----- 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@xxxxxxxxxx> > 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: 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!******/# > -- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/crash-utility
