There is no need round twice in memblock_add_range().
We can call memblock_double_array() to extand the size if type->cnt no
less than type->max before memblock_insert_region(), otherwise we can
insert the new region directly.
Signed-off-by: Yajun Deng <[email protected]>
---
mm/memblock.c | 54 +++++++++++++++------------------------------------
1 file changed, 16 insertions(+), 38 deletions(-)
diff --git a/mm/memblock.c b/mm/memblock.c
index 511d4783dcf1..1679244b4a1a 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -578,7 +578,6 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
phys_addr_t base, phys_addr_t size,
int nid, enum memblock_flags flags)
{
- bool insert = false;
phys_addr_t obase = base;
phys_addr_t end = base + memblock_cap_size(base, &size);
int idx, nr_new;
@@ -598,22 +597,6 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
return 0;
}
- /*
- * The worst case is when new range overlaps all existing regions,
- * then we'll need type->cnt + 1 empty regions in @type. So if
- * type->cnt * 2 + 1 is less than type->max, we know
- * that there is enough empty regions in @type, and we can insert
- * regions directly.
- */
- if (type->cnt * 2 + 1 < type->max)
- insert = true;
-
-repeat:
- /*
- * The following is executed twice. Once with %false @insert and
- * then with %true. The first counts the number of regions needed
- * to accommodate the new area. The second actually inserts them.
- */
base = obase;
nr_new = 0;
@@ -635,10 +618,14 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
#endif
WARN_ON(flags != rgn->flags);
nr_new++;
- if (insert)
- memblock_insert_region(type, idx++, base,
- rbase - base, nid,
- flags);
+
+ if ((type->cnt >= type->max) &&
+ (memblock_double_array(type, obase, size) < 0))
+ return -ENOMEM;
+
+ memblock_insert_region(type, idx++, base,
+ rbase - base, nid,
+ flags);
}
/* area below @rend is dealt with, forget about it */
base = min(rend, end);
@@ -647,28 +634,19 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
/* insert the remaining portion */
if (base < end) {
nr_new++;
- if (insert)
- memblock_insert_region(type, idx, base, end - base,
- nid, flags);
+ if ((type->cnt >= type->max) &&
+ (memblock_double_array(type, obase, size) < 0))
+ return -ENOMEM;
+
+ memblock_insert_region(type, idx, base, end - base,
+ nid, flags);
}
if (!nr_new)
return 0;
- /*
- * If this was the first round, resize array and repeat for actual
- * insertions; otherwise, merge and return.
- */
- if (!insert) {
- while (type->cnt + nr_new > type->max)
- if (memblock_double_array(type, obase, size) < 0)
- return -ENOMEM;
- insert = true;
- goto repeat;
- } else {
- memblock_merge_regions(type);
- return 0;
- }
+ memblock_merge_regions(type);
+ return 0;
}
/**
--
2.25.1
Hi,
On Wed, Oct 19, 2022 at 08:03:37PM +0800, Yajun Deng wrote:
> Subject: memblock: remove repeat round
Please make the patch subject more detailed. Say
membloc: don't run loop in memblock_add_range() twice
> There is no need round twice in memblock_add_range().
>
> We can call memblock_double_array() to extand the size if type->cnt no
^ extend
> less than type->max before memblock_insert_region(), otherwise we can
s/no less than/greater or equal to/
> insert the new region directly.
>
> Signed-off-by: Yajun Deng <[email protected]>
> ---
> mm/memblock.c | 54 +++++++++++++++------------------------------------
> 1 file changed, 16 insertions(+), 38 deletions(-)
>
> diff --git a/mm/memblock.c b/mm/memblock.c
> index 511d4783dcf1..1679244b4a1a 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -578,7 +578,6 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
> phys_addr_t base, phys_addr_t size,
> int nid, enum memblock_flags flags)
> {
> - bool insert = false;
> phys_addr_t obase = base;
> phys_addr_t end = base + memblock_cap_size(base, &size);
> int idx, nr_new;
> @@ -598,22 +597,6 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
> return 0;
> }
>
> - /*
> - * The worst case is when new range overlaps all existing regions,
> - * then we'll need type->cnt + 1 empty regions in @type. So if
> - * type->cnt * 2 + 1 is less than type->max, we know
> - * that there is enough empty regions in @type, and we can insert
> - * regions directly.
> - */
> - if (type->cnt * 2 + 1 < type->max)
> - insert = true;
> -
> -repeat:
> - /*
> - * The following is executed twice. Once with %false @insert and
> - * then with %true. The first counts the number of regions needed
> - * to accommodate the new area. The second actually inserts them.
> - */
> base = obase;
> nr_new = 0;
I believe nr_new variable is no longer needed, is it?
> @@ -635,10 +618,14 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
> #endif
> WARN_ON(flags != rgn->flags);
> nr_new++;
> - if (insert)
> - memblock_insert_region(type, idx++, base,
> - rbase - base, nid,
> - flags);
> +
> + if ((type->cnt >= type->max) &&
> + (memblock_double_array(type, obase, size) < 0))
if ((type->cnt >= type->max) &&
memblock_double_array(type, obase, size))
would be just fine.
I'd appreciate a comment above the if statement explaining when the
allocation is required.
> + return -ENOMEM;
> +
> + memblock_insert_region(type, idx++, base,
> + rbase - base, nid,
> + flags);
> }
> /* area below @rend is dealt with, forget about it */
> base = min(rend, end);
> @@ -647,28 +634,19 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
> /* insert the remaining portion */
> if (base < end) {
> nr_new++;
> - if (insert)
> - memblock_insert_region(type, idx, base, end - base,
> - nid, flags);
> + if ((type->cnt >= type->max) &&
> + (memblock_double_array(type, obase, size) < 0))
> + return -ENOMEM;
> +
> + memblock_insert_region(type, idx, base, end - base,
> + nid, flags);
> }
>
> if (!nr_new)
> return 0;
>
> - /*
> - * If this was the first round, resize array and repeat for actual
> - * insertions; otherwise, merge and return.
> - */
> - if (!insert) {
> - while (type->cnt + nr_new > type->max)
> - if (memblock_double_array(type, obase, size) < 0)
> - return -ENOMEM;
> - insert = true;
> - goto repeat;
> - } else {
> - memblock_merge_regions(type);
> - return 0;
> - }
> + memblock_merge_regions(type);
A blank line here would be nice.
> + return 0;
> }
>
> /**
> --
> 2.25.1
>
>
--
Sincerely yours,
Mike.
October 25, 2022 12:15 AM, "Mike Rapoport" <[email protected]> wrote:
> Hi,
>
> On Wed, Oct 19, 2022 at 08:03:37PM +0800, Yajun Deng wrote:
>
>> Subject: memblock: remove repeat round
>
> Please make the patch subject more detailed. Say
>
> membloc: don't run loop in memblock_add_range() twice
>
Okay!
>> There is no need round twice in memblock_add_range().
>>
>> We can call memblock_double_array() to extand the size if type->cnt no
>
> ^ extend
>
>> less than type->max before memblock_insert_region(), otherwise we can
>
> s/no less than/greater or equal to/
>
Got it.
>> insert the new region directly.
>>
>> Signed-off-by: Yajun Deng <[email protected]>
>> ---
>> mm/memblock.c | 54 +++++++++++++++------------------------------------
>> 1 file changed, 16 insertions(+), 38 deletions(-)
>>
>> diff --git a/mm/memblock.c b/mm/memblock.c
>> index 511d4783dcf1..1679244b4a1a 100644
>> --- a/mm/memblock.c
>> +++ b/mm/memblock.c
>> @@ -578,7 +578,6 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
>> phys_addr_t base, phys_addr_t size,
>> int nid, enum memblock_flags flags)
>> {
>> - bool insert = false;
>> phys_addr_t obase = base;
>> phys_addr_t end = base + memblock_cap_size(base, &size);
>> int idx, nr_new;
>> @@ -598,22 +597,6 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
>> return 0;
>> }
>>
>> - /*
>> - * The worst case is when new range overlaps all existing regions,
>> - * then we'll need type->cnt + 1 empty regions in @type. So if
>> - * type->cnt * 2 + 1 is less than type->max, we know
>> - * that there is enough empty regions in @type, and we can insert
>> - * regions directly.
>> - */
>> - if (type->cnt * 2 + 1 < type->max)
>> - insert = true;
>> -
>> -repeat:
>> - /*
>> - * The following is executed twice. Once with %false @insert and
>> - * then with %true. The first counts the number of regions needed
>> - * to accommodate the new area. The second actually inserts them.
>> - */
>> base = obase;
>> nr_new = 0;
>
> I believe nr_new variable is no longer needed, is it?
>
No, nr_new is needed before memblock_merge_regions() for return.
>> @@ -635,10 +618,14 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
>> #endif
>> WARN_ON(flags != rgn->flags);
>> nr_new++;
>> - if (insert)
>> - memblock_insert_region(type, idx++, base,
>> - rbase - base, nid,
>> - flags);
>> +
>> + if ((type->cnt >= type->max) &&
>> + (memblock_double_array(type, obase, size) < 0))
>
> if ((type->cnt >= type->max) &&
> memblock_double_array(type, obase, size))
>
> would be just fine.
>
> I'd appreciate a comment above the if statement explaining when the
> allocation is required.
>
Got it.
>> + return -ENOMEM;
>> +
>> + memblock_insert_region(type, idx++, base,
>> + rbase - base, nid,
>> + flags);
>> }
>> /* area below @rend is dealt with, forget about it */
>> base = min(rend, end);
>> @@ -647,28 +634,19 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
>> /* insert the remaining portion */
>> if (base < end) {
>> nr_new++;
>> - if (insert)
>> - memblock_insert_region(type, idx, base, end - base,
>> - nid, flags);
>> + if ((type->cnt >= type->max) &&
>> + (memblock_double_array(type, obase, size) < 0))
>> + return -ENOMEM;
>> +
>> + memblock_insert_region(type, idx, base, end - base,
>> + nid, flags);
>> }
>>
>> if (!nr_new)
>> return 0;
>>
>> - /*
>> - * If this was the first round, resize array and repeat for actual
>> - * insertions; otherwise, merge and return.
>> - */
>> - if (!insert) {
>> - while (type->cnt + nr_new > type->max)
>> - if (memblock_double_array(type, obase, size) < 0)
>> - return -ENOMEM;
>> - insert = true;
>> - goto repeat;
>> - } else {
>> - memblock_merge_regions(type);
>> - return 0;
>> - }
>> + memblock_merge_regions(type);
>
> A blank line here would be nice.
>
Got it.
>> + return 0;
>> }
>>
>> /**
>> --
>> 2.25.1
>
> --
> Sincerely yours,
> Mike.
On Tue, Oct 25, 2022 at 03:24:58AM +0000, Yajun Deng wrote:
> October 25, 2022 12:15 AM, "Mike Rapoport" <[email protected]> wrote:
>
> >> @@ -598,22 +597,6 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
> >> return 0;
> >> }
> >>
> >> - /*
> >> - * The worst case is when new range overlaps all existing regions,
> >> - * then we'll need type->cnt + 1 empty regions in @type. So if
> >> - * type->cnt * 2 + 1 is less than type->max, we know
> >> - * that there is enough empty regions in @type, and we can insert
> >> - * regions directly.
> >> - */
> >> - if (type->cnt * 2 + 1 < type->max)
> >> - insert = true;
> >> -
> >> -repeat:
> >> - /*
> >> - * The following is executed twice. Once with %false @insert and
> >> - * then with %true. The first counts the number of regions needed
> >> - * to accommodate the new area. The second actually inserts them.
> >> - */
> >> base = obase;
> >> nr_new = 0;
> >
> > I believe nr_new variable is no longer needed, is it?
> >
> No, nr_new is needed before memblock_merge_regions() for return.
Why?
--
Sincerely yours,
Mike.
October 26, 2022 2:04 PM, "Mike Rapoport" <[email protected]> wrote:
> On Tue, Oct 25, 2022 at 03:24:58AM +0000, Yajun Deng wrote:
>
>> October 25, 2022 12:15 AM, "Mike Rapoport" <[email protected]> wrote:
>>
>> @@ -598,22 +597,6 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
>> return 0;
>> }
>>
>> - /*
>> - * The worst case is when new range overlaps all existing regions,
>> - * then we'll need type->cnt + 1 empty regions in @type. So if
>> - * type->cnt * 2 + 1 is less than type->max, we know
>> - * that there is enough empty regions in @type, and we can insert
>> - * regions directly.
>> - */
>> - if (type->cnt * 2 + 1 < type->max)
>> - insert = true;
>> -
>> -repeat:
>> - /*
>> - * The following is executed twice. Once with %false @insert and
>> - * then with %true. The first counts the number of regions needed
>> - * to accommodate the new area. The second actually inserts them.
>> - */
>> base = obase;
>> nr_new = 0;
>>
>> I believe nr_new variable is no longer needed, is it?
>>
>> No, nr_new is needed before memblock_merge_regions() for return.
>
> Why?
>
Sorry, nr_new was removed, and added ocnt variable for the original of type->cnt.
I already sent another patch with '[PATCH v2] memblock: don't run loop in
memblock_add_range() twice' subject, you can see that.
> --
> Sincerely yours,
> Mike.