From: Feng Tang <feng.tang@intel.com>
To: Michal Hocko <mhocko@suse.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
David Rientjes <rientjes@google.com>,
Dave Hansen <dave.hansen@intel.com>,
Ben Widawsky <ben.widawsky@intel.com>,
linux-kernel@vger.kernel.org,
Andrea Arcangeli <aarcange@redhat.com>,
Mel Gorman <mgorman@techsingularity.net>,
Mike Kravetz <mike.kravetz@oracle.com>,
Randy Dunlap <rdunlap@infradead.org>,
Vlastimil Babka <vbabka@suse.cz>, Andi Kleen <ak@linux.intel.com>,
Dan Williams <dan.j.williams@intel.com>,
ying.huang@intel.com
Subject: Re: [v3 PATCH 1/3] mm/mempolicy: cleanup nodemask intersection check for oom
Date: Tue, 1 Jun 2021 19:08:40 +0800 [thread overview]
Message-ID: <20210601110840.GA80730@shbuild999.sh.intel.com> (raw)
In-Reply-To: <YLXtjRYUcaXcYfua@dhcp22.suse.cz>
On Tue, Jun 01, 2021 at 10:19:25AM +0200, Michal Hocko wrote:
> On Mon 31-05-21 22:05:54, Feng Tang wrote:
> > mempolicy_nodemask_intersects() is used in oom case to check if a
> > task may have memory allocated on some memory nodes.
> >
> > As it's only used by OOM check, rename it to mempolicy_in_oom_domain()
> > to reduce confusion.
> >
> > As only for 'bind' policy, the nodemask is a force requirement for
> > from where to allocate memory, only do the intesection check for it,
> > and return true for all other policies.
>
> I would slightly rephrase the above to
> "
> mempolicy_nodemask_intersects seem to be a general purpose mempolicy
> function. In fact it is partially tailored for the OOM purpose instead.
> The oom proper is the only existing user so rename the function to make
> that purpose explicit.
>
> While at it drop the MPOL_INTERLEAVE as those allocations never has a
> nodemask defined (see alloc_page_interleave) so this is a dead code
> and a confusing one because MPOL_INTERLEAVE is a hint rather than a hard
> requirement so it shouldn't be considered during the OOM.
>
> The final code can be reduced to a check for MPOL_BIND which is the only
> memory policy that is a hard requirement and thus relevant to a
> constrained OOM logic.
> "
This is much clearer, thanks!
Will change this and the descrition in over-letter.
> > Suggested-by: Michal Hocko <mhocko@suse.com>
> > Signed-off-by: Feng Tang <feng.tang@intel.com>
>
> To the change itself
> Acked-by: Michal Hocko <mhocko@suse.com>
Thanks!
- Feng
next prev parent reply other threads:[~2021-06-01 11:08 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-31 14:05 [v3 PATCH 0/3] mm/mempolicy: some fix and semantics cleanup Feng Tang
2021-05-31 14:05 ` [v3 PATCH 1/3] mm/mempolicy: cleanup nodemask intersection check for oom Feng Tang
2021-06-01 8:19 ` Michal Hocko
2021-06-01 11:08 ` Feng Tang [this message]
2021-06-01 23:56 ` Andrew Morton
2021-05-31 14:05 ` [v3 PATCH 2/3] mm/mempolicy: don't handle MPOL_LOCAL like a fake MPOL_PREFERRED policy Feng Tang
2021-06-01 8:44 ` Michal Hocko
2021-06-01 11:29 ` Feng Tang
2021-05-31 14:05 ` [v3 PATCH 3/3] mm/mempolicy: unify the parameter sanity check for mbind and set_mempolicy Feng Tang
2021-06-01 8:46 ` Michal Hocko
2021-05-31 21:41 ` [v3 PATCH 0/3] mm/mempolicy: some fix and semantics cleanup Andrew Morton
2021-06-01 0:55 ` Feng Tang
2021-06-01 8:48 ` Michal Hocko
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