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authorJaewon Kim <jaewon31.kim@samsung.com>2020-04-02 07:09:13 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-04-02 19:35:30 +0300
commitdf529cabb7a2553bbeb7bab725776f62fdcec972 (patch)
tree8e5e791a94c194acc9667059175ae55b2182dbce /mm/mmap.c
parentbaceaf1c8b99080ae5274d7262df8b09fa981762 (diff)
downloadlinux-df529cabb7a2553bbeb7bab725776f62fdcec972.tar.xz
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 [akpm@linux-foundation.org: prefix address printk with 0x, per Matthew] Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@suse.de> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michel Lespinasse <walken@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/20200320055823.27089-3-jaewon31.kim@samsung.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mmap.c')
-rw-r--r--mm/mmap.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index ba990c20ecc2..94ae18398c59 100644
--- a/mm/mmap.c
+++ b/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
@@ -2061,10 +2064,15 @@ 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