LinuxPPC-Dev Archive on lore.kernel.org
 help / color / Atom feed
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: linux-mm@kvack.org, akpm@linux-foundation.org
Cc: kaleshsingh@google.com, npiggin@gmail.com,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
	joel@joelfernandes.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v4 7/9] mm/mremap: Move TLB flush outside page table lock
Date: Wed, 14 Apr 2021 14:29:13 +0530
Message-ID: <20210414085915.301189-8-aneesh.kumar@linux.ibm.com> (raw)
In-Reply-To: <20210414085915.301189-1-aneesh.kumar@linux.ibm.com>

Move TLB flush outside page table lock so that kernel does
less with page table lock held. Releasing the ptl with old
TLB contents still valid will behave such that such access
happened before the level3 or level2 entry update.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 mm/mremap.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/mremap.c b/mm/mremap.c
index 0e7b11daafee..7ac1df8e6d51 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -259,7 +259,7 @@ static bool move_normal_pmd(struct vm_area_struct *vma, unsigned long old_addr,
 	 * We don't have to worry about the ordering of src and dst
 	 * ptlocks because exclusive mmap_lock prevents deadlock.
 	 */
-	old_ptl = pmd_lock(vma->vm_mm, old_pmd);
+	old_ptl = pmd_lock(mm, old_pmd);
 	new_ptl = pmd_lockptr(mm, new_pmd);
 	if (new_ptl != old_ptl)
 		spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
@@ -271,11 +271,11 @@ static bool move_normal_pmd(struct vm_area_struct *vma, unsigned long old_addr,
 	VM_BUG_ON(!pmd_none(*new_pmd));
 	pmd_populate(mm, new_pmd, (pgtable_t)pmd_page_vaddr(pmd));
 
-	flush_pte_tlb_pwc_range(vma, old_addr, old_addr + PMD_SIZE, true);
 	if (new_ptl != old_ptl)
 		spin_unlock(new_ptl);
 	spin_unlock(old_ptl);
 
+	flush_pte_tlb_pwc_range(vma, old_addr, old_addr + PMD_SIZE, true);
 	return true;
 }
 #else
@@ -306,7 +306,7 @@ static bool move_normal_pud(struct vm_area_struct *vma, unsigned long old_addr,
 	 * We don't have to worry about the ordering of src and dst
 	 * ptlocks because exclusive mmap_lock prevents deadlock.
 	 */
-	old_ptl = pud_lock(vma->vm_mm, old_pud);
+	old_ptl = pud_lock(mm, old_pud);
 	new_ptl = pud_lockptr(mm, new_pud);
 	if (new_ptl != old_ptl)
 		spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
@@ -318,11 +318,11 @@ static bool move_normal_pud(struct vm_area_struct *vma, unsigned long old_addr,
 	VM_BUG_ON(!pud_none(*new_pud));
 
 	pud_populate(mm, new_pud, (pmd_t *)pud_page_vaddr(pud));
-	flush_pte_tlb_pwc_range(vma, old_addr, old_addr + PUD_SIZE, true);
 	if (new_ptl != old_ptl)
 		spin_unlock(new_ptl);
 	spin_unlock(old_ptl);
 
+	flush_pte_tlb_pwc_range(vma, old_addr, old_addr + PUD_SIZE, true);
 	return true;
 }
 #else
-- 
2.30.2


  parent reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-14  8:59 [PATCH v4 0/9] Speedup mremap on ppc64 Aneesh Kumar K.V
2021-04-14  8:59 ` [PATCH v4 1/9] selftest/mremap_test: Update the test to handle pagesize other than 4K Aneesh Kumar K.V
2021-04-14  8:59 ` [PATCH v4 2/9] selftest/mremap_test: Avoid crash with static build Aneesh Kumar K.V
2021-04-14  8:59 ` [PATCH v4 3/9] mm/mremap: Use pmd/pud_poplulate to update page table entries Aneesh Kumar K.V
2021-04-14  8:59 ` [PATCH v4 4/9] powerpc/mm/book3s64: Fix possible build error Aneesh Kumar K.V
2021-04-20  3:43   ` Michael Ellerman
2021-04-14  8:59 ` [PATCH v4 5/9] powerpc/mm/book3s64: Update tlb flush routines to take a page walk cache flush argument Aneesh Kumar K.V
2021-04-14  8:59 ` [PATCH v4 6/9] mm/mremap: Use range flush that does TLB and page walk cache flush Aneesh Kumar K.V
2021-04-20  3:47   ` Michael Ellerman
2021-04-20  4:17     ` Aneesh Kumar K.V
2021-04-14  8:59 ` Aneesh Kumar K.V [this message]
2021-04-14  8:59 ` [PATCH v4 8/9] mm/mremap: Allow arch runtime override Aneesh Kumar K.V
2021-04-20  3:52   ` Michael Ellerman
2021-04-20  4:30     ` Aneesh Kumar K.V
2021-04-14  8:59 ` [PATCH v4 9/9] powerpc/mm: Enable move pmd/pud Aneesh Kumar K.V

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210414085915.301189-8-aneesh.kumar@linux.ibm.com \
    --to=aneesh.kumar@linux.ibm.com \
    --cc=akpm@linux-foundation.org \
    --cc=joel@joelfernandes.org \
    --cc=kaleshsingh@google.com \
    --cc=linux-mm@kvack.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=npiggin@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LinuxPPC-Dev Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linuxppc-dev/0 linuxppc-dev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linuxppc-dev linuxppc-dev/ https://lore.kernel.org/linuxppc-dev \
		linuxppc-dev@lists.ozlabs.org linuxppc-dev@ozlabs.org
	public-inbox-index linuxppc-dev

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.ozlabs.lists.linuxppc-dev


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git