| Message ID | 1580922215-5272-1-git-send-email-laoar.shao@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm, memcg: fix build error around the usage of kmem_caches | expand |
On 05.02.20 18:03, Yafang Shao wrote: > When I manually set default n to MEMCG_KMEM in init/Kconfig, bellow error > occurs, > > mm/slab_common.c: In function 'memcg_slab_start': > mm/slab_common.c:1530:30: error: 'struct mem_cgroup' has no member named > 'kmem_caches' > return seq_list_start(&memcg->kmem_caches, *pos); > ^ > mm/slab_common.c: In function 'memcg_slab_next': > mm/slab_common.c:1537:32: error: 'struct mem_cgroup' has no member named > 'kmem_caches' > return seq_list_next(p, &memcg->kmem_caches, pos); > ^ > mm/slab_common.c: In function 'memcg_slab_show': > mm/slab_common.c:1551:16: error: 'struct mem_cgroup' has no member named > 'kmem_caches' > if (p == memcg->kmem_caches.next) > ^ > CC arch/x86/xen/smp.o > mm/slab_common.c: In function 'memcg_slab_start': > mm/slab_common.c:1531:1: warning: control reaches end of non-void function > [-Wreturn-type] > } > ^ > mm/slab_common.c: In function 'memcg_slab_next': > mm/slab_common.c:1538:1: warning: control reaches end of non-void function > [-Wreturn-type] > } > ^ > > That's because kmem_caches is defined only when CONFIG_MEMCG_KMEM is set, > while memcg_slab_start() will use it no matter CONFIG_MEMCG_KMEM is defined > or not. > > By the way, the reason I mannuly undefined CONFIG_MEMCG_KMEM is to verify > whether my some other code change is still stable when CONFIG_MEMCG_KMEM is > not set. Unfortunately, the existing code has been already unstable since > v4.11. > > Fixes: bc2791f857e1 ("slab: link memcg kmem_caches on their associated memory cgroup") > Cc: Tejun Heo <tj@kernel.org> > Cc: Vladimir Davydov <vdavydov.dev@gmail.com> > Signed-off-by: Yafang Shao <laoar.shao@gmail.com> > --- > mm/memcontrol.c | 2 ++ > mm/slab_common.c | 2 +- > 2 files changed, 3 insertions(+), 1 deletion(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 6f6dc8712e39..43f0125b45bb 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -4723,6 +4723,7 @@ static struct cftype mem_cgroup_legacy_files[] = { > .write = mem_cgroup_reset, > .read_u64 = mem_cgroup_read_u64, > }, > +#ifdef CONFIG_MEMCG_KMEM > #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG) Not sure if #if defined(CONFIG_MEMCG_KMEM) && \ (defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)) is preffered
On Thu, Feb 6, 2020 at 1:19 AM David Hildenbrand <david@redhat.com> wrote: > > On 05.02.20 18:03, Yafang Shao wrote: > > When I manually set default n to MEMCG_KMEM in init/Kconfig, bellow error > > occurs, > > > > mm/slab_common.c: In function 'memcg_slab_start': > > mm/slab_common.c:1530:30: error: 'struct mem_cgroup' has no member named > > 'kmem_caches' > > return seq_list_start(&memcg->kmem_caches, *pos); > > ^ > > mm/slab_common.c: In function 'memcg_slab_next': > > mm/slab_common.c:1537:32: error: 'struct mem_cgroup' has no member named > > 'kmem_caches' > > return seq_list_next(p, &memcg->kmem_caches, pos); > > ^ > > mm/slab_common.c: In function 'memcg_slab_show': > > mm/slab_common.c:1551:16: error: 'struct mem_cgroup' has no member named > > 'kmem_caches' > > if (p == memcg->kmem_caches.next) > > ^ > > CC arch/x86/xen/smp.o > > mm/slab_common.c: In function 'memcg_slab_start': > > mm/slab_common.c:1531:1: warning: control reaches end of non-void function > > [-Wreturn-type] > > } > > ^ > > mm/slab_common.c: In function 'memcg_slab_next': > > mm/slab_common.c:1538:1: warning: control reaches end of non-void function > > [-Wreturn-type] > > } > > ^ > > > > That's because kmem_caches is defined only when CONFIG_MEMCG_KMEM is set, > > while memcg_slab_start() will use it no matter CONFIG_MEMCG_KMEM is defined > > or not. > > > > By the way, the reason I mannuly undefined CONFIG_MEMCG_KMEM is to verify > > whether my some other code change is still stable when CONFIG_MEMCG_KMEM is > > not set. Unfortunately, the existing code has been already unstable since > > v4.11. > > > > Fixes: bc2791f857e1 ("slab: link memcg kmem_caches on their associated memory cgroup") > > Cc: Tejun Heo <tj@kernel.org> > > Cc: Vladimir Davydov <vdavydov.dev@gmail.com> > > Signed-off-by: Yafang Shao <laoar.shao@gmail.com> > > --- > > mm/memcontrol.c | 2 ++ > > mm/slab_common.c | 2 +- > > 2 files changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > index 6f6dc8712e39..43f0125b45bb 100644 > > --- a/mm/memcontrol.c > > +++ b/mm/memcontrol.c > > @@ -4723,6 +4723,7 @@ static struct cftype mem_cgroup_legacy_files[] = { > > .write = mem_cgroup_reset, > > .read_u64 = mem_cgroup_read_u64, > > }, > > +#ifdef CONFIG_MEMCG_KMEM > > #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG) > > Not sure if > > #if defined(CONFIG_MEMCG_KMEM) && \ > (defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)) > > is preffered > Seems better. Thanks for your suggestion. Thanks Yafang
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 6f6dc8712e39..43f0125b45bb 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4723,6 +4723,7 @@ static struct cftype mem_cgroup_legacy_files[] = { .write = mem_cgroup_reset, .read_u64 = mem_cgroup_read_u64, }, +#ifdef CONFIG_MEMCG_KMEM #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG) { .name = "kmem.slabinfo", @@ -4731,6 +4732,7 @@ static struct cftype mem_cgroup_legacy_files[] = { .seq_stop = memcg_slab_stop, .seq_show = memcg_slab_show, }, +#endif #endif { .name = "kmem.tcp.limit_in_bytes", diff --git a/mm/slab_common.c b/mm/slab_common.c index 1907cb2903c7..5282f881d2f5 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -1521,7 +1521,7 @@ void dump_unreclaimable_slab(void) mutex_unlock(&slab_mutex); } -#if defined(CONFIG_MEMCG) +#if defined(CONFIG_MEMCG_KMEM) void *memcg_slab_start(struct seq_file *m, loff_t *pos) { struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
When I manually set default n to MEMCG_KMEM in init/Kconfig, bellow error occurs, mm/slab_common.c: In function 'memcg_slab_start': mm/slab_common.c:1530:30: error: 'struct mem_cgroup' has no member named 'kmem_caches' return seq_list_start(&memcg->kmem_caches, *pos); ^ mm/slab_common.c: In function 'memcg_slab_next': mm/slab_common.c:1537:32: error: 'struct mem_cgroup' has no member named 'kmem_caches' return seq_list_next(p, &memcg->kmem_caches, pos); ^ mm/slab_common.c: In function 'memcg_slab_show': mm/slab_common.c:1551:16: error: 'struct mem_cgroup' has no member named 'kmem_caches' if (p == memcg->kmem_caches.next) ^ CC arch/x86/xen/smp.o mm/slab_common.c: In function 'memcg_slab_start': mm/slab_common.c:1531:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ mm/slab_common.c: In function 'memcg_slab_next': mm/slab_common.c:1538:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ That's because kmem_caches is defined only when CONFIG_MEMCG_KMEM is set, while memcg_slab_start() will use it no matter CONFIG_MEMCG_KMEM is defined or not. By the way, the reason I mannuly undefined CONFIG_MEMCG_KMEM is to verify whether my some other code change is still stable when CONFIG_MEMCG_KMEM is not set. Unfortunately, the existing code has been already unstable since v4.11. Fixes: bc2791f857e1 ("slab: link memcg kmem_caches on their associated memory cgroup") Cc: Tejun Heo <tj@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Yafang Shao <laoar.shao@gmail.com> --- mm/memcontrol.c | 2 ++ mm/slab_common.c | 2 +- 2 files changed, 3 insertions(+), 1 deletion(-)