similar to: [PATCH v3 00/16] Support non-lru page migration

Recently, I got many reports about perfermance degradation in embedded system(Android mobile phone, webOS TV and so on) and failed to fork easily. The problem was fragmentation caused by zram and GPU driver pages. Their pages cannot be migrated so compaction cannot work well, either so reclaimer ends up shrinking all of working set pages. It made system very slow and even to fail to fork easily.

Recently, I got many reports about perfermance degradation in embedded system(Android mobile phone, webOS TV and so on) and failed to fork easily. The problem was fragmentation caused by zram and GPU driver pages. Their pages cannot be migrated so compaction cannot work well, either so reclaimer ends up shrinking all of working set pages. It made system very slow and even to fail to fork easily.

Recently, I got many reports about perfermance degradation in embedded system(Android mobile phone, webOS TV and so on) and failed to fork easily. The problem was fragmentation caused by zram and GPU driver pages. Their pages cannot be migrated so compaction cannot work well, either so reclaimer ends up shrinking all of working set pages. It made system very slow and even to fail to fork easily.

Recently, I got many reports about perfermance degradation in embedded system(Android mobile phone, webOS TV and so on) and failed to fork easily. The problem was fragmentation caused by zram and GPU driver pages. Their pages cannot be migrated so compaction cannot work well, either so reclaimer ends up shrinking all of working set pages. It made system very slow and even to fail to fork easily.

Hi Minchan, [auto build test WARNING on next-20160318] [cannot apply to v4.5-rc7 v4.5-rc6 v4.5-rc5 v4.5] [if your patch is applied to the wrong git tree, please drop us a note to help improving the system] url: https://github.com/0day-ci/linux/commits/Minchan-Kim/Support-non-lru-page-migration/20160321-143339 coccinelle warnings: (new ones prefixed by >>) >>

Hi Minchan, [auto build test WARNING on next-20160318] [cannot apply to v4.5-rc7 v4.5-rc6 v4.5-rc5 v4.5] [if your patch is applied to the wrong git tree, please drop us a note to help improving the system] url: https://github.com/0day-ci/linux/commits/Minchan-Kim/Support-non-lru-page-migration/20160321-143339 coccinelle warnings: (new ones prefixed by >>) >>

On 2016/3/11 15:30, Minchan Kim wrote: > Every zspage in a size_class has same number of max objects so > we could move it to a size_class. > > Signed-off-by: Minchan Kim <minchan at kernel.org> > --- > mm/zsmalloc.c | 29 ++++++++++++++--------------- > 1 file changed, 14 insertions(+), 15 deletions(-) > > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c > index

On 2016/3/11 15:30, Minchan Kim wrote: > Every zspage in a size_class has same number of max objects so > we could move it to a size_class. > > Signed-off-by: Minchan Kim <minchan at kernel.org> > --- > mm/zsmalloc.c | 29 ++++++++++++++--------------- > 1 file changed, 14 insertions(+), 15 deletions(-) > > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c > index

Hello Minchan, On (03/30/16 16:12), Minchan Kim wrote: [..] > @@ -1835,23 +1827,31 @@ static void __zs_compact(struct zs_pool *pool, struct size_class *class) > if (!migrate_zspage(pool, class, &cc)) > break; > > - putback_zspage(pool, class, dst_page); > + VM_BUG_ON_PAGE(putback_zspage(pool, class, > + dst_page) == ZS_EMPTY, dst_page); can this

Hello Minchan, On (03/30/16 16:12), Minchan Kim wrote: [..] > @@ -1835,23 +1827,31 @@ static void __zs_compact(struct zs_pool *pool, struct size_class *class) > if (!migrate_zspage(pool, class, &cc)) > break; > > - putback_zspage(pool, class, dst_page); > + VM_BUG_ON_PAGE(putback_zspage(pool, class, > + dst_page) == ZS_EMPTY, dst_page); can this

On 2016/3/11 15:30, Minchan Kim wrote: > For migration, we need to create sub-page chain of zspage > dynamically so this patch factors it out from alloc_zspage. > > As a minor refactoring, it makes OBJ_ALLOCATED_TAG assign > more clear in obj_malloc(it could be another patch but it's > trivial so I want to put together in this patch). > > Signed-off-by: Minchan Kim

On 2016/3/11 15:30, Minchan Kim wrote: > For migration, we need to create sub-page chain of zspage > dynamically so this patch factors it out from alloc_zspage. > > As a minor refactoring, it makes OBJ_ALLOCATED_TAG assign > more clear in obj_malloc(it could be another patch but it's > trivial so I want to put together in this patch). > > Signed-off-by: Minchan Kim

Hello, On (03/30/16 16:12), Minchan Kim wrote: [..] > +static int get_zspage_inuse(struct page *first_page) > +{ > + struct zs_meta *m; > + > + VM_BUG_ON_PAGE(!is_first_page(first_page), first_page); > + > + m = (struct zs_meta *)&first_page->mapping; .. > +static void set_zspage_inuse(struct page *first_page, int val) > +{ > + struct zs_meta *m; > + > +

Hello, On (03/30/16 16:12), Minchan Kim wrote: [..] > +static int get_zspage_inuse(struct page *first_page) > +{ > + struct zs_meta *m; > + > + VM_BUG_ON_PAGE(!is_first_page(first_page), first_page); > + > + m = (struct zs_meta *)&first_page->mapping; .. > +static void set_zspage_inuse(struct page *first_page, int val) > +{ > + struct zs_meta *m; > + > +

On (03/11/16 16:30), Minchan Kim wrote: > -static void *location_to_obj(struct page *page, unsigned long obj_idx) > +static void objidx_to_page_and_ofs(struct size_class *class, > + struct page *first_page, > + unsigned long obj_idx, > + struct page **obj_page, > + unsigned long *ofs_in_page) this looks big; 5 params, function "returning" both page and

On (03/11/16 16:30), Minchan Kim wrote: > -static void *location_to_obj(struct page *page, unsigned long obj_idx) > +static void objidx_to_page_and_ofs(struct size_class *class, > + struct page *first_page, > + unsigned long obj_idx, > + struct page **obj_page, > + unsigned long *ofs_in_page) this looks big; 5 params, function "returning" both page and

On 2016/3/15 14:51, Minchan Kim wrote: > On Tue, Mar 15, 2016 at 03:40:53PM +0900, Sergey Senozhatsky wrote: >> On (03/11/16 16:30), Minchan Kim wrote: >>> -static void *location_to_obj(struct page *page, unsigned long obj_idx) >>> +static void objidx_to_page_and_ofs(struct size_class *class, >>> + struct page *first_page, >>> + unsigned long

On 2016/3/15 14:51, Minchan Kim wrote: > On Tue, Mar 15, 2016 at 03:40:53PM +0900, Sergey Senozhatsky wrote: >> On (03/11/16 16:30), Minchan Kim wrote: >>> -static void *location_to_obj(struct page *page, unsigned long obj_idx) >>> +static void objidx_to_page_and_ofs(struct size_class *class, >>> + struct page *first_page, >>> + unsigned long

This patch enables tail page migration of zspage. In this point, I tested zsmalloc regression with micro-benchmark which does zs_malloc/map/unmap/zs_free for all size class in every CPU(my system is 12) during 20 sec. It shows 1% regression which is really small when we consider the benefit of this feature and realworkload overhead(i.e., most overhead comes from compression). Signed-off-by:

Currently, putback_zspage does free zspage under class->lock if fullness become ZS_EMPTY but it makes trouble to implement locking scheme for new zspage migration. So, this patch is to separate free_zspage from putback_zspage and free zspage out of class->lock which is preparation for zspage migration. Signed-off-by: Minchan Kim <minchan at kernel.org> --- mm/zsmalloc.c | 46