Re: [RFC PATCH 1/3] mm, memory_hotplug: try to migrate full section worth of pages

2018-11-20 Thread Michal Hocko
On Tue 20-11-18 15:51:32, Oscar Salvador wrote: > On Tue, 2018-11-20 at 14:43 +0100, Michal Hocko wrote: > > From: Michal Hocko > > > > do_migrate_range has been limiting the number of pages to migrate to > > 256 > > for some reason which is not documented. > > When looking back at old memory-h

Re: [RFC PATCH 1/3] mm, memory_hotplug: try to migrate full section worth of pages

2018-11-20 Thread osalvador
On Tue, 2018-11-20 at 14:43 +0100, Michal Hocko wrote: > From: Michal Hocko > > do_migrate_range has been limiting the number of pages to migrate to > 256 > for some reason which is not documented. When looking back at old memory-hotplug commits one feels pretty sad about the brevity of the cha

Re: [RFC PATCH 1/3] mm, memory_hotplug: try to migrate full section worth of pages

2018-11-20 Thread Pavel Tatashin
On 18-11-20 14:43:21, Michal Hocko wrote: > From: Michal Hocko > > do_migrate_range has been limiting the number of pages to migrate to 256 > for some reason which is not documented. Even if the limit made some > sense back then when it was introduced it doesn't really serve a good > purpose thes

Re: [RFC PATCH 1/3] mm, memory_hotplug: try to migrate full section worth of pages

2018-11-20 Thread David Hildenbrand
On 20.11.18 15:25, Michal Hocko wrote: > On Tue 20-11-18 15:18:41, David Hildenbrand wrote: > [...] >> (we could also check for pending signals inside that function if really >> required) > > do_migrate_pages is not the proper layer to check signals. Because the > loop only isolates pages and that

Re: [RFC PATCH 1/3] mm, memory_hotplug: try to migrate full section worth of pages

2018-11-20 Thread Michal Hocko
On Tue 20-11-18 15:18:41, David Hildenbrand wrote: [...] > (we could also check for pending signals inside that function if really > required) do_migrate_pages is not the proper layer to check signals. Because the loop only isolates pages and that is not expensive. The most expensive part is deepe

Re: [RFC PATCH 1/3] mm, memory_hotplug: try to migrate full section worth of pages

2018-11-20 Thread David Hildenbrand
On 20.11.18 14:43, Michal Hocko wrote: > From: Michal Hocko > > do_migrate_range has been limiting the number of pages to migrate to 256 > for some reason which is not documented. Even if the limit made some > sense back then when it was introduced it doesn't really serve a good > purpose these d

[RFC PATCH 1/3] mm, memory_hotplug: try to migrate full section worth of pages

2018-11-20 Thread Michal Hocko
From: Michal Hocko do_migrate_range has been limiting the number of pages to migrate to 256 for some reason which is not documented. Even if the limit made some sense back then when it was introduced it doesn't really serve a good purpose these days. If the range contains huge pages then we break