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Wed, 14 May 2025 23:06:04 -0400 X-MC-Unique: l7fB6TRJN6GM3IamP5VNFg-1 X-Mimecast-MFC-AGG-ID: l7fB6TRJN6GM3IamP5VNFg_1747278360 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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B1E581800261; Thu, 15 May 2025 03:05:59 +0000 (UTC) Received: from h1.redhat.com (unknown [10.22.88.116]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C329A1800268; Thu, 15 May 2025 03:05:43 +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 v6 09/12] khugepaged: avoid unnecessary mTHP collapse attempts Date: Wed, 14 May 2025 21:03:09 -0600 Message-ID: <20250515030312.125567-10-npache@redhat.com> In-Reply-To: <20250515030312.125567-9-npache@redhat.com> References: <20250515030312.125567-1-npache@redhat.com> <20250515030312.125567-2-npache@redhat.com> <20250515030312.125567-3-npache@redhat.com> <20250515030312.125567-4-npache@redhat.com> <20250515030312.125567-5-npache@redhat.com> <20250515030312.125567-6-npache@redhat.com> <20250515030312.125567-7-npache@redhat.com> <20250515030312.125567-8-npache@redhat.com> <20250515030312.125567-9-npache@redhat.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 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 5920d4715a11..517cf2b271d7 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1371,6 +1371,23 @@ 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