We rarely allocate a page with ALLOC_NO_WATERMARKS and it is used
in slow path. For helping compiler optimization, add unlikely macro to
ALLOC_NO_WATERMARKS checking.
This patch doesn't have any effect now, because gcc already optimize
this properly. But we cannot assume that gcc always does right and nobody
re-evaluate if gcc do proper optimization with their change, for example,
it is not optimized properly on v3.10. So adding compiler hint here
is reasonable.
Acked-by: Johannes Weiner <[email protected]>
Signed-off-by: Joonsoo Kim <[email protected]>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index f5c549c..04bec49 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1901,7 +1901,7 @@ zonelist_scan:
!cpuset_zone_allowed_softwall(zone, gfp_mask))
continue;
BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
- if (alloc_flags & ALLOC_NO_WATERMARKS)
+ if (unlikely(alloc_flags & ALLOC_NO_WATERMARKS))
goto try_this_zone;
/*
* Distribute pages in proportion to the individual
--
1.7.9.5
PageSwapCache() is always false when !CONFIG_SWAP, so compiler
properly discard related code. Therefore, we don't need #ifdef explicitly.
Acked-by: Johannes Weiner <[email protected]>
Signed-off-by: Joonsoo Kim <[email protected]>
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 24db914..c03c139 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -447,6 +447,7 @@ mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
#else /* CONFIG_SWAP */
+#define swap_address_space(entry) (NULL)
#define get_nr_swap_pages() 0L
#define total_swap_pages 0L
#define total_swapcache_pages() 0UL
diff --git a/mm/util.c b/mm/util.c
index 7441c41..eaf63fc2 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -388,15 +388,12 @@ struct address_space *page_mapping(struct page *page)
struct address_space *mapping = page->mapping;
VM_BUG_ON(PageSlab(page));
-#ifdef CONFIG_SWAP
if (unlikely(PageSwapCache(page))) {
swp_entry_t entry;
entry.val = page_private(page);
mapping = swap_address_space(entry);
- } else
-#endif
- if ((unsigned long)mapping & PAGE_MAPPING_ANON)
+ } else if ((unsigned long)mapping & PAGE_MAPPING_ANON)
mapping = NULL;
return mapping;
}
--
1.7.9.5
pgtable related functions are mostly in pgtable-generic.c.
So move remaining functions from memory.c to pgtable-generic.c.
Signed-off-by: Joonsoo Kim <[email protected]>
diff --git a/mm/memory.c b/mm/memory.c
index f2ab2a8..8fd4d42 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -374,30 +374,6 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table)
#endif /* CONFIG_HAVE_RCU_TABLE_FREE */
/*
- * If a p?d_bad entry is found while walking page tables, report
- * the error, before resetting entry to p?d_none. Usually (but
- * very seldom) called out from the p?d_none_or_clear_bad macros.
- */
-
-void pgd_clear_bad(pgd_t *pgd)
-{
- pgd_ERROR(*pgd);
- pgd_clear(pgd);
-}
-
-void pud_clear_bad(pud_t *pud)
-{
- pud_ERROR(*pud);
- pud_clear(pud);
-}
-
-void pmd_clear_bad(pmd_t *pmd)
-{
- pmd_ERROR(*pmd);
- pmd_clear(pmd);
-}
-
-/*
* Note: this doesn't free the actual pages themselves. That
* has been handled earlier when unmapping all the memory regions.
*/
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index e1a6e4f..3929a40 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -10,6 +10,30 @@
#include <asm/tlb.h>
#include <asm-generic/pgtable.h>
+/*
+ * If a p?d_bad entry is found while walking page tables, report
+ * the error, before resetting entry to p?d_none. Usually (but
+ * very seldom) called out from the p?d_none_or_clear_bad macros.
+ */
+
+void pgd_clear_bad(pgd_t *pgd)
+{
+ pgd_ERROR(*pgd);
+ pgd_clear(pgd);
+}
+
+void pud_clear_bad(pud_t *pud)
+{
+ pud_ERROR(*pud);
+ pud_clear(pud);
+}
+
+void pmd_clear_bad(pmd_t *pmd)
+{
+ pmd_ERROR(*pmd);
+ pmd_clear(pmd);
+}
+
#ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
/*
* Only sets the access flags (dirty, accessed), as well as write
--
1.7.9.5