2:56 a.m.
Hi,Dave
As per your suggestion, I updated the patch,and compiled successfully on arm64, x86,ppc64
architecture
________________________________________
From: Dave Anderson <anderson(a)redhat.com>
Sent: Friday, April 3, 2020 0:16
To: 赵乾利
Cc: d hatayama; Discussion list for crash utility usage, maintenance and development
Subject: Re: 答复: [External Mail]Re: [Crash-utility] zram decompress support for
gcore/crash-utility
----- Original Message -----
Hi,Dave & hatayama
I made two patchs in crash-utility and gcore to support zram decompress
1.In crash-utility,I add patch in readmem to support zram decompression,
readmem interface automatically recognizes and decompresses zram data.
There are some limitations to zram support,only support lzo decompress,kernel
support lzo,lz4,lz4hc,842,zstd,but lzo is default.
use "rd" command also read data even if mapping to zram
[without patch]
crash> rd 144fc000 2
rd: invalid user virtual address: 144fc000 type: "64-bit UVADDR"
[with patch]
crash> rd 144fc000 2
144fc000: 06ecdc6b06ecb280 06f027f906eebebe ....k........'..
With respect to the crash utility patch:
Apparently you wrote this patch to only support ARM64? Here's what happens on an
x86_64:
$ patch -p1 < $bos/0001-support-zram-decompress-in-readmem.patch
patching file defs.h
Hunk #5 succeeded at 5304 (offset 2 lines).
patching file memory.c
$ make warn
... [ cut ] ...
cc -c -g -DX86_64 -DLZO -DSNAPPY -DGDB_7_6 memory.c -Wall -O2 -Wstrict-prototypes
-Wmissing-prototypes -fstack-protector -Wformat-security
In file included from memory.c:19:0:
memory.c: In function 'zram_object_addr':
defs.h:5310:27: error: 'PHYS_MASK_SHIFT' undeclared (first use in this
function)
#define _PFN_BITS (PHYS_MASK_SHIFT - PAGESHIFT())
^
defs.h:5311:43: note: in expansion of macro '_PFN_BITS'
#define OBJ_INDEX_BITS (BITS_PER_LONG - _PFN_BITS - OBJ_TAG_BITS)
^
memory.c:19838:27: note: in expansion of macro 'OBJ_INDEX_BITS'
page = pfn_to_map(obj >> OBJ_INDEX_BITS);
^
defs.h:5310:27: note: each undeclared identifier is reported only once for each function
it appears in
#define _PFN_BITS (PHYS_MASK_SHIFT - PAGESHIFT())
^
defs.h:5311:43: note: in expansion of macro '_PFN_BITS'
#define OBJ_INDEX_BITS (BITS_PER_LONG - _PFN_BITS - OBJ_TAG_BITS)
^
memory.c:19838:27: note: in expansion of macro 'OBJ_INDEX_BITS'
page = pfn_to_map(obj >> OBJ_INDEX_BITS);
^
memory.c: In function 'try_zram_decompress':
memory.c:19940:16: error: 'PTE_VALID' undeclared (first use in this function)
if (pte_val & PTE_VALID)
^
memory.c:19932:8: warning: unused variable 'ret' [-Wunused-variable]
ulong ret = 0;
^
make[4]: *** [memory.o] Error 1
make[3]: *** [gdb] Error 2
make[2]: *** [rebuild] Error 2
make[1]: *** [gdb_merge] Error 2
make: *** [warn] Error 2
$
So that's a non-starter. If it can't be made architecture-neutral, then at
least the other major architectures need to be supported. At a minimum all
architectures need to be able to be compiled with LZO enabled.
If you can do that, other suggestions I have for the patch are:
(1) Move all the new offset_table entries to the end of the structure to prevent
the breakage of previously-compiled extension modules that use OFFSET().
(2) Move the new LZO specific functions to diskdump.c, which is the only C file
that is set up to deal with LZO being #define'd on the fly with "make
lzo".
(3) Create a dummy try_zram_decompress() function in diskdump.c that just
returns 0. Put it outside of the LZO function block, e.g.:
#ifdef LZO
zram_object_addr(args... )
...
lookup_swap_cache(args...)
...
try_zram_decompress(args...)
...
#else
try_zram_decompress(args...) { return 0; }
#endif
Alternatively, you could create a try_zram_decompress() macro in defs.h the same
way.
(4) Remove the #ifdef/#endif LZO section of readmem().
(5) PLEASE do not make all the white-space changes in memory.c. It's annoying
to have to review the patch when it's cluttered with changes that are
irrelevant to the task at hand.
Thanks,
Dave
2.In gcore, I have to make a small change ,change parameter of readmem from
PHYADDR to UVADDR, other work will be done by crash
Please help review.
Thanks
-----邮件原件-----
发件人: Dave Anderson <anderson(a)redhat.com>
发送时间: 2020年4月2日 0:29
收件人: 赵乾利 <zhaoqianli(a)xiaomi.com>
抄送: d hatayama <d.hatayama(a)fujitsu.com>; Discussion list for crash utility
usage, maintenance and development <crash-utility(a)redhat.com>
主题: Re: [External Mail]Re: [Crash-utility] zram decompress support for
gcore/crash-utility
----- Original Message -----
> Hi,Dave
> Zram is a virtual device,it simulated as a block device,it's part of
> memroy/ramdump,just enable CONFIG_ZRAM,no other settings needed.
> you can refer to drivers/block/zram/zram_drv.c driver calling
> zram_meta_alloc to alloc memory from RAM.
>
> We want to be able to access these zram page like a normal page.
I understand all that. I'm just curious how makedumpfile will handle/filter
the physical RAM pages that make up the zram block device.
Anyway, send a patch and I'll take a look.
Dave
>
> ________________________________________
> From: Dave Anderson <anderson(a)redhat.com>
> Sent: Wednesday, April 1, 2020 23:24
> To: 赵乾利
> Cc: d hatayama; Discussion list for crash utility usage, maintenance
> and development
> Subject: Re: [External Mail]Re: [Crash-utility] zram decompress
> support for gcore/crash-utility
>
> ----- Original Message -----
> > Hi,Dave
> > zram is same with other swap device,but every swaped page will be
> > compressed then saved to another memory address.
> > The process is same with the common swap device,non-swap just a
> > normal user address,pgd and mmu will translate to phy address
> >
> > please refer to below information:
> > crash> vm -p
> > PID: 1565 TASK: ffffffe1fce32d00 CPU: 7 COMMAND:
"system_server"
> > MM PGD RSS TOTAL_VM
> > ffffffe264431c00 ffffffe1f54ad000 528472k 9780384k
> > VMA START END FLAGS FILE
> > ffffffe0ea401300 12c00000 12e00000 100073
> > VIRTUAL PHYSICAL
> > ...
> > 144fc000 SWAP: /dev/block/zram0 OFFSET: 236750
> > ...
> > 1738e000 SWAP: /dev/block/zram0 OFFSET: 73426
> > 1738f000 21aa2c000
> > 17390000 1c3308000
> > 17391000 SWAP: /dev/block/zram0 OFFSET: 73431
> > 17392000 19c162000
> > 17393000 19c132000
> > 17394000 SWAP: /dev/block/zram0 OFFSET: 234576
> > 17395000 19c369000
> > 17396000 20b35c000
> > 17397000 18011e000
> > 17398000 SWAP: /dev/block/zram0 OFFSET: 73433
> > 17399000 1dc3d2000
> > 1739a000 1bc59f000
> > 1739b000 SWAP: /dev/block/zram0 OFFSET: 73437
> >
> >
> > crash> vtop -c 1565 144fc000
> > VIRTUAL PHYSICAL
> > 144fc000 (not mapped)
> >
> > PAGE DIRECTORY: ffffffe1f54ad000
> > PGD: ffffffe1f54ad000 => 1f54ab003
> > PMD: ffffffe1f54ab510 => 1f43b8003
> > PTE: ffffffe1f43b87e0 => 39cce00
> >
> > PTE SWAP OFFSET
> > 39cce00 /dev/block/zram0 236750
> >
> > VMA START END FLAGS FILE
> > ffffffe148bafe40 144c0000 14540000 100073
> >
> > SWAP: /dev/block/zram0 OFFSET: 236750
>
> Ok, so with respect to user-space virtual addresses, there is nothing
> other than handling zram swap-backed memory.
>
> So what you're proposing is that when reading user-space memory that
> happens to be backed-up on a zram swap device, then the user data
> could alternatively be read from the zram swap device, and presented
> as if it were present in physical memory?
>
> Are the physical RAM pages that make up the contents of a zram device
> collected with a typical filtered compressed kdump? If not, what
> makedumpfile -d flag is required for them to be captured?
>
> Dave
>
>
> #/******本邮件及其附件含有小米公司的保密信息，仅限于发送给上面地址中列出的个人或群组。禁止任何其他人以任何形式使用（包括但不限于全部
> 或部分地泄露、复制、或散发）本邮件中的信息。如果您错收了本邮件，请您立即电话或邮件通知发件人并删除本邮件！
> This e-mail and its attachments contain confidential information from
> XIAOMI, which is intended only for the person or entity whose address
> is listed above. Any use of the information contained herein in any
> way (including, but not limited to, total or partial disclosure,
> reproduction, or dissemination) by persons other than the intended
> recipient(s) is prohibited. If you receive this e-mail in error,
> please notify the sender by phone or email immediately and delete
> it!******/#
>
#/******本邮件及其附件含有小米公司的保密信息，仅限于发送给上面地址中列出的个人或群组。禁止任何其他人以任何形式使用（包括但不限于全部或部分地泄露、复制、或散发）本邮件中的信息。如果您错收了本邮件，请您立即电话或邮件通知发件人并删除本邮件！
This e-mail and its attachments contain confidential information from
XIAOMI, which is intended only for the person or entity whose address is
listed above. Any use of the information contained herein in any way
(including, but not limited to, total or partial disclosure, reproduction,
or dissemination) by persons other than the intended recipient(s) is
prohibited. If you receive this e-mail in error, please notify the sender by
phone or email immediately and delete it!******/#
#/******本邮件及其附件含有小米公司的保密信息，仅限于发送给上面地址中列出的个人或群组。禁止任何其他人以任何形式使用（包括但不限于全部或部分地泄露、复制、或散发）本邮件中的信息。如果您错收了本邮件，请您立即电话或邮件通知发件人并删除本邮件！
This e-mail and its attachments contain confidential information from XIAOMI, which is
intended only for the person or entity whose address is listed above. Any use of the
information contained herein in any way (including, but not limited to, total or partial
disclosure, reproduction, or dissemination) by persons other than the intended
recipient(s) is prohibited. If you receive this e-mail in error, please notify the sender
by phone or email immediately and delete it!******/#