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b=XQplAEaznmMrCJ6SgkIq5wf0WtoJXumBiFEkgJe3OJQ3oqPctce0aW2nZYm4W0EV9 EVEO6T6DZvaJkJgtRoQyey8sILh+2X1ppdtZjMdrzAGFlgVw5d/v3kZMlYTHDgsN+p e8XlPGTWv/0KH1oAVE/w9LK0MVoGRmZer55PopAVjX7qKAqIHUVX2QEaYZXvWA6hb3 LGby9WFIxqBZGFQxusZvD7q4PWlHUViAjzwCThkhysUMWQ2dJMEPFGZAw6T2f3z+o1 XLiPlOrX5K+2qxV3cSreRHlukrKItI+ujzkNpCxKnQDEVXgfm/L3e3nH6lJi7uhNqu PUuFrnPj9xacQ== Date: Tue, 24 Feb 2026 08:30:14 +0900 From: Masami Hiramatsu (Google) To: Thomas Ballasi Cc: akpm@linux-foundation.org, axelrasmussen@google.com, david@kernel.org, hannes@cmpxchg.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, lorenzo.stoakes@oracle.com, mhiramat@kernel.org, mhocko@kernel.org, rostedt@goodmis.org, shakeel.butt@linux.dev, weixugc@google.com, yuanchu@google.com, zhengqi.arch@bytedance.com Subject: Re: [PATCH v7 3/3] mm: vmscan: add PIDs to vmscan tracepoints Message-Id: <20260224083014.66bf222ffd81a3ebaa57a0e0@kernel.org> In-Reply-To: <20260223171544.4750-4-tballasi@linux.microsoft.com> References: <20260213181537.54350-1-tballasi@linux.microsoft.com> <20260223171544.4750-1-tballasi@linux.microsoft.com> <20260223171544.4750-4-tballasi@linux.microsoft.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam09 X-Stat-Signature: gi71s7b1fbusy14cr8wdh38arsfy1pr1 X-Rspamd-Queue-Id: 1A3334000E X-Rspam-User: X-HE-Tag: 1771889421-553515 X-HE-Meta: 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 g92bMMD8 bxOAK0c7lMa8NyP0ve6DOAzYdEbey7xK89gOhHC2kZHa6iKVLuJ2Qpcwl9elXm4RIyT6NaJNSsWQ9LBMlYGOenIKefDxpgfQnDP4lRoCzEhJvXiVG9pgGc5ZQLh42OdH2aDAc+Sok0JA3dbnZMhZfHJNiahk5oaNAjOG5aFiYNxtMNeeAAlzDio1ftl324sY407kl5EFajWdPakE+0h6MaXAVTFi6DzppPMCuBaYTu27Bao8ZFN5x9eMo7Oewd+aEJz3D1pS10+RXfmkAOq/m9/zusu4hH86E45NzmaUMQB7A638= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi, On Mon, 23 Feb 2026 09:15:44 -0800 Thomas Ballasi wrote: > The changes aims at adding additionnal tracepoints variables to help > debuggers attribute them to specific processes. > > The PID field uses in_task() to reliably detect when we're in process > context and can safely access current->pid. When not in process > context (such as in interrupt or in an asynchronous RCU context), the > field is set to -1 as a sentinel value. > > Signed-off-by: Thomas Ballasi > --- > include/trace/events/vmscan.h | 34 +++++++++++++++++++++++++--------- > 1 file changed, 25 insertions(+), 9 deletions(-) > > diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h > index 1212f6a7c223e..15b31281f0955 100644 > --- a/include/trace/events/vmscan.h > +++ b/include/trace/events/vmscan.h > @@ -122,18 +122,22 @@ DECLARE_EVENT_CLASS(mm_vmscan_direct_reclaim_begin_template, > __field( unsigned long, gfp_flags ) > __field( u64, memcg_id ) > __field( int, order ) > + __field( int, pid ) > ), > > TP_fast_assign( > __entry->gfp_flags = (__force unsigned long)gfp_flags; > __entry->order = order; > + __entry->pid = current->pid; All entries saves current->pid in common_pid field. Can you use this common field? # cat events/vmscan/mm_vmscan_reclaim_pages/format name: mm_vmscan_reclaim_pages ID: 590 format: field:unsigned short common_type; offset:0; size:2; signed:0; field:unsigned char common_flags; offset:2; size:1; signed:0; field:unsigned char common_preempt_count; offset:3; size:1; signed:0; field:int common_pid; offset:4; size:4; signed:1; ## <------------here field:int nid; offset:8; size:4; signed:1; field:unsigned long nr_scanned; offset:16; size:8; signed:0; field:unsigned long nr_reclaimed; offset:24; size:8; signed:0; field:unsigned long nr_dirty; offset:32; size:8; signed:0; field:unsigned long nr_writeback; offset:40; size:8; signed:0; field:unsigned long nr_congested; offset:48; size:8; signed:0; field:unsigned long nr_immediate; offset:56; size:8; signed:0; field:unsigned int nr_activate0; offset:64; size:4; signed:0; field:unsigned int nr_activate1; offset:68; size:4; signed:0; field:unsigned long nr_ref_keep; offset:72; size:8; signed:0; field:unsigned long nr_unmap_fail; offset:80; size:8; signed:0; Thank you, -- Masami Hiramatsu (Google)