diff mbox series

[v6,03/20] powerpc/mm: Avoid useless lock with single page fragments

Message ID 7126e8b14b566b756d1fbfa31f09898b35fd8bba.1539931702.git.christophe.leroy@c-s.fr (mailing list archive)
State Superseded
Headers show
Series Implement use of HW assistance on TLB table walk on 8xx | expand

Checks

Context Check Description
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Commit Message

Christophe Leroy Oct. 19, 2018, 6:54 a.m. UTC 
There is no point in taking the page table lock as pte_frag or
pmd_frag are always NULL when we have only one fragment.

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 arch/powerpc/mm/pgtable-book3s64.c | 3 +++
 arch/powerpc/mm/pgtable-frag.c     | 3 +++
 2 files changed, 6 insertions(+)
diff mbox series

Patch

diff --git a/arch/powerpc/mm/pgtable-book3s64.c b/arch/powerpc/mm/pgtable-book3s64.c
index 84ff3403239c..9f78db7c8c2a 100644
--- a/arch/powerpc/mm/pgtable-book3s64.c
+++ b/arch/powerpc/mm/pgtable-book3s64.c
@@ -243,6 +243,9 @@  static pmd_t *get_pmd_from_cache(struct mm_struct *mm)
 {
 	void *pmd_frag, *ret;
 
+	if (PMD_FRAG_NR == 1)
+		return NULL;
+
 	spin_lock(&mm->page_table_lock);
 	ret = mm->context.pmd_frag;
 	if (ret) {
diff --git a/arch/powerpc/mm/pgtable-frag.c b/arch/powerpc/mm/pgtable-frag.c
index d61e7c2a9a79..7544d0d7177d 100644
--- a/arch/powerpc/mm/pgtable-frag.c
+++ b/arch/powerpc/mm/pgtable-frag.c
@@ -34,6 +34,9 @@  static pte_t *get_pte_from_cache(struct mm_struct *mm)
 {
 	void *pte_frag, *ret;
 
+	if (PTE_FRAG_NR == 1)
+		return NULL;
+
 	spin_lock(&mm->page_table_lock);
 	ret = mm->context.pte_frag;
 	if (ret) {