The function memcg_rstat_updated() is used to track the memcg stats
updates for optimizing the flushes. At the moment, it is not re-entrant
safe and the callers disabled irqs before calling. However to achieve
the goal of updating memcg stats without irqs, memcg_rstat_updated()
needs to be re-entrant safe against irqs.
This patch makes memcg_rstat_updated() re-entrant safe using this_cpu_*
ops. On archs with CONFIG_ARCH_HAS_NMI_SAFE_THIS_CPU_OPS, this patch is
also making memcg_rstat_updated() nmi safe.
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
---
mm/memcontrol.c | 28 +++++++++++++++++-----------
1 file changed, 17 insertions(+), 11 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 89476a71a18d..2464a58fbf17 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -505,8 +505,8 @@ struct memcg_vmstats_percpu {
unsigned int stats_updates;
/* Cached pointers for fast iteration in memcg_rstat_updated() */
- struct memcg_vmstats_percpu *parent;
- struct memcg_vmstats *vmstats;
+ struct memcg_vmstats_percpu __percpu *parent_pcpu;
+ struct memcg_vmstats *vmstats;
/* The above should fit a single cacheline for memcg_rstat_updated() */
@@ -588,16 +588,21 @@ static bool memcg_vmstats_needs_flush(struct memcg_vmstats *vmstats)
static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val)
{
+ struct memcg_vmstats_percpu __percpu *statc_pcpu;
struct memcg_vmstats_percpu *statc;
- int cpu = smp_processor_id();
+ int cpu;
unsigned int stats_updates;
if (!val)
return;
+ /* Don't assume callers have preemption disabled. */
+ cpu = get_cpu();
+
cgroup_rstat_updated(memcg->css.cgroup, cpu);
- statc = this_cpu_ptr(memcg->vmstats_percpu);
- for (; statc; statc = statc->parent) {
+ statc_pcpu = memcg->vmstats_percpu;
+ for (; statc_pcpu; statc_pcpu = statc->parent_pcpu) {
+ statc = this_cpu_ptr(statc_pcpu);
/*
* If @memcg is already flushable then all its ancestors are
* flushable as well and also there is no need to increase
@@ -606,14 +611,15 @@ static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val)
if (memcg_vmstats_needs_flush(statc->vmstats))
break;
- stats_updates = READ_ONCE(statc->stats_updates) + abs(val);
- WRITE_ONCE(statc->stats_updates, stats_updates);
+ stats_updates = this_cpu_add_return(statc_pcpu->stats_updates,
+ abs(val));
if (stats_updates < MEMCG_CHARGE_BATCH)
continue;
+ stats_updates = this_cpu_xchg(statc_pcpu->stats_updates, 0);
atomic64_add(stats_updates, &statc->vmstats->stats_updates);
- WRITE_ONCE(statc->stats_updates, 0);
}
+ put_cpu();
}
static void __mem_cgroup_flush_stats(struct mem_cgroup *memcg, bool force)
@@ -3691,7 +3697,7 @@ static void mem_cgroup_free(struct mem_cgroup *memcg)
static struct mem_cgroup *mem_cgroup_alloc(struct mem_cgroup *parent)
{
- struct memcg_vmstats_percpu *statc, *pstatc;
+ struct memcg_vmstats_percpu *statc, __percpu *pstatc_pcpu;
struct mem_cgroup *memcg;
int node, cpu;
int __maybe_unused i;
@@ -3722,9 +3728,9 @@ static struct mem_cgroup *mem_cgroup_alloc(struct mem_cgroup *parent)
for_each_possible_cpu(cpu) {
if (parent)
- pstatc = per_cpu_ptr(parent->vmstats_percpu, cpu);
+ pstatc_pcpu = parent->vmstats_percpu;
statc = per_cpu_ptr(memcg->vmstats_percpu, cpu);
- statc->parent = parent ? pstatc : NULL;
+ statc->parent_pcpu = parent ? pstatc_pcpu : NULL;
statc->vmstats = memcg->vmstats;
}
--
2.47.1Shakeel - This breaks the build in mm-new for me:
CC mm/pt_reclaim.o
In file included from ./arch/x86/include/asm/rmwcc.h:5,
from ./arch/x86/include/asm/bitops.h:18,
from ./include/linux/bitops.h:68,
from ./include/linux/radix-tree.h:11,
from ./include/linux/idr.h:15,
from ./include/linux/cgroup-defs.h:13,
from mm/memcontrol.c:28:
mm/memcontrol.c: In function ‘mem_cgroup_alloc’:
./arch/x86/include/asm/percpu.h:39:45: error: expected identifier or ‘(’ before ‘__seg_gs’
39 | #define __percpu_seg_override CONCATENATE(__seg_, __percpu_seg)
| ^~~~~~
./include/linux/args.h:25:24: note: in definition of macro ‘__CONCAT’
25 | #define __CONCAT(a, b) a ## b
| ^
./arch/x86/include/asm/percpu.h:39:33: note: in expansion of macro ‘CONCATENATE’
39 | #define __percpu_seg_override CONCATENATE(__seg_, __percpu_seg)
| ^~~~~~~~~~~
./arch/x86/include/asm/percpu.h:93:33: note: in expansion of macro ‘__percpu_seg_override’
93 | # define __percpu_qual __percpu_seg_override
| ^~~~~~~~~~~~~~~~~~~~~
././include/linux/compiler_types.h:60:25: note: in expansion of macro ‘__percpu_qual’
60 | # define __percpu __percpu_qual BTF_TYPE_TAG(percpu)
| ^~~~~~~~~~~~~
mm/memcontrol.c:3700:45: note: in expansion of macro ‘__percpu’
3700 | struct memcg_vmstats_percpu *statc, __percpu *pstatc_pcpu;
| ^~~~~~~~
mm/memcontrol.c:3731:25: error: ‘pstatc_pcpu’ undeclared (first use in this function); did you mean ‘kstat_cpu’?
3731 | pstatc_pcpu = parent->vmstats_percpu;
| ^~~~~~~~~~~
| kstat_cpu
mm/memcontrol.c:3731:25: note: each undeclared identifier is reported only once for each function it appears in
The __percpu macro seems to be a bit screwy with comma-delimited decls, as it
seems that putting this on its own line fixes this problem:
From 28275e5d054506746d310cf5ebd1fafdb0881dba Mon Sep 17 00:00:00 2001
From: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Date: Thu, 15 May 2025 13:43:46 +0100
Subject: [PATCH] fix
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
---
mm/memcontrol.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2464a58fbf17..40fcc2259e5f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3697,7 +3697,8 @@ static void mem_cgroup_free(struct mem_cgroup *memcg)
static struct mem_cgroup *mem_cgroup_alloc(struct mem_cgroup *parent)
{
- struct memcg_vmstats_percpu *statc, __percpu *pstatc_pcpu;
+ struct memcg_vmstats_percpu *statc;
+ struct memcg_vmstats_percpu __percpu *pstatc_pcpu;
struct mem_cgroup *memcg;
int node, cpu;
int __maybe_unused i;
--
2.49.0
I have duplicated this again at the end of this mail for easy application.
Could we get this fix in or drop the series so the build is fixed for
mm-new? Thanks!
On Wed, May 14, 2025 at 11:41:52AM -0700, Shakeel Butt wrote:
> The function memcg_rstat_updated() is used to track the memcg stats
> updates for optimizing the flushes. At the moment, it is not re-entrant
> safe and the callers disabled irqs before calling. However to achieve
> the goal of updating memcg stats without irqs, memcg_rstat_updated()
> needs to be re-entrant safe against irqs.
>
> This patch makes memcg_rstat_updated() re-entrant safe using this_cpu_*
> ops. On archs with CONFIG_ARCH_HAS_NMI_SAFE_THIS_CPU_OPS, this patch is
> also making memcg_rstat_updated() nmi safe.
>
> Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> ---
> mm/memcontrol.c | 28 +++++++++++++++++-----------
> 1 file changed, 17 insertions(+), 11 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 89476a71a18d..2464a58fbf17 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -505,8 +505,8 @@ struct memcg_vmstats_percpu {
> unsigned int stats_updates;
>
> /* Cached pointers for fast iteration in memcg_rstat_updated() */
> - struct memcg_vmstats_percpu *parent;
> - struct memcg_vmstats *vmstats;
> + struct memcg_vmstats_percpu __percpu *parent_pcpu;
> + struct memcg_vmstats *vmstats;
>
> /* The above should fit a single cacheline for memcg_rstat_updated() */
>
> @@ -588,16 +588,21 @@ static bool memcg_vmstats_needs_flush(struct memcg_vmstats *vmstats)
>
> static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val)
> {
> + struct memcg_vmstats_percpu __percpu *statc_pcpu;
> struct memcg_vmstats_percpu *statc;
> - int cpu = smp_processor_id();
> + int cpu;
> unsigned int stats_updates;
>
> if (!val)
> return;
>
> + /* Don't assume callers have preemption disabled. */
> + cpu = get_cpu();
> +
> cgroup_rstat_updated(memcg->css.cgroup, cpu);
> - statc = this_cpu_ptr(memcg->vmstats_percpu);
> - for (; statc; statc = statc->parent) {
> + statc_pcpu = memcg->vmstats_percpu;
> + for (; statc_pcpu; statc_pcpu = statc->parent_pcpu) {
> + statc = this_cpu_ptr(statc_pcpu);
> /*
> * If @memcg is already flushable then all its ancestors are
> * flushable as well and also there is no need to increase
> @@ -606,14 +611,15 @@ static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val)
> if (memcg_vmstats_needs_flush(statc->vmstats))
> break;
>
> - stats_updates = READ_ONCE(statc->stats_updates) + abs(val);
> - WRITE_ONCE(statc->stats_updates, stats_updates);
> + stats_updates = this_cpu_add_return(statc_pcpu->stats_updates,
> + abs(val));
> if (stats_updates < MEMCG_CHARGE_BATCH)
> continue;
>
> + stats_updates = this_cpu_xchg(statc_pcpu->stats_updates, 0);
> atomic64_add(stats_updates, &statc->vmstats->stats_updates);
> - WRITE_ONCE(statc->stats_updates, 0);
> }
> + put_cpu();
> }
>
> static void __mem_cgroup_flush_stats(struct mem_cgroup *memcg, bool force)
> @@ -3691,7 +3697,7 @@ static void mem_cgroup_free(struct mem_cgroup *memcg)
>
> static struct mem_cgroup *mem_cgroup_alloc(struct mem_cgroup *parent)
> {
> - struct memcg_vmstats_percpu *statc, *pstatc;
> + struct memcg_vmstats_percpu *statc, __percpu *pstatc_pcpu;
> struct mem_cgroup *memcg;
> int node, cpu;
> int __maybe_unused i;
> @@ -3722,9 +3728,9 @@ static struct mem_cgroup *mem_cgroup_alloc(struct mem_cgroup *parent)
>
> for_each_possible_cpu(cpu) {
> if (parent)
> - pstatc = per_cpu_ptr(parent->vmstats_percpu, cpu);
> + pstatc_pcpu = parent->vmstats_percpu;
> statc = per_cpu_ptr(memcg->vmstats_percpu, cpu);
> - statc->parent = parent ? pstatc : NULL;
> + statc->parent_pcpu = parent ? pstatc_pcpu : NULL;
> statc->vmstats = memcg->vmstats;
> }
>
> --
> 2.47.1
>
>
----8<----
From 28275e5d054506746d310cf5ebd1fafdb0881dba Mon Sep 17 00:00:00 2001
From: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Date: Thu, 15 May 2025 13:43:46 +0100
Subject: [PATCH] fix
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
---
mm/memcontrol.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2464a58fbf17..40fcc2259e5f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3697,7 +3697,8 @@ static void mem_cgroup_free(struct mem_cgroup *memcg)
static struct mem_cgroup *mem_cgroup_alloc(struct mem_cgroup *parent)
{
- struct memcg_vmstats_percpu *statc, __percpu *pstatc_pcpu;
+ struct memcg_vmstats_percpu *statc;
+ struct memcg_vmstats_percpu __percpu *pstatc_pcpu;
struct mem_cgroup *memcg;
int node, cpu;
int __maybe_unused i;
--
2.49.0
On Thu, May 15, 2025 at 5:47 AM Lorenzo Stoakes
<lorenzo.stoakes@oracle.com> wrote:
>
> ----8<----
> From 28275e5d054506746d310cf5ebd1fafdb0881dba Mon Sep 17 00:00:00 2001
> From: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Date: Thu, 15 May 2025 13:43:46 +0100
> Subject: [PATCH] fix
>
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> ---
> mm/memcontrol.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 2464a58fbf17..40fcc2259e5f 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -3697,7 +3697,8 @@ static void mem_cgroup_free(struct mem_cgroup *memcg)
>
> static struct mem_cgroup *mem_cgroup_alloc(struct mem_cgroup *parent)
> {
> - struct memcg_vmstats_percpu *statc, __percpu *pstatc_pcpu;
> + struct memcg_vmstats_percpu *statc;
> + struct memcg_vmstats_percpu __percpu *pstatc_pcpu;
> struct mem_cgroup *memcg;
> int node, cpu;
> int __maybe_unused i;
> --
> 2.49.0
Tested-by: Alexei Starovoitov <ast@kernel.org>
Andrew,
Please pick up Lorenzo's fix into mm-new.
On Thu, May 15, 2025 at 5:47 AM Lorenzo Stoakes <lorenzo.stoakes@oracle.com> wrote: > > Shakeel - This breaks the build in mm-new for me: > > CC mm/pt_reclaim.o > In file included from ./arch/x86/include/asm/rmwcc.h:5, > from ./arch/x86/include/asm/bitops.h:18, > from ./include/linux/bitops.h:68, > from ./include/linux/radix-tree.h:11, > from ./include/linux/idr.h:15, > from ./include/linux/cgroup-defs.h:13, > from mm/memcontrol.c:28: > mm/memcontrol.c: In function ‘mem_cgroup_alloc’: > ./arch/x86/include/asm/percpu.h:39:45: error: expected identifier or ‘(’ before ‘__seg_gs’ > 39 | #define __percpu_seg_override CONCATENATE(__seg_, __percpu_seg) > | ^~~~~~ > ./include/linux/args.h:25:24: note: in definition of macro ‘__CONCAT’ > 25 | #define __CONCAT(a, b) a ## b > | ^ > ./arch/x86/include/asm/percpu.h:39:33: note: in expansion of macro ‘CONCATENATE’ > 39 | #define __percpu_seg_override CONCATENATE(__seg_, __percpu_seg) > | ^~~~~~~~~~~ > ./arch/x86/include/asm/percpu.h:93:33: note: in expansion of macro ‘__percpu_seg_override’ > 93 | # define __percpu_qual __percpu_seg_override > | ^~~~~~~~~~~~~~~~~~~~~ > ././include/linux/compiler_types.h:60:25: note: in expansion of macro ‘__percpu_qual’ > 60 | # define __percpu __percpu_qual BTF_TYPE_TAG(percpu) > | ^~~~~~~~~~~~~ > mm/memcontrol.c:3700:45: note: in expansion of macro ‘__percpu’ > 3700 | struct memcg_vmstats_percpu *statc, __percpu *pstatc_pcpu; > | ^~~~~~~~ > mm/memcontrol.c:3731:25: error: ‘pstatc_pcpu’ undeclared (first use in this function); did you mean ‘kstat_cpu’? > 3731 | pstatc_pcpu = parent->vmstats_percpu; > | ^~~~~~~~~~~ > | kstat_cpu > mm/memcontrol.c:3731:25: note: each undeclared identifier is reported only once for each function it appears in > > The __percpu macro seems to be a bit screwy with comma-delimited decls, as it > seems that putting this on its own line fixes this problem: > Which compiler (and version) is this? Thanks for the fix.
On 5/15/25 16:31, Shakeel Butt wrote: > On Thu, May 15, 2025 at 5:47 AM Lorenzo Stoakes > <lorenzo.stoakes@oracle.com> wrote: >> >> Shakeel - This breaks the build in mm-new for me: >> >> CC mm/pt_reclaim.o >> In file included from ./arch/x86/include/asm/rmwcc.h:5, >> from ./arch/x86/include/asm/bitops.h:18, >> from ./include/linux/bitops.h:68, >> from ./include/linux/radix-tree.h:11, >> from ./include/linux/idr.h:15, >> from ./include/linux/cgroup-defs.h:13, >> from mm/memcontrol.c:28: >> mm/memcontrol.c: In function ‘mem_cgroup_alloc’: >> ./arch/x86/include/asm/percpu.h:39:45: error: expected identifier or ‘(’ before ‘__seg_gs’ >> 39 | #define __percpu_seg_override CONCATENATE(__seg_, __percpu_seg) >> | ^~~~~~ >> ./include/linux/args.h:25:24: note: in definition of macro ‘__CONCAT’ >> 25 | #define __CONCAT(a, b) a ## b >> | ^ >> ./arch/x86/include/asm/percpu.h:39:33: note: in expansion of macro ‘CONCATENATE’ >> 39 | #define __percpu_seg_override CONCATENATE(__seg_, __percpu_seg) >> | ^~~~~~~~~~~ >> ./arch/x86/include/asm/percpu.h:93:33: note: in expansion of macro ‘__percpu_seg_override’ >> 93 | # define __percpu_qual __percpu_seg_override >> | ^~~~~~~~~~~~~~~~~~~~~ >> ././include/linux/compiler_types.h:60:25: note: in expansion of macro ‘__percpu_qual’ >> 60 | # define __percpu __percpu_qual BTF_TYPE_TAG(percpu) >> | ^~~~~~~~~~~~~ >> mm/memcontrol.c:3700:45: note: in expansion of macro ‘__percpu’ >> 3700 | struct memcg_vmstats_percpu *statc, __percpu *pstatc_pcpu; >> | ^~~~~~~~ >> mm/memcontrol.c:3731:25: error: ‘pstatc_pcpu’ undeclared (first use in this function); did you mean ‘kstat_cpu’? >> 3731 | pstatc_pcpu = parent->vmstats_percpu; >> | ^~~~~~~~~~~ >> | kstat_cpu >> mm/memcontrol.c:3731:25: note: each undeclared identifier is reported only once for each function it appears in >> >> The __percpu macro seems to be a bit screwy with comma-delimited decls, as it >> seems that putting this on its own line fixes this problem: >> > > Which compiler (and version) is this? Thanks for the fix. Hm right I see the same errors with gcc 7, 13, 14, 15 but not with clang.
On Thu, May 15, 2025 at 04:57:10PM +0200, Vlastimil Babka wrote: > On 5/15/25 16:31, Shakeel Butt wrote: > > On Thu, May 15, 2025 at 5:47 AM Lorenzo Stoakes > > <lorenzo.stoakes@oracle.com> wrote: > >> > >> Shakeel - This breaks the build in mm-new for me: > >> > >> CC mm/pt_reclaim.o > >> In file included from ./arch/x86/include/asm/rmwcc.h:5, > >> from ./arch/x86/include/asm/bitops.h:18, > >> from ./include/linux/bitops.h:68, > >> from ./include/linux/radix-tree.h:11, > >> from ./include/linux/idr.h:15, > >> from ./include/linux/cgroup-defs.h:13, > >> from mm/memcontrol.c:28: > >> mm/memcontrol.c: In function ‘mem_cgroup_alloc’: > >> ./arch/x86/include/asm/percpu.h:39:45: error: expected identifier or ‘(’ before ‘__seg_gs’ > >> 39 | #define __percpu_seg_override CONCATENATE(__seg_, __percpu_seg) > >> | ^~~~~~ > >> ./include/linux/args.h:25:24: note: in definition of macro ‘__CONCAT’ > >> 25 | #define __CONCAT(a, b) a ## b > >> | ^ > >> ./arch/x86/include/asm/percpu.h:39:33: note: in expansion of macro ‘CONCATENATE’ > >> 39 | #define __percpu_seg_override CONCATENATE(__seg_, __percpu_seg) > >> | ^~~~~~~~~~~ > >> ./arch/x86/include/asm/percpu.h:93:33: note: in expansion of macro ‘__percpu_seg_override’ > >> 93 | # define __percpu_qual __percpu_seg_override > >> | ^~~~~~~~~~~~~~~~~~~~~ > >> ././include/linux/compiler_types.h:60:25: note: in expansion of macro ‘__percpu_qual’ > >> 60 | # define __percpu __percpu_qual BTF_TYPE_TAG(percpu) > >> | ^~~~~~~~~~~~~ > >> mm/memcontrol.c:3700:45: note: in expansion of macro ‘__percpu’ > >> 3700 | struct memcg_vmstats_percpu *statc, __percpu *pstatc_pcpu; > >> | ^~~~~~~~ > >> mm/memcontrol.c:3731:25: error: ‘pstatc_pcpu’ undeclared (first use in this function); did you mean ‘kstat_cpu’? > >> 3731 | pstatc_pcpu = parent->vmstats_percpu; > >> | ^~~~~~~~~~~ > >> | kstat_cpu > >> mm/memcontrol.c:3731:25: note: each undeclared identifier is reported only once for each function it appears in > >> > >> The __percpu macro seems to be a bit screwy with comma-delimited decls, as it > >> seems that putting this on its own line fixes this problem: > >> > > > > Which compiler (and version) is this? Thanks for the fix. > > Hm right I see the same errors with gcc 7, 13, 14, 15 but not with clang. It seems to work with gcc 11.5.0, so weird.
On Thu, May 15, 2025 at 07:31:09AM -0700, Shakeel Butt wrote: > On Thu, May 15, 2025 at 5:47 AM Lorenzo Stoakes > <lorenzo.stoakes@oracle.com> wrote: > > > > Shakeel - This breaks the build in mm-new for me: > > > > CC mm/pt_reclaim.o > > In file included from ./arch/x86/include/asm/rmwcc.h:5, > > from ./arch/x86/include/asm/bitops.h:18, > > from ./include/linux/bitops.h:68, > > from ./include/linux/radix-tree.h:11, > > from ./include/linux/idr.h:15, > > from ./include/linux/cgroup-defs.h:13, > > from mm/memcontrol.c:28: > > mm/memcontrol.c: In function ‘mem_cgroup_alloc’: > > ./arch/x86/include/asm/percpu.h:39:45: error: expected identifier or ‘(’ before ‘__seg_gs’ > > 39 | #define __percpu_seg_override CONCATENATE(__seg_, __percpu_seg) > > | ^~~~~~ > > ./include/linux/args.h:25:24: note: in definition of macro ‘__CONCAT’ > > 25 | #define __CONCAT(a, b) a ## b > > | ^ > > ./arch/x86/include/asm/percpu.h:39:33: note: in expansion of macro ‘CONCATENATE’ > > 39 | #define __percpu_seg_override CONCATENATE(__seg_, __percpu_seg) > > | ^~~~~~~~~~~ > > ./arch/x86/include/asm/percpu.h:93:33: note: in expansion of macro ‘__percpu_seg_override’ > > 93 | # define __percpu_qual __percpu_seg_override > > | ^~~~~~~~~~~~~~~~~~~~~ > > ././include/linux/compiler_types.h:60:25: note: in expansion of macro ‘__percpu_qual’ > > 60 | # define __percpu __percpu_qual BTF_TYPE_TAG(percpu) > > | ^~~~~~~~~~~~~ > > mm/memcontrol.c:3700:45: note: in expansion of macro ‘__percpu’ > > 3700 | struct memcg_vmstats_percpu *statc, __percpu *pstatc_pcpu; > > | ^~~~~~~~ > > mm/memcontrol.c:3731:25: error: ‘pstatc_pcpu’ undeclared (first use in this function); did you mean ‘kstat_cpu’? > > 3731 | pstatc_pcpu = parent->vmstats_percpu; > > | ^~~~~~~~~~~ > > | kstat_cpu > > mm/memcontrol.c:3731:25: note: each undeclared identifier is reported only once for each function it appears in > > > > The __percpu macro seems to be a bit screwy with comma-delimited decls, as it > > seems that putting this on its own line fixes this problem: > > > > Which compiler (and version) is this? Thanks for the fix. gcc 15, but apparently 13, 14 also fail. It seems independent of config.
On Thu, May 15, 2025 at 03:53:17PM +0100, Lorenzo Stoakes wrote: > On Thu, May 15, 2025 at 07:31:09AM -0700, Shakeel Butt wrote: > > On Thu, May 15, 2025 at 5:47 AM Lorenzo Stoakes > > <lorenzo.stoakes@oracle.com> wrote: > > > > > > Shakeel - This breaks the build in mm-new for me: > > > > > > CC mm/pt_reclaim.o > > > In file included from ./arch/x86/include/asm/rmwcc.h:5, > > > from ./arch/x86/include/asm/bitops.h:18, > > > from ./include/linux/bitops.h:68, > > > from ./include/linux/radix-tree.h:11, > > > from ./include/linux/idr.h:15, > > > from ./include/linux/cgroup-defs.h:13, > > > from mm/memcontrol.c:28: > > > mm/memcontrol.c: In function ‘mem_cgroup_alloc’: > > > ./arch/x86/include/asm/percpu.h:39:45: error: expected identifier or ‘(’ before ‘__seg_gs’ > > > 39 | #define __percpu_seg_override CONCATENATE(__seg_, __percpu_seg) > > > | ^~~~~~ > > > ./include/linux/args.h:25:24: note: in definition of macro ‘__CONCAT’ > > > 25 | #define __CONCAT(a, b) a ## b > > > | ^ > > > ./arch/x86/include/asm/percpu.h:39:33: note: in expansion of macro ‘CONCATENATE’ > > > 39 | #define __percpu_seg_override CONCATENATE(__seg_, __percpu_seg) > > > | ^~~~~~~~~~~ > > > ./arch/x86/include/asm/percpu.h:93:33: note: in expansion of macro ‘__percpu_seg_override’ > > > 93 | # define __percpu_qual __percpu_seg_override > > > | ^~~~~~~~~~~~~~~~~~~~~ > > > ././include/linux/compiler_types.h:60:25: note: in expansion of macro ‘__percpu_qual’ > > > 60 | # define __percpu __percpu_qual BTF_TYPE_TAG(percpu) > > > | ^~~~~~~~~~~~~ > > > mm/memcontrol.c:3700:45: note: in expansion of macro ‘__percpu’ > > > 3700 | struct memcg_vmstats_percpu *statc, __percpu *pstatc_pcpu; > > > | ^~~~~~~~ > > > mm/memcontrol.c:3731:25: error: ‘pstatc_pcpu’ undeclared (first use in this function); did you mean ‘kstat_cpu’? > > > 3731 | pstatc_pcpu = parent->vmstats_percpu; > > > | ^~~~~~~~~~~ > > > | kstat_cpu > > > mm/memcontrol.c:3731:25: note: each undeclared identifier is reported only once for each function it appears in > > > > > > The __percpu macro seems to be a bit screwy with comma-delimited decls, as it > > > seems that putting this on its own line fixes this problem: > > > > > > > Which compiler (and version) is this? Thanks for the fix. > > gcc 15, but apparently 13, 14 also fail. It seems independent of config. Thanks, somehow it works with gcc 11.5.0.
On Thu, May 15, 2025 at 08:22:04AM -0700, Shakeel Butt wrote: > On Thu, May 15, 2025 at 03:53:17PM +0100, Lorenzo Stoakes wrote: > > On Thu, May 15, 2025 at 07:31:09AM -0700, Shakeel Butt wrote: > > > On Thu, May 15, 2025 at 5:47 AM Lorenzo Stoakes > > > <lorenzo.stoakes@oracle.com> wrote: > > > > > > > > Shakeel - This breaks the build in mm-new for me: > > > > > > > > CC mm/pt_reclaim.o > > > > In file included from ./arch/x86/include/asm/rmwcc.h:5, > > > > from ./arch/x86/include/asm/bitops.h:18, > > > > from ./include/linux/bitops.h:68, > > > > from ./include/linux/radix-tree.h:11, > > > > from ./include/linux/idr.h:15, > > > > from ./include/linux/cgroup-defs.h:13, > > > > from mm/memcontrol.c:28: > > > > mm/memcontrol.c: In function ‘mem_cgroup_alloc’: > > > > ./arch/x86/include/asm/percpu.h:39:45: error: expected identifier or ‘(’ before ‘__seg_gs’ > > > > 39 | #define __percpu_seg_override CONCATENATE(__seg_, __percpu_seg) > > > > | ^~~~~~ > > > > ./include/linux/args.h:25:24: note: in definition of macro ‘__CONCAT’ > > > > 25 | #define __CONCAT(a, b) a ## b > > > > | ^ > > > > ./arch/x86/include/asm/percpu.h:39:33: note: in expansion of macro ‘CONCATENATE’ > > > > 39 | #define __percpu_seg_override CONCATENATE(__seg_, __percpu_seg) > > > > | ^~~~~~~~~~~ > > > > ./arch/x86/include/asm/percpu.h:93:33: note: in expansion of macro ‘__percpu_seg_override’ > > > > 93 | # define __percpu_qual __percpu_seg_override > > > > | ^~~~~~~~~~~~~~~~~~~~~ > > > > ././include/linux/compiler_types.h:60:25: note: in expansion of macro ‘__percpu_qual’ > > > > 60 | # define __percpu __percpu_qual BTF_TYPE_TAG(percpu) > > > > | ^~~~~~~~~~~~~ > > > > mm/memcontrol.c:3700:45: note: in expansion of macro ‘__percpu’ > > > > 3700 | struct memcg_vmstats_percpu *statc, __percpu *pstatc_pcpu; > > > > | ^~~~~~~~ > > > > mm/memcontrol.c:3731:25: error: ‘pstatc_pcpu’ undeclared (first use in this function); did you mean ‘kstat_cpu’? > > > > 3731 | pstatc_pcpu = parent->vmstats_percpu; > > > > | ^~~~~~~~~~~ > > > > | kstat_cpu > > > > mm/memcontrol.c:3731:25: note: each undeclared identifier is reported only once for each function it appears in > > > > > > > > The __percpu macro seems to be a bit screwy with comma-delimited decls, as it > > > > seems that putting this on its own line fixes this problem: > > > > > > > > > > Which compiler (and version) is this? Thanks for the fix. > > > > gcc 15, but apparently 13, 14 also fail. It seems independent of config. > > Thanks, somehow it works with gcc 11.5.0. That is... both extremely bizarre, and VERY gnu... haha
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