* [PATCH 0/2] Reorderings in struct shrinker and struct shrink_control
@ 2018-07-19 10:51 Kirill Tkhai
2018-07-19 10:51 ` [PATCH 1/2] mm: Keep int fields in struct shrink_control together Kirill Tkhai
2018-07-19 10:51 ` [PATCH 2/2] mm: Make flags of unsigned type in struct shrinker Kirill Tkhai
0 siblings, 2 replies; 6+ messages in thread
From: Kirill Tkhai @ 2018-07-19 10:51 UTC (permalink / raw)
To: akpm, vdavydov.dev, penguin-kernel, chris, gregkh, linux-kernel, ktkhai
These structures are intensively used during reclaim and,
displace other data in cache, so there is no a reason they
have int fields not grouped together.
---
Kirill Tkhai (2):
mm: Keep int fields in struct shrink_control together
mm: Make flags of unsigned type in struct shrinker
include/linux/shrinker.h | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
--
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH 1/2] mm: Keep int fields in struct shrink_control together
2018-07-19 10:51 [PATCH 0/2] Reorderings in struct shrinker and struct shrink_control Kirill Tkhai
@ 2018-07-19 10:51 ` Kirill Tkhai
2018-07-19 11:10 ` Michal Hocko
2018-07-19 10:51 ` [PATCH 2/2] mm: Make flags of unsigned type in struct shrinker Kirill Tkhai
1 sibling, 1 reply; 6+ messages in thread
From: Kirill Tkhai @ 2018-07-19 10:51 UTC (permalink / raw)
To: akpm, vdavydov.dev, penguin-kernel, chris, gregkh, linux-kernel, ktkhai
gfp_t is of unsigned type, so let's move nid to keep
them together.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
---
include/linux/shrinker.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h
index b154fd2b084c..d58aaaed34a4 100644
--- a/include/linux/shrinker.h
+++ b/include/linux/shrinker.h
@@ -12,6 +12,9 @@
struct shrink_control {
gfp_t gfp_mask;
+ /* current node being shrunk (for NUMA aware shrinkers) */
+ int nid;
+
/*
* How many objects scan_objects should scan and try to reclaim.
* This is reset before every call, so it is safe for callees
@@ -26,9 +29,6 @@ struct shrink_control {
*/
unsigned long nr_scanned;
- /* current node being shrunk (for NUMA aware shrinkers) */
- int nid;
-
/* current memcg being shrunk (for memcg aware shrinkers) */
struct mem_cgroup *memcg;
};
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH 1/2] mm: Keep int fields in struct shrink_control together
2018-07-19 10:51 ` [PATCH 1/2] mm: Keep int fields in struct shrink_control together Kirill Tkhai
@ 2018-07-19 11:10 ` Michal Hocko
2018-07-19 11:14 ` Kirill Tkhai
0 siblings, 1 reply; 6+ messages in thread
From: Michal Hocko @ 2018-07-19 11:10 UTC (permalink / raw)
To: Kirill Tkhai
Cc: akpm, vdavydov.dev, penguin-kernel, chris, gregkh, linux-kernel
On Thu 19-07-18 13:51:19, Kirill Tkhai wrote:
> gfp_t is of unsigned type, so let's move nid to keep
> them together.
I guess you meant unsigned int so you can fill up a hole in
shrink_control and as such reduce the stack consumption a bit (at least
on 64b).
An output from pahole is usually a great tool to visualize this.
die__process_function: tag not supported (INVALID)!
struct shrink_control {
gfp_t gfp_mask; /* 0 4 */
/* XXX 4 bytes hole, try to pack */
long unsigned int nr_to_scan; /* 8 8 */
long unsigned int nr_scanned; /* 16 8 */
int nid; /* 24 4 */
/* XXX 4 bytes hole, try to pack */
struct mem_cgroup * memcg; /* 32 8 */
/* size: 40, cachelines: 1, members: 5 */
/* sum members: 32, holes: 2, sum holes: 8 */
/* last cacheline: 40 bytes */
};
>
> Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
> ---
> include/linux/shrinker.h | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h
> index b154fd2b084c..d58aaaed34a4 100644
> --- a/include/linux/shrinker.h
> +++ b/include/linux/shrinker.h
> @@ -12,6 +12,9 @@
> struct shrink_control {
> gfp_t gfp_mask;
>
> + /* current node being shrunk (for NUMA aware shrinkers) */
> + int nid;
> +
> /*
> * How many objects scan_objects should scan and try to reclaim.
> * This is reset before every call, so it is safe for callees
> @@ -26,9 +29,6 @@ struct shrink_control {
> */
> unsigned long nr_scanned;
>
> - /* current node being shrunk (for NUMA aware shrinkers) */
> - int nid;
> -
> /* current memcg being shrunk (for memcg aware shrinkers) */
> struct mem_cgroup *memcg;
> };
--
Michal Hocko
SUSE Labs
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH 1/2] mm: Keep int fields in struct shrink_control together
2018-07-19 11:10 ` Michal Hocko
@ 2018-07-19 11:14 ` Kirill Tkhai
0 siblings, 0 replies; 6+ messages in thread
From: Kirill Tkhai @ 2018-07-19 11:14 UTC (permalink / raw)
To: Michal Hocko
Cc: akpm, vdavydov.dev, penguin-kernel, chris, gregkh, linux-kernel
On 19.07.2018 14:10, Michal Hocko wrote:
> On Thu 19-07-18 13:51:19, Kirill Tkhai wrote:
>> gfp_t is of unsigned type, so let's move nid to keep
>> them together.
>
> I guess you meant unsigned int so you can fill up a hole in
> shrink_control and as such reduce the stack consumption a bit (at least
> on 64b).
Yes, I mean unsigned as synonym of unsigned int and this is the reason :)
> An output from pahole is usually a great tool to visualize this.
>
> die__process_function: tag not supported (INVALID)!
> struct shrink_control {
> gfp_t gfp_mask; /* 0 4 */
>
> /* XXX 4 bytes hole, try to pack */
>
> long unsigned int nr_to_scan; /* 8 8 */
> long unsigned int nr_scanned; /* 16 8 */
> int nid; /* 24 4 */
>
> /* XXX 4 bytes hole, try to pack */
>
> struct mem_cgroup * memcg; /* 32 8 */
>
> /* size: 40, cachelines: 1, members: 5 */
> /* sum members: 32, holes: 2, sum holes: 8 */
> /* last cacheline: 40 bytes */
> };
>>>
>> Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
>
> Acked-by: Michal Hocko <mhocko@suse.com>
>
>> ---
>> include/linux/shrinker.h | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h
>> index b154fd2b084c..d58aaaed34a4 100644
>> --- a/include/linux/shrinker.h
>> +++ b/include/linux/shrinker.h
>> @@ -12,6 +12,9 @@
>> struct shrink_control {
>> gfp_t gfp_mask;
>>
>> + /* current node being shrunk (for NUMA aware shrinkers) */
>> + int nid;
>> +
>> /*
>> * How many objects scan_objects should scan and try to reclaim.
>> * This is reset before every call, so it is safe for callees
>> @@ -26,9 +29,6 @@ struct shrink_control {
>> */
>> unsigned long nr_scanned;
>>
>> - /* current node being shrunk (for NUMA aware shrinkers) */
>> - int nid;
>> -
>> /* current memcg being shrunk (for memcg aware shrinkers) */
>> struct mem_cgroup *memcg;
>> };
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 2/2] mm: Make flags of unsigned type in struct shrinker
2018-07-19 10:51 [PATCH 0/2] Reorderings in struct shrinker and struct shrink_control Kirill Tkhai
2018-07-19 10:51 ` [PATCH 1/2] mm: Keep int fields in struct shrink_control together Kirill Tkhai
@ 2018-07-19 10:51 ` Kirill Tkhai
2018-07-19 11:14 ` Michal Hocko
1 sibling, 1 reply; 6+ messages in thread
From: Kirill Tkhai @ 2018-07-19 10:51 UTC (permalink / raw)
To: akpm, vdavydov.dev, penguin-kernel, chris, gregkh, linux-kernel, ktkhai
Currently, there are two flags only, so unsigned
is more then enough. Also, move int seeks to keep
these fields together.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
---
include/linux/shrinker.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h
index d58aaaed34a4..9443cafd1969 100644
--- a/include/linux/shrinker.h
+++ b/include/linux/shrinker.h
@@ -63,9 +63,9 @@ struct shrinker {
unsigned long (*scan_objects)(struct shrinker *,
struct shrink_control *sc);
- int seeks; /* seeks to recreate an obj */
long batch; /* reclaim batch size, 0 = default */
- unsigned long flags;
+ int seeks; /* seeks to recreate an obj */
+ unsigned flags;
/* These are for internal use */
struct list_head list;
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH 2/2] mm: Make flags of unsigned type in struct shrinker
2018-07-19 10:51 ` [PATCH 2/2] mm: Make flags of unsigned type in struct shrinker Kirill Tkhai
@ 2018-07-19 11:14 ` Michal Hocko
0 siblings, 0 replies; 6+ messages in thread
From: Michal Hocko @ 2018-07-19 11:14 UTC (permalink / raw)
To: Kirill Tkhai
Cc: akpm, vdavydov.dev, penguin-kernel, chris, gregkh, linux-kernel
On Thu 19-07-18 13:51:27, Kirill Tkhai wrote:
> Currently, there are two flags only, so unsigned
> is more then enough. Also, move int seeks to keep
> these fields together.
a slightly more explanation _why_ would be really helpful. I suspect
this is to pack the structure better,
struct shrinker {
long unsigned int (*count_objects)(struct shrinker *, struct shrink_control *); /* 0 8 */
long unsigned int (*scan_objects)(struct shrinker *, struct shrink_control *); /* 8 8 */
int seeks; /* 16 4 */
/* XXX 4 bytes hole, try to pack */
long int batch; /* 24 8 */
long unsigned int flags; /* 32 8 */
struct list_head list; /* 40 16 */
atomic_long_t * nr_deferred; /* 56 8 */
/* --- cacheline 1 boundary (64 bytes) --- */
/* size: 64, cachelines: 1, members: 7 */
/* sum members: 60, holes: 1, sum holes: 4 */
};
suggests so. Which is a good thing.
> Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
other than that looks reasonable to me
Acked-by: Michal Hocko <mhocko@suse.com>
> ---
> include/linux/shrinker.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h
> index d58aaaed34a4..9443cafd1969 100644
> --- a/include/linux/shrinker.h
> +++ b/include/linux/shrinker.h
> @@ -63,9 +63,9 @@ struct shrinker {
> unsigned long (*scan_objects)(struct shrinker *,
> struct shrink_control *sc);
>
> - int seeks; /* seeks to recreate an obj */
> long batch; /* reclaim batch size, 0 = default */
> - unsigned long flags;
> + int seeks; /* seeks to recreate an obj */
> + unsigned flags;
>
> /* These are for internal use */
> struct list_head list;
--
Michal Hocko
SUSE Labs
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2018-07-19 11:15 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2018-07-19 10:51 [PATCH 0/2] Reorderings in struct shrinker and struct shrink_control Kirill Tkhai
2018-07-19 10:51 ` [PATCH 1/2] mm: Keep int fields in struct shrink_control together Kirill Tkhai
2018-07-19 11:10 ` Michal Hocko
2018-07-19 11:14 ` Kirill Tkhai
2018-07-19 10:51 ` [PATCH 2/2] mm: Make flags of unsigned type in struct shrinker Kirill Tkhai
2018-07-19 11:14 ` Michal Hocko
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