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From: Lance Yang In-Reply-To: <20260627003813.ktpya35fx5doaz36@master> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 51DED140008 X-Stat-Signature: fy1udq7eb3kqza4k4qhmkxi4ifn157at X-HE-Tag: 1782528705-943746 X-HE-Meta: U2FsdGVkX1/6frEoTQPpY1dIVsTJz6iGPNIgfPD9541jKuCvf1aOjGQtSxjM6ZN5mhvNYprkuXFNPHnYRs2TAPmVfaUuEInhFuI96F3mrxNuZ9YWmg2ZS1+w62E2H7ERQk13tP03eomWxmQLe/emQtxXKsNwMEbnfolIZo17rsysLDnFRalfQXmQDG/7F3IPtS5FIF7lkTVdHpow1Ax4+di5l1F+sLY85BK+V6vfTmNWBLm7bcFnsFf3y42T2T+DVnmdNLmwBr37ChOTl8x98O0r4vqR6RSz+hq6tsBteLpS7XtLgKC/BbcTGtCrZ+3h7g84uBZWvL6gcZ6II/nmnGh7yEHu536HI8oddggY/dGbFzWdYiDnr29gSKnTIr6OX7XS/Gsn5axpTwJDt+fhW7+7hJHgX0eMlDJZf7N3IbJgXUg2WOCj+2xPqDz8ZfaOlOuMqfDYxz3AN9Gwmx5M7bJCmjIK2Yvp83BtLcmVYKj0AxHfGeBoiTL4EdiAV2aK/+rBtZQnWWWT/WzFpLUSXE0Y9umUr+tRluAUk7lh7arxoU/i8WbxHr8kTVC1Y2mq4GbnYqKS//CwKdcplqcxBKNdkflIFphNZP6UZBl3JYMuqAEJhdbcRooIXMIFhEuV5XU+tcma8i1KZTnR9U9onR0ebGZvVtBNhLm8sUPwtrVQ1uQ95z6EBoKyprxG9p3cnqTgYFsmAhfwje/0+dIL7a/IcEkLSqDdiWtfIT1tAjbgyU4op2cOkolsO69ugZYNckrRiSG8iuBdcDryFNuxHPvCebha7PRppoUsfgmugkO8GtoIWAQKgL3ixNqZqUVMU1sdPvfbzNCn/rH4fT/4dKfFHx6LB92xHqXk9hdIyQ/EjVR1Tl28z40yKjVurdCQ5qAzlcaSq+Y7uNv2u7KD5+h/Z+vFqY+sCqE6umMkqsmQwtuOWFgf3EzrnuAFWyrVU4wwnRvy7rEkaUdIqwM Bo3FWaq0 jcz92jGsmsc/DX2fSB5uF5O4rYN1MCjUAkj8Qh1HXJkWzlR+wz9qU+w0qnjnsy6J+/coKbjotioLN4WZGZR+cqotA2l/ZmiRfiJHtV4zhythxohiiUtVdHxheVWO0j5WtaUzRaTsm0MKNnZpOzbFaanZgIugsRWwjQtEKhJEBl6+mQg63O7Xvvmfa/Lm2LjiEbyKXSp4x91B4C0B8l0Yf0BrdufR1BuVSosPFMwGY28Nixqhb8r/EHMZgs5PcNx9TkmBf2uGCuOeBuIRSO8mpmc2ZDyeovWAhz5i+AjI24YVz9mEnfphCCM/6ynX4pmF9U0H1wbgtdnN9efk= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2026/6/27 08:38, Wei Yang wrote: [...] >> >> Might be good with this on top: >> >> ---8<--- >> diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c >> index cfa1230c87bb..8b7c062bd81d 100644 >> --- a/mm/page_vma_mapped.c >> +++ b/mm/page_vma_mapped.c >> @@ -281,7 +281,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) >> return not_found(pvmw); >> return true; >> } >> - /* THP pmd was split under us: handle on pte level */ >> + /* THP/device-private pmd was split under us: handle on pte level */ > > As the comment in commit 65edfda6f3f2 ("mm/rmap: extend rmap and migration > support device-private entries") says: > > Add device-private THP support... > > Per my understanding, we first already setup mapping and "migrate" to device > memory. This looks a kind of place holder. > > Not familiar with this. Just want to clarify, we want to treat device-private > pmd as some sort of THP or not? Not a regular THP, obviously. Just the PMD-sized device-private entry case. It can be split under us too; see commit 146287290023 ("mm/huge_memory: implement device-private THP splitting"). Nothing deeper meant here. After taking PTL, if that PMD-sized entry is gone, just drop to the PTE walk. > >> spin_unlock(pvmw->ptl); >> pvmw->ptl = NULL; >> } else if (!pmd_present(pmde)) { >> --