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authorRaghavendra K T <raghavendra.kt@amd.com>2023-03-01 15:19:01 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-04-06 06:03:03 +0300
commitfc137c0ddab29b591db6a091dc6d7ce20ccb73f2 (patch)
tree582d8a0e080aaf6b31d3cec59f65c88d8cb74e85 /mm/memory.c
parentef6a22b70f6d90449a5c797b8968a682824e2011 (diff)
downloadlinux-fc137c0ddab29b591db6a091dc6d7ce20ccb73f2.tar.xz
sched/numa: enhance vma scanning logic
During Numa scanning make sure only relevant vmas of the tasks are scanned. Before: All the tasks of a process participate in scanning the vma even if they do not access vma in it's lifespan. Now: Except cases of first few unconditional scans, if a process do not touch vma (exluding false positive cases of PID collisions) tasks no longer scan all vma Logic used: 1) 6 bits of PID used to mark active bit in vma numab status during fault to remember PIDs accessing vma. (Thanks Mel) 2) Subsequently in scan path, vma scanning is skipped if current PID had not accessed vma. 3) First two times we do allow unconditional scan to preserve earlier behaviour of scanning. Acknowledgement to Bharata B Rao <bharata@amd.com> for initial patch to store pid information and Peter Zijlstra <peterz@infradead.org> (Usage of test and set bit) Link: https://lkml.kernel.org/r/092f03105c7c1d3450f4636b1ea350407f07640e.1677672277.git.raghavendra.kt@amd.com Signed-off-by: Raghavendra K T <raghavendra.kt@amd.com> Suggested-by: Mel Gorman <mgorman@techsingularity.net> Cc: David Hildenbrand <david@redhat.com> Cc: Disha Talreja <dishaa.talreja@amd.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Mike Rapoport <rppt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 9999574a9636..f77fccb5310c 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4661,6 +4661,9 @@ int numa_migrate_prep(struct page *page, struct vm_area_struct *vma,
{
get_page(page);
+ /* Record the current PID acceesing VMA */
+ vma_set_access_pid_bit(vma);
+
count_vm_numa_event(NUMA_HINT_FAULTS);
if (page_nid == numa_node_id()) {
count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);