From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qt1-f171.google.com (mail-qt1-f171.google.com [209.85.160.171]) (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 EF20A46AF34 for ; Thu, 11 Jun 2026 20:40:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=209.85.160.171 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781210449; cv=pass; b=Pxi3RefY4Hc3L+iEKjI+MKAqDOjtiXR6Phlswtq8qiDC+Xg58nFoW56F6yxsEzstE8rwRT422Cu8Qf9xUXZNmgDLvYdVkSVuBV6deZWv7ObuqNy86zuS7xuVGa9K7CUqmcc1+OqYHe1iuMUmPoF1ytAD+FOXZ/RqyB7wJrYucJk= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781210449; c=relaxed/simple; bh=UW5h7kQOcsoL7dlEsXTdWsLlFYf/7tFpO4dUX5ItpCQ=; h=MIME-Version:References:In-Reply-To:From:Date:Message-ID:Subject: To:Cc:Content-Type; b=o/1s+ySC5OOOHE0HZKtGFxb5vV2+owbmccsKERSee2PTQzW19BjhJNy1y0O/Gn9W18FwlKGVK5Rd2QaKaPaSHGLqW2cLkndM+so96tLS+Hac1nkdlqQWe3b1HULhkUQSYy1iFvrNobpsXngGq9ZeKEVyOmTerXyk9PjGiaOiLS0= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=O0Z0cfmt; arc=pass smtp.client-ip=209.85.160.171 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=google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="O0Z0cfmt" Received: by mail-qt1-f171.google.com with SMTP id d75a77b69052e-51765331535so36891cf.1 for ; Thu, 11 Jun 2026 13:40:46 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1781210446; cv=none; d=google.com; s=arc-20240605; b=D68wwPA6DtfScafbW3yr4pSMQV1IlMvvJGhPslFTKmi65FgAa7GyX9kA5rnVXPEFD0 AWfitoAg3OEQYH/paFjp61gTCC4Ue1UZ6zbqObBtTIOUAEGSsOZlsIdNr2VlCEhVm+dN UnwHCVbDFwg10GTWxLKnwqYARLMRdbbpikk37DKrHOIulPV7aneYwR5EMBo12fv7YvmY MrAFH+L2AQ0268H4aff2Llfy7znvVClaCI8WoCzI3nA/b3aYkbInja37joAUJD6ec7Iw qap/Ou6PYMmwi1wIec9al/luwimN8qofFq4RcukAsPoMdkdR0SUQPgHhhY8GHI/VdaFb sXag== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20240605; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:dkim-signature; bh=a67OUTXkhjPmGT9xbEw7aC5sM6vpNtps3UHtPFQcUpU=; fh=7JHZRLnGqlSn5wZHlmFMZXs1RZTGFbGtHGqcGSNOtJs=; b=IydDL60uLQviHV6yCEm46B9wJV4hihnSXT+vbkRA5F4FDkugr9DPYTOeVUHFZXiOWV 7oWaoToxHP9lYeHGkZrvW23dit7FNzm/jMjE4B8EqqTpfsDFogLGDGG21vCmu1ksYkKj j8jfcBEAtryKuw88ynz2VcpNEjC1uH79rJWYP/+5vDuKxsVvcKDtMfKfS13EZH+i44iN Reo+a2o9nx1LlrUIx08nvq+ntKA75VtvRj+2G+hOT2E/dYUQIqcE0jK3qBfaW6kat8tL sDygzjG5jl5m5GX3RCw/FmG9OJ05Ot5zXgPHvvMCn69e9VJA35i4AjgOWCMfN8inccmw PdZw==; darn=vger.kernel.org ARC-Authentication-Results: i=1; mx.google.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1781210446; x=1781815246; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=a67OUTXkhjPmGT9xbEw7aC5sM6vpNtps3UHtPFQcUpU=; b=O0Z0cfmtaTkho6MN2MEcS/myzoixTpjQev5SeymIxvfcppNj46lu+w7Nw6soc8RGhI gTpdptNzCQuvCmTHjoG2KocIKRjn1dT8fOKnQ25b5pdn/peuyW0l6iIG3Fmifv+vVBIU s8Y1kz8C3lv4JnbMlt2v0s6QDz6mX0QrLYZPQQCkrcwpVCTwGDfWLwjeWFcexhdfPkOY cU2XgDI8Pt+pvTjVkf6060Ujj0bmhNiMdNhkevLCtzJm73+zbcbsIzlzpxl+Usx5e8Rj ZAW3F5q+sSDFIb8rE+tIYZMUXz+2MwHkPwCp882MSiUZeoj1Rh0kiqLl2TK2O8yXyNeF JLwQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1781210446; x=1781815246; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=a67OUTXkhjPmGT9xbEw7aC5sM6vpNtps3UHtPFQcUpU=; b=sR5sAQxGggOf60GdQwCoELbImEGHhJe7De8OPL4ZAGECE5iXtzhz1yUU2VGq6ErF6b 4TL2CqA38lpRa1fdiA3LsHHqOBtV1j7sl2tlInwgfSDuUjwVb6+/h+SmLhPpVOIXJVSt mzCKURJcBseXypOOOOV0kxh3/VNyTPbVjUi0PD2x9mGHb5hhfTc+f7bB0uEL5ca0YI76 ErPCjfOcFL0fFEeYvsO8e9152zpereDz7oDp3ceHzGtCPnpvPJmk2tJ5jjDuoawd/bvY VQi/AlILlZ2SlTCB++p7FB8Jt4jfC9XqXdELZgDgsmPK+31F/H9PQFXmgyAPj385m9iz R9Zg== X-Gm-Message-State: AOJu0Yy2q1Hu0zR3x25k2VjK54aiERPf5YEVdKnQAjqO/MGO5N/14/5N 9G7gcd2YhqJPueRd3iAN8kPKKdEJa3Z/jqL+KF6MNf4kuUtSbQoVYVRSc1enmbGoN+X8kX4Mr6P 7buB0V8DLi1I7zGLTPgRU4xiJPM/gbwuxefqWnETY X-Gm-Gg: Acq92OEKjdgu0EHXARsZpclHHGdLI4xD4J4+BPk+mwN6k1IeFX7n4xpY5+4twahqare Y24l5jWmE5r0qrXBdTZ1Mr+jgAKWlaldOPZZYRNOI9d7E0YcuHKRHtA7ObFXFeJGR72752GEdaG VUxuWZ46w+T6XvUVHnmWC3jVXLcsyWV1v9fb0G/8RD1+8qz9UcCIWFZpTH9g8O+x/V+QTNsVLU6 s66Y6vo9I/M305QyR3caHMxg41xGHMQIv+tgI1eP5SpGvO5cY81N/2E07X4KFDE1Xx3/qhCirMD fDCjp7hLk3KnqxHuRK7KmusqIcNIV/ze8U/2 X-Received: by 2002:ac8:7d0a:0:b0:516:4f62:85ef with SMTP id d75a77b69052e-517fb16d601mr2052891cf.20.1781210444924; Thu, 11 Jun 2026 13:40:44 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20260610230409.A44D29FA@davehans-spike.ostc.intel.com> <20260610230417.77D64DBB@davehans-spike.ostc.intel.com> In-Reply-To: <20260610230417.77D64DBB@davehans-spike.ostc.intel.com> From: Suren Baghdasaryan Date: Thu, 11 Jun 2026 13:40:32 -0700 X-Gm-Features: AVVi8Cew8aBPn6x6_sXyc7lWo3YXmdpq0raUK5xFBrEewhgPTGQ_KDM8NSP7OKA Message-ID: Subject: Re: [PATCH v2 4/5] binder: Remove mmap_lock fallback To: Dave Hansen Cc: linux-kernel@vger.kernel.org, Alice Ryhl , Andrew Morton , =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= , Carlos Llamas , Christian Brauner , David Ahern , "David S. Miller" , Greg Kroah-Hartman , "Liam R. Howlett" , linux-mm@kvack.org, Lorenzo Stoakes , netdev@vger.kernel.org, Shakeel Butt , Todd Kjos , Vlastimil Babka Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, Jun 10, 2026 at 4:04=E2=80=AFPM Dave Hansen wrote: > > > From: Dave Hansen > > Previously, the per-VMA locking could fail in the face of writers > which necessitate a fallback to mmap_lock. The new > vma_start_read_unlocked() will wait for writers instead of failing. > > Use the new helper. Wait for writers. Remove the fallback to mmap_lock. Nice! > > Signed-off-by: Dave Hansen > Acked-by: Lorenzo Stoakes > Reviewed-by: Suren Baghdasaryan > Cc: Andrew Morton > Cc: "Liam R. Howlett" > Cc: Vlastimil Babka > Cc: Shakeel Butt > Cc: linux-mm@kvack.org > Cc: Greg Kroah-Hartman > Cc: Arve Hj=C3=B8nnev=C3=A5g > Cc: Todd Kjos > Cc: Christian Brauner > Cc: Carlos Llamas > Cc: Alice Ryhl > Cc: "David S. Miller" > Cc: David Ahern > Cc: netdev@vger.kernel.org > > --- > > b/drivers/android/binder_alloc.c | 17 +++++------------ > 1 file changed, 5 insertions(+), 12 deletions(-) > > diff -puN drivers/android/binder_alloc.c~binder-vma-waiter drivers/androi= d/binder_alloc.c > --- a/drivers/android/binder_alloc.c~binder-vma-waiter 2026-06-10 15:57:= 56.419452721 -0700 > +++ b/drivers/android/binder_alloc.c 2026-06-10 15:57:56.423452863 -07= 00 > @@ -259,21 +259,14 @@ static int binder_page_insert(struct bin > struct vm_area_struct *vma; > int ret =3D -ESRCH; > > - /* attempt per-vma lock first */ > - vma =3D lock_vma_under_rcu(mm, addr); > - if (vma) { > - if (binder_alloc_is_mapped(alloc)) > - ret =3D vm_insert_page(vma, addr, page); > - vma_end_read(vma); > + vma =3D vma_start_read_unlocked(mm, addr); > + if (!vma) > return ret; > - } > > - /* fall back to mmap_lock */ > - mmap_read_lock(mm); > - vma =3D vma_lookup(mm, addr); > - if (vma && binder_alloc_is_mapped(alloc)) > + if (binder_alloc_is_mapped(alloc)) > ret =3D vm_insert_page(vma, addr, page); > - mmap_read_unlock(mm); > + > + vma_end_read(vma); > > return ret; > } > _