From nobody Sun Oct 5 18:14:32 2025 Received: from out30-124.freemail.mail.aliyun.com (out30-124.freemail.mail.aliyun.com [115.124.30.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B9CE717CA17 for ; Thu, 31 Jul 2025 01:53:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753926842; cv=none; b=MwdIQAw4V7B7BxKFdF6CPYrVIG5rDmKhDPCndQ27dmxjvaF5HnDjGFm84mMyvE/tr2EeCm1/UAtvGihwsYQhK8zyuUiM4h5+8UGo69DlXyoouf5fAHzlyRKi7QmNB/YItEeP540YfA46ramH86Gvm7eiFmbkUH+cII9VvOKcnZY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753926842; c=relaxed/simple; bh=5pxmsZhcPbm7r8AQRVFVnUWbrSGgKde+RUbAfCLQ/Mw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=o7M9GfPT5OLw3HqEKwVk3DEDkXKXoFoDBmWOnnqQWNVfXOT23TL5Pu+hQIJ1FluglCJDfOjs1Yza7TGTV1stUoADtTIA1utD4p+Gda6aZPNSpST2E3WuZCt0IR7ylXxUZWWccou6jhLmPYy3i0YYIM6m5gJ+tkjEqfzKohG9+mI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=TJovK3Wk; arc=none smtp.client-ip=115.124.30.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="TJovK3Wk" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1753926836; h=From:To:Subject:Date:Message-ID:MIME-Version:Content-Type; bh=9gSsqsMNfh6LJcBnky2k2FWl7tW2t0BIGDVockm4ir8=; b=TJovK3WkuO5dOfCiDLur8dXzs6cSz98yhhZXm+TM3Bv0dN5IIHJdRRzCf1H8qFK54Rr0xy6WX3kP1aoGIdHgxCnqoziX48qF+6+ue+SabZxpIR+oI8lCnJxgdArslN6vfoOAB+wktXmYPoLtz22C2dAWpV+jrKxu/CjiAGqtA68= Received: from localhost(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0WkWNcvl_1753926835 cluster:ay36) by smtp.aliyun-inc.com; Thu, 31 Jul 2025 09:53:55 +0800 From: Baolin Wang To: akpm@linux-foundation.org, hughd@google.com Cc: patryk@kowalczyk.ws, ville.syrjala@linux.intel.com, baolin.wang@linux.alibaba.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] mm: shmem: fix the shmem large folio allocation for the i915 driver Date: Thu, 31 Jul 2025 09:53:43 +0800 Message-ID: X-Mailer: git-send-email 2.43.5 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable After commit acd7ccb284b8 ("mm: shmem: add large folio support for tmpfs"), we extend the 'huge=3D' option to allow any sized large folios for tmpfs, which means tmpfs will allow getting a highest order hint based on the size of write() and fallocate() paths, and then will try each allowable large or= der. However, when the i915 driver allocates shmem memory, it doesn't provide hi= nt information about the size of the large folio to be allocated, resulting in the inability to allocate PMD-sized shmem, which in turn affects GPU perfor= mance. Patryk added: : In my tests, the performance drop ranges from a few percent up to 13% : in Unigine Superposition under heavy memory usage on the CPU Core Ultra : 155H with the Xe 128 EU GPU. Other users have reported performance : impact up to 30% on certain workloads. Please find more in the : regressions reports: : https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14645 : https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13845 : : I believe the change should be backported to all active kernel branches : after version 6.12. To fix this issue, we can use the inode's size as a write size hint in shmem_read_folio_gfp() to help allocate PMD-sized large folios. Fixes: acd7ccb284b8 ("mm: shmem: add large folio support for tmpfs") Reported-by: Patryk Kowalczyk Reported-by: Ville Syrj=C3=A4l=C3=A4 Tested-by: Patryk Kowalczyk Suggested-by: Hugh Dickins Signed-off-by: Baolin Wang --- Changes from v1: - Use inode size as the write size hint, per Hugh. --- mm/shmem.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index 41eb4aa60be5..e1e5d5f7f58d 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -5989,8 +5989,8 @@ struct folio *shmem_read_folio_gfp(struct address_spa= ce *mapping, struct folio *folio; int error; =20 - error =3D shmem_get_folio_gfp(inode, index, 0, &folio, SGP_CACHE, - gfp, NULL, NULL); + error =3D shmem_get_folio_gfp(inode, index, i_size_read(inode), + &folio, SGP_CACHE, gfp, NULL, NULL); if (error) return ERR_PTR(error); =20 --=20 2.43.5