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Sun, 30 Aug 2026 21:15:11 -0700 (PDT) Received: from google.com ([2a00:79e0:2031:6:6c22:caaa:530b:455d]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2d75988b6fcsm28017105ad.56.2026.08.30.21.15.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 30 Aug 2026 21:15:10 -0700 (PDT) Date: Mon, 31 Aug 2026 13:15:06 +0900 From: Sergey Senozhatsky To: Andrew Morton Cc: Hao Jia , minchan@kernel.org, senozhatsky@chromium.org, axboe@kernel.dk, bgeffon@google.com, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, Hao Jia , stable@vger.kernel.org Subject: Re: [PATCH v2] zram: fix idle age_sec underflow in idle_store() Message-ID: References: <20260828083149.45760-1-jiahao.kernel@gmail.com> <20260828102446.3eb7f3dc779753b831e33fe6@linux-foundation.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260828102446.3eb7f3dc779753b831e33fe6@linux-foundation.org> On (26/08/28 10:24), Andrew Morton wrote: > On Fri, 28 Aug 2026 16:31:49 +0800 Hao Jia wrote: [..] > > Thanks. Sashiko asked a couple of questions about this change: > https://sashiko.dev/#/patchset/20260828083149.45760-1-jiahao.kernel@gmail.com > Does this early return prevent marking valid boot-time pages as idle? > When a page is accessed during the first second of system boot, its ac_time > would be 0. There is no possibility for zram to hold pages during first second of system boot, regardless of whether zram was configured as a swap device or as a block device (mount-ed with real filesystem). > Can the early return above bypass this zram device initialization check? We already do that, e.g. when kstrtouint(buf, 0, &age_sec) fails. Apart from that, that's not how one checks if device was initialized. We may want to consolidate those checks, just for symmetry.