From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 D7E4D374192; Thu, 30 Jul 2026 15:51:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785426706; cv=none; b=XYds1olR/er/TrXDNeky4mygDE9bIaQy8whQR4TPoKIy8Af6ienQ/xi1+Mi597wmaFtPAmjNkrNpEM0Br171NQrPvqVfdGj+2txUaG1XlUi0A6/8HCD6UCcm38omR4/eJ7/OzaJMbEAqwqcJ8eIflEWIVdcWX4jni9t/hWTlXsw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785426706; c=relaxed/simple; bh=A2YJkbsq4rwAjJXhcpnjbyRZwC0lPOtblQwKNLB+1s4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=MC5yQmJdim17kNlKH5cHTIA24cpjsT6axY7tRVzhbmbrRX9ysHXUL27KMIAGR8t5ZR1VciT1ZKE4gAdKf9j6RlEpju47vJsewXiIYKjOaP3N7XiDJqrcGELqsRbWlpfJzg3RX5g3wRvTYIX1cRh1ECRfrHaSEJhz7dpEJdpNkY8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Q1BwG0/a; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Q1BwG0/a" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 470691F00A3A; Thu, 30 Jul 2026 15:51:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1785426704; bh=HqMzXHEdQFBnt3HPnV1BDsbI9P9sz0hBWnE7uLeEjdI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Q1BwG0/auTVGNaTBVxOMfDIbPCOPSSftZCIEi/UYL8tZcHUg71SEPH4ilPN1mvRHx hVAeFH2hDrhHmVBrYVckwdazyPnE0kNM2qGomGgYzp+qaEgNFJ12YGVd8Si2knTvFy GcQmv+rMJuP+AGtp7vkhdbInFGzom/sV3r1Vw28s= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Christian=20K=C3=B6nig?= , Matthew Auld , =?UTF-8?q?Timur=20Krist=C3=B3f?= , John Olender , Arunpravin Paneer Selvam , Sasha Levin Subject: [PATCH 6.12 511/602] gpu/buddy: bail out of try_harder when alignment cannot be honoured Date: Thu, 30 Jul 2026 16:15:03 +0200 Message-ID: <20260730141446.735601899@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260730141435.976815864@linuxfoundation.org> References: <20260730141435.976815864@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arunpravin Paneer Selvam [ Upstream commit 56bc6384314fb9ae98975fb2af8b143097ede3dc ] The try_harder contiguous fallback could return a range whose start offset did not match the caller's min_block_size. When a candidate's start is misaligned, realign it: free the misaligned run and reallocate exactly @size at the next lower min_block_size boundary. This keeps the returned size unchanged with no surplus to trim, and rejects the request only when no aligned candidate fits. v2: align misaligned candidates down to min_block_size instead of bailing out, for both the RHS and LHS paths (Matthew). Fixes: 0a1844bf0b53 ("drm/buddy: Improve contiguous memory allocation") Suggested-by: Christian König Cc: Matthew Auld Cc: Christian König Cc: Timur Kristóf Cc: stable@vger.kernel.org Reviewed-by: Matthew Auld Tested-by: John Olender Signed-off-by: Arunpravin Paneer Selvam Link: https://patch.msgid.link/20260709131050.1022759-1-Arunpravin.PaneerSelvam@amd.com Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/buddy.c | 65 ++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 45 insertions(+), 20 deletions(-) --- a/drivers/gpu/buddy.c +++ b/drivers/gpu/buddy.c @@ -901,22 +901,30 @@ static int __gpu_buddy_alloc_range(struc blocks, total_allocated_on_err); } +static int __alloc_contig_aligned_retry(struct gpu_buddy *mm, + u64 unaligned_offset, + u64 size, + u64 min_block_size, + struct list_head *blocks) +{ + u64 aligned_offset = round_down(unaligned_offset, min_block_size); + + return __gpu_buddy_alloc_range(mm, aligned_offset, size, NULL, blocks); +} + static int __alloc_contig_try_harder(struct gpu_buddy *mm, u64 size, u64 min_block_size, struct list_head *blocks) { - u64 rhs_offset, lhs_offset, lhs_size, filled; + u64 rhs_offset, lhs_offset, filled; struct gpu_buddy_block *block; unsigned int tree, order; - LIST_HEAD(blocks_lhs); - unsigned long pages; u64 modify_size; int err; modify_size = rounddown_pow_of_two(size); - pages = modify_size >> ilog2(mm->chunk_size); - order = fls(pages) - 1; + order = ilog2(modify_size) - ilog2(mm->chunk_size); if (order == 0) return -ENOSPC; @@ -932,31 +940,48 @@ static int __alloc_contig_try_harder(str while (iter) { block = rbtree_get_free_block(iter); - /* Allocate blocks traversing RHS */ rhs_offset = gpu_buddy_block_offset(block); + + /* Allocate blocks traversing RHS */ err = __gpu_buddy_alloc_range(mm, rhs_offset, size, &filled, blocks); - if (!err || err != -ENOSPC) + if (err && err != -ENOSPC) return err; - - lhs_size = max((size - filled), min_block_size); - if (!IS_ALIGNED(lhs_size, min_block_size)) - lhs_size = round_up(lhs_size, min_block_size); - - /* Allocate blocks traversing LHS */ - lhs_offset = gpu_buddy_block_offset(block) - lhs_size; - err = __gpu_buddy_alloc_range(mm, lhs_offset, lhs_size, - NULL, &blocks_lhs); + if (!err && IS_ALIGNED(rhs_offset, min_block_size)) + return 0; if (!err) { - list_splice(&blocks_lhs, blocks); + /* Allocate the unaligned RHS offset using round_down */ + gpu_buddy_free_list_internal(mm, blocks); + err = __alloc_contig_aligned_retry(mm, rhs_offset, + size, + min_block_size, + blocks); + if (!err) + return 0; + if (err != -ENOSPC) { + gpu_buddy_free_list_internal(mm, blocks); + return err; + } + goto next; + } + + if (size - filled > rhs_offset) + goto next; + + lhs_offset = rhs_offset - (size - filled); + + /* Allocate the unaligned LHS offset using round_down */ + gpu_buddy_free_list_internal(mm, blocks); + err = __alloc_contig_aligned_retry(mm, lhs_offset, size, + min_block_size, blocks); + if (!err) return 0; - } else if (err != -ENOSPC) { + if (err != -ENOSPC) { gpu_buddy_free_list_internal(mm, blocks); return err; } - /* Free blocks for the next iteration */ +next: gpu_buddy_free_list_internal(mm, blocks); - iter = rb_prev(iter); } }