Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-22 Thread Michal Hocko
On Fri 18-10-19 07:54:20, Dave Hansen wrote: > On 10/18/19 12:44 AM, Michal Hocko wrote: > > How does this compare to > > http://lkml.kernel.org/r/1560468577-101178-1-git-send-email-yang@linux.alibaba.com > > It's a _bit_ more tied to persistent memory and it appears a bit more > tied to two

Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-18 Thread Dan Williams
On Fri, Oct 18, 2019 at 2:40 PM Yang Shi wrote: > > On Fri, Oct 18, 2019 at 7:54 AM Dave Hansen wrote: > > > > On 10/18/19 12:44 AM, Michal Hocko wrote: > > > How does this compare to > > > http://lkml.kernel.org/r/1560468577-101178-1-git-send-email-yang@linux.alibaba.com > > > > It's a

Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-18 Thread Yang Shi
On Thu, Oct 17, 2019 at 3:58 PM Shakeel Butt wrote: > > On Thu, Oct 17, 2019 at 10:20 AM Yang Shi wrote: > > > > On Thu, Oct 17, 2019 at 7:26 AM Dave Hansen wrote: > > > > > > On 10/16/19 8:45 PM, Shakeel Butt wrote: > > > > On Wed, Oct 16, 2019 at 3:49 PM Dave Hansen > > > > wrote: > > > >>

Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-18 Thread Yang Shi
On Fri, Oct 18, 2019 at 7:54 AM Dave Hansen wrote: > > On 10/18/19 12:44 AM, Michal Hocko wrote: > > How does this compare to > > http://lkml.kernel.org/r/1560468577-101178-1-git-send-email-yang@linux.alibaba.com > > It's a _bit_ more tied to persistent memory and it appears a bit more > tied

Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-18 Thread Suleiman Souhlal
On Sat, Oct 19, 2019 at 12:10 AM Dave Hansen wrote: > > On 10/18/19 1:11 AM, Suleiman Souhlal wrote: > > Another issue we ran into, that I think might also apply to this patch > > series, is that because kernel memory can't be allocated on persistent > > memory, it's possible for all of DRAM to

Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-18 Thread Dave Hansen
On 10/18/19 1:11 AM, Suleiman Souhlal wrote: > Another issue we ran into, that I think might also apply to this patch > series, is that because kernel memory can't be allocated on persistent > memory, it's possible for all of DRAM to get filled by user memory and > have kernel allocations fail

Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-18 Thread Dave Hansen
On 10/18/19 12:44 AM, Michal Hocko wrote: > How does this compare to > http://lkml.kernel.org/r/1560468577-101178-1-git-send-email-yang@linux.alibaba.com It's a _bit_ more tied to persistent memory and it appears a bit more tied to two tiers rather something arbitrarily deep. They're pretty

Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-18 Thread Suleiman Souhlal
On Fri, Oct 18, 2019 at 1:32 AM Dave Hansen wrote: > > On 10/17/19 9:01 AM, Suleiman Souhlal wrote: > > One problem that came up is that if you get into direct reclaim, > > because persistent memory can have pretty low write throughput, you > > can end up stalling users for a pretty long time

Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-18 Thread Michal Hocko
On Wed 16-10-19 15:11:48, Dave Hansen wrote: > We're starting to see systems with more and more kinds of memory such > as Intel's implementation of persistent memory. > > Let's say you have a system with some DRAM and some persistent memory. > Today, once DRAM fills up, reclaim will start and

Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-17 Thread Shakeel Butt
On Thu, Oct 17, 2019 at 10:20 AM Yang Shi wrote: > > On Thu, Oct 17, 2019 at 7:26 AM Dave Hansen wrote: > > > > On 10/16/19 8:45 PM, Shakeel Butt wrote: > > > On Wed, Oct 16, 2019 at 3:49 PM Dave Hansen > > > wrote: > > >> This set implements a solution to these problems. At the end of the >

Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-17 Thread Dave Hansen
On 10/17/19 10:20 AM, Yang Shi wrote: > On Thu, Oct 17, 2019 at 7:26 AM Dave Hansen wrote: >> My expectation (and I haven't confirmed this) is that the any memory use >> is accounted to the owning cgroup, whether it is DRAM or PMEM. memcg >> limit reclaim and global reclaim both end up doing

Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-17 Thread Dave Hansen
On 10/17/19 9:58 AM, Shakeel Butt wrote: >> My expectation (and I haven't confirmed this) is that the any memory use >> is accounted to the owning cgroup, whether it is DRAM or PMEM. memcg >> limit reclaim and global reclaim both end up doing migrations and >> neither should have a net effect on

Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-17 Thread Yang Shi
On Thu, Oct 17, 2019 at 7:26 AM Dave Hansen wrote: > > On 10/16/19 8:45 PM, Shakeel Butt wrote: > > On Wed, Oct 16, 2019 at 3:49 PM Dave Hansen > > wrote: > >> This set implements a solution to these problems. At the end of the > >> reclaim process in shrink_page_list() just before the last

Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-17 Thread Shakeel Butt
On Thu, Oct 17, 2019 at 7:26 AM Dave Hansen wrote: > > On 10/16/19 8:45 PM, Shakeel Butt wrote: > > On Wed, Oct 16, 2019 at 3:49 PM Dave Hansen > > wrote: > >> This set implements a solution to these problems. At the end of the > >> reclaim process in shrink_page_list() just before the last

Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-17 Thread Shakeel Butt
On Thu, Oct 17, 2019 at 9:32 AM Dave Hansen wrote: > > On 10/17/19 9:01 AM, Suleiman Souhlal wrote: > > One problem that came up is that if you get into direct reclaim, > > because persistent memory can have pretty low write throughput, you > > can end up stalling users for a pretty long time

Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-17 Thread Dave Hansen
On 10/17/19 9:01 AM, Suleiman Souhlal wrote: > One problem that came up is that if you get into direct reclaim, > because persistent memory can have pretty low write throughput, you > can end up stalling users for a pretty long time while migrating > pages. Basically, you're saying that memory

Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-17 Thread Suleiman Souhlal
On Thu, Oct 17, 2019 at 7:14 AM Dave Hansen wrote: > > We're starting to see systems with more and more kinds of memory such > as Intel's implementation of persistent memory. > > Let's say you have a system with some DRAM and some persistent memory. > Today, once DRAM fills up, reclaim will start

Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-17 Thread Dave Hansen
On 10/16/19 8:45 PM, Shakeel Butt wrote: > On Wed, Oct 16, 2019 at 3:49 PM Dave Hansen > wrote: >> This set implements a solution to these problems. At the end of the >> reclaim process in shrink_page_list() just before the last page >> refcount is dropped, the page is migrated to persistent

Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-16 Thread Shakeel Butt
On Wed, Oct 16, 2019 at 3:49 PM Dave Hansen wrote: > > We're starting to see systems with more and more kinds of memory such > as Intel's implementation of persistent memory. > > Let's say you have a system with some DRAM and some persistent memory. > Today, once DRAM fills up, reclaim will start

[PATCH 0/4] [RFC] Migrate Pages in lieu of discard

2019-10-16 Thread Dave Hansen
We're starting to see systems with more and more kinds of memory such as Intel's implementation of persistent memory. Let's say you have a system with some DRAM and some persistent memory. Today, once DRAM fills up, reclaim will start and some of the DRAM contents will be thrown out. Allocations