2022-02-19 10:01:14

by Miaohe Lin

Subject: [PATCH 9/9] mm/z3fold: remove unneeded return value of z3fold_compact_page()

Remove the unneeded return value of z3fold_compact_page() as it's
never checked.

Signed-off-by: Miaohe Lin <[email protected]>
---
mm/z3fold.c | 14 +++++---------
1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/mm/z3fold.c b/mm/z3fold.c
index 83b5a3514427..db41b4227ec7 100644
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -746,18 +746,18 @@ static struct z3fold_header *compact_single_buddy(struct z3fold_header *zhdr)

#define BIG_CHUNK_GAP 3
/* Has to be called with lock held */
-static int z3fold_compact_page(struct z3fold_header *zhdr)
+static void z3fold_compact_page(struct z3fold_header *zhdr)
{
struct page *page = virt_to_page(zhdr);

if (test_bit(MIDDLE_CHUNK_MAPPED, &page->private))
- return 0; /* can't move middle chunk, it's used */
+ return; /* can't move middle chunk, it's used */

if (unlikely(PageIsolated(page)))
- return 0;
+ return;

if (zhdr->middle_chunks == 0)
- return 0; /* nothing to compact */
+ return; /* nothing to compact */

if (zhdr->first_chunks == 0 && zhdr->last_chunks == 0) {
/* move to the beginning */
@@ -766,7 +766,7 @@ static int z3fold_compact_page(struct z3fold_header *zhdr)
zhdr->middle_chunks = 0;
zhdr->start_middle = 0;
zhdr->first_num++;
- return 1;
+ return;
}

/*
@@ -778,7 +778,6 @@ static int z3fold_compact_page(struct z3fold_header *zhdr)
BIG_CHUNK_GAP) {
mchunk_memmove(zhdr, zhdr->first_chunks + ZHDR_CHUNKS);
zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS;
- return 1;
} else if (zhdr->last_chunks != 0 && zhdr->first_chunks == 0 &&
TOTAL_CHUNKS - (zhdr->last_chunks + zhdr->start_middle
+ zhdr->middle_chunks) >=
@@ -787,10 +786,7 @@ static int z3fold_compact_page(struct z3fold_header *zhdr)
zhdr->middle_chunks;
mchunk_memmove(zhdr, new_start);
zhdr->start_middle = new_start;
- return 1;
}
-
- return 0;
}

static void do_compact_page(struct z3fold_header *zhdr, bool locked)
--
2.23.0

2022-02-21 09:53:46

by Souptick Joarder

Subject: Re: [PATCH 9/9] mm/z3fold: remove unneeded return value of z3fold_compact_page()

On Sat, Feb 19, 2022 at 2:56 PM Miaohe Lin <[email protected]> wrote:
>
> Remove the unneeded return value of z3fold_compact_page() as it's
> never checked.
>
> Signed-off-by: Miaohe Lin <[email protected]>

Acked-by: Souptick Joarder <[email protected]>

> ---
> mm/z3fold.c | 14 +++++---------
> 1 file changed, 5 insertions(+), 9 deletions(-)
>
> diff --git a/mm/z3fold.c b/mm/z3fold.c
> index 83b5a3514427..db41b4227ec7 100644
> --- a/mm/z3fold.c
> +++ b/mm/z3fold.c
> @@ -746,18 +746,18 @@ static struct z3fold_header *compact_single_buddy(struct z3fold_header *zhdr)
>
> #define BIG_CHUNK_GAP 3
> /* Has to be called with lock held */
> -static int z3fold_compact_page(struct z3fold_header *zhdr)
> +static void z3fold_compact_page(struct z3fold_header *zhdr)
> {
> struct page *page = virt_to_page(zhdr);
>
> if (test_bit(MIDDLE_CHUNK_MAPPED, &page->private))
> - return 0; /* can't move middle chunk, it's used */
> + return; /* can't move middle chunk, it's used */
>
> if (unlikely(PageIsolated(page)))
> - return 0;
> + return;
>
> if (zhdr->middle_chunks == 0)
> - return 0; /* nothing to compact */
> + return; /* nothing to compact */
>
> if (zhdr->first_chunks == 0 && zhdr->last_chunks == 0) {
> /* move to the beginning */
> @@ -766,7 +766,7 @@ static int z3fold_compact_page(struct z3fold_header *zhdr)
> zhdr->middle_chunks = 0;
> zhdr->start_middle = 0;
> zhdr->first_num++;
> - return 1;
> + return;
> }
>
> /*
> @@ -778,7 +778,6 @@ static int z3fold_compact_page(struct z3fold_header *zhdr)
> BIG_CHUNK_GAP) {
> mchunk_memmove(zhdr, zhdr->first_chunks + ZHDR_CHUNKS);
> zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS;
> - return 1;
> } else if (zhdr->last_chunks != 0 && zhdr->first_chunks == 0 &&
> TOTAL_CHUNKS - (zhdr->last_chunks + zhdr->start_middle
> + zhdr->middle_chunks) >=
> @@ -787,10 +786,7 @@ static int z3fold_compact_page(struct z3fold_header *zhdr)
> zhdr->middle_chunks;
> mchunk_memmove(zhdr, new_start);
> zhdr->start_middle = new_start;
> - return 1;
> }
> -
> - return 0;
> }
>
> static void do_compact_page(struct z3fold_header *zhdr, bool locked)
> --
> 2.23.0
>
>

2022-03-02 10:04:45

by Vitaly Wool

Subject: Re: [PATCH 9/9] mm/z3fold: remove unneeded return value of z3fold_compact_page()

On Sat, Feb 19, 2022 at 10:26 AM Miaohe Lin <[email protected]> wrote:
>
> Remove the unneeded return value of z3fold_compact_page() as it's
> never checked.

It was a sort of hook for gathering extended compaction statistics in
future. Do you really gain a lot by removing this?

~Vitaly

> Signed-off-by: Miaohe Lin <[email protected]>
> ---
> mm/z3fold.c | 14 +++++---------
> 1 file changed, 5 insertions(+), 9 deletions(-)
>
> diff --git a/mm/z3fold.c b/mm/z3fold.c
> index 83b5a3514427..db41b4227ec7 100644
> --- a/mm/z3fold.c
> +++ b/mm/z3fold.c
> @@ -746,18 +746,18 @@ static struct z3fold_header *compact_single_buddy(struct z3fold_header *zhdr)
>
> #define BIG_CHUNK_GAP 3
> /* Has to be called with lock held */
> -static int z3fold_compact_page(struct z3fold_header *zhdr)
> +static void z3fold_compact_page(struct z3fold_header *zhdr)
> {
> struct page *page = virt_to_page(zhdr);
>
> if (test_bit(MIDDLE_CHUNK_MAPPED, &page->private))
> - return 0; /* can't move middle chunk, it's used */
> + return; /* can't move middle chunk, it's used */
>
> if (unlikely(PageIsolated(page)))
> - return 0;
> + return;
>
> if (zhdr->middle_chunks == 0)
> - return 0; /* nothing to compact */
> + return; /* nothing to compact */
>
> if (zhdr->first_chunks == 0 && zhdr->last_chunks == 0) {
> /* move to the beginning */
> @@ -766,7 +766,7 @@ static int z3fold_compact_page(struct z3fold_header *zhdr)
> zhdr->middle_chunks = 0;
> zhdr->start_middle = 0;
> zhdr->first_num++;
> - return 1;
> + return;
> }
>
> /*
> @@ -778,7 +778,6 @@ static int z3fold_compact_page(struct z3fold_header *zhdr)
> BIG_CHUNK_GAP) {
> mchunk_memmove(zhdr, zhdr->first_chunks + ZHDR_CHUNKS);
> zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS;
> - return 1;
> } else if (zhdr->last_chunks != 0 && zhdr->first_chunks == 0 &&
> TOTAL_CHUNKS - (zhdr->last_chunks + zhdr->start_middle
> + zhdr->middle_chunks) >=
> @@ -787,10 +786,7 @@ static int z3fold_compact_page(struct z3fold_header *zhdr)
> zhdr->middle_chunks;
> mchunk_memmove(zhdr, new_start);
> zhdr->start_middle = new_start;
> - return 1;
> }
> -
> - return 0;
> }
>
> static void do_compact_page(struct z3fold_header *zhdr, bool locked)
> --
> 2.23.0
>

2022-03-02 16:09:09

by Miaohe Lin

Subject: Re: [PATCH 9/9] mm/z3fold: remove unneeded return value of z3fold_compact_page()

On 2022/3/2 16:40, Vitaly Wool wrote:
> On Sat, Feb 19, 2022 at 10:26 AM Miaohe Lin <[email protected]> wrote:
>>
>> Remove the unneeded return value of z3fold_compact_page() as it's
>> never checked.
>
> It was a sort of hook for gathering extended compaction statistics in
> future. Do you really gain a lot by removing this?

I see. So I shouldn't discard the return value though it looks unused.
This is just for cleanup purpose so let's just drop this patch.

Many thanks for your time and Reviewed-by tag in this series! :)

>
> ~Vitaly
>
>> Signed-off-by: Miaohe Lin <[email protected]>
>> ---
>> mm/z3fold.c | 14 +++++---------
>> 1 file changed, 5 insertions(+), 9 deletions(-)
>>
>> diff --git a/mm/z3fold.c b/mm/z3fold.c
>> index 83b5a3514427..db41b4227ec7 100644
>> --- a/mm/z3fold.c
>> +++ b/mm/z3fold.c
>> @@ -746,18 +746,18 @@ static struct z3fold_header *compact_single_buddy(struct z3fold_header *zhdr)
>>
>> #define BIG_CHUNK_GAP 3
>> /* Has to be called with lock held */
>> -static int z3fold_compact_page(struct z3fold_header *zhdr)
>> +static void z3fold_compact_page(struct z3fold_header *zhdr)
>> {
>> struct page *page = virt_to_page(zhdr);
>>
>> if (test_bit(MIDDLE_CHUNK_MAPPED, &page->private))
>> - return 0; /* can't move middle chunk, it's used */
>> + return; /* can't move middle chunk, it's used */
>>
>> if (unlikely(PageIsolated(page)))
>> - return 0;
>> + return;
>>
>> if (zhdr->middle_chunks == 0)
>> - return 0; /* nothing to compact */
>> + return; /* nothing to compact */
>>
>> if (zhdr->first_chunks == 0 && zhdr->last_chunks == 0) {
>> /* move to the beginning */
>> @@ -766,7 +766,7 @@ static int z3fold_compact_page(struct z3fold_header *zhdr)
>> zhdr->middle_chunks = 0;
>> zhdr->start_middle = 0;
>> zhdr->first_num++;
>> - return 1;
>> + return;
>> }
>>
>> /*
>> @@ -778,7 +778,6 @@ static int z3fold_compact_page(struct z3fold_header *zhdr)
>> BIG_CHUNK_GAP) {
>> mchunk_memmove(zhdr, zhdr->first_chunks + ZHDR_CHUNKS);
>> zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS;
>> - return 1;
>> } else if (zhdr->last_chunks != 0 && zhdr->first_chunks == 0 &&
>> TOTAL_CHUNKS - (zhdr->last_chunks + zhdr->start_middle
>> + zhdr->middle_chunks) >=
>> @@ -787,10 +786,7 @@ static int z3fold_compact_page(struct z3fold_header *zhdr)
>> zhdr->middle_chunks;
>> mchunk_memmove(zhdr, new_start);
>> zhdr->start_middle = new_start;
>> - return 1;
>> }
>> -
>> - return 0;
>> }
>>
>> static void do_compact_page(struct z3fold_header *zhdr, bool locked)
>> --
>> 2.23.0
>>
> .
>