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Mon, 22 Dec 2025 22:34:03 -0800 (PST) From: Askar Safin To: gmazyland@gmail.com Cc: Dell.Client.Kernel@dell.com, dm-devel@lists.linux.dev, linux-block@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-crypto@vger.kernel.org, linux-lvm@lists.linux.dev, linux-mm@kvack.org, linux-pm@vger.kernel.org, linux-raid@vger.kernel.org, lvm-devel@lists.linux.dev, mpatocka@redhat.com, pavel@ucw.cz, rafael@kernel.org, safinaskar@gmail.com Subject: Re: [RFC PATCH 2/2] swsusp: make it possible to hibernate to device mapper devices Date: Tue, 23 Dec 2025 09:33:55 +0300 Message-ID: <20251223063355.2740782-1-safinaskar@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <86300955-72e4-42d5-892d-f49bdf14441e@gmail.com> References: <86300955-72e4-42d5-892d-f49bdf14441e@gmail.com> Precedence: bulk X-Mailing-List: dm-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Milan Broz : > Anyway, my understanding is that all device-mapper targets use mempools, > which should ensure that they can process even under memory pressure. Okay, I just read some more code and docs. dm-integrity fortunately uses bufio for checksums only. And bufio allocates memory without __GFP_IO (thus allocation should not lead to recursion). And bufio claims that "dm-bufio is resistant to allocation failures": https://elixir.bootlin.com/linux/v6.19-rc2/source/drivers/md/dm-bufio.c#L1603 . This still seems to be fragile. So I will change mode to 'D' and hope for the best. :) -- Askar Safin