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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1782888591; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zd2opAEZdyfY+D+0IbQCuD9WR9PIvtSdIduSxlL8mTg=; b=ZROQTcyaCG+fELLScxaOCHawW/fBPCebAni5xoGNnpS/3Jr2CCPf5rOPz3W5ERDJhOTiby m9DSyqQMsiV1ye850laC9XEqpHhBhkI4UPuCIsIWVD5Wc9yz1oSDERI4vJ7uRtQHMNoCmy eyRXQFirBLuTuDf+NKLcJTd0DbiT460= From: Lance Yang To: ziy@nvidia.com Cc: akpm@linux-foundation.org, vbabka@kernel.org, surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org, david@kernel.org, ljs@kernel.org, baolin.wang@linux.alibaba.com, liam@infradead.org, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, rppt@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/4] mm/compaction: stop recording free page order in page->private Date: Wed, 1 Jul 2026 14:49:37 +0800 Message-Id: <20260701064937.5131-1-lance.yang@linux.dev> In-Reply-To: <20260628-keep-subpage-private-zero-at-free-v1-1-f4ce3930d10f@nvidia.com> References: <20260628-keep-subpage-private-zero-at-free-v1-1-f4ce3930d10f@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: D452740003 X-Rspam-User: X-Stat-Signature: nag9yd4o5hbgps75mpdtwqrfti1ba6yx X-HE-Tag: 1782888593-300268 X-HE-Meta: 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 dNbkh/gN xJfL6eMDmhMACSrW5kQ3jt4pXc0AlnSN09oN50kL3hyvKK9QU1IQ/r3AMrVxZmNWNUcyFM/nT6knNjp3aLPfKF1BFFFC/vGdTbZHAOLCO3WwbL0oXtm58z9R6Whg0uoIIdwz1CgfuM7AfKZaoTwDhNyud4VvN7BzbjykGR2iDJjYOZ86HtqhbrpN4f06IALrGP6E2ISXRc74i6YiL6GERvBIn5DpAcvFyQiDv09Fq6cPbnoo= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sun, Jun 28, 2026 at 10:56:19PM -0400, Zi Yan wrote: >Commit 733aea0b3a7bb ("mm/compaction: add support for >0 order folio >memory compaction.") stores isolated free pages in an array indexed by free >page orders, it is no longer needed to store the order in each page's >->private field. And there is no code using the stored order. Stop doing >that. > >It also prepares for an upcoming change that ensures subpage->private is >zero at page free time and the removal of set_page_private(0) from >prep_compound_tail(). In alloc_contig_frozen_range_noprof(), >isolate_freepages_range() is used to grab free pages from buddy allocator >and it leaves the aforementioned page->private set until >either split_free_frozen_pages() or prep_new_page() is called. That >triggers the upcoming subpage->private nonzero check along once >set_page_private(0) is removed from prep_compound_tail(), which is called >via prep_new_page(). > >Signed-off-by: Zi Yan >--- IIUC, after isolation, the order is tracked by the per-order freelist :) LGTM, feel free to add: Reviewed-by: Lance Yang