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| author | Chengming Zhou <chengming.zhou@linux.dev> | 2024-06-21 09:54:29 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-07-05 03:05:50 +0200 |
| commit | ac90c56bbd734addc9bfb4567f64f1c180c64f5d (patch) | |
| tree | b6cb53d3bb23d10bb4e60005d53bd8900c7cc5f1 /mm/hugetlb.c | |
| parent | hugetlb: force allocating surplus hugepages on mempolicy allowed nodes (diff) | |
| download | linux-ac90c56bbd734addc9bfb4567f64f1c180c64f5d.tar.xz linux-ac90c56bbd734addc9bfb4567f64f1c180c64f5d.zip | |
mm/ksm: refactor out try_to_merge_with_zero_page()
Patch series "mm/ksm: cmp_and_merge_page() optimizations and cleanup", v2.
This series mainly optimizes cmp_and_merge_page() to have more efficient
separate code flow for ksm page and non-ksm anon page.
- ksm page: don't need to calculate the checksum obviously.
- anon page: don't need to search stable tree if changing fast and try
to merge with zero page before searching ksm page on stable tree.
Please see the patch-2 for details.
Patch-3 is cleanup also a little optimization for the chain()/chain_prune
interfaces, which made the stable_tree_search()/stable_tree_insert() over
complex.
I have done simple testing using "hackbench -g 1 -l 300000" (maybe I need
to use a better workload) on my machine, have seen a little CPU usage
decrease of ksmd and some improvements of cmp_and_merge_page() latency:
We can see the latency of cmp_and_merge_page() when handling non-ksm anon
pages has been improved.
This patch (of 3):
In preparation for later changes, refactor out a new function called
try_to_merge_with_zero_page(), which tries to merge with zero page.
Link: https://lkml.kernel.org/r/20240621-b4-ksm-scan-optimize-v2-0-1c328aa9e30b@linux.dev
Link: https://lkml.kernel.org/r/20240621-b4-ksm-scan-optimize-v2-1-1c328aa9e30b@linux.dev
Signed-off-by: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Stefan Roesch <shr@devkernel.io>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb.c')
| -rw-r--r-- | mm/hugetlb.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index c52810d82ee3..9691624fcb79 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2666,7 +2666,6 @@ static int gather_surplus_pages(struct hstate *h, long delta) retry: spin_unlock_irq(&hugetlb_lock); for (i = 0; i < needed; i++) { - folio = NULL; for_each_node_mask(node, cpuset_current_mems_allowed) { if (!mbind_nodemask || node_isset(node, *mbind_nodemask)) { folio = alloc_surplus_hugetlb_folio(h, htlb_alloc_mask(h), |