linux/{balloon_compaction.h => balloon_common.h} (99%)

Why rename the .h file?  It still handles the "balloon compaction"
logic.

thanks,

greg k-h

Re: [PATCH v2 1/4] Make place for common balloon code

[Alexander Atanasov]

Hello,

On 16.08.22 12:49, Greg Kroah-Hartman wrote:
> On Tue, Aug 16, 2022 at 12:41:14PM +0300, Alexander Atanasov wrote:

>>   rename include/linux/{balloon_compaction.h => balloon_common.h} (99%)
> 
> Why rename the .h file?  It still handles the "balloon compaction"
> logic.

File contains code that is common to balloon drivers,
compaction is only part of it. Series add more code to it.
Since it was suggested to use it for such common code.
I find that common becomes a better name for it so the rename.
I can drop the rename easy on next iteration if you suggest to.

-- 
Regards,
Alexander Atanasov

Re: [PATCH v2 1/4] Make place for common balloon code

[Greg Kroah-Hartman]

On Tue, Aug 16, 2022 at 02:47:22PM +0300, Alexander Atanasov wrote:
> Hello,
> 
> On 16.08.22 12:49, Greg Kroah-Hartman wrote:
> > On Tue, Aug 16, 2022 at 12:41:14PM +0300, Alexander Atanasov wrote:
> 
> > >   rename include/linux/{balloon_compaction.h => balloon_common.h} (99%)
> > 
> > Why rename the .h file?  It still handles the "balloon compaction"
> > logic.
> 
> File contains code that is common to balloon drivers,
> compaction is only part of it. Series add more code to it.
> Since it was suggested to use it for such common code.
> I find that common becomes a better name for it so the rename.
> I can drop the rename easy on next iteration if you suggest to.

"balloon_common.h" is very vague, you should only need one balloon.h
file in the include/linux/ directory, right, so of course it is "common"
:)

thanks,

greg "naming is hard" k-h

Re: [PATCH v2 1/4] Make place for common balloon code

[Michael S. Tsirkin]

On Tue, Aug 16, 2022 at 01:56:32PM +0200, Greg Kroah-Hartman wrote:
> On Tue, Aug 16, 2022 at 02:47:22PM +0300, Alexander Atanasov wrote:
> > Hello,
> > 
> > On 16.08.22 12:49, Greg Kroah-Hartman wrote:
> > > On Tue, Aug 16, 2022 at 12:41:14PM +0300, Alexander Atanasov wrote:
> > 
> > > >   rename include/linux/{balloon_compaction.h => balloon_common.h} (99%)
> > > 
> > > Why rename the .h file?  It still handles the "balloon compaction"
> > > logic.
> > 
> > File contains code that is common to balloon drivers,
> > compaction is only part of it. Series add more code to it.
> > Since it was suggested to use it for such common code.
> > I find that common becomes a better name for it so the rename.
> > I can drop the rename easy on next iteration if you suggest to.
> 
> "balloon_common.h" is very vague, you should only need one balloon.h
> file in the include/linux/ directory, right, so of course it is "common"
> :)
> 
> thanks,
> 
> greg "naming is hard" k-h

Yea, just call it balloon.h and balloon.c then.

-- 
MST

Re: [PATCH v2 1/4] Make place for common balloon code

[Ritesh Harjani]

On 22/08/16 12:41PM, Alexander Atanasov wrote:
> File already contains code that is common along balloon
> drivers so rename it to reflect its contents.
> mm/balloon_compaction.c -> mm/balloon_common.c
>
> Signed-off-by: Alexander Atanasov <alexander.atanasov@virtuozzo.com>
> ---
>  MAINTAINERS                                              | 4 ++--
>  arch/powerpc/platforms/pseries/cmm.c                     | 2 +-
>  drivers/misc/vmw_balloon.c                               | 2 +-
>  drivers/virtio/virtio_balloon.c                          | 2 +-
>  include/linux/{balloon_compaction.h => balloon_common.h} | 2 +-
>  mm/Makefile                                              | 2 +-
>  mm/{balloon_compaction.c => balloon_common.c}            | 4 ++--

>  mm/migrate.c                                             | 2 +-
>  mm/vmscan.c                                              | 2 +-
I think we don't need balloon headers in above two files at all.
I don't see any references of balloon functions in them.

I guess this commit removed it -

commit b1123ea6d3b3da25af5c8a9d843bd07ab63213f4
Author: Minchan Kim <minchan@kernel.org>
Date:   Tue Jul 26 15:23:09 2016 -0700

    mm: balloon: use general non-lru movable page feature

    Now, VM has a feature to migrate non-lru movable pages so balloon
    doesn't need custom migration hooks in migrate.c and compaction.c.

    Instead, this patch implements the page->mapping->a_ops->
    {isolate|migrate|putback} functions.

    With that, we could remove hooks for ballooning in general migration
    functions and make balloon compaction simple.

Since I don't often look into this side of code, it's better to confirm :)

-ritesh

Re: [PATCH v2 1/4] Make place for common balloon code

[Alexander Atanasov]

Hello,

On 18.08.22 7:41, Ritesh Harjani wrote:
> On 22/08/16 12:41PM, Alexander Atanasov wrote:
>> File already contains code that is common along balloon
>> drivers so rename it to reflect its contents.
>> mm/balloon_compaction.c -> mm/balloon_common.c
>>
>> Signed-off-by: Alexander Atanasov <alexander.atanasov@virtuozzo.com>
>> ---
>>   MAINTAINERS                                              | 4 ++--
>>   arch/powerpc/platforms/pseries/cmm.c                     | 2 +-
>>   drivers/misc/vmw_balloon.c                               | 2 +-
>>   drivers/virtio/virtio_balloon.c                          | 2 +-
>>   include/linux/{balloon_compaction.h => balloon_common.h} | 2 +-
>>   mm/Makefile                                              | 2 +-
>>   mm/{balloon_compaction.c => balloon_common.c}            | 4 ++--
> 
>>   mm/migrate.c                                             | 2 +-
>>   mm/vmscan.c                                              | 2 +-
> I think we don't need balloon headers in above two files at all.
> I don't see any references of balloon functions in them.

...

> Since I don't often look into this side of code, it's better to confirm :)

Yes, you are right. It passed a visual and compile verification.
I will remove them in the next iteration. Thanks for pointing it out :)

-- 
Regards,
Alexander Atanasov