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Thu, 24 Apr 2025 14:45:41 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEmWJQRNoeRYiwWhaf29I2g4K6mBLzf4Gyinz6SrGVsyt1zGLLxKhI16GxMUwLvAlbE6TQkXw== X-Received: by 2002:a05:6214:d06:b0:6f0:e2d4:5936 with SMTP id 6a1803df08f44-6f4cb9e51b5mr1010306d6.22.1745531141091; Thu, 24 Apr 2025 14:45:41 -0700 (PDT) Received: from x1.local ([85.131.185.92]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6f4c0933f01sm14461846d6.28.2025.04.24.14.45.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 24 Apr 2025 14:45:40 -0700 (PDT) Date: Thu, 24 Apr 2025 17:45:37 -0400 From: Peter Xu To: Matthew Wilcox Cc: Johannes Weiner , Jens Axboe , Andrew Morton , "linux-fsdevel@vger.kernel.org" , Linux-MM Subject: Re: [PATCH] mm/userfaultfd: prevent busy looping for tasks with signals pending Message-ID: References: <27c3a7f5-aad8-4f2a-a66e-ff5ae98f31eb@kernel.dk> <20250424140344.GA840@cmpxchg.org> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Thu, Apr 24, 2025 at 08:42:00PM +0100, Matthew Wilcox wrote: > On Thu, Apr 24, 2025 at 02:26:37PM -0400, Peter Xu wrote: > > Secondly, userfaultfd is indeed the only consumer of > > FAULT_FLAG_INTERRUPTIBLE but not necessary always in the future. While > > this patch resolves it for userfaultfd, it might get caught again later if > > something else in the kernel starts to respects the _INTERRUPTIBLE flag > > request. For example, __folio_lock_or_retry() ignores that flag so far, > > but logically it should obey too (with a folio_wait_locked_interruptible).. > > No. Hell, no. We don't want non-fatal signals being able to interrupt > that. There's a reason we introduced killable as a concept in the first > place. Not really proposing that as I don't have a use caes. Just curious, could you explain a bit why having it interruptible is against the killable concept if (IIUC) it is still killable? Thanks, -- Peter Xu