From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 97DC34A2E24 for ; Tue, 9 Jun 2026 16:31:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781022709; cv=none; b=XaOwsuFa193gHXr/7AOlXCSqkbssQ1wJyJW8hXFXXf6DcXL7pzb0XYvGxkf43eN+2BAofZsr10aSY9AUPOUkf+IV8E28ys1JQLbpBGODCK2ONI49UP3LKywb8RFXVwYyiw49NKQDKsqZPymE0csQnkVkfOSrJnwRC4QEXAfCNAM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781022709; c=relaxed/simple; bh=/3EAZdmqy+2X2Fp3Q8W+pzNCGzEZMflvf/FBSzpx7WU=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=paE3lg1jFelyr1K8mkjxJaWMvO59hpqf7GwDmx9AYjaLh5sXBUQjkJNs+7vLSTt2O2ttr+kVDDwjQ0tLEO4/qh/UcOudHID575wkQuK1aXN0z70CJqHezz5gPU9/FB62wodPxzHdVdmHBVd1isaarvDZMxl+a/LfK4T9m4Zu4Lk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=S/ggzkDS; arc=none smtp.client-ip=209.85.214.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="S/ggzkDS" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-2bf32fb7cb2so41739125ad.2 for ; Tue, 09 Jun 2026 09:31:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1781022706; x=1781627506; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=EI8CPPHCJ7Zmu9lqXV0PA5evSY9oUhH+2SIUAKzpTKg=; b=S/ggzkDSvRzhA24aDFCsM57gKUqK2aa6dwKoivz8+1qQ/Z0VJaNUYkM4k/p4NXz3XD yuVONhRWcUPqWv4/NFYcjCCBkPA2BBAxeDs9T4XClJ8g43+lRwXOwzj+f2/sxxf+Hi/y n5CMN333M9YfOQmrJe2unQ0in2NtB140jt/MbvrVO4UrNT0p07+5Lctxy2jvqUhkIfaj HqTmsd4CyUv95s2CprlDRtldQV8UlpSJnc3EjFQ8HaygGiBYFzmyptaEizeRYlj89yj+ YumEu1xBxRfK8K4fuGJn1vn4NWKCnyHuhF27RYsqITtpjP77hYSMLqxOS6nyEsM1IwhS Bcbg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1781022706; x=1781627506; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=EI8CPPHCJ7Zmu9lqXV0PA5evSY9oUhH+2SIUAKzpTKg=; b=Zk9lSOeoTsoVU+mlB8BJP+RUWRJ7vSyxV7fWDR2/mYKgKIrmm1nl9Qf2fsW70KcAAx mREIOVE9Dg+HTKkie8o2i+WOKVSRkXFyAwsZcAgDNI375xM3haizcBV4HeuZvdi8ALd6 XIUNGbe0cFOYwg2yL15W+e3svy2zcZZTjxRDk7O1+9peZ6ytb1ZUW3XmePvfhixkN0iU kTHOZujPwJGKy8gI/oLJgOMP0u5xpcCfUcNkpTZM/N9BZ46zWdhhVMVNsiKwIHcRdK7a tTDlbWE7/JArwRxmHfdPcD6ditd6GozXOD6IiM0GbZFOaKPV9jN4WoN+NPvC/wfDWXKn pMYw== X-Forwarded-Encrypted: i=1; AFNElJ90wIt3SmjZh5FOa52XtJEReqftVC8MSgtT59LgpPe9XqoDdg66K3x9KE1xToBLTpEpHStRWjJaj58jVH0=@vger.kernel.org X-Gm-Message-State: AOJu0YxDVUQB0lbMUXq+PCF17+441MXrDEqDwY+7/x0RBZSvhlg27xHl eo12GmkO1dc9o3UEeFfKU+X+nYwr1mHL8XLnctbi/fdi8RpgvNL2kw83dB99OTNJ2M8NPwrX0+n 7asWg2g== X-Received: from plge6.prod.google.com ([2002:a17:902:cf46:b0:2c0:e5f0:9416]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:c951:b0:2c0:a373:89b9 with SMTP id d9443c01a7336-2c1e79e22d1mr249344275ad.6.1781022705646; Tue, 09 Jun 2026 09:31:45 -0700 (PDT) Date: Tue, 9 Jun 2026 09:31:29 -0700 In-Reply-To: <0eff0a90667b900bee837d06b5db5025e1f304b5.1780501924.git.mst@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <0eff0a90667b900bee837d06b5db5025e1f304b5.1780501924.git.mst@redhat.com> X-Mailer: git-send-email 2.54.0.1099.g489fc7bff1-goog Message-ID: <178102235481.2735841.1203781071933134475.b4-ty@google.com> Subject: Re: [PATCH] KVM: guest_memfd: fix NUMA interleave index double-counting From: Sean Christopherson To: Sean Christopherson , linux-kernel@vger.kernel.org, "Michael S. Tsirkin" Cc: Paolo Bonzini , David Hildenbrand , Vlastimil Babka , Shivank Garg , kvm@vger.kernel.org Content-Type: text/plain; charset="utf-8" On Wed, 03 Jun 2026 11:57:33 -0400, Michael S. Tsirkin wrote: > kvm_gmem_get_policy() sets *ilx to the full page offset > (vm_pgoff + vma offset). But get_vma_policy() adds the page > offset on top of *ilx, so the offset is counted twice. This > causes NUMA interleaving to skip nodes: for order-0 pages the > effective index jumps by 2 for each consecutive page. > > The get_policy vm_op should return only a per-file bias in *ilx > (like shmem_get_policy does with inode->i_ino), letting > get_vma_policy() add the page-offset component. > > [...] Applied to kvm-x86 gmem, with a heavily massaged changelog to explicitly spell out that ilx == interleave index, and to try and explain the role of the index (it wasn't at all obvious to me why using the inode number was "correct"). Thanks! [1/1] KVM: guest_memfd: fix NUMA interleave index double-counting https://github.com/kvm-x86/linux/commit/48dbe4732198 -- https://github.com/kvm-x86/linux/tree/next