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>

4 files changed, 0 insertions, 111 deletions

diff --git a/mm/Kconfig b/mm/Kconfig
index 2fe4902ad755..f88be1cbcfb2 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -273,11 +273,6 @@ config BOUNCE
 	  by default when ZONE_DMA or HIGHMEM is selected, but you
 	  may say n to override this.
 
-config NR_QUICK
-	int
-	depends on QUICKLIST
-	default "1"
-
 config VIRT_TO_BUS
 	bool
 	help
diff --git a/mm/Makefile b/mm/Makefile
index d0b295c3b764..d11de59e9c3c 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -72,7 +72,6 @@ obj-$(CONFIG_FAILSLAB) += failslab.o
 obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o
 obj-$(CONFIG_MEMTEST)		+= memtest.o
 obj-$(CONFIG_MIGRATION) += migrate.o
-obj-$(CONFIG_QUICKLIST) += quicklist.o
 obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o khugepaged.o
 obj-$(CONFIG_PAGE_COUNTER) += page_counter.o
 obj-$(CONFIG_MEMCG) += memcontrol.o vmpressure.o
diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c
index 8c943a6e1696..7d70e5c78f97 100644
--- a/mm/mmu_gather.c
+++ b/mm/mmu_gather.c
@@ -271,8 +271,6 @@ void tlb_finish_mmu(struct mmu_gather *tlb,
 
 	tlb_flush_mmu(tlb);
 
-	/* keep the page table cache within bounds */
-	check_pgt_cache();
 #ifndef CONFIG_HAVE_MMU_GATHER_NO_GATHER
 	tlb_batch_list_free(tlb);
 #endif
diff --git a/mm/quicklist.c b/mm/quicklist.c
deleted file mode 100644
index 5e98ac78e410..000000000000
--- a/mm/quicklist.c
+++ /dev/null
@@ -1,103 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Quicklist support.
- *
- * Quicklists are light weight lists of pages that have a defined state
- * on alloc and free. Pages must be in the quicklist specific defined state
- * (zero by default) when the page is freed. It seems that the initial idea
- * for such lists first came from Dave Miller and then various other people
- * improved on it.
- *
- * Copyright (C) 2007 SGI,
- * 	Christoph Lameter <cl@linux.com>
- * 		Generalized, added support for multiple lists and
- * 		constructors / destructors.
- */
-#include <linux/kernel.h>
-
-#include <linux/gfp.h>
-#include <linux/mm.h>
-#include <linux/mmzone.h>
-#include <linux/quicklist.h>
-
-DEFINE_PER_CPU(struct quicklist [CONFIG_NR_QUICK], quicklist);
-
-#define FRACTION_OF_NODE_MEM	16
-
-static unsigned long max_pages(unsigned long min_pages)
-{
-	unsigned long node_free_pages, max;
-	int node = numa_node_id();
-	struct zone *zones = NODE_DATA(node)->node_zones;
-	int num_cpus_on_node;
-
-	node_free_pages =
-#ifdef CONFIG_ZONE_DMA
-		zone_page_state(&zones[ZONE_DMA], NR_FREE_PAGES) +
-#endif
-#ifdef CONFIG_ZONE_DMA32
-		zone_page_state(&zones[ZONE_DMA32], NR_FREE_PAGES) +
-#endif
-		zone_page_state(&zones[ZONE_NORMAL], NR_FREE_PAGES);
-
-	max = node_free_pages / FRACTION_OF_NODE_MEM;
-
-	num_cpus_on_node = cpumask_weight(cpumask_of_node(node));
-	max /= num_cpus_on_node;
-
-	return max(max, min_pages);
-}
-
-static long min_pages_to_free(struct quicklist *q,
-	unsigned long min_pages, long max_free)
-{
-	long pages_to_free;
-
-	pages_to_free = q->nr_pages - max_pages(min_pages);
-
-	return min(pages_to_free, max_free);
-}
-
-/*
- * Trim down the number of pages in the quicklist
- */
-void quicklist_trim(int nr, void (*dtor)(void *),
-	unsigned long min_pages, unsigned long max_free)
-{
-	long pages_to_free;
-	struct quicklist *q;
-
-	q = &get_cpu_var(quicklist)[nr];
-	if (q->nr_pages > min_pages) {
-		pages_to_free = min_pages_to_free(q, min_pages, max_free);
-
-		while (pages_to_free > 0) {
-			/*
-			 * We pass a gfp_t of 0 to quicklist_alloc here
-			 * because we will never call into the page allocator.
-			 */
-			void *p = quicklist_alloc(nr, 0, NULL);
-
-			if (dtor)
-				dtor(p);
-			free_page((unsigned long)p);
-			pages_to_free--;
-		}
-	}
-	put_cpu_var(quicklist);
-}
-
-unsigned long quicklist_total_size(void)
-{
-	unsigned long count = 0;
-	int cpu;
-	struct quicklist *ql, *q;
-
-	for_each_online_cpu(cpu) {
-		ql = per_cpu(quicklist, cpu);
-		for (q = ql; q < ql + CONFIG_NR_QUICK; q++)
-			count += q->nr_pages;
-	}
-	return count;
-}
-