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AJvYcCUVltg3vn4umlf0umZWQaGgJjimqtf6nhRqT/6PhoAXJariPD4uO9sTqHQoclWXkUDB1W/zQQqTOg==@kvack.org X-Gm-Message-State: AOJu0YxYgcbnBbkq0QVGRLXBy/adyjIpdOadW35PjYUzT5B2aVwESfJV NkcoNgRxlal7F656WVl1I+Q2zR1bRmZgN4coXtg15hBz0fxcKq44sNqNmT//a5UffjDs3mhcZeU 7O8ezUSLvRekvo6oSk3k+DmsERfu4sLE9C33L X-Google-Smtp-Source: AGHT+IH6GaCTFse8PHhR99yRvdJU42XjOZhxxrVWX7RUwgX5aK9xyEy94yBYp/VrB+JAVrmpWoM6bBGXa7q1ktnK+/A= X-Received: by 2002:a05:600c:b8d:b0:42b:a961:e51 with SMTP id 5b1f17b1804b1-4318a4ace7bmr5573175e9.0.1729787295526; Thu, 24 Oct 2024 09:28:15 -0700 (PDT) MIME-Version: 1.0 References: <20241010205644.3831427-1-andrii@kernel.org> <20241010205644.3831427-2-andrii@kernel.org> <20241023201031.GF11151@noisy.programming.kicks-ass.net> <20241024095659.GD9767@noisy.programming.kicks-ass.net> In-Reply-To: <20241024095659.GD9767@noisy.programming.kicks-ass.net> From: Suren Baghdasaryan Date: Thu, 24 Oct 2024 09:28:01 -0700 Message-ID: Subject: Re: [PATCH v3 tip/perf/core 1/4] mm: introduce mmap_lock_speculation_{start|end} To: Peter Zijlstra Cc: Andrii Nakryiko , linux-trace-kernel@vger.kernel.org, linux-mm@kvack.org, oleg@redhat.com, rostedt@goodmis.org, mhiramat@kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, jolsa@kernel.org, paulmck@kernel.org, willy@infradead.org, akpm@linux-foundation.org, mjguzik@gmail.com, brauner@kernel.org, jannh@google.com, mhocko@kernel.org, vbabka@suse.cz, shakeel.butt@linux.dev, hannes@cmpxchg.org, Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Queue-Id: 4BAAAC001E X-Rspamd-Server: rspam01 X-Stat-Signature: wg38e6fw1gfgmwfdxicsacs3g8hyc4cu X-HE-Tag: 1729787274-997976 X-HE-Meta: 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 aEQX3dNR 6lutiH+p3NSuabtJKeMuGrHjTTy+f+VFrsLlBWrbAYdmMDs1QBB3cSCJJviumPMqouRw0AGNwZe153IM/NQOPnxZOh4aQ018zNnXJm/dW/dA0P7DvF25PLgPOQzkqUcYJRl+7PoJRNAS909FliSyL0IaSCn18H/tIiDYzkeazZnWHq+gEBh0dfJ8k/nTRDT8J06kkRxFguje8n59RJb4K+ir91mh/1fpxjKAuZ0JNOJEKTl/n96/uTsohH1lub9EyeQUpdR1Yt+DMFUOc0pYtQhX2Ybx5MUiieF8LeMyFTdQRakM= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000010, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Oct 24, 2024 at 2:57=E2=80=AFAM Peter Zijlstra wrote: > > On Wed, Oct 23, 2024 at 03:17:01PM -0700, Suren Baghdasaryan wrote: > > > > Or better yet, just use seqcount... > > > > Yeah, with these changes it does look a lot like seqcount now... > > I can take another stab at rewriting this using seqcount_t but one > > issue that Jann was concerned about is the counter being int vs long. > > seqcount_t uses unsigned, so I'm not sure how to address that if I > > were to use seqcount_t. Any suggestions how to address that before I > > move forward with a rewrite? > > So if that issue is real, it is not specific to this case. Specifically > preemptible seqcount will be similarly affected. So we should probably > address that in the seqcount implementation. Sounds good. Let me try rewriting this patch using seqcount_t and I'll work with Jann on a separate patch to change seqcount_t. Thanks for the feedback! >