* [PATCH v2 0/2] tidy up zsmalloc implementation
@ 2022-08-15 12:39 Alexey Romanov
2022-08-15 12:39 ` [PATCH v2 1/2] zsmalloc: zs_object_copy: add clarifying comment Alexey Romanov
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Alexey Romanov @ 2022-08-15 12:39 UTC (permalink / raw)
To: minchan, senozhatsky, ngupta, akpm
Cc: linux-mm, linux-kernel, kernel, Alexey Romanov
Hello!
This patchset remove some unnecessary checks and adds clarifying
comment. While analysis zs_object_copy() function code, I spent
some time to understand what the call kunmap_atomic(d_addr) is for.
It seems that this point is not trivial and it is worth adding
a comment.
Alexey Romanov (2):
zsmalloc: zs_object_copy: add clarifying comment
zsmalloc: remove unnecessary size_class NULL check
mm/zsmalloc.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
--
2.30.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v2 1/2] zsmalloc: zs_object_copy: add clarifying comment
2022-08-15 12:39 [PATCH v2 0/2] tidy up zsmalloc implementation Alexey Romanov
@ 2022-08-15 12:39 ` Alexey Romanov
2022-08-15 12:39 ` [PATCH v2 2/2] zsmalloc: remove unnecessary size_class NULL check Alexey Romanov
2022-08-15 14:56 ` [PATCH v2 0/2] tidy up zsmalloc implementation Aleksey Romanov
2 siblings, 0 replies; 4+ messages in thread
From: Alexey Romanov @ 2022-08-15 12:39 UTC (permalink / raw)
To: minchan, senozhatsky, ngupta, akpm
Cc: linux-mm, linux-kernel, kernel, Alexey Romanov
Signed-off-by: Alexey Romanov <avromanov@sberdevices.ru>
---
mm/zsmalloc.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 5d5fc04385b8..df381ba891ea 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -1564,6 +1564,12 @@ static void zs_object_copy(struct size_class *class, unsigned long dst,
d_off += size;
d_size -= size;
+ /* Calling kunmap_atomic(d_addr) is necessary. kunmap_atomic()
+ * calls must occurs in reverse order of calls to kmap_atomic.
+ * So, to call kunmap_atomic(s_addr) we should first call
+ * kunmap_atomic(d_addr). For more details see:
+ * Documentation/mm/highmem
+ */
if (s_off >= PAGE_SIZE) {
kunmap_atomic(d_addr);
kunmap_atomic(s_addr);
--
2.30.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v2 2/2] zsmalloc: remove unnecessary size_class NULL check
2022-08-15 12:39 [PATCH v2 0/2] tidy up zsmalloc implementation Alexey Romanov
2022-08-15 12:39 ` [PATCH v2 1/2] zsmalloc: zs_object_copy: add clarifying comment Alexey Romanov
@ 2022-08-15 12:39 ` Alexey Romanov
2022-08-15 14:56 ` [PATCH v2 0/2] tidy up zsmalloc implementation Aleksey Romanov
2 siblings, 0 replies; 4+ messages in thread
From: Alexey Romanov @ 2022-08-15 12:39 UTC (permalink / raw)
To: minchan, senozhatsky, ngupta, akpm
Cc: linux-mm, linux-kernel, kernel, Alexey Romanov
pool->size_class array elements can't be NULL, so this check
is not needed.
In the whole code, we assign pool->size_class[i] values that are
not NULL. Releasing memory for these values occurs in the
zs_destroy_pool() function, which also releases and destroys the pool.
In addition, in the zs_stats_size_show() and async_free_zspage(),
with similar iterations over the array, we don't check it for NULL
pointer.
Signed-off-by: Alexey Romanov <avromanov@sberdevices.ru>
---
mm/zsmalloc.c | 7 -------
1 file changed, 7 deletions(-)
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index df381ba891ea..d064ce32e7b9 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -2154,8 +2154,6 @@ unsigned long zs_compact(struct zs_pool *pool)
for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) {
class = pool->size_class[i];
- if (!class)
- continue;
if (class->index != i)
continue;
pages_freed += __zs_compact(pool, class);
@@ -2200,8 +2198,6 @@ static unsigned long zs_shrinker_count(struct shrinker *shrinker,
for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) {
class = pool->size_class[i];
- if (!class)
- continue;
if (class->index != i)
continue;
@@ -2361,9 +2357,6 @@ void zs_destroy_pool(struct zs_pool *pool)
int fg;
struct size_class *class = pool->size_class[i];
- if (!class)
- continue;
-
if (class->index != i)
continue;
--
2.30.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2 0/2] tidy up zsmalloc implementation
2022-08-15 12:39 [PATCH v2 0/2] tidy up zsmalloc implementation Alexey Romanov
2022-08-15 12:39 ` [PATCH v2 1/2] zsmalloc: zs_object_copy: add clarifying comment Alexey Romanov
2022-08-15 12:39 ` [PATCH v2 2/2] zsmalloc: remove unnecessary size_class NULL check Alexey Romanov
@ 2022-08-15 14:56 ` Aleksey Romanov
2 siblings, 0 replies; 4+ messages in thread
From: Aleksey Romanov @ 2022-08-15 14:56 UTC (permalink / raw)
To: minchan, senozhatsky, ngupta, akpm; +Cc: linux-mm, linux-kernel, kernel
Hello!
I accidientally send v2 patchset instead of send a single change
from 1/2 patch based on linux-next tree. Please, ignore this patchset
and see the change I send in a separate email.
Sorry for the noise.
--
Thank you,
Alexey
^ permalink raw reply [flat|nested] 4+ messages in thread
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2022-08-15 12:39 [PATCH v2 0/2] tidy up zsmalloc implementation Alexey Romanov
2022-08-15 12:39 ` [PATCH v2 1/2] zsmalloc: zs_object_copy: add clarifying comment Alexey Romanov
2022-08-15 12:39 ` [PATCH v2 2/2] zsmalloc: remove unnecessary size_class NULL check Alexey Romanov
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