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author | Huang Ying <ying.huang@intel.com> | 2023-04-24 09:54:08 +0300 |
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committer | Andrew Morton <akpm@linux-foundation.org> | 2023-04-27 23:42:16 +0300 |
commit | 4d4b6d66db63ceed399f1fb1a4b24081d2590eb1 (patch) | |
tree | a92cbb17d4be5951c437e3bbc6b7544d63cdee5b /fs/nfs | |
parent | 01106e140835ff94fdef79d66f166b87b0c89824 (diff) | |
download | linux-4d4b6d66db63ceed399f1fb1a4b24081d2590eb1.tar.xz |
mm,unmap: avoid flushing TLB in batch if PTE is inaccessible
0Day/LKP reported a performance regression for commit 7e12beb8ca2a
("migrate_pages: batch flushing TLB"). In the commit, the TLB flushing
during page migration is batched. So, in try_to_migrate_one(),
ptep_clear_flush() is replaced with set_tlb_ubc_flush_pending(). In
further investigation, it is found that the TLB flushing can be avoided in
ptep_clear_flush() if the PTE is inaccessible. In fact, we can optimize
in similar way for the batched TLB flushing too to improve the
performance.
So in this patch, we check pte_accessible() before
set_tlb_ubc_flush_pending() in try_to_unmap/migrate_one(). Tests show
that the benchmark score of the anon-cow-rand-mt test case of
vm-scalability test suite can improve up to 2.1% with the patch on a Intel
server machine. The TLB flushing IPI can reduce up to 44.3%.
Link: https://lore.kernel.org/oe-lkp/202303192325.ecbaf968-yujie.liu@intel.com
Link: https://lore.kernel.org/oe-lkp/ab92aaddf1b52ede15e2c608696c36765a2602c1.camel@intel.com/
Link: https://lkml.kernel.org/r/20230424065408.188498-1-ying.huang@intel.com
Fixes: 7e12beb8ca2a ("migrate_pages: batch flushing TLB")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reported-by: kernel test robot <yujie.liu@intel.com>
Reviewed-by: Nadav Amit <namit@vmware.com>
Reviewed-by: Xin Hao <xhao@linux.alibaba.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/nfs')
0 files changed, 0 insertions, 0 deletions