On Mon, Mar 09, 2020 at 04:08:15PM +0100, Michal Hocko wrote:
On Mon 09-03-20 14:11:17, Oleksandr Natalenko wrote:
quoted
On Fri, Mar 06, 2020 at 05:08:18PM +0100, Vlastimil Babka wrote:
[...]
quoted
quoted
Dunno, it's nice to react to signals quickly, for any proces that gets them, no?
So, do you mean something like this?
===
diff --git a/mm/ksm.c b/mm/ksm.c
index 363ec8189561..b39c237cfcf4 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -849,7 +849,8 @@ static int unmerge_ksm_pages(struct vm_area_struct *vma,
for (addr = start; addr < end && !err; addr += PAGE_SIZE) {
if (ksm_test_exit(vma->vm_mm))
break;
- if (signal_pending(current))
+ if (signal_pending(current) ||
+ signal_pending(rcu_dereference(vma->vm_mm->owner)))
err = -ERESTARTSYS;
else
err = break_ksm(vma, addr);===
This is broken because mm might be attached to different tasks.
AFAIU this check is meant to allow quick backoff of the _calling_
process so that it doesn't waste time when the context is killed
already. I do not understand why should we care about any other context
here? What is the actual problem this would solve?
I agree with you, but still trying to understand what does Vlastimil mean
:).
--
Michal Hocko
SUSE Labs
--
Best regards,
Oleksandr Natalenko (post-factum)
Principal Software Maintenance Engineer