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Mon, 02 Mar 2026 12:28:36 -0800 (PST) MIME-Version: 1.0 References: <05e134d8-f600-4ee6-9ce5-4b2ef199b075@kernel.org> In-Reply-To: <05e134d8-f600-4ee6-9ce5-4b2ef199b075@kernel.org> From: Andre Ramos Date: Mon, 2 Mar 2026 17:28:24 -0300 X-Gm-Features: AaiRm50-wwZDnrdnRB_L5wVboZlzOioJZN31aY0zHl_4JPkDe7dIUnTDL8NUd6E Message-ID: Subject: Re: [PATCH] mm: add Adaptive Memory Pressure Signaling (AMPRESS) To: "David Hildenbrand (Arm)" Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, rostedt@goodmis.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: CD35FC0006 X-Stat-Signature: fjqqfdap9aeeapd36ucnksd9ab1tghed X-HE-Tag: 1772483318-199881 X-HE-Meta: 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 W7KOqwXs iQx+BRNlbzXfHTw9/2VlNlrGetk4952NfQnpmKml6uIbXaGcw5sfLjRYi+TXS2dhE+AJlHxxNSSSZqb3f5kBYkpVxKAvBj+MEdPc4/2kYckqMEQL2/Ewv84fIwM+5Ho00zLbp7lDgQf6ebrcGNQdfioJzbF5nn7HU0Gm35o2QxE/EUbmnEGzFIC3qu4B+7p1geQ3RNjkjp+UA9Dd4mqmATSNqYZzDrLnTTiagYYAEs+w7yvJI2dZAIBHopYVqTd1dig+7tKwnKyLtp0zBJfKQlu6UDI8J7FmTqC5DlfYyWKdc6AXzrplFAT1Q3sehdXA38voSnKEetyMCZmK5CiQDEG33U2eoR0bY/AA6UhGSR6h8lOuxGitZaioNOyobMuIXe2RYIjNNh2bqO2g= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Mar 02, 2026 at 02:00:00PM +0100, David Hildenbrand wrote: > Which value does exposing requested_kb really have if there are > multiply subscribers to notify? Doesn't quite make sense to even > expose that. You're right, that's a real design flaw. With N subscribers each independently acting on requested_kb, the aggregate reclaim is unbounded. The field would need to be either dropped or replaced with a hint that scales with subscriber count =E2=80=94 neither of which was thought through here. > If apps have droppable caches, a better solution might be to use > something like MAP_DROPPABLE where possible, still leaving the > kernel in charge of when and how much memory to reclaim. That's a much cleaner approach. I'll look into MAP_DROPPABLE. Thank you for the pointer. Andr=C3=A9