@@ -35,6 +35,7 @@ KCOV_INSTRUMENT_failslab.o := n
CFLAGS_init-mm.o += $(call cc-disable-warning, override-init)
CFLAGS_init-mm.o += $(call cc-disable-warning, initializer-overrides)
+CFLAGS_ksm.o := -I$(src)
mmu-y := nommu.o
mmu-$(CONFIG_MMU) := highmem.o memory.o mincore.o \
@@ -44,6 +44,10 @@
#include <asm/tlbflush.h>
#include "internal.h"
#include "mm_slot.h"
+#include "ksm.h"
+
+#define CREATE_TRACE_POINTS
+#include "ksm_trace.h"
#ifdef CONFIG_NUMA
#define NUMA(x) (x)
@@ -139,46 +143,6 @@ struct ksm_scan {
unsigned long seqnr;
};
-/**
- * struct ksm_stable_node - node of the stable rbtree
- * @node: rb node of this ksm page in the stable tree
- * @head: (overlaying parent) &migrate_nodes indicates temporarily on that list
- * @hlist_dup: linked into the stable_node->hlist with a stable_node chain
- * @list: linked into migrate_nodes, pending placement in the proper node tree
- * @hlist: hlist head of rmap_items using this ksm page
- * @kpfn: page frame number of this ksm page (perhaps temporarily on wrong nid)
- * @chain_prune_time: time of the last full garbage collection
- * @rmap_hlist_len: number of rmap_item entries in hlist or STABLE_NODE_CHAIN
- * @nid: NUMA node id of stable tree in which linked (may not match kpfn)
- */
-struct ksm_stable_node {
- union {
- struct rb_node node; /* when node of stable tree */
- struct { /* when listed for migration */
- struct list_head *head;
- struct {
- struct hlist_node hlist_dup;
- struct list_head list;
- };
- };
- };
- struct hlist_head hlist;
- union {
- unsigned long kpfn;
- unsigned long chain_prune_time;
- };
- /*
- * STABLE_NODE_CHAIN can be any negative number in
- * rmap_hlist_len negative range, but better not -1 to be able
- * to reliably detect underflows.
- */
-#define STABLE_NODE_CHAIN -1024
- int rmap_hlist_len;
-#ifdef CONFIG_NUMA
- int nid;
-#endif
-};
-
/**
* struct ksm_rmap_item - reverse mapping item for virtual addresses
* @rmap_list: next rmap_item in mm_slot's singly-linked rmap_list
@@ -655,10 +619,12 @@ static void remove_node_from_stable_tree(struct ksm_stable_node *stable_node)
BUG_ON(stable_node->rmap_hlist_len < 0);
hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) {
- if (rmap_item->hlist.next)
+ if (rmap_item->hlist.next) {
ksm_pages_sharing--;
- else
+ trace_ksm_remove_rmap_item(stable_node, rmap_item, rmap_item->mm);
+ } else {
ksm_pages_shared--;
+ }
rmap_item->mm->ksm_merging_pages--;
@@ -679,6 +645,7 @@ static void remove_node_from_stable_tree(struct ksm_stable_node *stable_node)
BUILD_BUG_ON(STABLE_NODE_DUP_HEAD <= &migrate_nodes);
BUILD_BUG_ON(STABLE_NODE_DUP_HEAD >= &migrate_nodes + 1);
+ trace_ksm_remove_ksm_page(stable_node);
if (stable_node->head == &migrate_nodes)
list_del(&stable_node->list);
else
@@ -1375,6 +1342,8 @@ static int try_to_merge_with_ksm_page(struct ksm_rmap_item *rmap_item,
get_anon_vma(vma->anon_vma);
out:
mmap_read_unlock(mm);
+ trace_ksm_merge_with_ksm_page(kpage, page_to_pfn(kpage ? kpage : page),
+ rmap_item, mm, err);
return err;
}
@@ -2122,6 +2091,9 @@ static int try_to_merge_with_kernel_zero_page(struct ksm_rmap_item *rmap_item,
if (vma) {
err = try_to_merge_one_page(vma, page,
ZERO_PAGE(rmap_item->address));
+ trace_ksm_merge_one_page(
+ page_to_pfn(ZERO_PAGE(rmap_item->address)),
+ rmap_item, mm, err);
if (!err) {
rmap_item->address |= ZERO_PAGE_FLAG;
ksm_zero_pages_sharing++;
@@ -2365,6 +2337,8 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
mm_slot = ksm_scan.mm_slot;
if (mm_slot == &ksm_mm_head) {
+ trace_ksm_start_scan(ksm_scan.seqnr, ksm_rmap_items);
+
/*
* A number of pages can hang around indefinitely on per-cpu
* pagevecs, raised page count preventing write_protect_page
@@ -2544,6 +2518,7 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
if (mm_slot != &ksm_mm_head)
goto next_mm;
+ trace_ksm_stop_scan(ksm_scan.seqnr, ksm_rmap_items);
ksm_scan.seqnr++;
return NULL;
}
@@ -2696,6 +2671,7 @@ int __ksm_enter(struct mm_struct *mm, int flag)
if (needs_wakeup)
wake_up_interruptible(&ksm_thread_wait);
+ trace_ksm_enter(mm);
return 0;
}
@@ -2764,6 +2740,8 @@ void __ksm_exit(struct mm_struct *mm, int flag)
mmap_write_lock(mm);
mmap_write_unlock(mm);
}
+
+ trace_ksm_exit(mm);
}
struct page *ksm_might_need_to_copy(struct page *page,
new file mode 100644
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __MM_KSM_H__
+#define __MM_KSM_H__
+
+/**
+ * struct ksm_stable_node - node of the stable rbtree
+ * @node: rb node of this ksm page in the stable tree
+ * @head: (overlaying parent) &migrate_nodes indicates temporarily on that list
+ * @hlist_dup: linked into the stable_node->hlist with a stable_node chain
+ * @list: linked into migrate_nodes, pending placement in the proper node tree
+ * @hlist: hlist head of rmap_items using this ksm page
+ * @kpfn: page frame number of this ksm page (perhaps temporarily on wrong nid)
+ * @chain_prune_time: time of the last full garbage collection
+ * @rmap_hlist_len: number of rmap_item entries in hlist or STABLE_NODE_CHAIN
+ * @nid: NUMA node id of stable tree in which linked (may not match kpfn)
+ */
+struct ksm_stable_node {
+ union {
+ struct rb_node node; /* when node of stable tree */
+ struct { /* when listed for migration */
+ struct list_head *head;
+ struct {
+ struct hlist_node hlist_dup;
+ struct list_head list;
+ };
+ };
+ };
+ struct hlist_head hlist;
+ union {
+ unsigned long kpfn;
+ unsigned long chain_prune_time;
+ };
+ /*
+ * STABLE_NODE_CHAIN can be any negative number in
+ * rmap_hlist_len negative range, but better not -1 to be able
+ * to reliably detect underflows.
+ */
+#define STABLE_NODE_CHAIN -1024
+ int rmap_hlist_len;
+#ifdef CONFIG_NUMA
+ int nid;
+#endif
+};
+
+#endif
new file mode 100644
@@ -0,0 +1,258 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM ksm
+
+#if !defined(_TRACE_KSM_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_KSM_H
+
+#include <linux/tracepoint.h>
+#include "ksm.h"
+
+/**
+ * ksm_scan_template - called for start / stop scan
+ *
+ * @seq: sequence number of scan
+ * @rmap_entries: actual number of rmap entries
+ *
+ * Allows to trace the start / stop of a ksm scan.
+ */
+DECLARE_EVENT_CLASS(ksm_scan_template,
+
+ TP_PROTO(int seq, u32 rmap_entries),
+
+ TP_ARGS(seq, rmap_entries),
+
+ TP_STRUCT__entry(
+ __field(int, seq)
+ __field(u32, rmap_entries)
+ ),
+
+ TP_fast_assign(
+ __entry->seq = seq;
+ __entry->rmap_entries = rmap_entries;
+ ),
+
+ TP_printk("seq %d rmap size %d",
+ __entry->seq, __entry->rmap_entries)
+);
+
+/**
+ * ksm_start_scan - called after a new ksm scan is started
+ *
+ * @seq: sequence number of scan
+ * @rmap_entries: actual number of rmap entries
+ *
+ * Allows to trace the start of a ksm scan.
+ */
+DEFINE_EVENT(ksm_scan_template, ksm_start_scan,
+
+ TP_PROTO(int seq, u32 rmap_entries),
+
+ TP_ARGS(seq, rmap_entries)
+);
+
+/**
+ * ksm_stop_scan - called after a new ksm scan has completed
+ *
+ * @seq: sequence number of scan
+ * @rmap_entries: actual number of rmap entries
+ *
+ * Allows to trace the completion of a ksm scan.
+ */
+DEFINE_EVENT(ksm_scan_template, ksm_stop_scan,
+
+ TP_PROTO(int seq, u32 rmap_entries),
+
+ TP_ARGS(seq, rmap_entries)
+);
+
+/**
+ * ksm_enter - called after a new process has been added / removed from ksm
+ *
+ * @mm: address of the mm object of the process
+ *
+ * Allows to trace the when a process has been added or removed from ksm.
+ */
+DECLARE_EVENT_CLASS(ksm_enter_exit_template,
+
+ TP_PROTO(void *mm),
+
+ TP_ARGS(mm),
+
+ TP_STRUCT__entry(
+ __field(void *, mm)
+ ),
+
+ TP_fast_assign(
+ __entry->mm = mm;
+ ),
+
+ TP_printk("mm %p", __entry->mm)
+);
+
+/**
+ * ksm_enter - called after a new process has been added to ksm
+ *
+ * @mm: address of the mm object of the process
+ *
+ * Allows to trace the when a process has been added to ksm.
+ */
+DEFINE_EVENT(ksm_enter_exit_template, ksm_enter,
+
+ TP_PROTO(void *mm),
+
+ TP_ARGS(mm)
+);
+
+/**
+ * ksm_exit - called after a new process has been removed from ksm
+ *
+ * @mm: address of the mm object of the process
+ *
+ * Allows to trace the when a process has been removed from ksm.
+ */
+DEFINE_EVENT(ksm_enter_exit_template, ksm_exit,
+
+ TP_PROTO(void *mm),
+
+ TP_ARGS(mm)
+);
+
+/**
+ * ksm_merge_one_page - called after a page has been merged
+ *
+ * @pfn: page frame number of ksm page
+ * @rmap_item: address of rmap_item object
+ * @mm: address of the process mm struct
+ * @err: success
+ *
+ * Allows to trace the ksm merging of individual pages.
+ */
+TRACE_EVENT(ksm_merge_one_page,
+
+ TP_PROTO(unsigned long pfn, void *rmap_item, void *mm, int err),
+
+ TP_ARGS(pfn, rmap_item, mm, err),
+
+ TP_STRUCT__entry(
+ __field(unsigned long, pfn)
+ __field(void *, rmap_item)
+ __field(void *, mm)
+ __field(int, err)
+ ),
+
+ TP_fast_assign(
+ __entry->pfn = pfn;
+ __entry->rmap_item = rmap_item;
+ __entry->mm = mm;
+ __entry->err = err;
+ ),
+
+ TP_printk("ksm pfn %lu rmap_item %p mm %p error %d",
+ __entry->pfn, __entry->rmap_item, __entry->mm, __entry->err)
+);
+
+/**
+ * ksm_merge_with_ksm_page - called after a page has been merged with a ksm page
+ *
+ * @ksm_page: address ksm page
+ * @pfn: page frame number of ksm page
+ * @rmap_item: address of rmap_item object
+ * @mm: address of the mm object of the process
+ * @err: success
+ *
+ * Allows to trace the merging of a page with a ksm page.
+ */
+TRACE_EVENT(ksm_merge_with_ksm_page,
+
+ TP_PROTO(void *ksm_page, unsigned long pfn, void *rmap_item, void *mm, int err),
+
+ TP_ARGS(ksm_page, pfn, rmap_item, mm, err),
+
+ TP_STRUCT__entry(
+ __field(void *, ksm_page)
+ __field(unsigned long, pfn)
+ __field(void *, rmap_item)
+ __field(void *, mm)
+ __field(int, err)
+ ),
+
+ TP_fast_assign(
+ __entry->ksm_page = ksm_page;
+ __entry->pfn = pfn;
+ __entry->rmap_item = rmap_item;
+ __entry->mm = mm;
+ __entry->err = err;
+ ),
+
+ TP_printk("%spfn %lu rmap_item %p mm %p error %d",
+ (__entry->ksm_page ? "ksm " : ""),
+ __entry->pfn, __entry->rmap_item, __entry->mm, __entry->err)
+);
+
+/**
+ * ksm_remove_ksm_page - called after a ksm page has been removed
+ *
+ * @stable_node: pointer to stable node
+ *
+ * Allows to trace the removing of stable ksm pages.
+ */
+TRACE_EVENT(ksm_remove_ksm_page,
+
+ TP_PROTO(struct ksm_stable_node *stable_node),
+
+ TP_ARGS(stable_node),
+
+ TP_STRUCT__entry(
+ __field(unsigned long, pfn)
+ ),
+
+ TP_fast_assign(
+ __entry->pfn = stable_node->kpfn;
+ ),
+
+ TP_printk("pfn %lu", __entry->pfn)
+);
+
+/**
+ * ksm_remove_rmap_item - called after a rmap_item has been removed from the
+ * stable tree
+ *
+ * @stable_node: pointer to stable node
+ * @rmap_item: address of rmap_item object
+ * @mm: address of the process mm struct
+ *
+ * Allows to trace the removal of pages from the stable tree list.
+ */
+TRACE_EVENT(ksm_remove_rmap_item,
+
+ TP_PROTO(struct ksm_stable_node *stable_node, void *rmap_item, void *mm),
+
+ TP_ARGS(stable_node, rmap_item, mm),
+
+ TP_STRUCT__entry(
+ __field(unsigned long, pfn)
+ __field(void *, rmap_item)
+ __field(void *, mm)
+ ),
+
+ TP_fast_assign(
+ __entry->pfn = stable_node->kpfn;
+ __entry->rmap_item = rmap_item;
+ __entry->mm = mm;
+ ),
+
+ TP_printk("pfn %lu rmap_item %p mm %p",
+ __entry->pfn, __entry->rmap_item, __entry->mm)
+);
+
+#endif /* _TRACE_KSM_H */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE ksm_trace
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>