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Date: Tue, 10 Mar 2020 15:24:08 -0700 From: Minchan Kim <minchan@...nel.org> To: Vlastimil Babka <vbabka@...e.cz> Cc: Andrew Morton <akpm@...ux-foundation.org>, LKML <linux-kernel@...r.kernel.org>, linux-mm <linux-mm@...ck.org>, linux-api@...r.kernel.org, oleksandr@...hat.com, Suren Baghdasaryan <surenb@...gle.com>, Tim Murray <timmurray@...gle.com>, Daniel Colascione <dancol@...gle.com>, Sandeep Patil <sspatil@...gle.com>, Sonny Rao <sonnyrao@...gle.com>, Brian Geffon <bgeffon@...gle.com>, Michal Hocko <mhocko@...e.com>, Johannes Weiner <hannes@...xchg.org>, Shakeel Butt <shakeelb@...gle.com>, John Dias <joaodias@...gle.com>, Joel Fernandes <joel@...lfernandes.org>, Jann Horn <jannh@...gle.com>, alexander.h.duyck@...ux.intel.com, sj38.park@...il.com Subject: Re: [PATCH v7 3/7] mm: check fatal signal pending of target process On Fri, Mar 06, 2020 at 11:22:07AM +0100, Vlastimil Babka wrote: > On 3/2/20 8:36 PM, Minchan Kim wrote: > > Bail out to prevent unnecessary CPU overhead if target process has > > pending fatal signal during (MADV_COLD|MADV_PAGEOUT) operation. > > > > Reviewed-by: Suren Baghdasaryan <surenb@...gle.com> > > Signed-off-by: Minchan Kim <minchan@...nel.org> > > Reviewed-by: Vlastimil Babka <vbabka@...e.cz> > > Nit below: > > > --- > > mm/madvise.c | 29 +++++++++++++++++++++-------- > > 1 file changed, 21 insertions(+), 8 deletions(-) > > > > diff --git a/mm/madvise.c b/mm/madvise.c > > index 349473fc6683..6543f2bfc3d8 100644 > > --- a/mm/madvise.c > > +++ b/mm/madvise.c > > @@ -36,6 +36,7 @@ > > struct madvise_walk_private { > > struct mmu_gather *tlb; > > bool pageout; > > + struct task_struct *target_task; > > }; > > > > /* > > @@ -316,6 +317,10 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd, > > if (fatal_signal_pending(current)) > > return -EINTR; > > > > + if (private->target_task && > > + fatal_signal_pending(private->target_task)) > > + return -EINTR; > > With madvise(2) private->target_task will be current, thus current will be > tested twice. Not wrong, but maybe add a "private->target_task != current" > condition? It was in old series but removed because reviewer(IIRC, suren) wanted it. I am not strong preference either way. Since you said it's nit and considering other reviewer wanted to remove it, I will not change further. Thanks!
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