mm: remove quicklist page table caches

Patch series "mm: remove quicklist page table caches".

A while ago Nicholas proposed to remove quicklist page table caches [1].

I've rebased his patch on the curren upstream and switched ia64 and sh to
use generic versions of PTE allocation.

[1] https://lore.kernel.org/linux-mm/20190711030339.20892-1-npiggin@gmail.com

This patch (of 3):

Remove page table allocator "quicklists".  These have been around for a
long time, but have not got much traction in the last decade and are only
used on ia64 and sh architectures.

The numbers in the initial commit look interesting but probably don't
apply anymore.  If anybody wants to resurrect this it's in the git
history, but it's unhelpful to have this code and divergent allocator
behaviour for minor archs.

Also it might be better to instead make more general improvements to page
allocator if this is still so slow.

Link: http://lkml.kernel.org/r/1565250728-21721-2-git-send-email-rppt@linux.ibm.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 12 insertions, 24 deletions

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 685a3df126ca..16714477eef4 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -72,10 +72,6 @@ config 64BIT
 config ZONE_DMA32
 	def_bool y
 
-config QUICKLIST
-	bool
-	default y
-
 config MMU
 	bool
 	default y
diff --git a/arch/ia64/include/asm/pgalloc.h b/arch/ia64/include/asm/pgalloc.h
index c9e481023c25..b03d993f5d7e 100644
--- a/arch/ia64/include/asm/pgalloc.h
+++ b/arch/ia64/include/asm/pgalloc.h
@@ -19,18 +19,17 @@
 #include <linux/mm.h>
 #include <linux/page-flags.h>
 #include <linux/threads.h>
-#include <linux/quicklist.h>
 
 #include <asm/mmu_context.h>
 
 static inline pgd_t *pgd_alloc(struct mm_struct *mm)
 {
-	return quicklist_alloc(0, GFP_KERNEL, NULL);
+	return (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
 }
 
 static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 {
-	quicklist_free(0, NULL, pgd);
+	free_page((unsigned long)pgd);
 }
 
 #if CONFIG_PGTABLE_LEVELS == 4
@@ -42,12 +41,12 @@ pgd_populate(struct mm_struct *mm, pgd_t * pgd_entry, pud_t * pud)
 
 static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
 {
-	return quicklist_alloc(0, GFP_KERNEL, NULL);
+	return (pud_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
 }
 
 static inline void pud_free(struct mm_struct *mm, pud_t *pud)
 {
-	quicklist_free(0, NULL, pud);
+	free_page((unsigned long)pud);
 }
 #define __pud_free_tlb(tlb, pud, address)	pud_free((tlb)->mm, pud)
 #endif /* CONFIG_PGTABLE_LEVELS == 4 */
@@ -60,12 +59,12 @@ pud_populate(struct mm_struct *mm, pud_t * pud_entry, pmd_t * pmd)
 
 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
 {
-	return quicklist_alloc(0, GFP_KERNEL, NULL);
+	return (pmd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
 }
 
 static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
 {
-	quicklist_free(0, NULL, pmd);
+	free_page((unsigned long)pmd);
 }
 
 #define __pmd_free_tlb(tlb, pmd, address)	pmd_free((tlb)->mm, pmd)
@@ -86,14 +85,12 @@ pmd_populate_kernel(struct mm_struct *mm, pmd_t * pmd_entry, pte_t * pte)
 static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
 {
 	struct page *page;
-	void *pg;
 
-	pg = quicklist_alloc(0, GFP_KERNEL, NULL);
-	if (!pg)
+	page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+	if (!page)
 		return NULL;
-	page = virt_to_page(pg);
 	if (!pgtable_page_ctor(page)) {
-		quicklist_free(0, NULL, pg);
+		__free_page(page);
 		return NULL;
 	}
 	return page;
@@ -101,23 +98,18 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
 
 static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
 {
-	return quicklist_alloc(0, GFP_KERNEL, NULL);
+	return (pte_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
 }
 
 static inline void pte_free(struct mm_struct *mm, pgtable_t pte)
 {
 	pgtable_page_dtor(pte);
-	quicklist_free_page(0, NULL, pte);
+	__free_page(pte);
 }
 
 static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 {
-	quicklist_free(0, NULL, pte);
-}
-
-static inline void check_pgt_cache(void)
-{
-	quicklist_trim(0, NULL, 25, 16);
+	free_page((unsigned long)pte);
 }
 
 #define __pte_free_tlb(tlb, pte, address)	pte_free((tlb)->mm, pte)