From: Miaohe Lin <linmiaohe@xxxxxxxxxx> Subject: mm/huge_memory.c: rework the function do_huge_pmd_numa_page() slightly The current code that checks if migrating misplaced transhuge page is needed is pretty hard to follow. Rework it and add a comment to make its logic more clear and improve readability. Link: https://lkml.kernel.org/r/20210318122722.13135-4-linmiaohe@xxxxxxxxxx Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx> Reviewed-by: Zi Yan <ziy@xxxxxxxxxx> Reviewed-by: Peter Xu <peterx@xxxxxxxxxx> Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Michel Lespinasse <walken@xxxxxxxxxx> Cc: Ralph Campbell <rcampbell@xxxxxxxxxx> Cc: Thomas Hellstrm (Intel) <thomas_os@xxxxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx> Cc: William Kucharski <william.kucharski@xxxxxxxxxx> Cc: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx> Cc: yuleixzhang <yulei.kernel@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/huge_memory.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) --- a/mm/huge_memory.c~mm-huge_memoryc-rework-the-function-do_huge_pmd_numa_page-slightly +++ a/mm/huge_memory.c @@ -1462,12 +1462,6 @@ vm_fault_t do_huge_pmd_numa_page(struct */ page_locked = trylock_page(page); target_nid = mpol_misplaced(page, vma, haddr); - if (target_nid == NUMA_NO_NODE) { - /* If the page was locked, there are no parallel migrations */ - if (page_locked) - goto clear_pmdnuma; - } - /* Migration could have started since the pmd_trans_migrating check */ if (!page_locked) { page_nid = NUMA_NO_NODE; @@ -1476,6 +1470,11 @@ vm_fault_t do_huge_pmd_numa_page(struct spin_unlock(vmf->ptl); put_and_wait_on_page_locked(page, TASK_UNINTERRUPTIBLE); goto out; + } else if (target_nid == NUMA_NO_NODE) { + /* There are no parallel migrations and page is in the right + * node. Clear the numa hinting info in this pmd. + */ + goto clear_pmdnuma; } /* _
