From: Andrew Morton <akpm@linux-foundation.org>
To: Usama Arif <usama.arif@linux.dev>
Cc: 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 <baoquan.he@linux.dev>,
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, Nico Pache <nico.pache@linux.dev>,
Liam R. Howlett <liam@infradead.org>,
ryan.roberts@arm.com, Vlastimil Babka <vbabka@kernel.org>,
lance.yang@linux.dev, linux-kernel@vger.kernel.org,
nphamcs@gmail.com, shikemeng@huaweicloud.com, yosry@kernel.org,
qi.zheng@linux.dev, luizcap@redhat.com, kernel-team@meta.com
Subject: Re: [RESEND v7 00/29] mm: PMD-level swap entries for anonymous THPs
Date: Mon, 14 Sep 2026 20:32:37 -0700 [thread overview]
Message-ID: <20260914203237.7cdfcd4c320470f4ae5cafd2@linux-foundation.org> (raw)
In-Reply-To: <20260914122950.3283997-1-usama.arif@linux.dev>
On Mon, 14 Sep 2026 05:27:50 -0700 Usama Arif <usama.arif@linux.dev> wrote:
> When reclaim swaps out a PMD-mapped anonymous THP today, the PMD is
> split into HPAGE_PMD_NR PTE-level swap entries via TTU_SPLIT_HUGE_PMD
> before unmap. This series introduces a PMD-level swap entry so the
> huge mapping can survive the swap round-trip and do_huge_pmd_swap_page()
> can restore the PMD mapping directly on swap-in, without waiting for
> khugepaged to collapse the range later.
Thanks. I'd describe this as an inevitable step along our thp journey.
Has to be done sometime.
I'll await more review, especially of the core parts: pmd swap fault
handler (#27) and swapout producer (#28).
And it's a 29-patch performance optimization without any performance
testing results ;) Is efficacy testing in the works?
prev parent reply other threads:[~2026-09-15 3:32 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-14 12:27 Usama Arif
2026-09-14 12:27 ` [RESEND v7 01/29] mm: rename pmd_to_softleaf_folio() to pmd_softleaf_to_folio() Usama Arif
2026-09-14 21:17 ` Barry Song
2026-09-15 3:06 ` Baoquan He
2026-09-15 3:34 ` Qi Zheng
2026-09-14 12:27 ` [RESEND v7 02/29] arm64: mm: add PMD swap-exclusive helpers Usama Arif
2026-09-14 12:27 ` [RESEND v7 03/29] loongarch: " Usama Arif
2026-09-14 12:27 ` [RESEND v7 04/29] powerpc: " Usama Arif
2026-09-14 12:27 ` [RESEND v7 05/29] riscv: " Usama Arif
2026-09-14 12:27 ` [RESEND v7 06/29] s390: " Usama Arif
2026-09-14 12:27 ` [RESEND v7 07/29] x86: " Usama Arif
2026-09-14 12:27 ` [RESEND v7 08/29] mm: recognize PMD swap entries in the softleaf layer Usama Arif
2026-09-14 12:27 ` [RESEND v7 09/29] mm/debug_vm_pgtable: test PMD swap-exclusive helpers Usama Arif
2026-09-14 12:28 ` [RESEND v7 10/29] mm: make PMD migration-entry splitting explicit Usama Arif
2026-09-14 12:28 ` [RESEND v7 11/29] mm: split PMD swap entries into PTE swap entries Usama Arif
2026-09-14 12:28 ` [RESEND v7 12/29] mm: handle PMD swap entries in fork path Usama Arif
2026-09-14 12:28 ` [RESEND v7 13/29] mm: zswap: reject high-order swap cache allocations backed by zswap Usama Arif
2026-09-14 12:28 ` [RESEND v7 14/29] mm: swap in PMD swap entries as whole THPs during swapoff Usama Arif
2026-09-14 12:28 ` [RESEND v7 15/29] fs/proc: account PMD swap entries in smaps Usama Arif
2026-09-14 12:28 ` [RESEND v7 16/29] mm: handle soft-dirty and uffd-wp on PMD swap entries Usama Arif
2026-09-14 12:28 ` [RESEND v7 17/29] mm/hmm: fault PMD swap entries on demand Usama Arif
2026-09-14 12:28 ` [RESEND v7 18/29] mm: free PMD swap entries in zap_huge_pmd() Usama Arif
2026-09-14 12:28 ` [RESEND v7 19/29] mm/madvise: free PMD swap entries with MADV_FREE Usama Arif
2026-09-14 12:28 ` [RESEND v7 20/29] mm/madvise: skip PMD swap entries for MADV_COLD and MADV_PAGEOUT Usama Arif
2026-09-14 12:28 ` [RESEND v7 21/29] mm/madvise: keep PMD swap entries whole for MADV_GUARD_INSTALL/REMOVE Usama Arif
2026-09-14 12:28 ` [RESEND v7 22/29] mm/mincore: report PMD swap-cache residency Usama Arif
2026-09-14 12:28 ` [RESEND v7 23/29] mm/khugepaged: treat PMD swap entries as mapped THPs Usama Arif
2026-09-14 12:28 ` [RESEND v7 24/29] mm: handle PMD swap entries in MADV_WILLNEED Usama Arif
2026-09-14 12:28 ` [RESEND v7 25/29] mm: handle PMD swap entries in UFFDIO_MOVE Usama Arif
2026-09-14 12:28 ` [RESEND v7 26/29] mm: don't PTE-batch a swap-in over a hardware-poisoned subpage Usama Arif
2026-09-14 12:28 ` [RESEND v7 27/29] mm: handle PMD swap entry faults on swap-in Usama Arif
2026-09-14 12:28 ` [RESEND v7 28/29] mm: install PMD swap entries on swap-out Usama Arif
2026-09-14 12:28 ` [RESEND v7 29/29] selftests/mm: add PMD swap entry tests Usama Arif
2026-09-15 3:32 ` Andrew Morton [this message]
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