Hi all,
This series contains just cleanups to save some possible memory in
zbud_pool and avoid exporting any unneeded zbud API. More details
can be found in the respective changelogs. Thanks!
v1->v2:
Use union and add comment per Andrew.
Miaohe Lin (2):
mm/zbud: reuse unbuddied[0] as buddied in zbud_pool
mm/zbud: don't export any zbud API
MAINTAINERS | 1 -
include/linux/zbud.h | 23 -----
mm/zbud.c | 229 +++++++++++++++++++++++--------------------
3 files changed, 120 insertions(+), 133 deletions(-)
delete mode 100644 include/linux/zbud.h
--
2.23.0
Since commit 9d8c5b5284e4 ("mm: zbud: fix condition check on allocation
size"), zbud_pool.unbuddied[0] is always unused. We can reuse it as buddied
field to save some possible memory.
Signed-off-by: Miaohe Lin <[email protected]>
---
mm/zbud.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/mm/zbud.c b/mm/zbud.c
index a200121da400..78e80ca58869 100644
--- a/mm/zbud.c
+++ b/mm/zbud.c
@@ -95,8 +95,14 @@
*/
struct zbud_pool {
spinlock_t lock;
- struct list_head unbuddied[NCHUNKS];
- struct list_head buddied;
+ union {
+ /*
+ * Reuse unbuddied[0] as buddied on the ground that
+ * unbuddied[0] is unused.
+ */
+ struct list_head buddied;
+ struct list_head unbuddied[NCHUNKS];
+ };
struct list_head lru;
u64 pages_nr;
const struct zbud_ops *ops;
--
2.23.0
The zbud doesn't need to export any API and it is meant to be used via
zpool API since the commit 12d79d64bfd3 ("mm/zpool: update zswap to use
zpool"). So we can remove the unneeded zbud.h and move down zpool API
to avoid any forward declaration.
Signed-off-by: Miaohe Lin <[email protected]>
---
MAINTAINERS | 1 -
include/linux/zbud.h | 23 -----
mm/zbud.c | 219 ++++++++++++++++++++++---------------------
3 files changed, 112 insertions(+), 131 deletions(-)
delete mode 100644 include/linux/zbud.h
diff --git a/MAINTAINERS b/MAINTAINERS
index d8648ee43199..625d66d7aacc 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -20264,7 +20264,6 @@ M: Seth Jennings <[email protected]>
M: Dan Streetman <[email protected]>
L: [email protected]
S: Maintained
-F: include/linux/zbud.h
F: mm/zbud.c
ZD1211RW WIRELESS DRIVER
diff --git a/include/linux/zbud.h b/include/linux/zbud.h
deleted file mode 100644
index b1eaf6e31735..000000000000
--- a/include/linux/zbud.h
+++ /dev/null
@@ -1,23 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ZBUD_H_
-#define _ZBUD_H_
-
-#include <linux/types.h>
-
-struct zbud_pool;
-
-struct zbud_ops {
- int (*evict)(struct zbud_pool *pool, unsigned long handle);
-};
-
-struct zbud_pool *zbud_create_pool(gfp_t gfp, const struct zbud_ops *ops);
-void zbud_destroy_pool(struct zbud_pool *pool);
-int zbud_alloc(struct zbud_pool *pool, size_t size, gfp_t gfp,
- unsigned long *handle);
-void zbud_free(struct zbud_pool *pool, unsigned long handle);
-int zbud_reclaim_page(struct zbud_pool *pool, unsigned int retries);
-void *zbud_map(struct zbud_pool *pool, unsigned long handle);
-void zbud_unmap(struct zbud_pool *pool, unsigned long handle);
-u64 zbud_get_pool_size(struct zbud_pool *pool);
-
-#endif /* _ZBUD_H_ */
diff --git a/mm/zbud.c b/mm/zbud.c
index 78e80ca58869..3f61304405cb 100644
--- a/mm/zbud.c
+++ b/mm/zbud.c
@@ -51,7 +51,6 @@
#include <linux/preempt.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
-#include <linux/zbud.h>
#include <linux/zpool.h>
/*****************
@@ -73,6 +72,12 @@
#define ZHDR_SIZE_ALIGNED CHUNK_SIZE
#define NCHUNKS ((PAGE_SIZE - ZHDR_SIZE_ALIGNED) >> CHUNK_SHIFT)
+struct zbud_pool;
+
+struct zbud_ops {
+ int (*evict)(struct zbud_pool *pool, unsigned long handle);
+};
+
/**
* struct zbud_pool - stores metadata for each zbud pool
* @lock: protects all pool fields and first|last_chunk fields of any
@@ -128,104 +133,6 @@ struct zbud_header {
bool under_reclaim;
};
-/*****************
- * zpool
- ****************/
-
-#ifdef CONFIG_ZPOOL
-
-static int zbud_zpool_evict(struct zbud_pool *pool, unsigned long handle)
-{
- if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict)
- return pool->zpool_ops->evict(pool->zpool, handle);
- else
- return -ENOENT;
-}
-
-static const struct zbud_ops zbud_zpool_ops = {
- .evict = zbud_zpool_evict
-};
-
-static void *zbud_zpool_create(const char *name, gfp_t gfp,
- const struct zpool_ops *zpool_ops,
- struct zpool *zpool)
-{
- struct zbud_pool *pool;
-
- pool = zbud_create_pool(gfp, zpool_ops ? &zbud_zpool_ops : NULL);
- if (pool) {
- pool->zpool = zpool;
- pool->zpool_ops = zpool_ops;
- }
- return pool;
-}
-
-static void zbud_zpool_destroy(void *pool)
-{
- zbud_destroy_pool(pool);
-}
-
-static int zbud_zpool_malloc(void *pool, size_t size, gfp_t gfp,
- unsigned long *handle)
-{
- return zbud_alloc(pool, size, gfp, handle);
-}
-static void zbud_zpool_free(void *pool, unsigned long handle)
-{
- zbud_free(pool, handle);
-}
-
-static int zbud_zpool_shrink(void *pool, unsigned int pages,
- unsigned int *reclaimed)
-{
- unsigned int total = 0;
- int ret = -EINVAL;
-
- while (total < pages) {
- ret = zbud_reclaim_page(pool, 8);
- if (ret < 0)
- break;
- total++;
- }
-
- if (reclaimed)
- *reclaimed = total;
-
- return ret;
-}
-
-static void *zbud_zpool_map(void *pool, unsigned long handle,
- enum zpool_mapmode mm)
-{
- return zbud_map(pool, handle);
-}
-static void zbud_zpool_unmap(void *pool, unsigned long handle)
-{
- zbud_unmap(pool, handle);
-}
-
-static u64 zbud_zpool_total_size(void *pool)
-{
- return zbud_get_pool_size(pool) * PAGE_SIZE;
-}
-
-static struct zpool_driver zbud_zpool_driver = {
- .type = "zbud",
- .sleep_mapped = true,
- .owner = THIS_MODULE,
- .create = zbud_zpool_create,
- .destroy = zbud_zpool_destroy,
- .malloc = zbud_zpool_malloc,
- .free = zbud_zpool_free,
- .shrink = zbud_zpool_shrink,
- .map = zbud_zpool_map,
- .unmap = zbud_zpool_unmap,
- .total_size = zbud_zpool_total_size,
-};
-
-MODULE_ALIAS("zpool-zbud");
-#endif /* CONFIG_ZPOOL */
-
/*****************
* Helpers
*****************/
@@ -312,7 +219,7 @@ static int num_free_chunks(struct zbud_header *zhdr)
* Return: pointer to the new zbud pool or NULL if the metadata allocation
* failed.
*/
-struct zbud_pool *zbud_create_pool(gfp_t gfp, const struct zbud_ops *ops)
+static struct zbud_pool *zbud_create_pool(gfp_t gfp, const struct zbud_ops *ops)
{
struct zbud_pool *pool;
int i;
@@ -336,7 +243,7 @@ struct zbud_pool *zbud_create_pool(gfp_t gfp, const struct zbud_ops *ops)
*
* The pool should be emptied before this function is called.
*/
-void zbud_destroy_pool(struct zbud_pool *pool)
+static void zbud_destroy_pool(struct zbud_pool *pool)
{
kfree(pool);
}
@@ -360,7 +267,7 @@ void zbud_destroy_pool(struct zbud_pool *pool)
* gfp arguments are invalid or -ENOMEM if the pool was unable to allocate
* a new page.
*/
-int zbud_alloc(struct zbud_pool *pool, size_t size, gfp_t gfp,
+static int zbud_alloc(struct zbud_pool *pool, size_t size, gfp_t gfp,
unsigned long *handle)
{
int chunks, i, freechunks;
@@ -435,7 +342,7 @@ int zbud_alloc(struct zbud_pool *pool, size_t size, gfp_t gfp,
* only sets the first|last_chunks to 0. The page is actually freed
* once both buddies are evicted (see zbud_reclaim_page() below).
*/
-void zbud_free(struct zbud_pool *pool, unsigned long handle)
+static void zbud_free(struct zbud_pool *pool, unsigned long handle)
{
struct zbud_header *zhdr;
int freechunks;
@@ -507,7 +414,7 @@ void zbud_free(struct zbud_pool *pool, unsigned long handle)
* no pages to evict or an eviction handler is not registered, -EAGAIN if
* the retry limit was hit.
*/
-int zbud_reclaim_page(struct zbud_pool *pool, unsigned int retries)
+static int zbud_reclaim_page(struct zbud_pool *pool, unsigned int retries)
{
int i, ret, freechunks;
struct zbud_header *zhdr;
@@ -589,7 +496,7 @@ int zbud_reclaim_page(struct zbud_pool *pool, unsigned int retries)
*
* Returns: a pointer to the mapped allocation
*/
-void *zbud_map(struct zbud_pool *pool, unsigned long handle)
+static void *zbud_map(struct zbud_pool *pool, unsigned long handle)
{
return (void *)(handle);
}
@@ -599,7 +506,7 @@ void *zbud_map(struct zbud_pool *pool, unsigned long handle)
* @pool: pool in which the allocation resides
* @handle: handle associated with the allocation to be unmapped
*/
-void zbud_unmap(struct zbud_pool *pool, unsigned long handle)
+static void zbud_unmap(struct zbud_pool *pool, unsigned long handle)
{
}
@@ -610,11 +517,109 @@ void zbud_unmap(struct zbud_pool *pool, unsigned long handle)
* Returns: size in pages of the given pool. The pool lock need not be
* taken to access pages_nr.
*/
-u64 zbud_get_pool_size(struct zbud_pool *pool)
+static u64 zbud_get_pool_size(struct zbud_pool *pool)
{
return pool->pages_nr;
}
+/*****************
+ * zpool
+ ****************/
+
+#ifdef CONFIG_ZPOOL
+
+static int zbud_zpool_evict(struct zbud_pool *pool, unsigned long handle)
+{
+ if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict)
+ return pool->zpool_ops->evict(pool->zpool, handle);
+ else
+ return -ENOENT;
+}
+
+static const struct zbud_ops zbud_zpool_ops = {
+ .evict = zbud_zpool_evict
+};
+
+static void *zbud_zpool_create(const char *name, gfp_t gfp,
+ const struct zpool_ops *zpool_ops,
+ struct zpool *zpool)
+{
+ struct zbud_pool *pool;
+
+ pool = zbud_create_pool(gfp, zpool_ops ? &zbud_zpool_ops : NULL);
+ if (pool) {
+ pool->zpool = zpool;
+ pool->zpool_ops = zpool_ops;
+ }
+ return pool;
+}
+
+static void zbud_zpool_destroy(void *pool)
+{
+ zbud_destroy_pool(pool);
+}
+
+static int zbud_zpool_malloc(void *pool, size_t size, gfp_t gfp,
+ unsigned long *handle)
+{
+ return zbud_alloc(pool, size, gfp, handle);
+}
+static void zbud_zpool_free(void *pool, unsigned long handle)
+{
+ zbud_free(pool, handle);
+}
+
+static int zbud_zpool_shrink(void *pool, unsigned int pages,
+ unsigned int *reclaimed)
+{
+ unsigned int total = 0;
+ int ret = -EINVAL;
+
+ while (total < pages) {
+ ret = zbud_reclaim_page(pool, 8);
+ if (ret < 0)
+ break;
+ total++;
+ }
+
+ if (reclaimed)
+ *reclaimed = total;
+
+ return ret;
+}
+
+static void *zbud_zpool_map(void *pool, unsigned long handle,
+ enum zpool_mapmode mm)
+{
+ return zbud_map(pool, handle);
+}
+static void zbud_zpool_unmap(void *pool, unsigned long handle)
+{
+ zbud_unmap(pool, handle);
+}
+
+static u64 zbud_zpool_total_size(void *pool)
+{
+ return zbud_get_pool_size(pool) * PAGE_SIZE;
+}
+
+static struct zpool_driver zbud_zpool_driver = {
+ .type = "zbud",
+ .sleep_mapped = true,
+ .owner = THIS_MODULE,
+ .create = zbud_zpool_create,
+ .destroy = zbud_zpool_destroy,
+ .malloc = zbud_zpool_malloc,
+ .free = zbud_zpool_free,
+ .shrink = zbud_zpool_shrink,
+ .map = zbud_zpool_map,
+ .unmap = zbud_zpool_unmap,
+ .total_size = zbud_zpool_total_size,
+};
+
+MODULE_ALIAS("zpool-zbud");
+#endif /* CONFIG_ZPOOL */
+
static int __init init_zbud(void)
{
/* Make sure the zbud header will fit in one chunk */
--
2.23.0
On Tue, Jun 08, 2021 at 07:45:15PM +0800, Miaohe Lin wrote:
> The zbud doesn't need to export any API and it is meant to be used via
> zpool API since the commit 12d79d64bfd3 ("mm/zpool: update zswap to use
> zpool"). So we can remove the unneeded zbud.h and move down zpool API
> to avoid any forward declaration.
>
> Signed-off-by: Miaohe Lin <[email protected]>
This patch causes several new warnings when CONFIG_ZPOOL is disabled:
mm/zbud.c:222:26: warning: unused function 'zbud_create_pool' [-Wunused-function]
mm/zbud.c:246:13: warning: unused function 'zbud_destroy_pool' [-Wunused-function]
mm/zbud.c:270:12: warning: unused function 'zbud_alloc' [-Wunused-function]
mm/zbud.c:345:13: warning: unused function 'zbud_free' [-Wunused-function]
mm/zbud.c:417:12: warning: unused function 'zbud_reclaim_page' [-Wunused-function]
mm/zbud.c:499:14: warning: unused function 'zbud_map' [-Wunused-function]
mm/zbud.c:509:13: warning: unused function 'zbud_unmap' [-Wunused-function]
mm/zbud.c:520:12: warning: unused function 'zbud_get_pool_size' [-Wunused-function]
It seems to me like all of these functions should be sunk into their
callers and eliminated entirely as part of this refactoring. I took a
whack at it but got lost with the kernel docs so someone who is familiar
with this should probably do it.
Cheers,
Nathan
On 6/17/2021 7:28 PM, Miaohe Lin wrote:
> Hi:
> On 2021/6/18 8:44, Nathan Chancellor wrote:
>> On Tue, Jun 08, 2021 at 07:45:15PM +0800, Miaohe Lin wrote:
>>> The zbud doesn't need to export any API and it is meant to be used via
>>> zpool API since the commit 12d79d64bfd3 ("mm/zpool: update zswap to use
>>> zpool"). So we can remove the unneeded zbud.h and move down zpool API
>>> to avoid any forward declaration.
>>>
>>> Signed-off-by: Miaohe Lin <[email protected]>
>>
>
> Thank you for help figure these warnings out. It seems zbud module won't do
> anything when CONFIG_ZPOOL is disabled. I think we should make zbud depends
> on ZPOOL and eliminate the CONFIG_ZPOOL macro in zbud.c like what z3fold does.
> Does this make sense for you?
> Thanks again. :)
That seems logical to me. It probably makes sense to send that as a fix
patch for this one so Andrew can squash it in.
Cheers,
Nathan
> diff --git a/mm/Kconfig b/mm/Kconfig
> index 8f748010f7ea..5dc28e9205e0 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -674,6 +674,7 @@ config ZPOOL
>
> config ZBUD
> tristate "Low (Up to 2x) density storage for compressed pages"
> + depends on ZPOOL
> help
> A special purpose allocator for storing compressed pages.
> It is designed to store up to two compressed pages per physical
> diff --git a/mm/zbud.c b/mm/zbud.c
> index 3f61304405cb..6348932430b8 100644
> --- a/mm/zbud.c
> +++ b/mm/zbud.c
> @@ -111,10 +111,8 @@ struct zbud_pool {
> struct list_head lru;
> u64 pages_nr;
> const struct zbud_ops *ops;
> -#ifdef CONFIG_ZPOOL
> struct zpool *zpool;
> const struct zpool_ops *zpool_ops;
> -#endif
> };
>
> /*
> @@ -526,8 +524,6 @@ static u64 zbud_get_pool_size(struct zbud_pool *pool)
> * zpool
> ****************/
>
> -#ifdef CONFIG_ZPOOL
> -
> static int zbud_zpool_evict(struct zbud_pool *pool, unsigned long handle)
> {
> if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict)
> @@ -618,7 +614,6 @@ static struct zpool_driver zbud_zpool_driver = {
> };
>
> MODULE_ALIAS("zpool-zbud");
> -#endif /* CONFIG_ZPOOL */
>
> static int __init init_zbud(void)
> {
> @@ -626,19 +621,14 @@ static int __init init_zbud(void)
> BUILD_BUG_ON(sizeof(struct zbud_header) > ZHDR_SIZE_ALIGNED);
> pr_info("loaded\n");
>
> -#ifdef CONFIG_ZPOOL
> zpool_register_driver(&zbud_zpool_driver);
> -#endif
>
> return 0;
> }
>
> static void __exit exit_zbud(void)
> {
> -#ifdef CONFIG_ZPOOL
> zpool_unregister_driver(&zbud_zpool_driver);
> -#endif
> -
> pr_info("unloaded\n");
> }
>
>> This patch causes several new warnings when CONFIG_ZPOOL is disabled:
>>
>> mm/zbud.c:222:26: warning: unused function 'zbud_create_pool' [-Wunused-function]
>> mm/zbud.c:246:13: warning: unused function 'zbud_destroy_pool' [-Wunused-function]
>> mm/zbud.c:270:12: warning: unused function 'zbud_alloc' [-Wunused-function]
>> mm/zbud.c:345:13: warning: unused function 'zbud_free' [-Wunused-function]
>> mm/zbud.c:417:12: warning: unused function 'zbud_reclaim_page' [-Wunused-function]
>> mm/zbud.c:499:14: warning: unused function 'zbud_map' [-Wunused-function]
>> mm/zbud.c:509:13: warning: unused function 'zbud_unmap' [-Wunused-function]
>> mm/zbud.c:520:12: warning: unused function 'zbud_get_pool_size' [-Wunused-function]
>>
>> It seems to me like all of these functions should be sunk into their
>> callers and eliminated entirely as part of this refactoring. I took a
>> whack at it but got lost with the kernel docs so someone who is familiar
>> with this should probably do it.
>>
>> Cheers,
>> Nathan
>> .
>>
>
On 2021/6/18 10:42, Nathan Chancellor wrote:
> On 6/17/2021 7:28 PM, Miaohe Lin wrote:
>> Hi:
>> On 2021/6/18 8:44, Nathan Chancellor wrote:
>>> On Tue, Jun 08, 2021 at 07:45:15PM +0800, Miaohe Lin wrote:
>>>> The zbud doesn't need to export any API and it is meant to be used via
>>>> zpool API since the commit 12d79d64bfd3 ("mm/zpool: update zswap to use
>>>> zpool"). So we can remove the unneeded zbud.h and move down zpool API
>>>> to avoid any forward declaration.
>>>>
>>>> Signed-off-by: Miaohe Lin <[email protected]>
>>>
>>
>> Thank you for help figure these warnings out. It seems zbud module won't do
>> anything when CONFIG_ZPOOL is disabled. I think we should make zbud depends
>> on ZPOOL and eliminate the CONFIG_ZPOOL macro in zbud.c like what z3fold does.
>> Does this make sense for you?
>> Thanks again. :)
>
> That seems logical to me. It probably makes sense to send that as a fix patch for this one so Andrew can squash it in.
Sure. This is also what I meant to do. Will do it later.
Many thanks!
>
> Cheers,
> Nathan
>
>> diff --git a/mm/Kconfig b/mm/Kconfig
>> index 8f748010f7ea..5dc28e9205e0 100644
>> --- a/mm/Kconfig
>> +++ b/mm/Kconfig
>> @@ -674,6 +674,7 @@ config ZPOOL
>>
>> config ZBUD
>> tristate "Low (Up to 2x) density storage for compressed pages"
>> + depends on ZPOOL
>> help
>> A special purpose allocator for storing compressed pages.
>> It is designed to store up to two compressed pages per physical
>> diff --git a/mm/zbud.c b/mm/zbud.c
>> index 3f61304405cb..6348932430b8 100644
>> --- a/mm/zbud.c
>> +++ b/mm/zbud.c
>> @@ -111,10 +111,8 @@ struct zbud_pool {
>> struct list_head lru;
>> u64 pages_nr;
>> const struct zbud_ops *ops;
>> -#ifdef CONFIG_ZPOOL
>> struct zpool *zpool;
>> const struct zpool_ops *zpool_ops;
>> -#endif
>> };
>>
>> /*
>> @@ -526,8 +524,6 @@ static u64 zbud_get_pool_size(struct zbud_pool *pool)
>> * zpool
>> ****************/
>>
>> -#ifdef CONFIG_ZPOOL
>> -
>> static int zbud_zpool_evict(struct zbud_pool *pool, unsigned long handle)
>> {
>> if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict)
>> @@ -618,7 +614,6 @@ static struct zpool_driver zbud_zpool_driver = {
>> };
>>
>> MODULE_ALIAS("zpool-zbud");
>> -#endif /* CONFIG_ZPOOL */
>>
>> static int __init init_zbud(void)
>> {
>> @@ -626,19 +621,14 @@ static int __init init_zbud(void)
>> BUILD_BUG_ON(sizeof(struct zbud_header) > ZHDR_SIZE_ALIGNED);
>> pr_info("loaded\n");
>>
>> -#ifdef CONFIG_ZPOOL
>> zpool_register_driver(&zbud_zpool_driver);
>> -#endif
>>
>> return 0;
>> }
>>
>> static void __exit exit_zbud(void)
>> {
>> -#ifdef CONFIG_ZPOOL
>> zpool_unregister_driver(&zbud_zpool_driver);
>> -#endif
>> -
>> pr_info("unloaded\n");
>> }
>>
>>> This patch causes several new warnings when CONFIG_ZPOOL is disabled:
>>>
>>> mm/zbud.c:222:26: warning: unused function 'zbud_create_pool' [-Wunused-function]
>>> mm/zbud.c:246:13: warning: unused function 'zbud_destroy_pool' [-Wunused-function]
>>> mm/zbud.c:270:12: warning: unused function 'zbud_alloc' [-Wunused-function]
>>> mm/zbud.c:345:13: warning: unused function 'zbud_free' [-Wunused-function]
>>> mm/zbud.c:417:12: warning: unused function 'zbud_reclaim_page' [-Wunused-function]
>>> mm/zbud.c:499:14: warning: unused function 'zbud_map' [-Wunused-function]
>>> mm/zbud.c:509:13: warning: unused function 'zbud_unmap' [-Wunused-function]
>>> mm/zbud.c:520:12: warning: unused function 'zbud_get_pool_size' [-Wunused-function]
>>>
>>> It seems to me like all of these functions should be sunk into their
>>> callers and eliminated entirely as part of this refactoring. I took a
>>> whack at it but got lost with the kernel docs so someone who is familiar
>>> with this should probably do it.
>>>
>>> Cheers,
>>> Nathan
>>> .
>>>
>>
>
> .
Hi:
On 2021/6/18 8:44, Nathan Chancellor wrote:
> On Tue, Jun 08, 2021 at 07:45:15PM +0800, Miaohe Lin wrote:
>> The zbud doesn't need to export any API and it is meant to be used via
>> zpool API since the commit 12d79d64bfd3 ("mm/zpool: update zswap to use
>> zpool"). So we can remove the unneeded zbud.h and move down zpool API
>> to avoid any forward declaration.
>>
>> Signed-off-by: Miaohe Lin <[email protected]>
>
Thank you for help figure these warnings out. It seems zbud module won't do
anything when CONFIG_ZPOOL is disabled. I think we should make zbud depends
on ZPOOL and eliminate the CONFIG_ZPOOL macro in zbud.c like what z3fold does.
Does this make sense for you?
Thanks again. :)
diff --git a/mm/Kconfig b/mm/Kconfig
index 8f748010f7ea..5dc28e9205e0 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -674,6 +674,7 @@ config ZPOOL
config ZBUD
tristate "Low (Up to 2x) density storage for compressed pages"
+ depends on ZPOOL
help
A special purpose allocator for storing compressed pages.
It is designed to store up to two compressed pages per physical
diff --git a/mm/zbud.c b/mm/zbud.c
index 3f61304405cb..6348932430b8 100644
--- a/mm/zbud.c
+++ b/mm/zbud.c
@@ -111,10 +111,8 @@ struct zbud_pool {
struct list_head lru;
u64 pages_nr;
const struct zbud_ops *ops;
-#ifdef CONFIG_ZPOOL
struct zpool *zpool;
const struct zpool_ops *zpool_ops;
-#endif
};
/*
@@ -526,8 +524,6 @@ static u64 zbud_get_pool_size(struct zbud_pool *pool)
* zpool
****************/
-#ifdef CONFIG_ZPOOL
-
static int zbud_zpool_evict(struct zbud_pool *pool, unsigned long handle)
{
if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict)
@@ -618,7 +614,6 @@ static struct zpool_driver zbud_zpool_driver = {
};
MODULE_ALIAS("zpool-zbud");
-#endif /* CONFIG_ZPOOL */
static int __init init_zbud(void)
{
@@ -626,19 +621,14 @@ static int __init init_zbud(void)
BUILD_BUG_ON(sizeof(struct zbud_header) > ZHDR_SIZE_ALIGNED);
pr_info("loaded\n");
-#ifdef CONFIG_ZPOOL
zpool_register_driver(&zbud_zpool_driver);
-#endif
return 0;
}
static void __exit exit_zbud(void)
{
-#ifdef CONFIG_ZPOOL
zpool_unregister_driver(&zbud_zpool_driver);
-#endif
-
pr_info("unloaded\n");
}
> This patch causes several new warnings when CONFIG_ZPOOL is disabled:
>
> mm/zbud.c:222:26: warning: unused function 'zbud_create_pool' [-Wunused-function]
> mm/zbud.c:246:13: warning: unused function 'zbud_destroy_pool' [-Wunused-function]
> mm/zbud.c:270:12: warning: unused function 'zbud_alloc' [-Wunused-function]
> mm/zbud.c:345:13: warning: unused function 'zbud_free' [-Wunused-function]
> mm/zbud.c:417:12: warning: unused function 'zbud_reclaim_page' [-Wunused-function]
> mm/zbud.c:499:14: warning: unused function 'zbud_map' [-Wunused-function]
> mm/zbud.c:509:13: warning: unused function 'zbud_unmap' [-Wunused-function]
> mm/zbud.c:520:12: warning: unused function 'zbud_get_pool_size' [-Wunused-function]
>
> It seems to me like all of these functions should be sunk into their
> callers and eliminated entirely as part of this refactoring. I took a
> whack at it but got lost with the kernel docs so someone who is familiar
> with this should probably do it.
>
> Cheers,
> Nathan
> .
>