Re: [PATCH v7 7/7] mm/madvise: allow KSM hints for remote API
From: Michal Hocko <mhocko@kernel.org>
Date: 2020-03-09 15:08:20
Also in:
linux-mm, lkml
On Mon 09-03-20 14:11:17, Oleksandr Natalenko wrote:
On Fri, Mar 06, 2020 at 05:08:18PM +0100, Vlastimil Babka wrote:
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quoted hunk ↗ jump to hunk
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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? -- Michal Hocko SUSE Labs