Messages in this thread | | | Date | Wed, 25 Feb 2009 15:09:20 +0800 | From | Li Zefan <> | Subject | Re: [PATCH] use CSS ID in swap_cgroup for saving memory |
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> static inline > -struct mem_cgroup *swap_cgroup_record(swp_entry_t ent, struct mem_cgroup *mem) > +unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id) > { > return NULL;
return 0;
> } > > static inline > -struct mem_cgroup *lookup_swap_cgroup(swp_entry_t ent) > +unsigned short lookup_swap_cgroup(swp_entry_t ent) > { > return NULL;
return 0;
> }
> @@ -1265,12 +1286,20 @@ int mem_cgroup_cache_charge(struct page > > if (do_swap_account && !ret && PageSwapCache(page)) { > swp_entry_t ent = {.val = page_private(page)}; > + unsigned short id; > /* avoid double counting */ > - mem = swap_cgroup_record(ent, NULL); > + id = swap_cgroup_record(ent, 0); > + rcu_read_lock(); > + mem = mem_cgroup_lookup(id); > if (mem) { > + /* > + * Recorded ID can be obsolete. We avoid calling > + * css_tryget() > + */ > res_counter_uncharge(&mem->memsw, PAGE_SIZE); > mem_cgroup_put(mem); > } > + rcu_read_unlock(); > } > return ret; > } > @@ -1335,13 +1364,21 @@ void mem_cgroup_commit_charge_swapin(str > */ > if (do_swap_account && PageSwapCache(page)) { > swp_entry_t ent = {.val = page_private(page)}; > + unsigned short id; > struct mem_cgroup *memcg; > - memcg = swap_cgroup_record(ent, NULL); > + > + id = swap_cgroup_record(ent, 0); > + rcu_read_lock(); > + memcg = mem_cgroup_lookup(id); > if (memcg) { > + /* > + * This recorded memcg can be obsolete one. So, avoid > + * calling css_tryget > + */ > res_counter_uncharge(&memcg->memsw, PAGE_SIZE); > mem_cgroup_put(memcg); > } > - > + rcu_read_unlock(); > } > /* add this page(page_cgroup) to the LRU we want. */ > > @@ -1462,7 +1499,7 @@ void mem_cgroup_uncharge_swapcache(struc > MEM_CGROUP_CHARGE_TYPE_SWAPOUT); > /* record memcg information */ > if (do_swap_account && memcg) { > - swap_cgroup_record(ent, memcg); > + swap_cgroup_record(ent, css_id(&memcg->css)); > mem_cgroup_get(memcg); > } > if (memcg) > @@ -1477,15 +1514,22 @@ void mem_cgroup_uncharge_swapcache(struc > void mem_cgroup_uncharge_swap(swp_entry_t ent) > { > struct mem_cgroup *memcg; > + unsigned short id; > > if (!do_swap_account) > return; > > - memcg = swap_cgroup_record(ent, NULL); > + id = swap_cgroup_record(ent, 0); > + rcu_read_lock(); > + memcg = mem_cgroup_lookup(id); > if (memcg) { > + /* > + * This memcg can be obsolete one. We avoid calling css_tryget > + */ > res_counter_uncharge(&memcg->memsw, PAGE_SIZE); > mem_cgroup_put(memcg); > } > + rcu_read_unlock();
can we have a common function for the above 3 pieces of code?
> } > #endif > > Index: mmotm-2.6.29-Feb24/mm/page_cgroup.c > =================================================================== > --- mmotm-2.6.29-Feb24.orig/mm/page_cgroup.c > +++ mmotm-2.6.29-Feb24/mm/page_cgroup.c > @@ -290,7 +290,7 @@ struct swap_cgroup_ctrl swap_cgroup_ctrl > * cgroup rather than pointer. > */
this comment should be updated/removed:
/* * This 8bytes seems big..maybe we can reduce this when we can use "id" for * cgroup rather than pointer. */
> struct swap_cgroup { > - struct mem_cgroup *val; > + unsigned short id; > }; > #define SC_PER_PAGE (PAGE_SIZE/sizeof(struct swap_cgroup)) > #define SC_POS_MASK (SC_PER_PAGE - 1)
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