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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1783605060; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=z8FqW5eq3Uh1W5agsXYXom0eXyZ/LkbEOhFOOkLyqNU=; b=qj3MKYulS0/NJ/Qjk8zhEIgCr9AW0b51sFXof////YFtj5/yXTLY4yyzdVD1+/8HM/hfFX 3KOoV5n2sVnAjg3GVW2moiIW/UcY/2XiWIKzaUzuBzVYyPCsOS8yDqeFxjEiYGcGgV66ta CLG9sXAFewOyZ2U5Vgpi+8YvYKSCbX4= From: Usama Arif To: Usama Arif Cc: Andrew Morton , david@kernel.org, chrisl@kernel.org, kasong@tencent.com, ljs@kernel.org, ziy@nvidia.com, linux-mm@kvack.org, ying.huang@linux.alibaba.com, Baoquan He , willy@infradead.org, youngjun.park@lge.com, hannes@cmpxchg.org, riel@surriel.com, shakeel.butt@linux.dev, alex@ghiti.fr, kas@kernel.org, baohua@kernel.org, dev.jain@arm.com, baolin.wang@linux.alibaba.com, npache@redhat.com, "Liam R . Howlett" , ryan.roberts@arm.com, Vlastimil Babka , lance.yang@linux.dev, linux-kernel@vger.kernel.org, nphamcs@gmail.com, shikemeng@huaweicloud.com, kernel-team@meta.com Subject: Re: [PATCH v3 01/11] mm: add PMD swap entry detection support Date: Thu, 9 Jul 2026 06:50:49 -0700 Message-ID: <20260709135050.2910286-1-usama.arif@linux.dev> In-Reply-To: <20260703173903.3789516-2-usama.arif@linux.dev> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 29873140006 X-Stat-Signature: gmntci4ykrpbiupf1qdry7twme8ejndt X-HE-Tag: 1783605062-724020 X-HE-Meta: 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 Zb93/9iF GaSUCfKHxZCtWPyx7atpIXtNyAocENkOzmhnF2ucpjybvG0wLVJJk2GppM/8jHxckXWPahSmXvuVuonYyDwMqlXIpDIY3uEZEX9PRPtkKlhOfFv03l6ugxn2qmntt21QKh4HdKvROaP4bnQmKtuer3dyfreTPhI7ZprYkna8pPo+8Hva6TXB+fQqY0Do0/+VZOtAt Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, 3 Jul 2026 10:38:18 -0700 Usama Arif wrote: > Currently when a PMD-mapped THP is swapped out, the PMD is always split into 512 PTE-level swap entries. To preserve huge page information across swap cycles, later patches will install a single PMD-level swap entry instead. This patch adds the infrastructure to detect those entries. > > Teach the softleaf layer to recognise PMD swap entries: pmd_is_swap_entry() detects them and softleaf_is_valid_pmd_entry() accepts them as a valid non-present type. Clear the exclusive overlay bit in softleaf_from_pmd() before decoding, matching how soft_dirty and uffd_wp bits are already stripped. > > Add pmd_swp_mkexclusive(), pmd_swp_exclusive(), and pmd_swp_clear_exclusive() helpers to each architecture that supports PMD softleaf entries (x86, arm64, s390, riscv, loongarch, powerpc), mirroring the existing PTE swap exclusive helpers in each arch's pgtable.h. Provide generic no-op PMD swap exclusive fallbacks for architectures without PMD softleaf support, matching the generic PMD swap soft-dirty fallbacks. > > Signed-off-by: Usama Arif I forgot to format the commit message before sending this patch, sorry about this, will fix in the next revision.