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Message-ID: <4B17D506.7030701@gmail.com>
Date: Fri, 04 Dec 2009 00:11:02 +0900
From: Minchan Kim <minchan.kim@...il.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
CC: "linux-mm@...ck.org" <linux-mm@...ck.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
cl@...ux-foundation.org,
"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
yanmin_zhang@...ux.intel.com
Subject: Re: [RFC][mmotm][PATCH] percpu mm struct counter cache
Hi, Kame.
KAMEZAWA Hiroyuki wrote:
> Christophs's mm_counter+percpu implemtation has scalability at updates but
> read-side had some problems. Inspired by that, I tried to write percpu-cache
> counter + synchronization method. My own tiny benchmark shows something good
> but this patch's hooks may summon other troubles...
>
> Now, I start from sharing codes here. Any comments are welcome.
> (Especially, moving hooks to somewhere better is my concern.)
> My test proram will be posted in reply to this mail.
>
> Regards,
> -Kame
> ==
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
>
> This patch is for implemanting light-weight per-mm statistics.
> Now, when split-pagetable-lock is used, statistics per mm struct
> is maintainer by atomic_long_t value. This costs one atomic_inc()
> under page_table_lock and if multi-thread program runs and shares
> mm_struct, this tend to cause cache-miss+atomic_ops.
Both cases are (page_table_lock + atomic inc) cost?
AFAIK,
If we don't use split lock, we get the just spinlock of page_table_lock.
If we use split lock, we get the just atomic_op cost + page->ptl lock.
In case of split lock, ptl lock contention for rss accounting is little, I think.
If I am wrong, could you write down changelog more clearly?
>
> This patch adds per-cpu mm statistics cache and sync it in periodically.
> Cached Information are synchronized into mm_struct at
> - tick
> - context_switch.
> if there is difference.
Should we sync mm statistics periodically?
Couldn't we sync statistics when we need it?
ex) get_mm_counter.
I am not sure it's possible. :)
>
> Tiny test progam on x86-64/4core/2socket machine shows (small) improvements.
> This test program measures # of page faults on cpu 0 and 4.
> (Using all 8cpus, most of time is used for spinlock and you can't see
> benefits of this patch..)
>
> [Before Patch]
> Performance counter stats for './multi-fault 2' (5 runs):
>
> 44282223 page-faults ( +- 0.912% )
> 1015540330 cache-references ( +- 1.701% )
> 210497140 cache-misses ( +- 0.731% )
> 29262804803383988 bus-cycles ( +- 0.003% )
>
> 60.003401467 seconds time elapsed ( +- 0.004% )
>
> 4.75 miss/faults
> 660825108.1564714580837551899777 bus-cycles/faults
>
> [After Patch]
> Performance counter stats for './multi-fault 2' (5 runs):
>
> 45543398 page-faults ( +- 0.499% )
> 1031865896 cache-references ( +- 2.720% )
> 184901499 cache-misses ( +- 0.626% )
> 29261889737265056 bus-cycles ( +- 0.002% )
>
> 60.001218501 seconds time elapsed ( +- 0.000% )
>
> 4.05 miss/faults
> 642505632.5 bus-cycles/faults
>
> Note: to enable split-pagetable-lock, you have to disable SPINLOCK_DEBUG.
>
> This patch moves mm_counter definitions to mm.h+memory.c from sched.h.
> So, total patch size seems to be big.
What's your goal/benefit?
You cut down atomic operations with (cache and sync) method?
Please, write down the your goal/benefit. :)
>
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
> ---
> fs/proc/task_mmu.c | 4 -
> include/linux/mm.h | 55 ++++++++++++++++++
> include/linux/mm_types.h | 23 +++++--
> include/linux/sched.h | 54 ------------------
> kernel/exit.c | 4 +
> kernel/fork.c | 3 -
> kernel/sched.c | 1
> kernel/timer.c | 2
> mm/filemap_xip.c | 2
> mm/fremap.c | 2
> mm/memory.c | 139 ++++++++++++++++++++++++++++++++++++++++++-----
> mm/oom_kill.c | 4 -
> mm/rmap.c | 10 +--
> mm/swapfile.c | 2
> 14 files changed, 217 insertions(+), 88 deletions(-)
>
> Index: mmotm-2.6.32-Nov24/include/linux/mm_types.h
> ===================================================================
> --- mmotm-2.6.32-Nov24.orig/include/linux/mm_types.h
> +++ mmotm-2.6.32-Nov24/include/linux/mm_types.h
> @@ -24,11 +24,6 @@ struct address_space;
>
> #define USE_SPLIT_PTLOCKS (NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS)
>
> -#if USE_SPLIT_PTLOCKS
> -typedef atomic_long_t mm_counter_t;
> -#else /* !USE_SPLIT_PTLOCKS */
> -typedef unsigned long mm_counter_t;
> -#endif /* !USE_SPLIT_PTLOCKS */
>
> /*
> * Each physical page in the system has a struct page associated with
> @@ -199,6 +194,21 @@ struct core_state {
> struct completion startup;
> };
>
> +/*
> + * for per-mm accounting.
> + */
> +#if USE_SPLIT_PTLOCKS
> +typedef atomic_long_t mm_counter_t;
> +#else /* !USE_SPLIT_PTLOCKS */
> +typedef unsigned long mm_counter_t;
> +#endif /* !USE_SPLIT_PTLOCKS */
> +
> +enum {
> + MM_FILEPAGES,
> + MM_ANONPAGES,
> + NR_MM_STATS,
> +};
> +
> struct mm_struct {
> struct vm_area_struct * mmap; /* list of VMAs */
> struct rb_root mm_rb;
> @@ -226,8 +236,7 @@ struct mm_struct {
> /* Special counters, in some configurations protected by the
> * page_table_lock, in other configurations by being atomic.
> */
> - mm_counter_t _file_rss;
> - mm_counter_t _anon_rss;
> + mm_counter_t counters[NR_MM_STATS];
>
> unsigned long hiwater_rss; /* High-watermark of RSS usage */
> unsigned long hiwater_vm; /* High-water virtual memory usage */
> Index: mmotm-2.6.32-Nov24/include/linux/sched.h
> ===================================================================
> --- mmotm-2.6.32-Nov24.orig/include/linux/sched.h
> +++ mmotm-2.6.32-Nov24/include/linux/sched.h
> @@ -385,60 +385,6 @@ arch_get_unmapped_area_topdown(struct fi
> extern void arch_unmap_area(struct mm_struct *, unsigned long);
> extern void arch_unmap_area_topdown(struct mm_struct *, unsigned long);
>
> -#if USE_SPLIT_PTLOCKS
> -/*
> - * The mm counters are not protected by its page_table_lock,
> - * so must be incremented atomically.
> - */
> -#define set_mm_counter(mm, member, value) atomic_long_set(&(mm)->_##member, value)
> -#define get_mm_counter(mm, member) ((unsigned long)atomic_long_read(&(mm)->_##member))
> -#define add_mm_counter(mm, member, value) atomic_long_add(value, &(mm)->_##member)
> -#define inc_mm_counter(mm, member) atomic_long_inc(&(mm)->_##member)
> -#define dec_mm_counter(mm, member) atomic_long_dec(&(mm)->_##member)
> -
> -#else /* !USE_SPLIT_PTLOCKS */
> -/*
> - * The mm counters are protected by its page_table_lock,
> - * so can be incremented directly.
> - */
> -#define set_mm_counter(mm, member, value) (mm)->_##member = (value)
> -#define get_mm_counter(mm, member) ((mm)->_##member)
> -#define add_mm_counter(mm, member, value) (mm)->_##member += (value)
> -#define inc_mm_counter(mm, member) (mm)->_##member++
> -#define dec_mm_counter(mm, member) (mm)->_##member--
> -
> -#endif /* !USE_SPLIT_PTLOCKS */
> -
> -#define get_mm_rss(mm) \
> - (get_mm_counter(mm, file_rss) + get_mm_counter(mm, anon_rss))
> -#define update_hiwater_rss(mm) do { \
> - unsigned long _rss = get_mm_rss(mm); \
> - if ((mm)->hiwater_rss < _rss) \
> - (mm)->hiwater_rss = _rss; \
> -} while (0)
> -#define update_hiwater_vm(mm) do { \
> - if ((mm)->hiwater_vm < (mm)->total_vm) \
> - (mm)->hiwater_vm = (mm)->total_vm; \
> -} while (0)
> -
> -static inline unsigned long get_mm_hiwater_rss(struct mm_struct *mm)
> -{
> - return max(mm->hiwater_rss, get_mm_rss(mm));
> -}
> -
> -static inline void setmax_mm_hiwater_rss(unsigned long *maxrss,
> - struct mm_struct *mm)
> -{
> - unsigned long hiwater_rss = get_mm_hiwater_rss(mm);
> -
> - if (*maxrss < hiwater_rss)
> - *maxrss = hiwater_rss;
> -}
> -
> -static inline unsigned long get_mm_hiwater_vm(struct mm_struct *mm)
> -{
> - return max(mm->hiwater_vm, mm->total_vm);
> -}
>
> extern void set_dumpable(struct mm_struct *mm, int value);
> extern int get_dumpable(struct mm_struct *mm);
> Index: mmotm-2.6.32-Nov24/mm/memory.c
> ===================================================================
> --- mmotm-2.6.32-Nov24.orig/mm/memory.c
> +++ mmotm-2.6.32-Nov24/mm/memory.c
> @@ -121,6 +121,115 @@ static int __init init_zero_pfn(void)
> }
> core_initcall(init_zero_pfn);
>
> +
> +#ifdef USE_SPLIT_PTLOCKS
> +
> +struct pcp_mm_cache {
> + struct mm_struct *mm;
> + long counters[NR_MM_STATS];
> +};
> +static DEFINE_PER_CPU(struct pcp_mm_cache, curr_mmc);
> +/*
> + * The mm counters are not protected by its page_table_lock,
> + * so must be incremented atomically.
> + */
> +void set_mm_counter(struct mm_struct *mm, int member, long value)
> +{
> + atomic_long_set(&mm->counters[member], value);
> +}
> +
> +unsigned long get_mm_counter(struct mm_struct *mm, int member)
> +{
> + long ret = atomic_long_read(&mm->counters[member]);
Which case do we get the minus 'ret'?
> + if (ret < 0)
> + return 0;
> + return ret;
> +}
> +
> +void add_mm_counter(struct mm_struct *mm, int member, long value)
> +{
> + atomic_long_add(value, &mm->counters[member]);
> +}
> +
> +/*
> + * Always called under pte_lock....irq off, mm != curr_mmc.mm if called
> + * by get_user_pages() etc.
> + */
> +static void
> +add_mm_counter_fast(struct mm_struct *mm, int member, long val)
> +{
> + if (likely(percpu_read(curr_mmc.mm) == mm))
> + percpu_add(curr_mmc.counters[member], val);
> + else
> + add_mm_counter(mm, member, val);
> +}
> +
> +/* Called by not-preemptable context */
non-preemptible
> +void sync_tsk_mm_counters(void)
> +{
> + struct pcp_mm_cache *cache = &per_cpu(curr_mmc, smp_processor_id());
> + int i;
> +
> + if (!cache->mm)
> + return;
> +
> + for (i = 0; i < NR_MM_STATS; i++) {
> + if (!cache->counters[i])
> + continue;
> + add_mm_counter(cache->mm, i, cache->counters[i]);
> + cache->counters[i] = 0;
> + }
> +}
> +
> +void prepare_mm_switch(struct task_struct *prev, struct task_struct *next)
> +{
> + if (prev->mm == next->mm)
> + return;
> + /* If task is exited, sync is already done and prev->mm is NULL */
> + if (prev->mm)
> + sync_tsk_mm_counters();
> + percpu_write(curr_mmc.mm, next->mm);
> +}
Further optimization.
In case of (A-> kernel thread -> A), we don't need sync only if
we update statistics when we need it as i suggested.
> +
> +#else /* !USE_SPLIT_PTLOCKS */
> +/*
> + * The mm counters are protected by its page_table_lock,
> + * so can be incremented directly.
> + */
> +void set_mm_counter(struct mm_struct *mm, int member, long value)
> +{
> + mm->counters[member] = value;
> +}
> +
> +unsigned long get_mm_counter(struct mm_struct *mm, int member)
> +{
> + return mm->counters[member];
> +}
> +
> +void add_mm_counter(struct mm_struct *mm, int member, long val)
> +{
> + mm->counters[member] += val;
> +}
> +
> +void sync_tsk_mm_counters(struct task_struct *tsk)
> +{
> +}
> +
> +#define add_mm_counter_fast(mm, member, val) add_mm_counter(mm, member, val)
> +
> +#endif /* !USE_SPLIT_PTLOCKS */
> +/* Special asynchronous routine for page fault path */
> +#define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1)
> +#define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1)
> +
> +void init_mm_counters(struct mm_struct *mm)
> +{
> + int i;
> +
> + for (i = 0; i < NR_MM_STATS; i++)
> + set_mm_counter(mm, i, 0);
> +}
> +
> /*
> * If a p?d_bad entry is found while walking page tables, report
> * the error, before resetting entry to p?d_none. Usually (but
> @@ -378,10 +487,11 @@ int __pte_alloc_kernel(pmd_t *pmd, unsig
>
> static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
> {
> + /* use synchronous updates here */
> if (file_rss)
> - add_mm_counter(mm, file_rss, file_rss);
> + add_mm_counter(mm, MM_FILEPAGES, file_rss);
We can divide MM_[FILEP|ANON]AGES on another patches.
Things like rss[0] and rss[1] were not good.
> if (anon_rss)
> - add_mm_counter(mm, anon_rss, anon_rss);
> + add_mm_counter(mm, MM_ANONPAGES, anon_rss);
> }
>
> /*
> @@ -632,7 +742,10 @@ copy_one_pte(struct mm_struct *dst_mm, s
> if (page) {
> get_page(page);
> page_dup_rmap(page);
> - rss[PageAnon(page)]++;
> + if (PageAnon(page))
> + rss[MM_ANONPAGES]++;
> + else
> + rss[MM_FILEPAGES]++;
> }
>
> out_set_pte:
> @@ -648,7 +761,7 @@ static int copy_pte_range(struct mm_stru
> pte_t *src_pte, *dst_pte;
> spinlock_t *src_ptl, *dst_ptl;
> int progress = 0;
> - int rss[2];
> + int rss[NR_MM_STATS];
> swp_entry_t entry = (swp_entry_t){0};
>
> again:
> @@ -688,7 +801,7 @@ again:
> arch_leave_lazy_mmu_mode();
> spin_unlock(src_ptl);
> pte_unmap_nested(orig_src_pte);
> - add_mm_rss(dst_mm, rss[0], rss[1]);
> + add_mm_rss(dst_mm, rss[MM_FILEPAGES], rss[MM_ANONPAGES]);
> pte_unmap_unlock(orig_dst_pte, dst_ptl);
> cond_resched();
>
> @@ -1527,7 +1640,7 @@ static int insert_page(struct vm_area_st
>
> /* Ok, finally just insert the thing.. */
> get_page(page);
> - inc_mm_counter(mm, file_rss);
> + inc_mm_counter_fast(mm, MM_FILEPAGES);
> page_add_file_rmap(page);
> set_pte_at(mm, addr, pte, mk_pte(page, prot));
>
> @@ -2163,11 +2276,11 @@ gotten:
> if (likely(pte_same(*page_table, orig_pte))) {
> if (old_page) {
> if (!PageAnon(old_page)) {
> - dec_mm_counter(mm, file_rss);
> - inc_mm_counter(mm, anon_rss);
> + dec_mm_counter_fast(mm, MM_FILEPAGES);
> + inc_mm_counter_fast(mm, MM_ANONPAGES);
> }
> } else
> - inc_mm_counter(mm, anon_rss);
> + inc_mm_counter_fast(mm, MM_ANONPAGES);
> flush_cache_page(vma, address, pte_pfn(orig_pte));
> entry = mk_pte(new_page, vma->vm_page_prot);
> entry = maybe_mkwrite(pte_mkdirty(entry), vma);
> @@ -2600,7 +2713,7 @@ static int do_swap_page(struct mm_struct
> * discarded at swap_free().
> */
>
> - inc_mm_counter(mm, anon_rss);
> + inc_mm_counter_fast(mm, MM_ANONPAGES);
> pte = mk_pte(page, vma->vm_page_prot);
> if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {
> pte = maybe_mkwrite(pte_mkdirty(pte), vma);
> @@ -2684,7 +2797,7 @@ static int do_anonymous_page(struct mm_s
> if (!pte_none(*page_table))
> goto release;
>
> - inc_mm_counter(mm, anon_rss);
> + inc_mm_counter_fast(mm, MM_ANONPAGES);
> page_add_new_anon_rmap(page, vma, address);
> setpte:
> set_pte_at(mm, address, page_table, entry);
> @@ -2838,10 +2951,10 @@ static int __do_fault(struct mm_struct *
> if (flags & FAULT_FLAG_WRITE)
> entry = maybe_mkwrite(pte_mkdirty(entry), vma);
> if (anon) {
> - inc_mm_counter(mm, anon_rss);
> + inc_mm_counter_fast(mm, MM_ANONPAGES);
> page_add_new_anon_rmap(page, vma, address);
> } else {
> - inc_mm_counter(mm, file_rss);
> + inc_mm_counter_fast(mm, MM_FILEPAGES);
> page_add_file_rmap(page);
> if (flags & FAULT_FLAG_WRITE) {
> dirty_page = page;
> Index: mmotm-2.6.32-Nov24/kernel/fork.c
> ===================================================================
> --- mmotm-2.6.32-Nov24.orig/kernel/fork.c
> +++ mmotm-2.6.32-Nov24/kernel/fork.c
> @@ -452,8 +452,7 @@ static struct mm_struct * mm_init(struct
> (current->mm->flags & MMF_INIT_MASK) : default_dump_filter;
> mm->core_state = NULL;
> mm->nr_ptes = 0;
> - set_mm_counter(mm, file_rss, 0);
> - set_mm_counter(mm, anon_rss, 0);
> + init_mm_counters(mm);
> spin_lock_init(&mm->page_table_lock);
> mm->free_area_cache = TASK_UNMAPPED_BASE;
> mm->cached_hole_size = ~0UL;
> Index: mmotm-2.6.32-Nov24/mm/fremap.c
> ===================================================================
> --- mmotm-2.6.32-Nov24.orig/mm/fremap.c
> +++ mmotm-2.6.32-Nov24/mm/fremap.c
> @@ -40,7 +40,7 @@ static void zap_pte(struct mm_struct *mm
> page_remove_rmap(page);
> page_cache_release(page);
> update_hiwater_rss(mm);
> - dec_mm_counter(mm, file_rss);
> + dec_mm_counter(mm, MM_FILEPAGES);
> }
> } else {
> if (!pte_file(pte))
> Index: mmotm-2.6.32-Nov24/mm/rmap.c
> ===================================================================
> --- mmotm-2.6.32-Nov24.orig/mm/rmap.c
> +++ mmotm-2.6.32-Nov24/mm/rmap.c
> @@ -815,9 +815,9 @@ int try_to_unmap_one(struct page *page,
>
> if (PageHWPoison(page) && !(flags & TTU_IGNORE_HWPOISON)) {
> if (PageAnon(page))
> - dec_mm_counter(mm, anon_rss);
> + dec_mm_counter(mm, MM_ANONPAGES);
> else
> - dec_mm_counter(mm, file_rss);
> + dec_mm_counter(mm, MM_FILEPAGES);
> set_pte_at(mm, address, pte,
> swp_entry_to_pte(make_hwpoison_entry(page)));
> } else if (PageAnon(page)) {
> @@ -839,7 +839,7 @@ int try_to_unmap_one(struct page *page,
> list_add(&mm->mmlist, &init_mm.mmlist);
> spin_unlock(&mmlist_lock);
> }
> - dec_mm_counter(mm, anon_rss);
> + dec_mm_counter(mm, MM_ANONPAGES);
> } else if (PAGE_MIGRATION) {
> /*
> * Store the pfn of the page in a special migration
> @@ -857,7 +857,7 @@ int try_to_unmap_one(struct page *page,
> entry = make_migration_entry(page, pte_write(pteval));
> set_pte_at(mm, address, pte, swp_entry_to_pte(entry));
> } else
> - dec_mm_counter(mm, file_rss);
> + dec_mm_counter(mm, MM_FILEPAGES);
>
> page_remove_rmap(page);
> page_cache_release(page);
> @@ -995,7 +995,7 @@ static int try_to_unmap_cluster(unsigned
>
> page_remove_rmap(page);
> page_cache_release(page);
> - dec_mm_counter(mm, file_rss);
> + dec_mm_counter(mm, MM_FILEPAGES);
> (*mapcount)--;
> }
> pte_unmap_unlock(pte - 1, ptl);
> Index: mmotm-2.6.32-Nov24/mm/swapfile.c
> ===================================================================
> --- mmotm-2.6.32-Nov24.orig/mm/swapfile.c
> +++ mmotm-2.6.32-Nov24/mm/swapfile.c
> @@ -839,7 +839,7 @@ static int unuse_pte(struct vm_area_stru
> goto out;
> }
>
> - inc_mm_counter(vma->vm_mm, anon_rss);
> + add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1);
Why can't we use inc_mm_counter_fast in here?
> get_page(page);
> set_pte_at(vma->vm_mm, addr, pte,
> pte_mkold(mk_pte(page, vma->vm_page_prot)));
> Index: mmotm-2.6.32-Nov24/kernel/timer.c
> ===================================================================
> --- mmotm-2.6.32-Nov24.orig/kernel/timer.c
> +++ mmotm-2.6.32-Nov24/kernel/timer.c
> @@ -1200,6 +1200,8 @@ void update_process_times(int user_tick)
> account_process_tick(p, user_tick);
> run_local_timers();
> rcu_check_callbacks(cpu, user_tick);
> + /* sync cached mm stat information */
> + sync_tsk_mm_counters();
> printk_tick();
> scheduler_tick();
> run_posix_cpu_timers(p);
> Index: mmotm-2.6.32-Nov24/mm/filemap_xip.c
> ===================================================================
> --- mmotm-2.6.32-Nov24.orig/mm/filemap_xip.c
> +++ mmotm-2.6.32-Nov24/mm/filemap_xip.c
> @@ -194,7 +194,7 @@ retry:
> flush_cache_page(vma, address, pte_pfn(*pte));
> pteval = ptep_clear_flush_notify(vma, address, pte);
> page_remove_rmap(page);
> - dec_mm_counter(mm, file_rss);
> + dec_mm_counter(mm, MM_FILEPAGES);
> BUG_ON(pte_dirty(pteval));
> pte_unmap_unlock(pte, ptl);
> page_cache_release(page);
> Index: mmotm-2.6.32-Nov24/include/linux/mm.h
> ===================================================================
> --- mmotm-2.6.32-Nov24.orig/include/linux/mm.h
> +++ mmotm-2.6.32-Nov24/include/linux/mm.h
> @@ -863,6 +863,61 @@ extern int mprotect_fixup(struct vm_area
> struct vm_area_struct **pprev, unsigned long start,
> unsigned long end, unsigned long newflags);
>
> +/* For per-mm stat accounting */
> +extern void set_mm_counter(struct mm_struct *mm, int member, long value);
> +extern unsigned long get_mm_counter(struct mm_struct *mm, int member);
> +extern void add_mm_counter(struct mm_struct *mm, int member, long value);
> +extern void sync_tsk_mm_counters(void);
> +extern void init_mm_counters(struct mm_struct *mm);
> +
> +#ifdef USE_SPLIT_PTLOCKS
> +extern void prepare_mm_switch(struct task_struct *prev,
> + struct task_struct *next);
> +#else
> +static inline prepare_mm_switch(struct task_struct *prev,
> + struct task_struct *next)
> +{
> +}
> +#endif
> +
> +#define inc_mm_counter(mm, member) add_mm_counter((mm), (member), 1)
> +#define dec_mm_counter(mm, member) add_mm_counter((mm), (member), -1)
> +
> +#define get_mm_rss(mm) \
> + (get_mm_counter(mm, MM_FILEPAGES) +\
> + get_mm_counter(mm, MM_ANONPAGES))
> +
> +#define update_hiwater_rss(mm) do { \
> + unsigned long _rss = get_mm_rss(mm); \
> + if ((mm)->hiwater_rss < _rss) \
> + (mm)->hiwater_rss = _rss; \
> +} while (0)
> +
> +#define update_hiwater_vm(mm) do { \
> + if ((mm)->hiwater_vm < (mm)->total_vm) \
> + (mm)->hiwater_vm = (mm)->total_vm; \
> +} while (0)
> +
> +static inline unsigned long get_mm_hiwater_rss(struct mm_struct *mm)
> +{
> + return max(mm->hiwater_rss, get_mm_rss(mm));
> +}
> +
> +static inline void setmax_mm_hiwater_rss(unsigned long *maxrss,
> + struct mm_struct *mm)
> +{
> + unsigned long hiwater_rss = get_mm_hiwater_rss(mm);
> +
> + if (*maxrss < hiwater_rss)
> + *maxrss = hiwater_rss;
> +}
> +
> +static inline unsigned long get_mm_hiwater_vm(struct mm_struct *mm)
> +{
> + return max(mm->hiwater_vm, mm->total_vm);
> +}
> +
> +
> /*
> * doesn't attempt to fault and will return short.
> */
> Index: mmotm-2.6.32-Nov24/fs/proc/task_mmu.c
> ===================================================================
> --- mmotm-2.6.32-Nov24.orig/fs/proc/task_mmu.c
> +++ mmotm-2.6.32-Nov24/fs/proc/task_mmu.c
> @@ -65,11 +65,11 @@ unsigned long task_vsize(struct mm_struc
> int task_statm(struct mm_struct *mm, int *shared, int *text,
> int *data, int *resident)
> {
> - *shared = get_mm_counter(mm, file_rss);
> + *shared = get_mm_counter(mm, MM_FILEPAGES);
> *text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
> >> PAGE_SHIFT;
> *data = mm->total_vm - mm->shared_vm;
> - *resident = *shared + get_mm_counter(mm, anon_rss);
> + *resident = *shared + get_mm_counter(mm, MM_ANONPAGES);
> return mm->total_vm;
> }
>
> Index: mmotm-2.6.32-Nov24/mm/oom_kill.c
> ===================================================================
> --- mmotm-2.6.32-Nov24.orig/mm/oom_kill.c
> +++ mmotm-2.6.32-Nov24/mm/oom_kill.c
> @@ -400,8 +400,8 @@ static void __oom_kill_task(struct task_
> "vsz:%lukB, anon-rss:%lukB, file-rss:%lukB\n",
> task_pid_nr(p), p->comm,
> K(p->mm->total_vm),
> - K(get_mm_counter(p->mm, anon_rss)),
> - K(get_mm_counter(p->mm, file_rss)));
> + K(get_mm_counter(p->mm, MM_ANONPAGES)),
> + K(get_mm_counter(p->mm, MM_FILEPAGES)));
> task_unlock(p);
>
> /*
> Index: mmotm-2.6.32-Nov24/kernel/exit.c
> ===================================================================
> --- mmotm-2.6.32-Nov24.orig/kernel/exit.c
> +++ mmotm-2.6.32-Nov24/kernel/exit.c
> @@ -681,6 +681,10 @@ static void exit_mm(struct task_struct *
> }
> atomic_inc(&mm->mm_count);
> BUG_ON(mm != tsk->active_mm);
> + /* drop cached information */
> + preempt_disable();
> + sync_tsk_mm_counters();
> + preempt_enable();
How about (get|put)_cpu in sync_tsk_mm_counters?
It disable and enable preemption.
> /* more a memory barrier than a real lock */
> task_lock(tsk);
> tsk->mm = NULL;
> Index: mmotm-2.6.32-Nov24/kernel/sched.c
> ===================================================================
> --- mmotm-2.6.32-Nov24.orig/kernel/sched.c
> +++ mmotm-2.6.32-Nov24/kernel/sched.c
> @@ -2858,6 +2858,7 @@ context_switch(struct rq *rq, struct tas
> trace_sched_switch(rq, prev, next);
> mm = next->mm;
> oldmm = prev->active_mm;
> + prepare_mm_switch(prev, next);
> /*
> * For paravirt, this is coupled with an exit in switch_to to
> * combine the page table reload and the switch backend into
>
I think code is not bad but I don't know how effective this patch is in practice.
Thanks for good effort. Kame. :)
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