linux-kernel - [PATCH 3/6] mm/huge_memory.c: rework the function do_huge_pmd_numa

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20210313103225.16607-5-linmiaohe@huawei.com>
Date:   Sat, 13 Mar 2021 05:32:22 -0500
From:   Miaohe Lin <linmiaohe@...wei.com>
To:     <akpm@...ux-foundation.org>
CC:     <ziy@...dia.com>, <willy@...radead.org>,
        <william.kucharski@...cle.com>, <vbabka@...e.cz>,
        <richard.weiyang@...ux.alibaba.com>, <peterx@...hat.com>,
        <anshuman.khandual@....com>, <thomas_os@...pmail.org>,
        <rcampbell@...dia.com>, <aneesh.kumar@...ux.ibm.com>,
        <yang.shi@...ux.alibaba.com>, <linux-kernel@...r.kernel.org>,
        <linux-mm@...ck.org>, <linmiaohe@...wei.com>
Subject: [PATCH 3/6] 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.

Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
---
 mm/huge_memory.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 6d13ca5441e2..26f91bf15613 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1462,12 +1462,6 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd)
 	 */
 	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 vm_fault *vmf, pmd_t pmd)
 		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;
 	}
 
 	/*
-- 
2.19.1