mm: remove vmacache

By using the maple tree and the maple tree state, the vmacache is no
longer beneficial and is complicating the VMA code.  Remove the vmacache
to reduce the work in keeping it up to date and code complexity.

Link: https://lkml.kernel.org/r/20220906194824.2110408-26-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

6 files changed, 0 insertions, 52 deletions

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index ac747273c4d6..4541b74b1bdb 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -475,7 +475,6 @@ struct mm_struct {
 	struct {
 		struct vm_area_struct *mmap;		/* list of VMAs */
 		struct maple_tree mm_mt;
-		u64 vmacache_seqnum;                   /* per-thread vmacache */
 #ifdef CONFIG_MMU
 		unsigned long (*get_unmapped_area) (struct file *filp,
 				unsigned long addr, unsigned long len,
diff --git a/include/linux/mm_types_task.h b/include/linux/mm_types_task.h
index c1bc6731125c..0bb4b6da9993 100644
--- a/include/linux/mm_types_task.h
+++ b/include/linux/mm_types_task.h
@@ -25,18 +25,6 @@
 #define ALLOC_SPLIT_PTLOCKS	(SPINLOCK_SIZE > BITS_PER_LONG/8)
 
 /*
- * The per task VMA cache array:
- */
-#define VMACACHE_BITS 2
-#define VMACACHE_SIZE (1U << VMACACHE_BITS)
-#define VMACACHE_MASK (VMACACHE_SIZE - 1)
-
-struct vmacache {
-	u64 seqnum;
-	struct vm_area_struct *vmas[VMACACHE_SIZE];
-};
-
-/*
  * When updating this, please also update struct resident_page_types[] in
  * kernel/fork.c
  */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index a2dcfb91df03..fbac3c19fe35 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -861,7 +861,6 @@ struct task_struct {
 	struct mm_struct		*active_mm;
 
 	/* Per-thread vma caching: */
-	struct vmacache			vmacache;
 
 #ifdef SPLIT_RSS_COUNTING
 	struct task_rss_stat		rss_stat;
diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index f3fc36cd2276..3518dba1e02f 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -129,10 +129,6 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
 		NR_TLB_LOCAL_FLUSH_ALL,
 		NR_TLB_LOCAL_FLUSH_ONE,
 #endif /* CONFIG_DEBUG_TLBFLUSH */
-#ifdef CONFIG_DEBUG_VM_VMACACHE
-		VMACACHE_FIND_CALLS,
-		VMACACHE_FIND_HITS,
-#endif
 #ifdef CONFIG_SWAP
 		SWAP_RA,
 		SWAP_RA_HIT,
diff --git a/include/linux/vmacache.h b/include/linux/vmacache.h
deleted file mode 100644
index 6fce268a4588..000000000000
--- a/include/linux/vmacache.h
+++ /dev/null
@@ -1,28 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __LINUX_VMACACHE_H
-#define __LINUX_VMACACHE_H
-
-#include <linux/sched.h>
-#include <linux/mm.h>
-
-static inline void vmacache_flush(struct task_struct *tsk)
-{
-	memset(tsk->vmacache.vmas, 0, sizeof(tsk->vmacache.vmas));
-}
-
-extern void vmacache_update(unsigned long addr, struct vm_area_struct *newvma);
-extern struct vm_area_struct *vmacache_find(struct mm_struct *mm,
-						    unsigned long addr);
-
-#ifndef CONFIG_MMU
-extern struct vm_area_struct *vmacache_find_exact(struct mm_struct *mm,
-						  unsigned long start,
-						  unsigned long end);
-#endif
-
-static inline void vmacache_invalidate(struct mm_struct *mm)
-{
-	mm->vmacache_seqnum++;
-}
-
-#endif /* __LINUX_VMACACHE_H */
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index bfe38869498d..19cf5b6892ce 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -125,12 +125,6 @@ static inline void vm_events_fold_cpu(int cpu)
 #define count_vm_tlb_events(x, y) do { (void)(y); } while (0)
 #endif
 
-#ifdef CONFIG_DEBUG_VM_VMACACHE
-#define count_vm_vmacache_event(x) count_vm_event(x)
-#else
-#define count_vm_vmacache_event(x) do {} while (0)
-#endif
-
 #define __count_zid_vm_events(item, zid, delta) \
 	__count_vm_events(item##_NORMAL - ZONE_NORMAL + zid, delta)