From: Peter Zijlstra <peterz@infradead.org>
To: Raghavendra K T <raghavendra.kt@amd.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Ingo Molnar <mingo@redhat.com>, Mel Gorman <mgorman@suse.de>,
Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@redhat.com>,
rppt@kernel.org, Bharata B Rao <bharata@amd.com>,
Disha Talreja <dishaa.talreja@amd.com>
Subject: Re: [PATCH V2 2/3] sched/numa: Enhance vma scanning logic
Date: Fri, 3 Feb 2023 12:27:23 +0100 [thread overview]
Message-ID: <Y9zvm4aB2B412drn@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <Y9zs5A/T1WQpJTuM@hirez.programming.kicks-ass.net>
On Fri, Feb 03, 2023 at 12:15:48PM +0100, Peter Zijlstra wrote:
> > +static inline void vma_set_active_pid_bit(struct vm_area_struct *vma)
> > +{
> > + unsigned int active_pid_bit;
> > +
> > + if (vma->numab) {
> > + active_pid_bit = current->pid % BITS_PER_LONG;
> > + vma->numab->accessing_pids |= 1UL << active_pid_bit;
> > + }
> > +}
>
> Perhaps:
>
> if (vma->numab)
> __set_bit(current->pid % BITS_PER_LONG, &vma->numab->pids);
>
> ?
>
> Or maybe even:
>
> bit = current->pid % BITS_PER_LONG;
> if (vma->numab && !__test_bit(bit, &vma->numab->pids))
> __set_bit(bit, &vma->numab->pids);
>
The alternative to just taking the low n bits is to use:
hash_32(current->pid, BITS_PER_LONG)
That mixes things up a bit.
next prev parent reply other threads:[~2023-02-03 11:27 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-01 8:02 [PATCH V2 0/3] sched/numa: Enhance vma scanning Raghavendra K T
2023-02-01 8:02 ` [PATCH V2 1/3] sched/numa: Apply the scan delay to every vma instead of tasks Raghavendra K T
2023-02-03 10:24 ` Peter Zijlstra
2023-02-04 17:19 ` Raghavendra K T
2023-02-01 8:02 ` [PATCH V2 2/3] sched/numa: Enhance vma scanning logic Raghavendra K T
2023-02-03 11:15 ` Peter Zijlstra
2023-02-03 11:27 ` Peter Zijlstra [this message]
2023-02-04 18:18 ` Raghavendra K T
2023-02-04 18:14 ` Raghavendra K T
2023-02-07 6:41 ` Raghavendra K T
2023-02-27 6:40 ` Raghavendra K T
2023-02-27 10:06 ` Peter Zijlstra
2023-02-27 10:12 ` Raghavendra K T
2023-02-28 4:59 ` Raghavendra K T
2023-02-01 8:02 ` [PATCH V2 3/3] sched/numa: Reset the accessing PID information periodically Raghavendra K T
2023-02-03 11:35 ` Peter Zijlstra
2023-02-04 18:32 ` Raghavendra K T
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