Re: [Crash-utility] [PATCH] Add -m option to kmem

----- Original Message ----- > 于 2013年03月02日 05:20, Dave Anderson 写道: >> >> >> ----- Original Message ----- >>> kmem -m is used for displaying information of all ksm pages or >>> some ksm pages for specified ksm stable tree node addresses >>> The information includes: >>> - physical address of ksm page, >>> - pid of tasks using this ksm page, >>> - counts of ksm page references for each task >>> >>> for example: >>> crash> kmem -m ffff8803573964c0 >>> PID: 15864 16781 >>> 793005000: 8713 5584 >>> >>> ffff8803573964c0 is the address of ksm stable tree node. >>> task 15864 has 8713 virtual pages mapping the page with address 793005000. >>> task 16781 has 5584 virtual pages mapping the page with address 793005000. >>> >>> P.S. >>> This patch is based on the patch from >>> Qiao(qiaonuohan(a)cn.fujitsu.com) >>> 0001-make-rbtree-manipulation-functions-global.patch >>> Because this patch also uses rb_tree operations. >> >> I'll get to this patch after I get Qiao's patch straightened out and >> checked in. >> >> But a couple quick questions... >> >> What does "kmem -m" alone look like? Your help page example only >> shows the command passing a "ksm stable tree node address". > > 'kmem -m' will display all the ksm pages. I meant could you show an example of "kmem -m"... > >> How would a user know what one of those addresses would be? > > From the structure "rmap_item" ? it has a member "head" that points > to a ksm stable tree node. So does "kmem -m" show a list of those addresses?

>> >> And for "kmem -m <address>", what if there are dozens of PIDs that >> are mapping the same physical address? Regardless of the size of >> the display window, eventually it would get messy if it extends to >> more than one line. I try to avoid having commands extend beyond >> 80 columns if at all possible. >> > > Hmm. If there are quite many PIDs, can the output be like below? > > PID: 15864 16781 16782 16783 > 793005000: 8713 5584 23 23 > 12222 13333 14444 15555 > 232 232 334 456 > ... Well, that's not much clearer -- it's difficult to tell whether the numbers are PIDs or counts.