From: Michal Hocko <mhocko@suse.com>
To: Feng Tang <feng.tang@intel.com>
Cc: linux-mm@kvack.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>,
Dave Hansen <dave.hansen@intel.com>,
Ben Widawsky <ben.widawsky@intel.com>,
Andi Kleen <ak@linux.intel.com>,
Dan Williams <dan.j.williams@intel.com>
Subject: Re: [PATCH v4 10/13] mm/mempolicy: VMA allocation for many preferred
Date: Wed, 14 Apr 2021 15:14:31 +0200 [thread overview]
Message-ID: <YHbqt0fdhFpVZAz5@dhcp22.suse.cz> (raw)
In-Reply-To: <1615952410-36895-11-git-send-email-feng.tang@intel.com>
On Wed 17-03-21 11:40:07, Feng Tang wrote:
[...]
> @@ -2301,10 +2300,26 @@ alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
> * does not allow the current node in its nodemask, we allocate
> * the standard way.
> */
> - if ((pol->mode == MPOL_PREFERRED ||
> - pol->mode == MPOL_PREFERRED_MANY) &&
> - !(pol->flags & MPOL_F_LOCAL))
> + if (pol->mode == MPOL_PREFERRED || !(pol->flags & MPOL_F_LOCAL)) {
> hpage_node = first_node(pol->nodes);
> + } else if (pol->mode == MPOL_PREFERRED_MANY) {
> + struct zoneref *z;
> +
> + /*
> + * In this policy, with direct reclaim, the normal
> + * policy based allocation will do the right thing - try
> + * twice using the preferred nodes first, and all nodes
> + * second.
> + */
> + if (gfp & __GFP_DIRECT_RECLAIM) {
> + page = alloc_pages_policy(pol, gfp, order, NUMA_NO_NODE);
> + goto out;
> + }
> +
> + z = first_zones_zonelist(node_zonelist(numa_node_id(), GFP_HIGHUSER),
> + gfp_zone(GFP_HIGHUSER), &pol->nodes);
> + hpage_node = zone_to_nid(z->zone);
> + }
>
> nmask = policy_nodemask(gfp, pol);
> if (!nmask || node_isset(hpage_node, *nmask)) {
> @@ -2330,9 +2345,7 @@ alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
> }
> }
>
> - nmask = policy_nodemask(gfp, pol);
> - preferred_nid = policy_node(gfp, pol, node);
> - page = __alloc_pages_nodemask(gfp, order, preferred_nid, nmask);
> + page = alloc_pages_policy(pol, gfp, order, NUMA_NO_NODE);
> mpol_cond_put(pol);
> out:
> return page;
OK, it took me a while to grasp this but the code is a mess I have to
say. Not that it was an act of beauty before but this just makes it much
harder to follow. And alloc_pages_policy doesn't really help I have to
say. I would have expected that a dedicated alloc_pages_preferred and a
general fallback to __alloc_pages_nodemask would have been much easier
to follow.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2021-04-14 13:14 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-17 3:39 [PATCH v4 00/13] Introduced multi-preference mempolicy Feng Tang
2021-03-17 3:39 ` [PATCH v4 01/13] mm/mempolicy: Add comment for missing LOCAL Feng Tang
2021-03-17 3:39 ` [PATCH v4 02/13] mm/mempolicy: convert single preferred_node to full nodemask Feng Tang
2021-04-14 12:17 ` Michal Hocko
2021-03-17 3:40 ` [PATCH v4 03/13] mm/mempolicy: Add MPOL_PREFERRED_MANY for multiple preferred nodes Feng Tang
2021-04-14 12:50 ` Michal Hocko
2021-04-20 7:16 ` Feng Tang
2021-05-13 7:23 ` Feng Tang
2021-05-13 7:25 ` [RFC PATCH 2/2] mempolicy: kill MPOL_F_LOCAL bit Feng Tang
2021-05-13 13:55 ` Andi Kleen
2021-03-17 3:40 ` [PATCH v4 04/13] mm/mempolicy: allow preferred code to take a nodemask Feng Tang
2021-04-14 12:55 ` Michal Hocko
2021-04-19 8:49 ` Feng Tang
2021-03-17 3:40 ` [PATCH v4 05/13] mm/mempolicy: refactor rebind code for PREFERRED_MANY Feng Tang
2021-04-14 12:57 ` Michal Hocko
2021-03-17 3:40 ` [PATCH v4 06/13] mm/mempolicy: kill v.preferred_nodes Feng Tang
2021-04-14 12:58 ` Michal Hocko
2021-03-17 3:40 ` [PATCH v4 07/13] mm/mempolicy: handle MPOL_PREFERRED_MANY like BIND Feng Tang
2021-04-14 13:01 ` Michal Hocko
2021-03-17 3:40 ` [PATCH v4 08/13] mm/mempolicy: Create a page allocator for policy Feng Tang
2021-04-14 13:08 ` Michal Hocko
2021-04-15 8:17 ` Feng Tang
2021-03-17 3:40 ` [PATCH v4 09/13] mm/mempolicy: Thread allocation for many preferred Feng Tang
2021-03-17 3:40 ` [PATCH v4 10/13] mm/mempolicy: VMA " Feng Tang
2021-04-14 13:14 ` Michal Hocko [this message]
2021-03-17 3:40 ` [PATCH v4 11/13] mm/mempolicy: huge-page " Feng Tang
2021-03-17 7:19 ` kernel test robot
2021-04-14 13:25 ` Michal Hocko
2021-04-15 7:41 ` Feng Tang
2021-03-17 3:40 ` [PATCH v4 12/13] mm/mempolicy: Advertise new MPOL_PREFERRED_MANY Feng Tang
2021-03-17 3:40 ` [PATCH v4 13/13] mem/mempolicy: unify mpol_new_preferred() and mpol_new_preferred_many() Feng Tang
2021-04-14 11:21 ` [PATCH v4 00/13] Introduced multi-preference mempolicy Michal Hocko
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