Re: [PATCH -mm -v10 3/3] mm, THP, swap: Enable THP swap optimization only if has compound map

2017-04-28 Thread Kirill A. Shutemov
On Tue, Apr 25, 2017 at 05:46:18PM -0400, Johannes Weiner wrote: > On Tue, Apr 25, 2017 at 08:56:58PM +0800, Huang, Ying wrote: > > From: Huang Ying > > > > If there is no compound map for a THP (Transparent Huge Page), it is > > possible that the map count of some

Re: [PATCH -mm -v10 3/3] mm, THP, swap: Enable THP swap optimization only if has compound map

2017-04-28 Thread Kirill A. Shutemov
On Tue, Apr 25, 2017 at 05:46:18PM -0400, Johannes Weiner wrote: > On Tue, Apr 25, 2017 at 08:56:58PM +0800, Huang, Ying wrote: > > From: Huang Ying > > > > If there is no compound map for a THP (Transparent Huge Page), it is > > possible that the map count of some sub-pages of the THP is 0. So

Re: [PATCH -mm -v10 3/3] mm, THP, swap: Enable THP swap optimization only if has compound map

2017-04-25 Thread Johannes Weiner
On Tue, Apr 25, 2017 at 08:56:58PM +0800, Huang, Ying wrote: > From: Huang Ying > > If there is no compound map for a THP (Transparent Huge Page), it is > possible that the map count of some sub-pages of the THP is 0. So it > is better to split the THP before swapping out.

Re: [PATCH -mm -v10 3/3] mm, THP, swap: Enable THP swap optimization only if has compound map

2017-04-25 Thread Johannes Weiner
On Tue, Apr 25, 2017 at 08:56:58PM +0800, Huang, Ying wrote: > From: Huang Ying > > If there is no compound map for a THP (Transparent Huge Page), it is > possible that the map count of some sub-pages of the THP is 0. So it > is better to split the THP before swapping out. In this way, the >

[PATCH -mm -v10 3/3] mm, THP, swap: Enable THP swap optimization only if has compound map

2017-04-25 Thread Huang, Ying
From: Huang Ying If there is no compound map for a THP (Transparent Huge Page), it is possible that the map count of some sub-pages of the THP is 0. So it is better to split the THP before swapping out. In this way, the sub-pages not mapped will be freed, and we can avoid

[PATCH -mm -v10 3/3] mm, THP, swap: Enable THP swap optimization only if has compound map

2017-04-25 Thread Huang, Ying
From: Huang Ying If there is no compound map for a THP (Transparent Huge Page), it is possible that the map count of some sub-pages of the THP is 0. So it is better to split the THP before swapping out. In this way, the sub-pages not mapped will be freed, and we can avoid the unnecessary swap