On 7/27/2022 6:59 PM, Vlastimil Babka (SUSE) wrote:
On 7/27/22 09:44, Kassey Li wrote:
On 7/26/2022 10:03 PM, Vlastimil Babka (SUSE) wrote:
On 7/25/22 10:39, Kassey Li wrote:
hi, Matthew:
sorry for the delay, I just started to learn how to upstream patch, and
setup my Thunderbird with plain text only.
you are right, two users will cause problem here.
the uses case is dump CMA area to understand the page usage in a given
cma pool. 2nd, dump whole memory page owner is very time cost, mostly our
android device has 8G memory now.
I will research and check again, if you have more idea on this , please
kindly to share.
You could try employing lseek() to specify the start pfn, and as for end
pfn, the process can just stop reading and close when it has seen enough?
lseek is a good idea.
read_page_owner start with below
pfn = min_low_pfn + *ppos;
so we need to export the min_low_pfn to user then decide the ppos to seek.
(my_cma.base_pfn - min_low_pfn) is the ppos we want to set.
Hm could we just pfn = *ppos and then anything below min_low_pfn is skipped
internally? So we don't need to teach userspace min_low_pfn.
that makes sense.
I send out a new path "mm/page_owner.c: add llseek for page_owner"
according your suggest, please help to review again, thanks.
is there concern to export min_low_pfn ?
or use a mutex lock for my previous debugfs version patch ?
BR
Kassey
On 7/22/2022 11:38 PM, Matthew Wilcox wrote:
On Fri, Jul 22, 2022 at 11:08:10PM +0800, Kassey Li wrote:
by default, page_owner iterates all page from min_low_pfn to
max_pfn, this cost too much time if we want an alternative pfn range.
with this patch it allows user to set pfn range to dump the page_onwer.
This is a really bad UI. If two users try to do different ranges at the
same time, it'll go wrong. What use cases are you actually trying to
solve?
