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b=uFu15vSVeCbd/xfajB+QwNZhuZioYxLjTI1mGglrm4J0QShB+T3gRGJokeM8hGL+Y bY3Jo6fbu5Iy1BzYcY4Z7m6/qPiSbF/8Zn9Lw3iQ/uiRo57oDs9zp95keg7nZjD69N mOuQGZ2PJp/EUfXNflU1a1imc23H9nphhzIpgkWVuf+YHwr1bLfrYcLWdN/MUqeuWk X/9AKvtbTl4xba8p6NUVYDLWiA/jmTu5OO+0/xJMCuc6Ob9cUi3RBLNZ7QWJtyils7 UiBPaTP0wYTxvzxrFAjJ/8pWybyXWBMUsQMAugGYB6L7h3vRNp/bYWv/H93AYBOwYZ ruOTNJDd2kKVg== Message-ID: <837fe882-0d42-47eb-9234-9d5787148650@kernel.org> Date: Mon, 30 Mar 2026 13:43:57 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm/memory_hotplug: maintain N_NORMAL_MEMORY during hotplug Content-Language: en-US To: Hao Li , Joshua Hahn Cc: david@kernel.org, osalvador@suse.de, akpm@linux-foundation.org, vbabka@suse.cz, harry.yoo@oracle.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org References: <2356614e-d9b8-4639-8e2a-96c5e4eaef61@kernel.org> <20260327163554.42487-1-joshua.hahnjy@gmail.com> From: "Vlastimil Babka (SUSE)" In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 0F09940012 X-Stat-Signature: bjxg8ncgrxjxecm54378htqbnx414kcb X-Rspam-User: X-HE-Tag: 1774871042-587695 X-HE-Meta: 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 9Mlg7WeT A+jCZ/SVxYFYFmdIZu1vC1AKKGxp5CTjkmwXNZW9JPqmJEfq3edcuR4JiOdb5XkhhfZfhR+LeTi742u9Y5ziHvSeevsDvm7GP0mHaHz2CCkc9jROeg4kz0rmn8rs0kbDaAxUL9rZ6jkmNurzAzjoCp4EjNaKt+guO7kFPeGewNtdW2ZRm307DFF5RU+DVTCHIyhOi1fRDghO0jdvWP22Bc7mQMRC8J20QwoBNdSlYBQqLepCk2dYzRZ20xdI9ASJFunMzfR427KpnvCIVBwazit1A/QVEfpVRfDfuAtHk7EoNEp1XW9lx1dkuWwChTfzWw2OsYDAve1CCk4ZaY+wihaqX54R4h5awLuDzpxbVolaWfJmFR3+lKlDh3VHghVEz6KRXTnAA39/xL1pK4yJAwAFU+Q== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 3/28/26 05:03, Hao Li wrote: > On Fri, Mar 27, 2026 at 09:35:54AM -0700, Joshua Hahn wrote: >> On Fri, 27 Mar 2026 15:44:18 +0100 "Vlastimil Babka (SUSE)" wrote: >> >> > >> Restore N_NORMAL_MEMORY maintenance directly in online_pages() and >> > >> offline_pages(). Set the bit when a node that currently lacks normal >> > >> memory onlines pages into a zone <= ZONE_NORMAL, and clear it when >> > >> offlining removes the last present pages from zones <= ZONE_NORMAL. >> > >> >> > >> This restores the intended semantics without bringing back the old >> > >> status_change_nid_normal notifier plumbing which was removed in >> > >> 8d2882a8edb8. >> > >> > But commit 8d2882a8edb8 didn't introduce the current state, or did it? >> >> I don't mean to speak on Hao's behalf, but as far as I can tell I think this >> would have been the commit to introduce the state, since >> node_states_check_changes_online would set status_change_nid_normal to nid, >> then nodes_states_set_node would come around and set it to N_NORMAL_MEMORY. >> Maybe I'm missing something? :0 > > Thanks for this analysis. I was thinking the same. N_NORMAL_MEMORY is no longer > updated after this commit. You're right. Initially I found a much older commit that seemed to remove updating N_NORMAL_MEMORY shortly after it was introduced. But seems it was reintroduced later and indeed 8d2882a8edb8 removed it again. Partially my fault as I reviewed that commit and was blind to that aspect - that it's not just removing an unused status_change_nid_normal. Thanks for figuring that out! >> >> Thanks for the reply, Vlastimil. I hope you have a great day : -) >> Joshua >