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h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XJfjDTDOyC/FjwMNQylaD5MrDantTgYxOhKCCP5U3juDPgS14qRbG2gc9z1//5vld U5qStXNYcvSwPpKgLhqJRC2eTZZPrGY8vYdl08nF14ofhNRa45ZtQD2z52X3pXJxEH jv0Nj2iq+tgTWN1+Xt30cECOfbsxtLCkXQ9EGo3wN2q6lvANrqmRuHbkjjqvwJ5cA1 Suq++GZGLNfjSz91IkxN0TVeO+Y7npqe0mB+o0RP8Hqwf1b6KIlMLPvFoxVQ+Avj4K BjL4vzqg4vlgpK4F7uhQrPR8BYEnEKBuMU2gZu2D/YwId8MtYUZGBwx06E7gHtYVoZ p+cqXQjQvXWAQ== Date: Thu, 23 Oct 2025 10:20:54 +0300 From: Mike Rapoport To: Pratyush Yadav Cc: Pasha Tatashin , akpm@linux-foundation.org, brauner@kernel.org, corbet@lwn.net, graf@amazon.com, jgg@ziepe.ca, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, masahiroy@kernel.org, ojeda@kernel.org, rdunlap@infradead.org, tj@kernel.org Subject: Re: [PATCHv7 5/7] kho: don't unpreserve memory during abort Message-ID: References: <20251022005719.3670224-1-pasha.tatashin@soleen.com> <20251022005719.3670224-6-pasha.tatashin@soleen.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Stat-Signature: mnn9hnehxj9ystnwf457ia9yk4qhqbw3 X-Rspamd-Queue-Id: 9A8481C0005 X-Rspamd-Server: rspam09 X-HE-Tag: 1761204064-393784 X-HE-Meta: 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 bc9i8GxJ CJfijrVUb0zdNWCNkFdKcbMKe6IAfKnKbLEjFduP4fRhY3EsHOHBi8M1r6bD3C1TZMZVZbe8GGLW+F0hcpFJrAzkdost/Z5/Wvzk12k31B9+GsFnEmHTx7YcLKwfJl+2e5wwF4WziSTaTwM/qLcc27g8tqXbC9dN/+VZV/2sVhXmVL/k6FBlVg8ZFtSQkm9mg0mTwfXe2X6jFqqsZgSf6617g6abIl95FUNxiY2Dj30M0D6m8ThjtV6b3K3F9PetgKDFq+GBuggYxNVZ3SJj1IuxcHOUUvsqhnNcYe+H5OqQvNn0qsz8862gb8w== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, 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 Wed, Oct 22, 2025 at 01:15:30PM +0200, Pratyush Yadav wrote: > On Tue, Oct 21 2025, Pasha Tatashin wrote: > > > KHO allows clients to preserve memory regions at any point before the > > KHO state is finalized. The finalization process itself involves KHO > > performing its own actions, such as serializing the overall > > preserved memory map. > > > > If this finalization process is aborted, the current implementation > > destroys KHO's internal memory tracking structures > > (`kho_out.ser.track.orders`). This behavior effectively unpreserves > > all memory from KHO's perspective, regardless of whether those > > preservations were made by clients before the finalization attempt > > or by KHO itself during finalization. > > > > This premature unpreservation is incorrect. An abort of the > > finalization process should only undo actions taken by KHO as part of > > that specific finalization attempt. Individual memory regions > > preserved by clients prior to finalization should remain preserved, > > as their lifecycle is managed by the clients themselves. These > > clients might still need to call kho_unpreserve_folio() or > > kho_unpreserve_phys() based on their own logic, even after a KHO > > finalization attempt is aborted. > > I think you also need to update test_kho and reserve_mem to do this > since right now they assume all memory gets unpreserved on failure. I agree. > > Signed-off-by: Pasha Tatashin > > --- > [...] > > -- > Regards, > Pratyush Yadav -- Sincerely yours, Mike.