The patch titled
Subject: sched/numa: use hash_32 to mix up PIDs accessing VMA
has been added to the -mm mm-unstable branch. Its filename is
sched-numa-use-hash_32-to-mix-up-pids-accessing-vma.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/sched-numa-use-hash_32-to-mix-up-pids-accessing-vma.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Raghavendra K T <raghavendra.kt@xxxxxxx>
Subject: sched/numa: use hash_32 to mix up PIDs accessing VMA
Date: Wed, 1 Mar 2023 17:49:03 +0530
before: last 6 bits of PID is used as index to store information about
tasks accessing VMA's.
after: hash_32 is used to take of cases where tasks are created over a
period of time, and thus improve collision probability.
Result:
The patch series overall improves autonuma cost.
Kernbench around more than 5% improvement and system time in mmtest
autonuma showed more than 80% improvement
Link: https://lkml.kernel.org/r/d5a9f75513300caed74e5c8570bba9317b963c2b.1677672277.git.raghavendra.kt@xxxxxxx
Signed-off-by: Raghavendra K T <raghavendra.kt@xxxxxxx>
Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Bharata B Rao <bharata@xxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Disha Talreja <dishaa.talreja@xxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/include/linux/mm.h~sched-numa-use-hash_32-to-mix-up-pids-accessing-vma
+++ a/include/linux/mm.h
@@ -1671,7 +1671,7 @@ static inline void vma_set_access_pid_bi
{
unsigned int pid_bit;
- pid_bit = current->pid % BITS_PER_LONG;
+ pid_bit = hash_32(current->pid, ilog2(BITS_PER_LONG));
if (vma->numab_state && !test_bit(pid_bit, &vma->numab_state->access_pids[1])) {
__set_bit(pid_bit, &vma->numab_state->access_pids[1]);
}
--- a/kernel/sched/fair.c~sched-numa-use-hash_32-to-mix-up-pids-accessing-vma
+++ a/kernel/sched/fair.c
@@ -2941,7 +2941,7 @@ static bool vma_is_accessed(struct vm_ar
return true;
pids = vma->numab_state->access_pids[0] | vma->numab_state->access_pids[1];
- return test_bit(current->pid % BITS_PER_LONG, &pids);
+ return test_bit(hash_32(current->pid, ilog2(BITS_PER_LONG)), &pids);
}
#define VMA_PID_RESET_PERIOD (4 * sysctl_numa_balancing_scan_delay)
_
Patches currently in -mm which might be from raghavendra.kt@xxxxxxx are
sched-numa-enhance-vma-scanning-logic.patch
sched-numa-implement-access-pid-reset-logic.patch
sched-numa-use-hash_32-to-mix-up-pids-accessing-vma.patch
