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b=DDJ39niqZe2VuO/AOLrzUooRI8Kka+AUG+I1QqX+ccRej9XGpX1EbT70usNhhk0WH 3Hu1gO3Ih1pLLyIG5cjeuauIWOpNPoeNBimlhBzm5QQn83fZQ4LEjsJahWO3pg2IBG d30nTWCiO7p4rjwOuPX9iWX3LM2+YsfD51tEFGridpXeu1HHs2AId1rxRc/7st1xtH Ry6XiQ2Y6xcEi+GZAo3TlYGrvKP1Xx7rhkNulXHlZxZXAelXAkKYShnmXXZjcV5QWq UENkuT2Noc7TmRmYMZ+/Y3TAjnZ32LzBvpgcmcA4px9sZ9QEMRYqpxH7t9TVwSz9dg zKGepBss2dzGw== From: SeongJae Park To: gutierrez.asier@huawei-partners.com Cc: SeongJae Park , artem.kuzin@huawei.com, stepanov.anatoly@huawei.com, wangkefeng.wang@huawei.com, yanquanmin1@huawei.com, zuoze1@huawei.com, damon@lists.linux.dev, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v2 2/4] mm/damon: Support for synchrounous huge pages collapse Date: Tue, 10 Mar 2026 18:02:21 -0700 Message-ID: <20260311010222.90548-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260310162420.4180562-3-gutierrez.asier@huawei-partners.com> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 112B9C0006 X-Stat-Signature: ydzw33amiprr5nfzpqrb85eced7cujob X-Rspam-User: X-HE-Tag: 1773190945-614740 X-HE-Meta: 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 /XCm76c+ 6WU5xtqKfWsez3w6zIOOcH8nokU3xknG0DmI3KRy+jHOWyYTdzSKhwok9Tl0ic57v37MRmnY36vEW9kZCwb0eVg2YZ4gqKzPOJhmX4z5+jagIY2mlXJv59ZDdG2SlmEZRkHk1pUHmeL6wFcFA4VG9g9GpPn5+fPgOVWyro6SnSI7i+lMvZIpioVtMBE/eHLJOn38XVlxBNNKwLOrWvUQxhzbGsg2kH70Icp5qSts4EgaQBaOMPigO37KHBmPoYfcAMfiyvCIqzFzVMbn5gmBWhXNyAfvtXluBjiePuiqsEImkMxmZZT7ebjzh/toGGoYMGBwQ Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, 10 Mar 2026 16:24:18 +0000 wrote: > From: Asier Gutierrez Please add more descriptions of the change, including the motivation. I assume the motivation is similar to MADV_COLLAPSE that aims to make synchronous and therefore faster huge page collapsing impacts copared to MADV_HUGEPAGE? It would be nice to make it clear here. Also, if my assumption is not wrong, adding a test results showing the benefit of DAMOS_COLLAPSE over DAMOS_HUGEPAGE here would be nice. > > Signed-off-by: Asier Gutierrez > Co-developed-by: Anatoly Stepanov > --- > include/linux/damon.h | 1 + > mm/damon/vaddr.c | 3 +++ > 2 files changed, 4 insertions(+) > > diff --git a/include/linux/damon.h b/include/linux/damon.h > index a4fea23da857..a9cf17b9e8fa 100644 > --- a/include/linux/damon.h > +++ b/include/linux/damon.h > @@ -142,6 +142,7 @@ enum damos_action { > DAMOS_LRU_DEPRIO, > DAMOS_MIGRATE_HOT, > DAMOS_MIGRATE_COLD, > + DAMOS_COLLAPSE, > DAMOS_STAT, /* Do nothing but only record the stat */ > NR_DAMOS_ACTIONS, > }; > diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c > index 729b7ffd3565..36791a9a1094 100644 > --- a/mm/damon/vaddr.c > +++ b/mm/damon/vaddr.c > @@ -969,6 +969,9 @@ static unsigned long damon_va_apply_scheme(struct damon_ctx *ctx, > case DAMOS_NOHUGEPAGE: > madv_action = MADV_NOHUGEPAGE; > break; > + case DAMOS_COLLAPSE: > + madv_action = MADV_COLLAPSE; > + break; > case DAMOS_MIGRATE_HOT: > case DAMOS_MIGRATE_COLD: > return damos_va_migrate(t, r, scheme, sz_filter_passed); > -- > 2.43.0 The code looks good to me. Thanks, SJ [...]