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a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1747640929; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Dj6t1QtJ/3TjO2Q3bAtCDbyF4+BBNIY3eGFJJVh8W28=; b=0dATO9k/3o0eSpEurwzhECT0CZXobj2GyEw5lZ6emH47oV3KGA6XUn8Y2l0g3TYxfyE6Cz LZc5Uih1YNE5NipUAaJZeccFtGuvOFYXe0sCJwQKIna8xEtfYZZxngPBSxaKRAu0j2J3hO G37sx1eahlKQ7zRCtojrTQDIyynEpZg= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5444B168F; Mon, 19 May 2025 00:48:35 -0700 (PDT) Received: from K4MQJ0H1H2.blr.arm.com (unknown [10.164.18.48]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 9E5D03F6A8; Mon, 19 May 2025 00:48:41 -0700 (PDT) From: Dev Jain To: akpm@linux-foundation.org Cc: ryan.roberts@arm.com, david@redhat.com, willy@infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, catalin.marinas@arm.com, will@kernel.org, Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, vbabka@suse.cz, jannh@google.com, anshuman.khandual@arm.com, peterx@redhat.com, joey.gouly@arm.com, ioworker0@gmail.com, baohua@kernel.org, kevin.brodsky@arm.com, quic_zhenhuah@quicinc.com, christophe.leroy@csgroup.eu, yangyicong@hisilicon.com, linux-arm-kernel@lists.infradead.org, hughd@google.com, yang@os.amperecomputing.com, ziy@nvidia.com, Dev Jain Subject: [PATCH v3 1/5] mm: Optimize mprotect() by batch-skipping PTEs Date: Mon, 19 May 2025 13:18:20 +0530 Message-Id: <20250519074824.42909-2-dev.jain@arm.com> X-Mailer: git-send-email 2.39.3 (Apple Git-146) In-Reply-To: <20250519074824.42909-1-dev.jain@arm.com> References: <20250519074824.42909-1-dev.jain@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 361078000A X-Rspam-User: X-Stat-Signature: t55ohb46jumjg9rrqnphkt6mr79nrag7 X-HE-Tag: 1747640929-380590 X-HE-Meta: U2FsdGVkX19V0rQdJCDzIOqhUK+8tKVPw8iV+z5pHkr206NIMKEYdFVNENupks+LLBYOYzsw9Xo63ZHqU3a35uPogyZcL0AwfRSal+wq42VMjoOcJ/E13X5I57+LPfQPnZlqkkM6TOoO9nKng0pAS8b0XvDXvcjHwrzVLJ2+qSQ33H63ai1t6Z4/EFUpye9D7gtYBE2EXvNpCp9zPoIFsBYKkomvDLIU0035V+b0yS2jsmEgp1lP839BmB3aPo8b0H/jeo2ZtVIt+ek/uRnssMUK30Lh9wlvZYqNdnAbVNeQnRZupO3sBWx7QueFDdCRdtugtFTgU/IjDot1HwOQ5D8/ko3WZ+1n6PUhp+f1kEw9twxud/AMwYR9iTI//ThIcmpHery0f7mNZiiESV8dUKQOG1i0wswqZ1k5+gJRFUnVKF1p3OP3Rfom4rIQzisryEAv0smf9CeETIdY53WcisbilqrqIB+DqD7Q8R8RlYZ6DSipP2nhHLk/WINPk2sWo4S2x+fOrklEjwidD/1J8CxoFUiMhl0RE8bDhTE3WkIFJdVnFzKmM0RuScoQSMfMsmgwhG+6RYxPLtyQ1VRhRWw1vdAfqR9pXmZI+szx42+joedMHmiW0eekeadfsB+/dSOMG5sIYu1Q65nEQoktGFE4ReH9HvccbO8+rYBZhX++M1bpMgztjTlCpk5u3Nzp0etEmCsNdvU6/XBAszaccDXh9w7YLvspmmJoKy0XsyKcq98v0rtB1VdpMyS5TVmKg+VATobN5+uwNSQkkgnekN3fAnglvPA96I3yb9NIIgQ8uBThldllw/vjvFV2WXesm+3W3TEHzbkawIPXMnpIPNBwvzUlnDwIL1mkQXQbFjQTwPxFy95XdvUgPSLzUIkhclNKcT9+e+YxIGixhfhMzOssLoh+jVv5DDWcQl/T1cyrc8h42CuiXI9CdMe89Z+wSuSl0OOrXGDDvwV2cor ZGAQ/L1v 11d6E4KZvAAW3KUtocLYSHZtvi1+218j+R97YjsBt2Atmz5bicVKjaVlghkR1DAIB0JjEAcq1Sa35kTzz4YcqzttSAYZKdnl75eu3tKTRmsOA02+qY9rRmDLOyxD1hkCosBF6mZZ/u4eYweupeyl2NJdIYQ== 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: In case of prot_numa, there are various cases in which we can skip to the next iteration. Since the skip condition is based on the folio and not the PTEs, we can skip a PTE batch. Signed-off-by: Dev Jain --- mm/mprotect.c | 36 +++++++++++++++++++++++++++++------- 1 file changed, 29 insertions(+), 7 deletions(-) diff --git a/mm/mprotect.c b/mm/mprotect.c index 88608d0dc2c2..1ee160ed0b14 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -83,6 +83,18 @@ bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr, return pte_dirty(pte); } +static int mprotect_batch(struct folio *folio, unsigned long addr, pte_t *ptep, + pte_t pte, int max_nr_ptes) +{ + const fpb_t flags = FPB_IGNORE_DIRTY | FPB_IGNORE_SOFT_DIRTY; + + if (!folio_test_large(folio) || (max_nr_ptes == 1)) + return 1; + + return folio_pte_batch(folio, addr, ptep, pte, max_nr_ptes, flags, + NULL, NULL, NULL); +} + static long change_pte_range(struct mmu_gather *tlb, struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, unsigned long end, pgprot_t newprot, unsigned long cp_flags) @@ -94,6 +106,7 @@ static long change_pte_range(struct mmu_gather *tlb, bool prot_numa = cp_flags & MM_CP_PROT_NUMA; bool uffd_wp = cp_flags & MM_CP_UFFD_WP; bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; + int nr_ptes; tlb_change_page_size(tlb, PAGE_SIZE); pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); @@ -108,8 +121,10 @@ static long change_pte_range(struct mmu_gather *tlb, flush_tlb_batched_pending(vma->vm_mm); arch_enter_lazy_mmu_mode(); do { + nr_ptes = 1; oldpte = ptep_get(pte); if (pte_present(oldpte)) { + int max_nr_ptes = (end - addr) >> PAGE_SHIFT; pte_t ptent; /* @@ -126,15 +141,18 @@ static long change_pte_range(struct mmu_gather *tlb, continue; folio = vm_normal_folio(vma, addr, oldpte); - if (!folio || folio_is_zone_device(folio) || - folio_test_ksm(folio)) + if (!folio) continue; + if (folio_is_zone_device(folio) || + folio_test_ksm(folio)) + goto skip_batch; + /* Also skip shared copy-on-write pages */ if (is_cow_mapping(vma->vm_flags) && (folio_maybe_dma_pinned(folio) || folio_maybe_mapped_shared(folio))) - continue; + goto skip_batch; /* * While migration can move some dirty pages, @@ -143,7 +161,7 @@ static long change_pte_range(struct mmu_gather *tlb, */ if (folio_is_file_lru(folio) && folio_test_dirty(folio)) - continue; + goto skip_batch; /* * Don't mess with PTEs if page is already on the node @@ -151,7 +169,7 @@ static long change_pte_range(struct mmu_gather *tlb, */ nid = folio_nid(folio); if (target_node == nid) - continue; + goto skip_batch; toptier = node_is_toptier(nid); /* @@ -159,8 +177,12 @@ static long change_pte_range(struct mmu_gather *tlb, * balancing is disabled */ if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && - toptier) + toptier) { +skip_batch: + nr_ptes = mprotect_batch(folio, addr, pte, + oldpte, max_nr_ptes); continue; + } if (folio_use_access_time(folio)) folio_xchg_access_time(folio, jiffies_to_msecs(jiffies)); @@ -280,7 +302,7 @@ static long change_pte_range(struct mmu_gather *tlb, pages++; } } - } while (pte++, addr += PAGE_SIZE, addr != end); + } while (pte += nr_ptes, addr += nr_ptes * PAGE_SIZE, addr != end); arch_leave_lazy_mmu_mode(); pte_unmap_unlock(pte - 1, ptl); -- 2.30.2