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Sat, 17 Jan 2026 10:23:11 +0000 (GMT) Message-ID: <4728530f-41c8-4a26-aa8a-30f53f1fe629@linux.ibm.com> Date: Sat, 17 Jan 2026 15:53:10 +0530 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/6] powerpc64/bpf: Support tailcalls with subprogs To: adubey@linux.ibm.com, bpf@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Cc: sachinpb@linux.ibm.com, venkat88@linux.ibm.com, andrii@kernel.org, eddyz87@gmail.com, mykolal@fb.com, ast@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, christophe.leroy@csgroup.eu, naveen@kernel.org, maddy@linux.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com, memxor@gmail.com, iii@linux.ibm.com, shuah@kernel.org References: <20260114114450.30405-1-adubey@linux.ibm.com> <20260114114450.30405-3-adubey@linux.ibm.com> Content-Language: en-US From: Hari Bathini In-Reply-To: <20260114114450.30405-3-adubey@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: ng6asMzW3uKJzarXjSutdbXzQzx0rxcL X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMTE3MDA4NCBTYWx0ZWRfX8TmSMslTMghW Tk0jZXS1PaHbIBAXpZNs+FUzVQvGkIq2ZLVfsagAirL7PGd4fvTSuHkLausxtSVqNO1WZUEZ+v+ gAIgRqIL6Tj7A/aJaZ4uiyNFG5YLKtGtDvsVpGGK9hPLXsVNvFe/MKIVcs87g3ICoITRlWXU1f1 GvFN3pdDy0J41TOIE7qxbjslEA8twIDp99ELaW81MIQMjuhLOBj3gmcCb+r30jdVFCszAdhX7dP M27rxtxwnv9H75wpZzDxxpZRmnVTtDBx0tNLCOAmvb3AzEEBcORE+Nzcmhn28IRIuS0yB+aKFeG k16Qt5YBS4bwCp1VMLQX7oq9iOSYICH/uZoBcE/Mdi0bWtnBJEhST91vbBBf+mG9Hrb5Ra9DCRv HXWf7TJoihTbYzD1lVYQ0NkfMqvSTn6jDJhUeXYQm0dw24MNPyfxoQ4ht0VwXrEh1rrZfd9slM2 TVweamg7XPo94YbcqKA== X-Authority-Analysis: v=2.4 cv=J9SnLQnS c=1 sm=1 tr=0 ts=696b631b cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=IkcTkHD0fZMA:10 a=vUbySO9Y5rIA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VnNF1IyMAAAA:8 a=ZXRHoZGWT0CIhGHxh5MA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-ORIG-GUID: Ffd4gLHO7pbALdnPDjaTPn6owAgbrQ2o X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2026-01-16_09,2026-01-15_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 impostorscore=0 adultscore=0 suspectscore=0 spamscore=0 lowpriorityscore=0 malwarescore=0 clxscore=1015 bulkscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2601150000 definitions=main-2601170084 On 14/01/26 5:14 pm, adubey@linux.ibm.com wrote: > From: Abhishek Dubey > > Enabling tailcalls with subprog combinations by referencing > method. The actual tailcall count is always maintained in the > tail_call_info variable present in the frame of main function > (also called entry function). The tail_call_info variables in > the frames of all other subprog contains reference to the > tail_call_info present in frame of main function. I would rephrase: "The tail_call_info variables in the frames of all other subprog contains reference to the tail_call_info present in frame of main function." to: "The tail_call_info field in the stack frame of subprogs contains reference to the tail_call_info field in the stack frame of main BPF program." - Hari