mm/memory.c: refactor insert_page to prepare for batched-lock insert
Add helper methods for vm_insert_page()/insert_page() to prepare for
vm_insert_pages(), which batch-inserts pages to reduce spinlock
operations when inserting multiple consecutive pages into the user page
table.
The intention of this patch-set is to reduce atomic ops for tcp zerocopy
receives, which normally hits the same spinlock multiple times
consecutively.
Signed-off-by: Arjun Roy <arjunroy@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Miller <davem@davemloft.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Link: http://lkml.kernel.org/r/20200128025958.43490-1-arjunroy.kdev@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memory.c b/mm/memory.c
index 19874d1..52a3303 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1442,6 +1442,27 @@
return pte_alloc_map_lock(mm, pmd, addr, ptl);
}
+static int validate_page_before_insert(struct page *page)
+{
+ if (PageAnon(page) || PageSlab(page) || page_has_type(page))
+ return -EINVAL;
+ flush_dcache_page(page);
+ return 0;
+}
+
+static int insert_page_into_pte_locked(struct mm_struct *mm, pte_t *pte,
+ unsigned long addr, struct page *page, pgprot_t prot)
+{
+ if (!pte_none(*pte))
+ return -EBUSY;
+ /* Ok, finally just insert the thing.. */
+ get_page(page);
+ inc_mm_counter_fast(mm, mm_counter_file(page));
+ page_add_file_rmap(page, false);
+ set_pte_at(mm, addr, pte, mk_pte(page, prot));
+ return 0;
+}
+
/*
* This is the old fallback for page remapping.
*
@@ -1457,26 +1478,14 @@
pte_t *pte;
spinlock_t *ptl;
- retval = -EINVAL;
- if (PageAnon(page) || PageSlab(page) || page_has_type(page))
+ retval = validate_page_before_insert(page);
+ if (retval)
goto out;
retval = -ENOMEM;
- flush_dcache_page(page);
pte = get_locked_pte(mm, addr, &ptl);
if (!pte)
goto out;
- retval = -EBUSY;
- if (!pte_none(*pte))
- goto out_unlock;
-
- /* Ok, finally just insert the thing.. */
- get_page(page);
- inc_mm_counter_fast(mm, mm_counter_file(page));
- page_add_file_rmap(page, false);
- set_pte_at(mm, addr, pte, mk_pte(page, prot));
-
- retval = 0;
-out_unlock:
+ retval = insert_page_into_pte_locked(mm, pte, addr, page, prot);
pte_unmap_unlock(pte, ptl);
out:
return retval;
