2017-06-01 23:02:18

by Yu Zhao

[permalink] [raw]
Subject: [PATCH] memcg: refactor mem_cgroup_resize_limit()

mem_cgroup_resize_limit() and mem_cgroup_resize_memsw_limit() have
identical logics. Refactor code so we don't need to keep two pieces
of code that does same thing.

Signed-off-by: Yu Zhao <[email protected]>
---
mm/memcontrol.c | 71 +++++++++------------------------------------------------
1 file changed, 11 insertions(+), 60 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 94172089f52f..a4f0daaff704 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2422,13 +2422,14 @@ static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
static DEFINE_MUTEX(memcg_limit_mutex);

static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
- unsigned long limit)
+ unsigned long limit, bool memsw)
{
unsigned long curusage;
unsigned long oldusage;
bool enlarge = false;
int retry_count;
int ret;
+ struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;

/*
* For keeping hierarchical_reclaim simple, how long we should retry
@@ -2438,58 +2439,7 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
retry_count = MEM_CGROUP_RECLAIM_RETRIES *
mem_cgroup_count_children(memcg);

- oldusage = page_counter_read(&memcg->memory);
-
- do {
- if (signal_pending(current)) {
- ret = -EINTR;
- break;
- }
-
- mutex_lock(&memcg_limit_mutex);
- if (limit > memcg->memsw.limit) {
- mutex_unlock(&memcg_limit_mutex);
- ret = -EINVAL;
- break;
- }
- if (limit > memcg->memory.limit)
- enlarge = true;
- ret = page_counter_limit(&memcg->memory, limit);
- mutex_unlock(&memcg_limit_mutex);
-
- if (!ret)
- break;
-
- try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, true);
-
- curusage = page_counter_read(&memcg->memory);
- /* Usage is reduced ? */
- if (curusage >= oldusage)
- retry_count--;
- else
- oldusage = curusage;
- } while (retry_count);
-
- if (!ret && enlarge)
- memcg_oom_recover(memcg);
-
- return ret;
-}
-
-static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
- unsigned long limit)
-{
- unsigned long curusage;
- unsigned long oldusage;
- bool enlarge = false;
- int retry_count;
- int ret;
-
- /* see mem_cgroup_resize_res_limit */
- retry_count = MEM_CGROUP_RECLAIM_RETRIES *
- mem_cgroup_count_children(memcg);
-
- oldusage = page_counter_read(&memcg->memsw);
+ oldusage = page_counter_read(counter);

do {
if (signal_pending(current)) {
@@ -2498,22 +2448,23 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
}

mutex_lock(&memcg_limit_mutex);
- if (limit < memcg->memory.limit) {
+ if (memsw ? limit < memcg->memory.limit :
+ limit > memcg->memsw.limit) {
mutex_unlock(&memcg_limit_mutex);
ret = -EINVAL;
break;
}
- if (limit > memcg->memsw.limit)
+ if (limit > counter->limit)
enlarge = true;
- ret = page_counter_limit(&memcg->memsw, limit);
+ ret = page_counter_limit(counter, limit);
mutex_unlock(&memcg_limit_mutex);

if (!ret)
break;

- try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, false);
+ try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, !memsw);

- curusage = page_counter_read(&memcg->memsw);
+ curusage = page_counter_read(counter);
/* Usage is reduced ? */
if (curusage >= oldusage)
retry_count--;
@@ -2975,10 +2926,10 @@ static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
}
switch (MEMFILE_TYPE(of_cft(of)->private)) {
case _MEM:
- ret = mem_cgroup_resize_limit(memcg, nr_pages);
+ ret = mem_cgroup_resize_limit(memcg, nr_pages, false);
break;
case _MEMSWAP:
- ret = mem_cgroup_resize_memsw_limit(memcg, nr_pages);
+ ret = mem_cgroup_resize_limit(memcg, nr_pages, true);
break;
case _KMEM:
ret = memcg_update_kmem_limit(memcg, nr_pages);
--
2.13.0.506.g27d5fe0cd-goog


2017-06-02 07:32:59

by Nikolay Borisov

[permalink] [raw]
Subject: Re: [PATCH] memcg: refactor mem_cgroup_resize_limit()



On 2.06.2017 02:02, Yu Zhao wrote:
> mem_cgroup_resize_limit() and mem_cgroup_resize_memsw_limit() have
> identical logics. Refactor code so we don't need to keep two pieces
> of code that does same thing.
>
> Signed-off-by: Yu Zhao <[email protected]>
> ---
> mm/memcontrol.c | 71 +++++++++------------------------------------------------
> 1 file changed, 11 insertions(+), 60 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 94172089f52f..a4f0daaff704 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2422,13 +2422,14 @@ static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
> static DEFINE_MUTEX(memcg_limit_mutex);
>
> static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
> - unsigned long limit)
> + unsigned long limit, bool memsw)
> {
> unsigned long curusage;
> unsigned long oldusage;
> bool enlarge = false;
> int retry_count;
> int ret;
> + struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;
>
> /*
> * For keeping hierarchical_reclaim simple, how long we should retry
> @@ -2438,58 +2439,7 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
> retry_count = MEM_CGROUP_RECLAIM_RETRIES *
> mem_cgroup_count_children(memcg);
>
> - oldusage = page_counter_read(&memcg->memory);
> -
> - do {
> - if (signal_pending(current)) {
> - ret = -EINTR;
> - break;
> - }
> -
> - mutex_lock(&memcg_limit_mutex);
> - if (limit > memcg->memsw.limit) {
> - mutex_unlock(&memcg_limit_mutex);
> - ret = -EINVAL;
> - break;
> - }
> - if (limit > memcg->memory.limit)
> - enlarge = true;
> - ret = page_counter_limit(&memcg->memory, limit);
> - mutex_unlock(&memcg_limit_mutex);
> -
> - if (!ret)
> - break;
> -
> - try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, true);
> -
> - curusage = page_counter_read(&memcg->memory);
> - /* Usage is reduced ? */
> - if (curusage >= oldusage)
> - retry_count--;
> - else
> - oldusage = curusage;
> - } while (retry_count);
> -
> - if (!ret && enlarge)
> - memcg_oom_recover(memcg);
> -
> - return ret;
> -}
> -
> -static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
> - unsigned long limit)
> -{
> - unsigned long curusage;
> - unsigned long oldusage;
> - bool enlarge = false;
> - int retry_count;
> - int ret;
> -
> - /* see mem_cgroup_resize_res_limit */
> - retry_count = MEM_CGROUP_RECLAIM_RETRIES *
> - mem_cgroup_count_children(memcg);
> -
> - oldusage = page_counter_read(&memcg->memsw);
> + oldusage = page_counter_read(counter);
>
> do {
> if (signal_pending(current)) {
> @@ -2498,22 +2448,23 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
> }
>
> mutex_lock(&memcg_limit_mutex);
> - if (limit < memcg->memory.limit) {
> + if (memsw ? limit < memcg->memory.limit :
> + limit > memcg->memsw.limit) {

No, just no. Please createa a local variable and use that. Using the
ternary operator in an 'if' statement is just ugly!

> mutex_unlock(&memcg_limit_mutex);
> ret = -EINVAL;
> break;
> }
> - if (limit > memcg->memsw.limit)
> + if (limit > counter->limit)
> enlarge = true;
> - ret = page_counter_limit(&memcg->memsw, limit);
> + ret = page_counter_limit(counter, limit);
> mutex_unlock(&memcg_limit_mutex);
>
> if (!ret)
> break;
>
> - try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, false);
> + try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, !memsw);
>
> - curusage = page_counter_read(&memcg->memsw);
> + curusage = page_counter_read(counter);
> /* Usage is reduced ? */
> if (curusage >= oldusage)
> retry_count--;
> @@ -2975,10 +2926,10 @@ static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
> }
> switch (MEMFILE_TYPE(of_cft(of)->private)) {
> case _MEM:
> - ret = mem_cgroup_resize_limit(memcg, nr_pages);
> + ret = mem_cgroup_resize_limit(memcg, nr_pages, false);
> break;
> case _MEMSWAP:
> - ret = mem_cgroup_resize_memsw_limit(memcg, nr_pages);
> + ret = mem_cgroup_resize_limit(memcg, nr_pages, true);
> break;
> case _KMEM:
> ret = memcg_update_kmem_limit(memcg, nr_pages);
>

2017-06-03 15:15:16

by Vladimir Davydov

[permalink] [raw]
Subject: Re: [PATCH] memcg: refactor mem_cgroup_resize_limit()

On Thu, Jun 01, 2017 at 04:02:12PM -0700, Yu Zhao wrote:
> mem_cgroup_resize_limit() and mem_cgroup_resize_memsw_limit() have
> identical logics. Refactor code so we don't need to keep two pieces
> of code that does same thing.
>
> Signed-off-by: Yu Zhao <[email protected]>
> ---
> mm/memcontrol.c | 71 +++++++++------------------------------------------------
> 1 file changed, 11 insertions(+), 60 deletions(-)

Makes sense to me.

Acked-by: Vladimir Davydov <[email protected]>

2017-06-04 19:44:21

by Yu Zhao

[permalink] [raw]
Subject: Re: [PATCH] memcg: refactor mem_cgroup_resize_limit()

On Fri, Jun 02, 2017 at 10:32:52AM +0300, Nikolay Borisov wrote:
>
>
> On 2.06.2017 02:02, Yu Zhao wrote:
> > mem_cgroup_resize_limit() and mem_cgroup_resize_memsw_limit() have
> > identical logics. Refactor code so we don't need to keep two pieces
> > of code that does same thing.
> >
> > Signed-off-by: Yu Zhao <[email protected]>
> > ---
> > mm/memcontrol.c | 71 +++++++++------------------------------------------------
> > 1 file changed, 11 insertions(+), 60 deletions(-)
> >
> > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> > index 94172089f52f..a4f0daaff704 100644
> > --- a/mm/memcontrol.c
> > +++ b/mm/memcontrol.c
> > @@ -2422,13 +2422,14 @@ static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
> > static DEFINE_MUTEX(memcg_limit_mutex);
> >
> > static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
> > - unsigned long limit)
> > + unsigned long limit, bool memsw)
> > {
> > unsigned long curusage;
> > unsigned long oldusage;
> > bool enlarge = false;
> > int retry_count;
> > int ret;
> > + struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;
> >
> > /*
> > * For keeping hierarchical_reclaim simple, how long we should retry
> > @@ -2438,58 +2439,7 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
> > retry_count = MEM_CGROUP_RECLAIM_RETRIES *
> > mem_cgroup_count_children(memcg);
> >
> > - oldusage = page_counter_read(&memcg->memory);
> > -
> > - do {
> > - if (signal_pending(current)) {
> > - ret = -EINTR;
> > - break;
> > - }
> > -
> > - mutex_lock(&memcg_limit_mutex);
> > - if (limit > memcg->memsw.limit) {
> > - mutex_unlock(&memcg_limit_mutex);
> > - ret = -EINVAL;
> > - break;
> > - }
> > - if (limit > memcg->memory.limit)
> > - enlarge = true;
> > - ret = page_counter_limit(&memcg->memory, limit);
> > - mutex_unlock(&memcg_limit_mutex);
> > -
> > - if (!ret)
> > - break;
> > -
> > - try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, true);
> > -
> > - curusage = page_counter_read(&memcg->memory);
> > - /* Usage is reduced ? */
> > - if (curusage >= oldusage)
> > - retry_count--;
> > - else
> > - oldusage = curusage;
> > - } while (retry_count);
> > -
> > - if (!ret && enlarge)
> > - memcg_oom_recover(memcg);
> > -
> > - return ret;
> > -}
> > -
> > -static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
> > - unsigned long limit)
> > -{
> > - unsigned long curusage;
> > - unsigned long oldusage;
> > - bool enlarge = false;
> > - int retry_count;
> > - int ret;
> > -
> > - /* see mem_cgroup_resize_res_limit */
> > - retry_count = MEM_CGROUP_RECLAIM_RETRIES *
> > - mem_cgroup_count_children(memcg);
> > -
> > - oldusage = page_counter_read(&memcg->memsw);
> > + oldusage = page_counter_read(counter);
> >
> > do {
> > if (signal_pending(current)) {
> > @@ -2498,22 +2448,23 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
> > }
> >
> > mutex_lock(&memcg_limit_mutex);
> > - if (limit < memcg->memory.limit) {
> > + if (memsw ? limit < memcg->memory.limit :
> > + limit > memcg->memsw.limit) {
>
> No, just no. Please createa a local variable and use that. Using the
> ternary operator in an 'if' statement is just ugly!

Thanks. It is uncommon but seems no aesthetic difference to me. I'll
replace it with an extra variable and resend the patch.

2017-06-04 20:04:55

by Yu Zhao

[permalink] [raw]
Subject: [PATCH v2] memcg: refactor mem_cgroup_resize_limit()

mem_cgroup_resize_limit() and mem_cgroup_resize_memsw_limit() have
identical logics. Refactor code so we don't need to keep two pieces
of code that does same thing.

Signed-off-by: Yu Zhao <[email protected]>
Acked-by: Vladimir Davydov <[email protected]>
---
Changelog since v1:
* minor style change

mm/memcontrol.c | 73 ++++++++++-----------------------------------------------
1 file changed, 13 insertions(+), 60 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 94172089f52f..08a97a381b2a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2422,13 +2422,15 @@ static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
static DEFINE_MUTEX(memcg_limit_mutex);

static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
- unsigned long limit)
+ unsigned long limit, bool memsw)
{
unsigned long curusage;
unsigned long oldusage;
bool enlarge = false;
int retry_count;
int ret;
+ bool inverted;
+ struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;

/*
* For keeping hierarchical_reclaim simple, how long we should retry
@@ -2438,58 +2440,7 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
retry_count = MEM_CGROUP_RECLAIM_RETRIES *
mem_cgroup_count_children(memcg);

- oldusage = page_counter_read(&memcg->memory);
-
- do {
- if (signal_pending(current)) {
- ret = -EINTR;
- break;
- }
-
- mutex_lock(&memcg_limit_mutex);
- if (limit > memcg->memsw.limit) {
- mutex_unlock(&memcg_limit_mutex);
- ret = -EINVAL;
- break;
- }
- if (limit > memcg->memory.limit)
- enlarge = true;
- ret = page_counter_limit(&memcg->memory, limit);
- mutex_unlock(&memcg_limit_mutex);
-
- if (!ret)
- break;
-
- try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, true);
-
- curusage = page_counter_read(&memcg->memory);
- /* Usage is reduced ? */
- if (curusage >= oldusage)
- retry_count--;
- else
- oldusage = curusage;
- } while (retry_count);
-
- if (!ret && enlarge)
- memcg_oom_recover(memcg);
-
- return ret;
-}
-
-static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
- unsigned long limit)
-{
- unsigned long curusage;
- unsigned long oldusage;
- bool enlarge = false;
- int retry_count;
- int ret;
-
- /* see mem_cgroup_resize_res_limit */
- retry_count = MEM_CGROUP_RECLAIM_RETRIES *
- mem_cgroup_count_children(memcg);
-
- oldusage = page_counter_read(&memcg->memsw);
+ oldusage = page_counter_read(counter);

do {
if (signal_pending(current)) {
@@ -2498,22 +2449,24 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
}

mutex_lock(&memcg_limit_mutex);
- if (limit < memcg->memory.limit) {
+ inverted = memsw ? limit < memcg->memory.limit :
+ limit > memcg->memsw.limit;
+ if (inverted)
mutex_unlock(&memcg_limit_mutex);
ret = -EINVAL;
break;
}
- if (limit > memcg->memsw.limit)
+ if (limit > counter->limit)
enlarge = true;
- ret = page_counter_limit(&memcg->memsw, limit);
+ ret = page_counter_limit(counter, limit);
mutex_unlock(&memcg_limit_mutex);

if (!ret)
break;

- try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, false);
+ try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, !memsw);

- curusage = page_counter_read(&memcg->memsw);
+ curusage = page_counter_read(counter);
/* Usage is reduced ? */
if (curusage >= oldusage)
retry_count--;
@@ -2975,10 +2928,10 @@ static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
}
switch (MEMFILE_TYPE(of_cft(of)->private)) {
case _MEM:
- ret = mem_cgroup_resize_limit(memcg, nr_pages);
+ ret = mem_cgroup_resize_limit(memcg, nr_pages, false);
break;
case _MEMSWAP:
- ret = mem_cgroup_resize_memsw_limit(memcg, nr_pages);
+ ret = mem_cgroup_resize_limit(memcg, nr_pages, true);
break;
case _KMEM:
ret = memcg_update_kmem_limit(memcg, nr_pages);
--
2.13.0.506.g27d5fe0cd-goog

2017-06-04 20:10:00

by Vladimir Davydov

[permalink] [raw]
Subject: Re: [PATCH v2] memcg: refactor mem_cgroup_resize_limit()

On Sun, Jun 04, 2017 at 01:04:37PM -0700, Yu Zhao wrote:
> @@ -2498,22 +2449,24 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
> }
>
> mutex_lock(&memcg_limit_mutex);
> - if (limit < memcg->memory.limit) {
> + inverted = memsw ? limit < memcg->memory.limit :
> + limit > memcg->memsw.limit;
> + if (inverted)
> mutex_unlock(&memcg_limit_mutex);
> ret = -EINVAL;
> break;
> }

For some reason, I liked this patch more without this extra variable :-)

2017-06-04 20:31:26

by Yu Zhao

[permalink] [raw]
Subject: Re: [PATCH v2] memcg: refactor mem_cgroup_resize_limit()

On Sun, Jun 04, 2017 at 11:09:42PM +0300, Vladimir Davydov wrote:
> On Sun, Jun 04, 2017 at 01:04:37PM -0700, Yu Zhao wrote:
> > @@ -2498,22 +2449,24 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
> > }
> >
> > mutex_lock(&memcg_limit_mutex);
> > - if (limit < memcg->memory.limit) {
> > + inverted = memsw ? limit < memcg->memory.limit :
> > + limit > memcg->memsw.limit;
> > + if (inverted)
> > mutex_unlock(&memcg_limit_mutex);
> > ret = -EINVAL;
> > break;
> > }
>
> For some reason, I liked this patch more without this extra variable :-)
Well, I'll refrain myself from commenting more because we are now at
the risk of starting a coding style war over this.

2017-06-04 21:00:56

by kernel test robot

[permalink] [raw]
Subject: Re: [PATCH v2] memcg: refactor mem_cgroup_resize_limit()

Hi Yu,

[auto build test ERROR on mmotm/master]
[also build test ERROR on v4.12-rc3 next-20170602]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url: https://github.com/0day-ci/linux/commits/Yu-Zhao/memcg-refactor-mem_cgroup_resize_limit/20170605-041444
base: git://git.cmpxchg.org/linux-mmotm.git master
config: x86_64-randconfig-x002-201723 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64

All error/warnings (new ones prefixed by >>):

In file included from arch/x86/include/asm/atomic.h:4:0,
from include/linux/atomic.h:4,
from include/linux/page_counter.h:4,
from mm/memcontrol.c:34:
mm/memcontrol.c: In function 'mem_cgroup_resize_limit':
include/linux/compiler.h:156:2: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
if (__builtin_constant_p(!!(cond)) ? !!(cond) : \
^
include/linux/compiler.h:154:23: note: in expansion of macro '__trace_if'
#define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
^~~~~~~~~~
>> mm/memcontrol.c:2453:3: note: in expansion of macro 'if'
if (inverted)
^~
mm/memcontrol.c:2455:4: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
ret = -EINVAL;
^~~
In file included from arch/x86/include/asm/atomic.h:4:0,
from include/linux/atomic.h:4,
from include/linux/page_counter.h:4,
from mm/memcontrol.c:34:
>> include/linux/compiler.h:156:2: error: expected 'while' before 'if'
if (__builtin_constant_p(!!(cond)) ? !!(cond) : \
^
include/linux/compiler.h:154:23: note: in expansion of macro '__trace_if'
#define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
^~~~~~~~~~
mm/memcontrol.c:2458:3: note: in expansion of macro 'if'
if (limit > counter->limit)
^~
>> include/linux/compiler.h:170:3: error: expected statement before ')' token
}))
^
include/linux/compiler.h:154:23: note: in expansion of macro '__trace_if'
#define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
^~~~~~~~~~
mm/memcontrol.c:2458:3: note: in expansion of macro 'if'
if (limit > counter->limit)
^~
include/linux/compiler.h:170:4: error: expected statement before ')' token
}))
^
include/linux/compiler.h:154:23: note: in expansion of macro '__trace_if'
#define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
^~~~~~~~~~
mm/memcontrol.c:2458:3: note: in expansion of macro 'if'
if (limit > counter->limit)
^~
mm/memcontrol.c:2464:4: error: break statement not within loop or switch
break;
^~~~~
mm/memcontrol.c:2474:2: warning: no return statement in function returning non-void [-Wreturn-type]
} while (retry_count);
^
mm/memcontrol.c: At top level:
mm/memcontrol.c:2474:4: error: expected identifier or '(' before 'while'
} while (retry_count);
^~~~~
In file included from arch/x86/include/asm/atomic.h:4:0,
from include/linux/atomic.h:4,
from include/linux/page_counter.h:4,
from mm/memcontrol.c:34:
>> include/linux/compiler.h:156:2: error: expected identifier or '(' before 'if'
if (__builtin_constant_p(!!(cond)) ? !!(cond) : \
^
include/linux/compiler.h:154:23: note: in expansion of macro '__trace_if'
#define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
^~~~~~~~~~
mm/memcontrol.c:2476:2: note: in expansion of macro 'if'
if (!ret && enlarge)
^~
>> include/linux/compiler.h:170:3: error: expected identifier or '(' before ')' token
}))
^
include/linux/compiler.h:154:23: note: in expansion of macro '__trace_if'
#define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
^~~~~~~~~~
mm/memcontrol.c:2476:2: note: in expansion of macro 'if'
if (!ret && enlarge)
^~
mm/memcontrol.c:2479:2: error: expected identifier or '(' before 'return'
return ret;
^~~~~~
mm/memcontrol.c:2480:1: error: expected identifier or '(' before '}' token
}
^

vim +/if +2453 mm/memcontrol.c

2437 * of # of children which we should visit in this loop.
2438 */
2439 retry_count = MEM_CGROUP_RECLAIM_RETRIES *
2440 mem_cgroup_count_children(memcg);
2441
2442 oldusage = page_counter_read(counter);
2443
2444 do {
2445 if (signal_pending(current)) {
2446 ret = -EINTR;
2447 break;
2448 }
2449
2450 mutex_lock(&memcg_limit_mutex);
2451 inverted = memsw ? limit < memcg->memory.limit :
2452 limit > memcg->memsw.limit;
> 2453 if (inverted)
2454 mutex_unlock(&memcg_limit_mutex);
2455 ret = -EINVAL;
2456 break;
2457 }
2458 if (limit > counter->limit)
2459 enlarge = true;
2460 ret = page_counter_limit(counter, limit);
2461 mutex_unlock(&memcg_limit_mutex);

---
0-DAY kernel test infrastructure Open Source Technology Center
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2017-06-04 21:12:58

by kernel test robot

[permalink] [raw]
Subject: Re: [PATCH v2] memcg: refactor mem_cgroup_resize_limit()

Hi Yu,

[auto build test ERROR on mmotm/master]
[also build test ERROR on v4.12-rc3 next-20170602]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url: https://github.com/0day-ci/linux/commits/Yu-Zhao/memcg-refactor-mem_cgroup_resize_limit/20170605-041444
base: git://git.cmpxchg.org/linux-mmotm.git master
config: x86_64-randconfig-x019-201723 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64

All error/warnings (new ones prefixed by >>):

mm/memcontrol.c: In function 'mem_cgroup_resize_limit':
>> mm/memcontrol.c:2453:3: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
if (inverted)
^~
mm/memcontrol.c:2455:4: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
ret = -EINVAL;
^~~
>> mm/memcontrol.c:2458:3: error: expected 'while' before 'if'
if (limit > counter->limit)
^~
>> mm/memcontrol.c:2464:4: error: break statement not within loop or switch
break;
^~~~~
mm/memcontrol.c:2428:7: warning: unused variable 'enlarge' [-Wunused-variable]
bool enlarge = false;
^~~~~~~
>> mm/memcontrol.c:2474:2: warning: no return statement in function returning non-void [-Wreturn-type]
} while (retry_count);
^
mm/memcontrol.c: At top level:
>> mm/memcontrol.c:2474:4: error: expected identifier or '(' before 'while'
} while (retry_count);
^~~~~
>> mm/memcontrol.c:2476:2: error: expected identifier or '(' before 'if'
if (!ret && enlarge)
^~
>> mm/memcontrol.c:2479:2: error: expected identifier or '(' before 'return'
return ret;
^~~~~~
>> mm/memcontrol.c:2480:1: error: expected identifier or '(' before '}' token
}
^

vim +2458 mm/memcontrol.c

2422
2423 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
2424 unsigned long limit, bool memsw)
2425 {
2426 unsigned long curusage;
2427 unsigned long oldusage;
> 2428 bool enlarge = false;
2429 int retry_count;
2430 int ret;
2431 bool inverted;
2432 struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;
2433
2434 /*
2435 * For keeping hierarchical_reclaim simple, how long we should retry
2436 * is depends on callers. We set our retry-count to be function
2437 * of # of children which we should visit in this loop.
2438 */
2439 retry_count = MEM_CGROUP_RECLAIM_RETRIES *
2440 mem_cgroup_count_children(memcg);
2441
2442 oldusage = page_counter_read(counter);
2443
2444 do {
2445 if (signal_pending(current)) {
2446 ret = -EINTR;
2447 break;
2448 }
2449
2450 mutex_lock(&memcg_limit_mutex);
2451 inverted = memsw ? limit < memcg->memory.limit :
2452 limit > memcg->memsw.limit;
> 2453 if (inverted)
2454 mutex_unlock(&memcg_limit_mutex);
2455 ret = -EINVAL;
2456 break;
2457 }
> 2458 if (limit > counter->limit)
2459 enlarge = true;
2460 ret = page_counter_limit(counter, limit);
2461 mutex_unlock(&memcg_limit_mutex);
2462
2463 if (!ret)
> 2464 break;
2465
2466 try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, !memsw);
2467
2468 curusage = page_counter_read(counter);
2469 /* Usage is reduced ? */
2470 if (curusage >= oldusage)
2471 retry_count--;
2472 else
2473 oldusage = curusage;
> 2474 } while (retry_count);
2475
> 2476 if (!ret && enlarge)
2477 memcg_oom_recover(memcg);
2478
> 2479 return ret;
> 2480 }
2481
2482 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
2483 gfp_t gfp_mask,

---
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2017-06-04 21:18:23

by Yu Zhao

[permalink] [raw]
Subject: [PATCH v3] memcg: refactor mem_cgroup_resize_limit()

mem_cgroup_resize_limit() and mem_cgroup_resize_memsw_limit() have
identical logics. Refactor code so we don't need to keep two pieces
of code that does same thing.

Signed-off-by: Yu Zhao <[email protected]>
Acked-by: Vladimir Davydov <[email protected]>
---
Changelog since v1:
* minor style change
Changelog since v2:
* fix build error

mm/memcontrol.c | 73 ++++++++++-----------------------------------------------
1 file changed, 13 insertions(+), 60 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 94172089f52f..08a97a381b2a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2422,13 +2422,15 @@ static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
static DEFINE_MUTEX(memcg_limit_mutex);

static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
- unsigned long limit)
+ unsigned long limit, bool memsw)
{
unsigned long curusage;
unsigned long oldusage;
bool enlarge = false;
int retry_count;
int ret;
+ bool inverted;
+ struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;

/*
* For keeping hierarchical_reclaim simple, how long we should retry
@@ -2438,58 +2440,7 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
retry_count = MEM_CGROUP_RECLAIM_RETRIES *
mem_cgroup_count_children(memcg);

- oldusage = page_counter_read(&memcg->memory);
-
- do {
- if (signal_pending(current)) {
- ret = -EINTR;
- break;
- }
-
- mutex_lock(&memcg_limit_mutex);
- if (limit > memcg->memsw.limit) {
- mutex_unlock(&memcg_limit_mutex);
- ret = -EINVAL;
- break;
- }
- if (limit > memcg->memory.limit)
- enlarge = true;
- ret = page_counter_limit(&memcg->memory, limit);
- mutex_unlock(&memcg_limit_mutex);
-
- if (!ret)
- break;
-
- try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, true);
-
- curusage = page_counter_read(&memcg->memory);
- /* Usage is reduced ? */
- if (curusage >= oldusage)
- retry_count--;
- else
- oldusage = curusage;
- } while (retry_count);
-
- if (!ret && enlarge)
- memcg_oom_recover(memcg);
-
- return ret;
-}
-
-static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
- unsigned long limit)
-{
- unsigned long curusage;
- unsigned long oldusage;
- bool enlarge = false;
- int retry_count;
- int ret;
-
- /* see mem_cgroup_resize_res_limit */
- retry_count = MEM_CGROUP_RECLAIM_RETRIES *
- mem_cgroup_count_children(memcg);
-
- oldusage = page_counter_read(&memcg->memsw);
+ oldusage = page_counter_read(counter);

do {
if (signal_pending(current)) {
@@ -2498,22 +2449,24 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
}

mutex_lock(&memcg_limit_mutex);
- if (limit < memcg->memory.limit) {
+ inverted = memsw ? limit < memcg->memory.limit :
+ limit > memcg->memsw.limit;
+ if (inverted) {
mutex_unlock(&memcg_limit_mutex);
ret = -EINVAL;
break;
}
- if (limit > memcg->memsw.limit)
+ if (limit > counter->limit)
enlarge = true;
- ret = page_counter_limit(&memcg->memsw, limit);
+ ret = page_counter_limit(counter, limit);
mutex_unlock(&memcg_limit_mutex);

if (!ret)
break;

- try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, false);
+ try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, !memsw);

- curusage = page_counter_read(&memcg->memsw);
+ curusage = page_counter_read(counter);
/* Usage is reduced ? */
if (curusage >= oldusage)
retry_count--;
@@ -2975,10 +2928,10 @@ static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
}
switch (MEMFILE_TYPE(of_cft(of)->private)) {
case _MEM:
- ret = mem_cgroup_resize_limit(memcg, nr_pages);
+ ret = mem_cgroup_resize_limit(memcg, nr_pages, false);
break;
case _MEMSWAP:
- ret = mem_cgroup_resize_memsw_limit(memcg, nr_pages);
+ ret = mem_cgroup_resize_limit(memcg, nr_pages, true);
break;
case _KMEM:
ret = memcg_update_kmem_limit(memcg, nr_pages);
--
2.13.0.506.g27d5fe0cd-goog

2017-06-13 11:35:53

by Michal Hocko

[permalink] [raw]
Subject: Re: [PATCH v3] memcg: refactor mem_cgroup_resize_limit()

[Sorry for a late reponse]

On Sun 04-06-17 14:18:07, Yu Zhao wrote:
> mem_cgroup_resize_limit() and mem_cgroup_resize_memsw_limit() have
> identical logics. Refactor code so we don't need to keep two pieces
> of code that does same thing.
>
> Signed-off-by: Yu Zhao <[email protected]>
> Acked-by: Vladimir Davydov <[email protected]>

It is nice to see removal of the code duplication. I have one comment
though

[...]

> @@ -2498,22 +2449,24 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
> }
>
> mutex_lock(&memcg_limit_mutex);
> - if (limit < memcg->memory.limit) {
> + inverted = memsw ? limit < memcg->memory.limit :
> + limit > memcg->memsw.limit;
> + if (inverted) {
> mutex_unlock(&memcg_limit_mutex);
> ret = -EINVAL;
> break;
> }

This is just too ugly and hard to understand. inverted just doesn't give
you a good clue what is going on. What do you think about something like

/*
* Make sure that the new limit (memsw or hard limit) doesn't
* break our basic invariant that memory.limit <= memsw.limit
*/
limits_invariant = memsw ? limit >= memcg->memory.limit :
limit <= mmecg->memsw.limit;
if (!limits_invariant) {
mutex_unlock(&memcg_limit_mutex);
ret = -EINVAL;
break;
}

with that feel free to add
Acked-by: Michal Hocko <[email protected]>
--
Michal Hocko
SUSE Labs

2017-06-14 21:20:18

by Yu Zhao

[permalink] [raw]
Subject: [PATCH v4] memcg: refactor mem_cgroup_resize_limit()

mem_cgroup_resize_limit() and mem_cgroup_resize_memsw_limit() have
identical logics. Refactor code so we don't need to keep two pieces
of code that does same thing.

Signed-off-by: Yu Zhao <[email protected]>
Acked-by: Vladimir Davydov <[email protected]>
Acked-by: Michal Hocko <[email protected]>
---
Changelog since v1:
* minor style change
Changelog since v2:
* fix build error
Changelog since v3:
* minor style change

mm/memcontrol.c | 77 +++++++++++++--------------------------------------------
1 file changed, 17 insertions(+), 60 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 94172089f52f..401f64a3dda1 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2422,13 +2422,15 @@ static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
static DEFINE_MUTEX(memcg_limit_mutex);

static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
- unsigned long limit)
+ unsigned long limit, bool memsw)
{
unsigned long curusage;
unsigned long oldusage;
bool enlarge = false;
int retry_count;
int ret;
+ bool limits_invariant;
+ struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;

/*
* For keeping hierarchical_reclaim simple, how long we should retry
@@ -2438,7 +2440,7 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
retry_count = MEM_CGROUP_RECLAIM_RETRIES *
mem_cgroup_count_children(memcg);

- oldusage = page_counter_read(&memcg->memory);
+ oldusage = page_counter_read(counter);

do {
if (signal_pending(current)) {
@@ -2447,73 +2449,28 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
}

mutex_lock(&memcg_limit_mutex);
- if (limit > memcg->memsw.limit) {
- mutex_unlock(&memcg_limit_mutex);
- ret = -EINVAL;
- break;
- }
- if (limit > memcg->memory.limit)
- enlarge = true;
- ret = page_counter_limit(&memcg->memory, limit);
- mutex_unlock(&memcg_limit_mutex);
-
- if (!ret)
- break;
-
- try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, true);
-
- curusage = page_counter_read(&memcg->memory);
- /* Usage is reduced ? */
- if (curusage >= oldusage)
- retry_count--;
- else
- oldusage = curusage;
- } while (retry_count);
-
- if (!ret && enlarge)
- memcg_oom_recover(memcg);
-
- return ret;
-}
-
-static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
- unsigned long limit)
-{
- unsigned long curusage;
- unsigned long oldusage;
- bool enlarge = false;
- int retry_count;
- int ret;
-
- /* see mem_cgroup_resize_res_limit */
- retry_count = MEM_CGROUP_RECLAIM_RETRIES *
- mem_cgroup_count_children(memcg);
-
- oldusage = page_counter_read(&memcg->memsw);
-
- do {
- if (signal_pending(current)) {
- ret = -EINTR;
- break;
- }
-
- mutex_lock(&memcg_limit_mutex);
- if (limit < memcg->memory.limit) {
+ /*
+ * Make sure that the new limit (memsw or memory limit) doesn't
+ * break our basic invariant rule memory.limit <= memsw.limit.
+ */
+ limits_invariant = memsw ? limit >= memcg->memory.limit :
+ limit <= memcg->memsw.limit;
+ if (!limits_invariant) {
mutex_unlock(&memcg_limit_mutex);
ret = -EINVAL;
break;
}
- if (limit > memcg->memsw.limit)
+ if (limit > counter->limit)
enlarge = true;
- ret = page_counter_limit(&memcg->memsw, limit);
+ ret = page_counter_limit(counter, limit);
mutex_unlock(&memcg_limit_mutex);

if (!ret)
break;

- try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, false);
+ try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, !memsw);

- curusage = page_counter_read(&memcg->memsw);
+ curusage = page_counter_read(counter);
/* Usage is reduced ? */
if (curusage >= oldusage)
retry_count--;
@@ -2975,10 +2932,10 @@ static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
}
switch (MEMFILE_TYPE(of_cft(of)->private)) {
case _MEM:
- ret = mem_cgroup_resize_limit(memcg, nr_pages);
+ ret = mem_cgroup_resize_limit(memcg, nr_pages, false);
break;
case _MEMSWAP:
- ret = mem_cgroup_resize_memsw_limit(memcg, nr_pages);
+ ret = mem_cgroup_resize_limit(memcg, nr_pages, true);
break;
case _KMEM:
ret = memcg_update_kmem_limit(memcg, nr_pages);
--
2.13.1.508.gb3defc5cc-goog

2018-01-08 22:43:02

by Yu Zhao

[permalink] [raw]
Subject: [PATCH v4] memcg: refactor mem_cgroup_resize_limit()

mem_cgroup_resize_limit() and mem_cgroup_resize_memsw_limit() have
identical logics. Refactor code so we don't need to keep two pieces
of code that does same thing.

Signed-off-by: Yu Zhao <[email protected]>
Acked-by: Vladimir Davydov <[email protected]>
Acked-by: Michal Hocko <[email protected]>
---
mm/memcontrol.c | 77 +++++++++++++--------------------------------------------
1 file changed, 17 insertions(+), 60 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ac2ffd5e02b9..9af733fa9381 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2467,13 +2467,15 @@ static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
static DEFINE_MUTEX(memcg_limit_mutex);

static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
- unsigned long limit)
+ unsigned long limit, bool memsw)
{
unsigned long curusage;
unsigned long oldusage;
bool enlarge = false;
int retry_count;
int ret;
+ bool limits_invariant;
+ struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;

/*
* For keeping hierarchical_reclaim simple, how long we should retry
@@ -2483,7 +2485,7 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
retry_count = MEM_CGROUP_RECLAIM_RETRIES *
mem_cgroup_count_children(memcg);

- oldusage = page_counter_read(&memcg->memory);
+ oldusage = page_counter_read(counter);

do {
if (signal_pending(current)) {
@@ -2492,73 +2494,28 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
}

mutex_lock(&memcg_limit_mutex);
- if (limit > memcg->memsw.limit) {
- mutex_unlock(&memcg_limit_mutex);
- ret = -EINVAL;
- break;
- }
- if (limit > memcg->memory.limit)
- enlarge = true;
- ret = page_counter_limit(&memcg->memory, limit);
- mutex_unlock(&memcg_limit_mutex);
-
- if (!ret)
- break;
-
- try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, true);
-
- curusage = page_counter_read(&memcg->memory);
- /* Usage is reduced ? */
- if (curusage >= oldusage)
- retry_count--;
- else
- oldusage = curusage;
- } while (retry_count);
-
- if (!ret && enlarge)
- memcg_oom_recover(memcg);
-
- return ret;
-}
-
-static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
- unsigned long limit)
-{
- unsigned long curusage;
- unsigned long oldusage;
- bool enlarge = false;
- int retry_count;
- int ret;
-
- /* see mem_cgroup_resize_res_limit */
- retry_count = MEM_CGROUP_RECLAIM_RETRIES *
- mem_cgroup_count_children(memcg);
-
- oldusage = page_counter_read(&memcg->memsw);
-
- do {
- if (signal_pending(current)) {
- ret = -EINTR;
- break;
- }
-
- mutex_lock(&memcg_limit_mutex);
- if (limit < memcg->memory.limit) {
+ /*
+ * Make sure that the new limit (memsw or memory limit) doesn't
+ * break our basic invariant rule memory.limit <= memsw.limit.
+ */
+ limits_invariant = memsw ? limit >= memcg->memory.limit :
+ limit <= memcg->memsw.limit;
+ if (!limits_invariant) {
mutex_unlock(&memcg_limit_mutex);
ret = -EINVAL;
break;
}
- if (limit > memcg->memsw.limit)
+ if (limit > counter->limit)
enlarge = true;
- ret = page_counter_limit(&memcg->memsw, limit);
+ ret = page_counter_limit(counter, limit);
mutex_unlock(&memcg_limit_mutex);

if (!ret)
break;

- try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, false);
+ try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, !memsw);

- curusage = page_counter_read(&memcg->memsw);
+ curusage = page_counter_read(counter);
/* Usage is reduced ? */
if (curusage >= oldusage)
retry_count--;
@@ -3020,10 +2977,10 @@ static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
}
switch (MEMFILE_TYPE(of_cft(of)->private)) {
case _MEM:
- ret = mem_cgroup_resize_limit(memcg, nr_pages);
+ ret = mem_cgroup_resize_limit(memcg, nr_pages, false);
break;
case _MEMSWAP:
- ret = mem_cgroup_resize_memsw_limit(memcg, nr_pages);
+ ret = mem_cgroup_resize_limit(memcg, nr_pages, true);
break;
case _KMEM:
ret = memcg_update_kmem_limit(memcg, nr_pages);
--
2.16.0.rc0.223.g4a4ac83678-goog