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Howlett" , Lorenzo Stoakes , Vlastimil Babka , Jann Horn Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 60812100002 X-Stat-Signature: b5fjkt6s87grbqzyqcjxxr6yyjcn5s85 X-Rspam-User: X-HE-Tag: 1745290358-250064 X-HE-Meta: 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 itQyeCC1 Gm6tL+d4qklA1p+1Fphwt2UYUR9aGyqdxsbSZp9s0MGqVvKNDa6G/Mfk01nyMh4dcfxJyYODN6QzR82EUj/DpQLT5rfCiNNAwM2qPnhAcDzKm6BB9aYSenIM0rB26UPmAS99Bekd+mAwtAxv7ER53vDUbpTqyzuOUo0k6zytyx08UXRKaikmNT9Svnvc3aynFCKdYBensJelnFNTplIakhaoKcH/lKdknMTWUQOgkURwm6R+OrG+bLGotBVIY/GoXB6tq5nCjVnfjPSOShuY9t15KYT9NN5r/MELXAuEdNzHuxYASZu0BUJGnJl1FaqwfLfv7fuAayi/0hxjkws9NaQjYA3PKGrkVE5ERnWfTvMHidMiPCOAFv9G5mg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sun, Apr 20, 2025 at 12:35=E2=80=AFAM Kairui Song wro= te: > > On Sun, Apr 20, 2025 at 12:32=E2=80=AFAM David Hildenbrand wrote: > > > > On 19.04.25 18:25, David Hildenbrand wrote: > > > > Oh, re-reading the condition 3 times, I realize that the sanity check i= s wrong ... > > > > diff --git a/mm/memory.c b/mm/memory.c > > index 037b6ce211f1f..a17eeef3f1f89 100644 > > --- a/mm/memory.c > > +++ b/mm/memory.c > > @@ -3789,7 +3789,7 @@ static bool __wp_can_reuse_large_anon_folio(struc= t folio *folio, > > > > /* Stabilize the mapcount vs. refcount and recheck. */ > > folio_lock_large_mapcount(folio); > > - VM_WARN_ON_ONCE(folio_large_mapcount(folio) < folio_ref_count(f= olio)); > > + VM_WARN_ON_ONCE(folio_large_mapcount(folio) > folio_ref_count(f= olio)); > > Ah, now it makes sense to me now :) > > Thanks for the quick response. > > > > > if (folio_test_large_maybe_mapped_shared(folio)) > > goto unlock; > > > > Our refcount must be at least the mapcount, that's what we want to asse= rt. > > > > Can you test and send a fix patch if that makes it fly for you? > > Sure I'll keep the testing, I think it will just fix it, I have a few > WARN_ON_FOLIO reports all reporting mapcount is smaller than refcount. Hi David, I'm no longer seeing any warning after this, it fixed the problem well.