The patch titled
Subject: mm: mmap: add trace point of vm_unmapped_area
has been added to the -mm tree. Its filename is
mm-mmap-add-trace-point-of-vm_unmapped_area.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-mmap-add-trace-point-of-vm_unmapped_area.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-mmap-add-trace-point-of-vm_unmapped_area.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Jaewon Kim <jaewon31.kim@xxxxxxxxxxx>
Subject: mm: mmap: add trace point of vm_unmapped_area
Even on 64 bit kernel, the mmap failure can happen for a 32 bit task.
Virtual memory space shortage of a task on mmap is reported to userspace
as -ENOMEM. It can be confused as physical memory shortage of overall
system.
The vm_unmapped_area can be called to by some drivers or other kernel core
system like filesystem. In my platform, GPU driver calls to
vm_unmapped_area and the driver returns -ENOMEM even in GPU side shortage.
It can be hard to distinguish which code layer returns the -ENOMEM.
Create mmap trace file and add trace point of vm_unmapped_area.
i.e.)
277.156599: vm_unmapped_area: addr=77e0d03000 err=0 total_vm=0x17014b flags=0x1 len=0x400000 lo=0x8000 hi=0x7878c27000 mask=0x0 ofs=0x1
342.838740: vm_unmapped_area: addr=0 err=-12 total_vm=0xffb08 flags=0x0 len=0x100000 lo=0x40000000 hi=0xfffff000 mask=0x0 ofs=0x22
Link: http://lkml.kernel.org/r/20200320055823.27089-3-jaewon31.kim@xxxxxxxxxxx
Signed-off-by: Jaewon Kim <jaewon31.kim@xxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Michel Lespinasse <walken@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/trace/events/mmap.h | 48 ++++++++++++++++++++++++++++++++++
mm/mmap.c | 12 +++++++-
2 files changed, 58 insertions(+), 2 deletions(-)
--- /dev/null
+++ a/include/trace/events/mmap.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM mmap
+
+#if !defined(_TRACE_MMAP_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_MMAP_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(vm_unmapped_area,
+
+ TP_PROTO(unsigned long addr, struct vm_unmapped_area_info *info),
+
+ TP_ARGS(addr, info),
+
+ TP_STRUCT__entry(
+ __field(unsigned long, addr)
+ __field(unsigned long, total_vm)
+ __field(unsigned long, flags)
+ __field(unsigned long, length)
+ __field(unsigned long, low_limit)
+ __field(unsigned long, high_limit)
+ __field(unsigned long, align_mask)
+ __field(unsigned long, align_offset)
+ ),
+
+ TP_fast_assign(
+ __entry->addr = addr;
+ __entry->total_vm = current->mm->total_vm;
+ __entry->flags = info->flags;
+ __entry->length = info->length;
+ __entry->low_limit = info->low_limit;
+ __entry->high_limit = info->high_limit;
+ __entry->align_mask = info->align_mask;
+ __entry->align_offset = info->align_offset;
+ ),
+
+ TP_printk("addr=%lx err=%ld total_vm=0x%lx flags=0x%lx len=0x%lx lo=0x%lx hi=0x%lx mask=0x%lx ofs=0x%lx\n",
+ IS_ERR_VALUE(__entry->addr) ? 0 : __entry->addr,
+ IS_ERR_VALUE(__entry->addr) ? __entry->addr : 0,
+ __entry->total_vm, __entry->flags, __entry->length,
+ __entry->low_limit, __entry->high_limit, __entry->align_mask,
+ __entry->align_offset)
+);
+#endif
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
--- a/mm/mmap.c~mm-mmap-add-trace-point-of-vm_unmapped_area
+++ a/mm/mmap.c
@@ -53,6 +53,9 @@
#include <asm/tlb.h>
#include <asm/mmu_context.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/mmap.h>
+
#include "internal.h"
#ifndef arch_mmap_check
@@ -2076,10 +2079,15 @@ found_highest:
*/
unsigned long vm_unmapped_area(struct vm_unmapped_area_info *info)
{
+ unsigned long addr;
+
if (info->flags & VM_UNMAPPED_AREA_TOPDOWN)
- return unmapped_area_topdown(info);
+ addr = unmapped_area_topdown(info);
else
- return unmapped_area(info);
+ addr = unmapped_area(info);
+
+ trace_vm_unmapped_area(addr, info);
+ return addr;
}
#ifndef arch_get_mmap_end
_
Patches currently in -mm which might be from jaewon31.kim@xxxxxxxxxxx are
mmap-remove-inline-of-vm_unmapped_area.patch
mm-mmap-add-trace-point-of-vm_unmapped_area.patch
