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Wysocki" , Pavel Machek , Catalin Marinas , Will Deacon , linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Shuah Khan , linux-kselftest@vger.kernel.org Subject: Re: [RFC PATCH v2 0/4] mm/swap: reserve swap areas for deliberate offload Message-ID: References: <20260926045517.3458413-1-matthias.goergens@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260926045517.3458413-1-matthias.goergens@gmail.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 1FC5AC0004 X-Stat-Signature: mjrjb4wyqf85ce3auf57aw7tshjizp3n X-HE-Tag: 1790572752-113909 X-HE-Meta: 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 V5V48oox 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sat, Sep 26, 2026 at 12:55:13PM +0800, Matthias Goergens wrote: > This RFC adds offload-only swap areas for deliberate cold-page offload to > backends unsuitable for pressure reclaim. ZFS zvol swap has documented > deadlocks under memory pressure [3]; compressed swap is another target > because writes may need memory despite free logical slots. Out of tree code not matter. Out of tree that violates the linux license terms even less. Either way block devices must be safe to be called from paging paths, not just for swap but also for file system based paging. So this is a bug in the implementation, and not something worked around in the swap code.