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>,
Dave Hansen <dave.hansen@linux.intel.com>
Subject: Re: [PATCH v4 04/13] mm/mempolicy: allow preferred code to take a nodemask
Date: Wed, 14 Apr 2021 14:55:39 +0200 [thread overview]
Message-ID: <YHbmS6R+CpSDWtAD@dhcp22.suse.cz> (raw)
In-Reply-To: <1615952410-36895-5-git-send-email-feng.tang@intel.com>
On Wed 17-03-21 11:40:01, Feng Tang wrote:
> From: Dave Hansen <dave.hansen@linux.intel.com>
>
> Create a helper function (mpol_new_preferred_many()) which is usable
> both by the old, single-node MPOL_PREFERRED and the new
> MPOL_PREFERRED_MANY.
>
> Enforce the old single-node MPOL_PREFERRED behavior in the "new"
> version of mpol_new_preferred() which calls mpol_new_preferred_many().
>
> v3:
> * fix a stack overflow caused by emty nodemask (Feng)
>
> Link: https://lore.kernel.org/r/20200630212517.308045-5-ben.widawsky@intel.com
> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
> Signed-off-by: Feng Tang <feng.tang@intel.com>
> ---
> mm/mempolicy.c | 21 +++++++++++++++++++--
> 1 file changed, 19 insertions(+), 2 deletions(-)
>
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 1228d8e..6fb2cab 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -203,17 +203,34 @@ static int mpol_new_interleave(struct mempolicy *pol, const nodemask_t *nodes)
> return 0;
> }
>
> -static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
> +static int mpol_new_preferred_many(struct mempolicy *pol,
> + const nodemask_t *nodes)
> {
> if (!nodes)
> pol->flags |= MPOL_F_LOCAL; /* local allocation */
Now you have confused me. I thought that MPOL_PREFERRED_MANY for NULL
nodemask will be disallowed as it is effectively MPOL_PREFERRED aka
MPOL_F_LOCAL. Or do I misread the code?
> else if (nodes_empty(*nodes))
> return -EINVAL; /* no allowed nodes */
> else
> - pol->v.preferred_nodes = nodemask_of_node(first_node(*nodes));
> + pol->v.preferred_nodes = *nodes;
> return 0;
> }
>
> +static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
> +{
> + if (nodes) {
> + /* MPOL_PREFERRED can only take a single node: */
> + nodemask_t tmp;
> +
> + if (nodes_empty(*nodes))
> + return -EINVAL;
> +
> + tmp = nodemask_of_node(first_node(*nodes));
> + return mpol_new_preferred_many(pol, &tmp);
> + }
> +
> + return mpol_new_preferred_many(pol, NULL);
> +}
> +
> static int mpol_new_bind(struct mempolicy *pol, const nodemask_t *nodes)
> {
> if (nodes_empty(*nodes))
> --
> 2.7.4
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2021-04-14 12:55 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 [this message]
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
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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