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b=dIHMmeylOq5MWUgqcV6cJduFvFXbZ9gggbTGpRsf8yqQofigkJGwMiMHUomt8BbwX UTjpQ5OsQRm1SNtpYd4AwPyP2+yqhfQCBOJUws+zh1rpj26jP1ynwGsvt3sPMQxfaL BKQo2ktSt/KGxbcgj55b8dYfG3ZSo4cqdO9S5ky1LFNDvtRFt7If6nC8TIeHtnPLni +S02xVS28/9xA7StPjQp55zdHH68c1/Zg/7rkYe8jPVDRBFjW8lLWjv12ZO/dDiHql EFGngsjnHjcLCoFnNVIisaJhz/qWPm61r7hfpFGBjubc8iSb5Fz3bXRgvJQ/XQrfCF i4LsJ2ZwSmbQw== Date: Fri, 29 May 2026 19:34:36 +0200 From: "Oscar Salvador (SUSE)" To: Alexander Gordeev Cc: Andrew Morton , David Hildenbrand , Lorenzo Stoakes , Anshuman Khandual , Oscar Salvador , Wei Yang , linux-s390@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] mm/page_vma_mapped_walk: Use ptep_get_lockless() for lockless access Message-ID: References: <20260528075507.1821939-1-agordeev@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260528075507.1821939-1-agordeev@linux.ibm.com> X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 4B9B280002 X-Stat-Signature: 6d3z3ojw77ii43ggw7b4g9eap819mmao X-HE-Tag: 1780076084-778711 X-HE-Meta: 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 5n3PuJ5z 51LRh8BfxV+pcrI39L0dZJ0kcJfSKZ99qVAHL+o79DQG8ecI2sK5Jq2z0KT8hkwopeijYnYfEUJ9LUqMWdwmDGzbOSXE4G5Mzf2gTmqJkgUhcpzxtYxoS20DDi48eodh5cvIjK1GM2IT9+6eqOL7flutW+rvg7Mk9FQZXp154y8AhKK6LTUcfUBJyqV4nF5D/8Yokq6pIK4g8q/I1zTlG0vNL7XGep+VJSa+4frmcIo6SGWhUMmZQZofVpVlietFgXG0t7mSdCQOLbS8PCxxANnClaBlPwOeR6SH0YhAaSXhsiX6Xdalm/uRgVPglR4cJI9RdJQHH1Un4sqg6lIcyr7sJbxsUvxcB3FIsIu/f6/65iGUmV7odp50aOg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, May 28, 2026 at 09:55:07AM +0200, Alexander Gordeev wrote: > Switch from ptep_get() to ptep_get_lockless() accessor for > PTE reads when no lock is taken. > > Signed-off-by: Alexander Gordeev I see Andrew has picked up the patch with the amended changelog, so with that: Reviewed-by: Oscar Salvador (SUSE) > --- > mm/page_vma_mapped.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c > index a4d52fdb3056..2ccbabfb2cc1 100644 > --- a/mm/page_vma_mapped.c > +++ b/mm/page_vma_mapped.c > @@ -41,7 +41,7 @@ static bool map_pte(struct page_vma_mapped_walk *pvmw, pmd_t *pmdvalp, > if (!pvmw->pte) > return false; > > - ptent = ptep_get(pvmw->pte); > + ptent = ptep_get_lockless(pvmw->pte); > > if (pte_none(ptent)) { > return false; > @@ -183,6 +183,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) > struct mm_struct *mm = vma->vm_mm; > unsigned long end; > spinlock_t *ptl; > + pte_t pteval; > pgd_t *pgd; > p4d_t *p4d; > pud_t *pud; > @@ -310,7 +311,11 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) > goto restart; > } > pvmw->pte++; > - } while (pte_none(ptep_get(pvmw->pte))); > + if (!pvmw->ptl) > + pteval = ptep_get_lockless(pvmw->pte); > + else > + pteval = ptep_get(pvmw->pte); > + } while (pte_none(pteval)); > > if (!pvmw->ptl) { > spin_lock(ptl); > -- > 2.51.0 > -- Oscar Salvador SUSE Labs