| Message ID | 20200320055823.27089-3-jaewon31.kim@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm: mmap: add mmap trace point | expand |
On Fri, Mar 20, 2020 at 02:58:23PM +0900, Jaewon Kim wrote:
> + 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",
Shouldn't addr be printed as 0x%lx? I think it's arguable whether to print
len as %ld or 0x%lx.
On Fri, Mar 20, 2020 at 02:58:23PM +0900, Jaewon Kim wrote: > + 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, I didn't see the IS_ERR_VALUE problem that Vlastimil mentioned get resolved? I might suggest ... +++ b/include/linux/err.h @@ -19,7 +19,8 @@ #ifndef __ASSEMBLY__ -#define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO) +#define __IS_ERR_VALUE(x) ((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO) +#define IS_ERR_VALUE(x) unlikely(__IS_ERR_VALUE(x)) static inline void * __must_check ERR_PTR(long error) { and then you can use __IS_ERR_VALUE() which removes the unlikely() problem.
On 2020년 03월 30일 01:14, Matthew Wilcox wrote: > On Fri, Mar 20, 2020 at 02:58:23PM +0900, Jaewon Kim wrote: >> + 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, > I didn't see the IS_ERR_VALUE problem that Vlastimil mentioned get resolved? Sorry I missed the problem. And thank you for your comment and suggestion. I still do not understand why the unlikely incurs [FAILED TO PARSE] problem on trace-cmd. Then trace log should not use the unlikely? I may need to resubmit a new patch set with your suggestion. Thank you > > I might suggest ... > > +++ b/include/linux/err.h > @@ -19,7 +19,8 @@ > > #ifndef __ASSEMBLY__ > > -#define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO) > +#define __IS_ERR_VALUE(x) ((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO) > +#define IS_ERR_VALUE(x) unlikely(__IS_ERR_VALUE(x)) > > static inline void * __must_check ERR_PTR(long error) > { > > and then you can use __IS_ERR_VALUE() which removes the unlikely() problem. > >
On 3/29/20 6:14 PM, Matthew Wilcox wrote: > On Fri, Mar 20, 2020 at 02:58:23PM +0900, Jaewon Kim wrote: >> + 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, > > I didn't see the IS_ERR_VALUE problem that Vlastimil mentioned get resolved? Steven is fixing it in trace-cmd: https://lore.kernel.org/r/20200324200956.821799393@goodmis.org > I might suggest ... > > +++ b/include/linux/err.h > @@ -19,7 +19,8 @@ > > #ifndef __ASSEMBLY__ > > -#define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO) > +#define __IS_ERR_VALUE(x) ((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO) > +#define IS_ERR_VALUE(x) unlikely(__IS_ERR_VALUE(x)) So this shouldn't be needed, as we are adding a new tracepoint, not "breaking" an existing one? > static inline void * __must_check ERR_PTR(long error) > { > > and then you can use __IS_ERR_VALUE() which removes the unlikely() problem. >
On 2020년 03월 30일 18:56, Vlastimil Babka wrote: > On 3/29/20 6:14 PM, Matthew Wilcox wrote: >> On Fri, Mar 20, 2020 at 02:58:23PM +0900, Jaewon Kim wrote: >>> + 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, >> I didn't see the IS_ERR_VALUE problem that Vlastimil mentioned get resolved? > Steven is fixing it in trace-cmd: > https://lore.kernel.org/r/20200324200956.821799393@goodmis.org Good news for me. Thank you > >> I might suggest ... >> >> +++ b/include/linux/err.h >> @@ -19,7 +19,8 @@ >> >> #ifndef __ASSEMBLY__ >> >> -#define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO) >> +#define __IS_ERR_VALUE(x) ((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO) >> +#define IS_ERR_VALUE(x) unlikely(__IS_ERR_VALUE(x)) > So this shouldn't be needed, as we are adding a new tracepoint, not "breaking" > an existing one? > >> static inline void * __must_check ERR_PTR(long error) >> { >> >> and then you can use __IS_ERR_VALUE() which removes the unlikely() problem. >> > >
On Sun, Mar 29, 2020 at 09:08:58AM -0700, Matthew Wilcox wrote: > On Fri, Mar 20, 2020 at 02:58:23PM +0900, Jaewon Kim wrote: > > + 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", > > Shouldn't addr be printed as 0x%lx? %#lx should do the trick.
diff --git a/include/trace/events/mmap.h b/include/trace/events/mmap.h new file mode 100644 index 000000000000..986a41b6cfa9 --- /dev/null +++ b/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> 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 @@ static unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info) */ 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
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 Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com> --- v3: reduce fast_assign and print format v2: use trace point rather than printk with ratelimit v1: use printk with ratelimit --- include/trace/events/mmap.h | 48 +++++++++++++++++++++++++++++++++++++++++++++ mm/mmap.c | 12 ++++++++++-- 2 files changed, 58 insertions(+), 2 deletions(-) create mode 100644 include/trace/events/mmap.h