On Sat 01-11-14 23:15:55, Johannes Weiner wrote:
> Now that the external page_cgroup data structure and its lookup is
> gone, the only code remaining in there is swap slot accounting.
>
> Rename it and move the conditional compilation into mm/Makefile.
>
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxx>
> ---
> MAINTAINERS | 2 +-
> include/linux/page_cgroup.h | 40 ---------
> include/linux/swap_cgroup.h | 42 +++++++++
> mm/Makefile | 3 +-
> mm/memcontrol.c | 2 +-
> mm/page_cgroup.c | 211 --------------------------------------------
> mm/swap_cgroup.c | 208 +++++++++++++++++++++++++++++++++++++++++++
> mm/swap_state.c | 1 -
> mm/swapfile.c | 2 +-
> 9 files changed, 255 insertions(+), 256 deletions(-)
> delete mode 100644 include/linux/page_cgroup.h
> create mode 100644 include/linux/swap_cgroup.h
> delete mode 100644 mm/page_cgroup.c
> create mode 100644 mm/swap_cgroup.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 7e31be07197e..3a60389d3a13 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -2583,7 +2583,7 @@ L: cgroups@xxxxxxxxxxxxxxx
> L: linux-mm@xxxxxxxxx
> S: Maintained
> F: mm/memcontrol.c
> -F: mm/page_cgroup.c
> +F: mm/swap_cgroup.c
>
> CORETEMP HARDWARE MONITORING DRIVER
> M: Fenghua Yu <fenghua.yu@xxxxxxxxx>
> diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h
> deleted file mode 100644
> index 65be35785c86..000000000000
> --- a/include/linux/page_cgroup.h
> +++ /dev/null
> @@ -1,40 +0,0 @@
> -#ifndef __LINUX_PAGE_CGROUP_H
> -#define __LINUX_PAGE_CGROUP_H
> -
> -#include <linux/swap.h>
> -
> -#ifdef CONFIG_MEMCG_SWAP
> -extern unsigned short swap_cgroup_cmpxchg(swp_entry_t ent,
> - unsigned short old, unsigned short new);
> -extern unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id);
> -extern unsigned short lookup_swap_cgroup_id(swp_entry_t ent);
> -extern int swap_cgroup_swapon(int type, unsigned long max_pages);
> -extern void swap_cgroup_swapoff(int type);
> -#else
> -
> -static inline
> -unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id)
> -{
> - return 0;
> -}
> -
> -static inline
> -unsigned short lookup_swap_cgroup_id(swp_entry_t ent)
> -{
> - return 0;
> -}
> -
> -static inline int
> -swap_cgroup_swapon(int type, unsigned long max_pages)
> -{
> - return 0;
> -}
> -
> -static inline void swap_cgroup_swapoff(int type)
> -{
> - return;
> -}
> -
> -#endif /* CONFIG_MEMCG_SWAP */
> -
> -#endif /* __LINUX_PAGE_CGROUP_H */
> diff --git a/include/linux/swap_cgroup.h b/include/linux/swap_cgroup.h
> new file mode 100644
> index 000000000000..145306bdc92f
> --- /dev/null
> +++ b/include/linux/swap_cgroup.h
> @@ -0,0 +1,42 @@
> +#ifndef __LINUX_SWAP_CGROUP_H
> +#define __LINUX_SWAP_CGROUP_H
> +
> +#include <linux/swap.h>
> +
> +#ifdef CONFIG_MEMCG_SWAP
> +
> +extern unsigned short swap_cgroup_cmpxchg(swp_entry_t ent,
> + unsigned short old, unsigned short new);
> +extern unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id);
> +extern unsigned short lookup_swap_cgroup_id(swp_entry_t ent);
> +extern int swap_cgroup_swapon(int type, unsigned long max_pages);
> +extern void swap_cgroup_swapoff(int type);
> +
> +#else
> +
> +static inline
> +unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id)
> +{
> + return 0;
> +}
> +
> +static inline
> +unsigned short lookup_swap_cgroup_id(swp_entry_t ent)
> +{
> + return 0;
> +}
> +
> +static inline int
> +swap_cgroup_swapon(int type, unsigned long max_pages)
> +{
> + return 0;
> +}
> +
> +static inline void swap_cgroup_swapoff(int type)
> +{
> + return;
> +}
> +
> +#endif /* CONFIG_MEMCG_SWAP */
> +
> +#endif /* __LINUX_SWAP_CGROUP_H */
> diff --git a/mm/Makefile b/mm/Makefile
> index 27ddb80403a9..d9d579484f15 100644
> --- a/mm/Makefile
> +++ b/mm/Makefile
> @@ -56,7 +56,8 @@ obj-$(CONFIG_MIGRATION) += migrate.o
> obj-$(CONFIG_QUICKLIST) += quicklist.o
> obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o
> obj-$(CONFIG_PAGE_COUNTER) += page_counter.o
> -obj-$(CONFIG_MEMCG) += memcontrol.o page_cgroup.o vmpressure.o
> +obj-$(CONFIG_MEMCG) += memcontrol.o vmpressure.o
> +obj-$(CONFIG_MEMCG_SWAP) += swap_cgroup.o
> obj-$(CONFIG_CGROUP_HUGETLB) += hugetlb_cgroup.o
> obj-$(CONFIG_MEMORY_FAILURE) += memory-failure.o
> obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index dc5e0abb18cb..fbb41a170eae 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -51,7 +51,7 @@
> #include <linux/seq_file.h>
> #include <linux/vmpressure.h>
> #include <linux/mm_inline.h>
> -#include <linux/page_cgroup.h>
> +#include <linux/swap_cgroup.h>
> #include <linux/cpu.h>
> #include <linux/oom.h>
> #include <linux/lockdep.h>
> diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
> deleted file mode 100644
> index f0f31c1d4d0c..000000000000
> --- a/mm/page_cgroup.c
> +++ /dev/null
> @@ -1,211 +0,0 @@
> -#include <linux/mm.h>
> -#include <linux/page_cgroup.h>
> -#include <linux/vmalloc.h>
> -#include <linux/swapops.h>
> -
> -#ifdef CONFIG_MEMCG_SWAP
> -
> -static DEFINE_MUTEX(swap_cgroup_mutex);
> -struct swap_cgroup_ctrl {
> - struct page **map;
> - unsigned long length;
> - spinlock_t lock;
> -};
> -
> -static struct swap_cgroup_ctrl swap_cgroup_ctrl[MAX_SWAPFILES];
> -
> -struct swap_cgroup {
> - unsigned short id;
> -};
> -#define SC_PER_PAGE (PAGE_SIZE/sizeof(struct swap_cgroup))
> -
> -/*
> - * SwapCgroup implements "lookup" and "exchange" operations.
> - * In typical usage, this swap_cgroup is accessed via memcg's charge/uncharge
> - * against SwapCache. At swap_free(), this is accessed directly from swap.
> - *
> - * This means,
> - * - we have no race in "exchange" when we're accessed via SwapCache because
> - * SwapCache(and its swp_entry) is under lock.
> - * - When called via swap_free(), there is no user of this entry and no race.
> - * Then, we don't need lock around "exchange".
> - *
> - * TODO: we can push these buffers out to HIGHMEM.
> - */
> -
> -/*
> - * allocate buffer for swap_cgroup.
> - */
> -static int swap_cgroup_prepare(int type)
> -{
> - struct page *page;
> - struct swap_cgroup_ctrl *ctrl;
> - unsigned long idx, max;
> -
> - ctrl = &swap_cgroup_ctrl[type];
> -
> - for (idx = 0; idx < ctrl->length; idx++) {
> - page = alloc_page(GFP_KERNEL | __GFP_ZERO);
> - if (!page)
> - goto not_enough_page;
> - ctrl->map[idx] = page;
> - }
> - return 0;
> -not_enough_page:
> - max = idx;
> - for (idx = 0; idx < max; idx++)
> - __free_page(ctrl->map[idx]);
> -
> - return -ENOMEM;
> -}
> -
> -static struct swap_cgroup *lookup_swap_cgroup(swp_entry_t ent,
> - struct swap_cgroup_ctrl **ctrlp)
> -{
> - pgoff_t offset = swp_offset(ent);
> - struct swap_cgroup_ctrl *ctrl;
> - struct page *mappage;
> - struct swap_cgroup *sc;
> -
> - ctrl = &swap_cgroup_ctrl[swp_type(ent)];
> - if (ctrlp)
> - *ctrlp = ctrl;
> -
> - mappage = ctrl->map[offset / SC_PER_PAGE];
> - sc = page_address(mappage);
> - return sc + offset % SC_PER_PAGE;
> -}
> -
> -/**
> - * swap_cgroup_cmpxchg - cmpxchg mem_cgroup's id for this swp_entry.
> - * @ent: swap entry to be cmpxchged
> - * @old: old id
> - * @new: new id
> - *
> - * Returns old id at success, 0 at failure.
> - * (There is no mem_cgroup using 0 as its id)
> - */
> -unsigned short swap_cgroup_cmpxchg(swp_entry_t ent,
> - unsigned short old, unsigned short new)
> -{
> - struct swap_cgroup_ctrl *ctrl;
> - struct swap_cgroup *sc;
> - unsigned long flags;
> - unsigned short retval;
> -
> - sc = lookup_swap_cgroup(ent, &ctrl);
> -
> - spin_lock_irqsave(&ctrl->lock, flags);
> - retval = sc->id;
> - if (retval == old)
> - sc->id = new;
> - else
> - retval = 0;
> - spin_unlock_irqrestore(&ctrl->lock, flags);
> - return retval;
> -}
> -
> -/**
> - * swap_cgroup_record - record mem_cgroup for this swp_entry.
> - * @ent: swap entry to be recorded into
> - * @id: mem_cgroup to be recorded
> - *
> - * Returns old value at success, 0 at failure.
> - * (Of course, old value can be 0.)
> - */
> -unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id)
> -{
> - struct swap_cgroup_ctrl *ctrl;
> - struct swap_cgroup *sc;
> - unsigned short old;
> - unsigned long flags;
> -
> - sc = lookup_swap_cgroup(ent, &ctrl);
> -
> - spin_lock_irqsave(&ctrl->lock, flags);
> - old = sc->id;
> - sc->id = id;
> - spin_unlock_irqrestore(&ctrl->lock, flags);
> -
> - return old;
> -}
> -
> -/**
> - * lookup_swap_cgroup_id - lookup mem_cgroup id tied to swap entry
> - * @ent: swap entry to be looked up.
> - *
> - * Returns ID of mem_cgroup at success. 0 at failure. (0 is invalid ID)
> - */
> -unsigned short lookup_swap_cgroup_id(swp_entry_t ent)
> -{
> - return lookup_swap_cgroup(ent, NULL)->id;
> -}
> -
> -int swap_cgroup_swapon(int type, unsigned long max_pages)
> -{
> - void *array;
> - unsigned long array_size;
> - unsigned long length;
> - struct swap_cgroup_ctrl *ctrl;
> -
> - if (!do_swap_account)
> - return 0;
> -
> - length = DIV_ROUND_UP(max_pages, SC_PER_PAGE);
> - array_size = length * sizeof(void *);
> -
> - array = vzalloc(array_size);
> - if (!array)
> - goto nomem;
> -
> - ctrl = &swap_cgroup_ctrl[type];
> - mutex_lock(&swap_cgroup_mutex);
> - ctrl->length = length;
> - ctrl->map = array;
> - spin_lock_init(&ctrl->lock);
> - if (swap_cgroup_prepare(type)) {
> - /* memory shortage */
> - ctrl->map = NULL;
> - ctrl->length = 0;
> - mutex_unlock(&swap_cgroup_mutex);
> - vfree(array);
> - goto nomem;
> - }
> - mutex_unlock(&swap_cgroup_mutex);
> -
> - return 0;
> -nomem:
> - printk(KERN_INFO "couldn't allocate enough memory for swap_cgroup.\n");
> - printk(KERN_INFO
> - "swap_cgroup can be disabled by swapaccount=0 boot option\n");
> - return -ENOMEM;
> -}
> -
> -void swap_cgroup_swapoff(int type)
> -{
> - struct page **map;
> - unsigned long i, length;
> - struct swap_cgroup_ctrl *ctrl;
> -
> - if (!do_swap_account)
> - return;
> -
> - mutex_lock(&swap_cgroup_mutex);
> - ctrl = &swap_cgroup_ctrl[type];
> - map = ctrl->map;
> - length = ctrl->length;
> - ctrl->map = NULL;
> - ctrl->length = 0;
> - mutex_unlock(&swap_cgroup_mutex);
> -
> - if (map) {
> - for (i = 0; i < length; i++) {
> - struct page *page = map[i];
> - if (page)
> - __free_page(page);
> - }
> - vfree(map);
> - }
> -}
> -
> -#endif
> diff --git a/mm/swap_cgroup.c b/mm/swap_cgroup.c
> new file mode 100644
> index 000000000000..b5f7f24b8dd1
> --- /dev/null
> +++ b/mm/swap_cgroup.c
> @@ -0,0 +1,208 @@
> +#include <linux/swap_cgroup.h>
> +#include <linux/vmalloc.h>
> +#include <linux/mm.h>
> +
> +#include <linux/swapops.h> /* depends on mm.h include */
> +
> +static DEFINE_MUTEX(swap_cgroup_mutex);
> +struct swap_cgroup_ctrl {
> + struct page **map;
> + unsigned long length;
> + spinlock_t lock;
> +};
> +
> +static struct swap_cgroup_ctrl swap_cgroup_ctrl[MAX_SWAPFILES];
> +
> +struct swap_cgroup {
> + unsigned short id;
> +};
> +#define SC_PER_PAGE (PAGE_SIZE/sizeof(struct swap_cgroup))
> +
> +/*
> + * SwapCgroup implements "lookup" and "exchange" operations.
> + * In typical usage, this swap_cgroup is accessed via memcg's charge/uncharge
> + * against SwapCache. At swap_free(), this is accessed directly from swap.
> + *
> + * This means,
> + * - we have no race in "exchange" when we're accessed via SwapCache because
> + * SwapCache(and its swp_entry) is under lock.
> + * - When called via swap_free(), there is no user of this entry and no race.
> + * Then, we don't need lock around "exchange".
> + *
> + * TODO: we can push these buffers out to HIGHMEM.
> + */
> +
> +/*
> + * allocate buffer for swap_cgroup.
> + */
> +static int swap_cgroup_prepare(int type)
> +{
> + struct page *page;
> + struct swap_cgroup_ctrl *ctrl;
> + unsigned long idx, max;
> +
> + ctrl = &swap_cgroup_ctrl[type];
> +
> + for (idx = 0; idx < ctrl->length; idx++) {
> + page = alloc_page(GFP_KERNEL | __GFP_ZERO);
> + if (!page)
> + goto not_enough_page;
> + ctrl->map[idx] = page;
> + }
> + return 0;
> +not_enough_page:
> + max = idx;
> + for (idx = 0; idx < max; idx++)
> + __free_page(ctrl->map[idx]);
> +
> + return -ENOMEM;
> +}
> +
> +static struct swap_cgroup *lookup_swap_cgroup(swp_entry_t ent,
> + struct swap_cgroup_ctrl **ctrlp)
> +{
> + pgoff_t offset = swp_offset(ent);
> + struct swap_cgroup_ctrl *ctrl;
> + struct page *mappage;
> + struct swap_cgroup *sc;
> +
> + ctrl = &swap_cgroup_ctrl[swp_type(ent)];
> + if (ctrlp)
> + *ctrlp = ctrl;
> +
> + mappage = ctrl->map[offset / SC_PER_PAGE];
> + sc = page_address(mappage);
> + return sc + offset % SC_PER_PAGE;
> +}
> +
> +/**
> + * swap_cgroup_cmpxchg - cmpxchg mem_cgroup's id for this swp_entry.
> + * @ent: swap entry to be cmpxchged
> + * @old: old id
> + * @new: new id
> + *
> + * Returns old id at success, 0 at failure.
> + * (There is no mem_cgroup using 0 as its id)
> + */
> +unsigned short swap_cgroup_cmpxchg(swp_entry_t ent,
> + unsigned short old, unsigned short new)
> +{
> + struct swap_cgroup_ctrl *ctrl;
> + struct swap_cgroup *sc;
> + unsigned long flags;
> + unsigned short retval;
> +
> + sc = lookup_swap_cgroup(ent, &ctrl);
> +
> + spin_lock_irqsave(&ctrl->lock, flags);
> + retval = sc->id;
> + if (retval == old)
> + sc->id = new;
> + else
> + retval = 0;
> + spin_unlock_irqrestore(&ctrl->lock, flags);
> + return retval;
> +}
> +
> +/**
> + * swap_cgroup_record - record mem_cgroup for this swp_entry.
> + * @ent: swap entry to be recorded into
> + * @id: mem_cgroup to be recorded
> + *
> + * Returns old value at success, 0 at failure.
> + * (Of course, old value can be 0.)
> + */
> +unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id)
> +{
> + struct swap_cgroup_ctrl *ctrl;
> + struct swap_cgroup *sc;
> + unsigned short old;
> + unsigned long flags;
> +
> + sc = lookup_swap_cgroup(ent, &ctrl);
> +
> + spin_lock_irqsave(&ctrl->lock, flags);
> + old = sc->id;
> + sc->id = id;
> + spin_unlock_irqrestore(&ctrl->lock, flags);
> +
> + return old;
> +}
> +
> +/**
> + * lookup_swap_cgroup_id - lookup mem_cgroup id tied to swap entry
> + * @ent: swap entry to be looked up.
> + *
> + * Returns ID of mem_cgroup at success. 0 at failure. (0 is invalid ID)
> + */
> +unsigned short lookup_swap_cgroup_id(swp_entry_t ent)
> +{
> + return lookup_swap_cgroup(ent, NULL)->id;
> +}
> +
> +int swap_cgroup_swapon(int type, unsigned long max_pages)
> +{
> + void *array;
> + unsigned long array_size;
> + unsigned long length;
> + struct swap_cgroup_ctrl *ctrl;
> +
> + if (!do_swap_account)
> + return 0;
> +
> + length = DIV_ROUND_UP(max_pages, SC_PER_PAGE);
> + array_size = length * sizeof(void *);
> +
> + array = vzalloc(array_size);
> + if (!array)
> + goto nomem;
> +
> + ctrl = &swap_cgroup_ctrl[type];
> + mutex_lock(&swap_cgroup_mutex);
> + ctrl->length = length;
> + ctrl->map = array;
> + spin_lock_init(&ctrl->lock);
> + if (swap_cgroup_prepare(type)) {
> + /* memory shortage */
> + ctrl->map = NULL;
> + ctrl->length = 0;
> + mutex_unlock(&swap_cgroup_mutex);
> + vfree(array);
> + goto nomem;
> + }
> + mutex_unlock(&swap_cgroup_mutex);
> +
> + return 0;
> +nomem:
> + printk(KERN_INFO "couldn't allocate enough memory for swap_cgroup.\n");
> + printk(KERN_INFO
> + "swap_cgroup can be disabled by swapaccount=0 boot option\n");
> + return -ENOMEM;
> +}
> +
> +void swap_cgroup_swapoff(int type)
> +{
> + struct page **map;
> + unsigned long i, length;
> + struct swap_cgroup_ctrl *ctrl;
> +
> + if (!do_swap_account)
> + return;
> +
> + mutex_lock(&swap_cgroup_mutex);
> + ctrl = &swap_cgroup_ctrl[type];
> + map = ctrl->map;
> + length = ctrl->length;
> + ctrl->map = NULL;
> + ctrl->length = 0;
> + mutex_unlock(&swap_cgroup_mutex);
> +
> + if (map) {
> + for (i = 0; i < length; i++) {
> + struct page *page = map[i];
> + if (page)
> + __free_page(page);
> + }
> + vfree(map);
> + }
> +}
> diff --git a/mm/swap_state.c b/mm/swap_state.c
> index 154444918685..9711342987a0 100644
> --- a/mm/swap_state.c
> +++ b/mm/swap_state.c
> @@ -17,7 +17,6 @@
> #include <linux/blkdev.h>
> #include <linux/pagevec.h>
> #include <linux/migrate.h>
> -#include <linux/page_cgroup.h>
>
> #include <asm/pgtable.h>
>
> diff --git a/mm/swapfile.c b/mm/swapfile.c
> index 8798b2e0ac59..63f55ccb9b26 100644
> --- a/mm/swapfile.c
> +++ b/mm/swapfile.c
> @@ -38,7 +38,7 @@
> #include <asm/pgtable.h>
> #include <asm/tlbflush.h>
> #include <linux/swapops.h>
> -#include <linux/page_cgroup.h>
> +#include <linux/swap_cgroup.h>
>
> static bool swap_count_continued(struct swap_info_struct *, pgoff_t,
> unsigned char);
> --
> 2.1.3
>
--
Michal Hocko
SUSE Labs
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