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Wed, 02 Jul 2025 02:00:53 -0400 X-MC-Unique: cY2WhJ9yNnWCB4gRyLU_-g-1 X-Mimecast-MFC-AGG-ID: cY2WhJ9yNnWCB4gRyLU_-g_1751436048 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4E0671955EC3; Wed, 2 Jul 2025 06:00:48 +0000 (UTC) Received: from h1.redhat.com (unknown [10.22.88.112]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C9E7A180045B; Wed, 2 Jul 2025 06:00:32 +0000 (UTC) From: Nico Pache To: linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: david@redhat.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, ryan.roberts@arm.com, dev.jain@arm.com, corbet@lwn.net, rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, akpm@linux-foundation.org, baohua@kernel.org, willy@infradead.org, peterx@redhat.com, wangkefeng.wang@huawei.com, usamaarif642@gmail.com, sunnanyong@huawei.com, vishal.moola@gmail.com, thomas.hellstrom@linux.intel.com, yang@os.amperecomputing.com, kirill.shutemov@linux.intel.com, aarcange@redhat.com, raquini@redhat.com, anshuman.khandual@arm.com, catalin.marinas@arm.com, tiwai@suse.de, will@kernel.org, dave.hansen@linux.intel.com, jack@suse.cz, cl@gentwo.org, jglisse@google.com, surenb@google.com, zokeefe@google.com, hannes@cmpxchg.org, rientjes@google.com, mhocko@suse.com, rdunlap@infradead.org Subject: [PATCH v8 09/15] khugepaged: avoid unnecessary mTHP collapse attempts Date: Tue, 1 Jul 2025 23:57:36 -0600 Message-ID: <20250702055742.102808-10-npache@redhat.com> In-Reply-To: <20250702055742.102808-1-npache@redhat.com> References: <20250702055742.102808-1-npache@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 186954000B X-Stat-Signature: ac3tmk71thhtfzz7wwhp5z6rkx4su5uu X-HE-Tag: 1751436056-983248 X-HE-Meta: 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 ej8icnUr WiHubDK04pv7mst9uEaN9SgXXIJEMZz49wF9pyCD089urbipYJwKUqrJIERpqxJP3x/k/4Uf4gbDfGCSiarTA3YXXFZAxEoFfX/2Jz+oGJ9jHhk4ZOPCl5HfjZ57V10rOwH4xm69Kbqu5g6+dygsgmXDb89SSV+gTsua99KpcUxHnJ5/3qvGeeiTkP0OFlZb5IRi77lIcC3NE7E6ZfI+5o0NsCCG4GYYKLfzStuboJbeUlCIeXHbyh5S9lR6JyX38eRuCEob3yNW6daZoRjqx9xOtubw0Lw1AYviWcRoAZvH7s8B3sSxFMUxNNIRRSIk466acL2lPW70eFyfnPOKBquCa8UBKdEN6xsrKiwMj/j3cVpKvV+6P9XANe/Lfyx85A2MHmoI6MvzOsZTo4t8LRgCy4A== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: There are cases where, if an attempted collapse fails, all subsequent orders are guaranteed to also fail. Avoid these collapse attempts by bailing out early. Signed-off-by: Nico Pache --- mm/khugepaged.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 61d2b3ebc7ac..50e1d7ef7e6d 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1358,6 +1358,23 @@ static int khugepaged_scan_bitmap(struct mm_struct *mm, unsigned long address, collapsed += (1 << order); continue; } + /* + * Some ret values indicate all lower order will also + * fail, dont trying to collapse smaller orders + */ + if (ret == SCAN_EXCEED_NONE_PTE || + ret == SCAN_EXCEED_SWAP_PTE || + ret == SCAN_EXCEED_SHARED_PTE || + ret == SCAN_PTE_NON_PRESENT || + ret == SCAN_PTE_UFFD_WP || + ret == SCAN_ALLOC_HUGE_PAGE_FAIL || + ret == SCAN_CGROUP_CHARGE_FAIL || + ret == SCAN_COPY_MC || + ret == SCAN_PAGE_LOCK || + ret == SCAN_PAGE_COUNT) + goto next; + else + break; } next: -- 2.49.0