From: Michal Hocko <mhocko@suse.com>
To: Feng Tang <feng.tang@intel.com>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
David Rientjes <rientjes@google.com>,
Mel Gorman <mgorman@techsingularity.net>,
Mike Kravetz <mike.kravetz@oracle.com>,
Randy Dunlap <rdunlap@infradead.org>,
Vlastimil Babka <vbabka@suse.cz>,
"Hansen, Dave" <dave.hansen@intel.com>,
"Widawsky, Ben" <ben.widawsky@intel.com>,
Andi leen <ak@linux.intel.com>,
"Williams, Dan J" <dan.j.williams@intel.com>
Subject: Re: [PATCH v3 RFC 14/14] mm: speedup page alloc for MPOL_PREFERRED_MANY by adding a NO_SLOWPATH gfp bit
Date: Wed, 3 Mar 2021 14:59:35 +0100 [thread overview]
Message-ID: <YD+WR5cpuWhybm2L@dhcp22.suse.cz> (raw)
In-Reply-To: <20210303134644.GC78458@shbuild999.sh.intel.com>
On Wed 03-03-21 21:46:44, Feng Tang wrote:
> On Wed, Mar 03, 2021 at 09:18:32PM +0800, Tang, Feng wrote:
> > On Wed, Mar 03, 2021 at 01:32:11PM +0100, Michal Hocko wrote:
> > > On Wed 03-03-21 20:18:33, Feng Tang wrote:
[...]
> > > > One thing I tried which can fix the slowness is:
> > > >
> > > > + gfp_mask &= ~(__GFP_DIRECT_RECLAIM | __GFP_KSWAPD_RECLAIM);
> > > >
> > > > which explicitly clears the 2 kinds of reclaim. And I thought it's too
> > > > hacky and didn't mention it in the commit log.
> > >
> > > Clearing __GFP_DIRECT_RECLAIM would be the right way to achieve
> > > GFP_NOWAIT semantic. Why would you want to exclude kswapd as well?
> >
> > When I tried gfp_mask &= ~__GFP_DIRECT_RECLAIM, the slowness couldn't
> > be fixed.
>
> I just double checked by rerun the test, 'gfp_mask &= ~__GFP_DIRECT_RECLAIM'
> can also accelerate the allocation much! though is still a little slower than
> this patch. Seems I've messed some of the tries, and sorry for the confusion!
>
> Could this be used as the solution? or the adding another fallback_nodemask way?
> but the latter will change the current API quite a bit.
I haven't got to the whole series yet. The real question is whether the
first attempt to enforce the preferred mask is a general win. I would
argue that it resembles the existing single node preferred memory policy
because that one doesn't push heavily on the preferred node either. So
dropping just the direct reclaim mode makes some sense to me.
IIRC this is something I was recommending in an early proposal of the
feature.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2021-03-03 14:00 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-03 10:20 [PATCH v3 00/14] Introduced multi-preference mempolicy Feng Tang
2021-03-03 10:20 ` [PATCH v3 01/14] mm/mempolicy: Add comment for missing LOCAL Feng Tang
2021-03-10 6:27 ` Feng Tang
2021-03-03 10:20 ` [PATCH v3 02/14] mm/mempolicy: convert single preferred_node to full nodemask Feng Tang
2021-03-03 10:20 ` [PATCH v3 03/14] mm/mempolicy: Add MPOL_PREFERRED_MANY for multiple preferred nodes Feng Tang
2021-03-03 10:20 ` [PATCH v3 04/14] mm/mempolicy: allow preferred code to take a nodemask Feng Tang
2021-03-03 10:20 ` [PATCH v3 05/14] mm/mempolicy: refactor rebind code for PREFERRED_MANY Feng Tang
2021-03-03 10:20 ` [PATCH v3 06/14] mm/mempolicy: kill v.preferred_nodes Feng Tang
2021-03-03 10:20 ` [PATCH v3 07/14] mm/mempolicy: handle MPOL_PREFERRED_MANY like BIND Feng Tang
2021-03-03 10:20 ` [PATCH v3 08/14] mm/mempolicy: Create a page allocator for policy Feng Tang
2021-03-03 10:20 ` [PATCH v3 09/14] mm/mempolicy: Thread allocation for many preferred Feng Tang
2021-03-03 10:20 ` [PATCH v3 10/14] mm/mempolicy: VMA " Feng Tang
2021-03-03 10:20 ` [PATCH v3 11/14] mm/mempolicy: huge-page " Feng Tang
2021-03-03 10:20 ` [PATCH v3 12/14] mm/mempolicy: Advertise new MPOL_PREFERRED_MANY Feng Tang
2021-03-03 10:20 ` [PATCH v3 13/14] mem/mempolicy: unify mpol_new_preferred() and mpol_new_preferred_many() Feng Tang
2021-03-03 10:20 ` [PATCH v3 RFC 14/14] mm: speedup page alloc for MPOL_PREFERRED_MANY by adding a NO_SLOWPATH gfp bit Feng Tang
2021-03-03 11:39 ` Michal Hocko
2021-03-03 12:07 ` Feng Tang
2021-03-03 12:18 ` Feng Tang
2021-03-03 12:32 ` Michal Hocko
2021-03-03 13:18 ` Feng Tang
2021-03-03 13:46 ` Feng Tang
2021-03-03 13:59 ` Michal Hocko [this message]
2021-03-03 16:31 ` Ben Widawsky
2021-03-03 16:48 ` Dave Hansen
2021-03-10 5:19 ` Feng Tang
2021-03-10 9:44 ` Michal Hocko
2021-03-10 11:49 ` Feng Tang
2021-03-03 17:14 ` Michal Hocko
2021-03-03 17:22 ` Ben Widawsky
2021-03-04 8:14 ` Feng Tang
2021-03-04 12:59 ` Michal Hocko
2021-03-05 2:21 ` Feng Tang
2021-03-04 12:57 ` Michal Hocko
2021-03-03 13:53 ` Michal Hocko
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