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[147.75.48.161]) by mx.google.com with ESMTPS id v188-20020a6261c5000000b006e62522d2d5si10894953pfb.47.2024.04.02.04.11.15 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Apr 2024 04:11:16 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel+bounces-127788-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) client-ip=147.75.48.161; Authentication-Results: mx.google.com; arc=pass (i=1 spf=pass spfdomain=arm.com dmarc=pass fromdomain=arm.com); spf=pass (google.com: domain of linux-kernel+bounces-127788-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) smtp.mailfrom="linux-kernel+bounces-127788-linux.lists.archive=gmail.com@vger.kernel.org"; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=arm.com Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sy.mirrors.kernel.org (Postfix) with ESMTPS id 39026B2288B for ; Tue, 2 Apr 2024 10:56:38 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 84C305FBB9; Tue, 2 Apr 2024 10:56:31 +0000 (UTC) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 8D65D59B4B for ; Tue, 2 Apr 2024 10:56:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712055390; cv=none; b=RxjEXNEF7+2RvCxmiFA2MRQRfty/Y/8kHYqtJh/+hBTq8KETQ60cK5YncOIbaFylj73MfGiVvRWmShZFzxUZ09vDNqEzD6l1kZVNV67YXGRh9nKthGVfNvG2lXk6J84EzgwLVmndQUUXsAc8ReQnRYHaPswETvU7zYNFOEcFkzI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712055390; c=relaxed/simple; bh=sMFLkRqbhkb1xoxB44kni5wkLDnf1+oVzB0VSiy6eas=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=X/7uO7eXjDH6nWR4gEn+RCUknRz4Kl/SmK8Frnp8HHPNEFto3gLnxVw6xDKdb0a8Ai4KO+I/PgKCLfwovLC40GrkWNJ1MwuLPZqH6svOH90VAmvdoEhLnN5cCqDz6K6kNqOgWmK48p9W1bnxmCPMIrnTp+YBObA4f7Sq4VskFAU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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 3C439FEC; Tue, 2 Apr 2024 03:56:58 -0700 (PDT) Received: from [10.1.38.163] (XHFQ2J9959.cambridge.arm.com [10.1.38.163]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 70DC03F766; Tue, 2 Apr 2024 03:56:24 -0700 (PDT) Message-ID: Date: Tue, 2 Apr 2024 11:56:23 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 6/6] mm: madvise: Avoid split during MADV_PAGEOUT and MADV_COLD Content-Language: en-GB To: Barry Song <21cnbao@gmail.com> Cc: Andrew Morton , David Hildenbrand , Matthew Wilcox , Huang Ying , Gao Xiang , Yu Zhao , Yang Shi , Michal Hocko , Kefeng Wang , Chris Li , Lance Yang , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Barry Song References: <20240327144537.4165578-1-ryan.roberts@arm.com> <20240327144537.4165578-7-ryan.roberts@arm.com> From: Ryan Roberts In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 02/04/2024 11:16, Barry Song wrote: > On Thu, Mar 28, 2024 at 3:46 AM Ryan Roberts wrote: >> >> Rework madvise_cold_or_pageout_pte_range() to avoid splitting any large >> folio that is fully and contiguously mapped in the pageout/cold vm >> range. This change means that large folios will be maintained all the >> way to swap storage. This both improves performance during swap-out, by >> eliding the cost of splitting the folio, and sets us up nicely for >> maintaining the large folio when it is swapped back in (to be covered in >> a separate series). >> >> Folios that are not fully mapped in the target range are still split, >> but note that behavior is changed so that if the split fails for any >> reason (folio locked, shared, etc) we now leave it as is and move to the >> next pte in the range and continue work on the proceeding folios. >> Previously any failure of this sort would cause the entire operation to >> give up and no folios mapped at higher addresses were paged out or made >> cold. Given large folios are becoming more common, this old behavior >> would have likely lead to wasted opportunities. >> >> While we are at it, change the code that clears young from the ptes to >> use ptep_test_and_clear_young(), via the new mkold_ptes() batch helper >> function. This is more efficent than get_and_clear/modify/set, >> especially for contpte mappings on arm64, where the old approach would >> require unfolding/refolding and the new approach can be done in place. >> >> Reviewed-by: Barry Song >> Signed-off-by: Ryan Roberts >> --- > > Hi Ryan, > > I'm not entirely certain if this issue is related to this patch, but > I've encountered > the KNIC twice while using the latest mm-unstable kernel. Each time I attempted > to debug it, the issue vanished. I'm posting here to see if you have > any ideas on it :-) Thanks for the report! I think I see the problem below... > > [ 50.444066] > [ 50.444495] ===================================== > [ 50.444954] WARNING: bad unlock balance detected! > [ 50.445443] 6.9.0-rc2-00257-g2d9f63c285db #128 Not tainted > [ 50.446233] ------------------------------------- > [ 50.446684] singlethread/102 is trying to release lock > (ptlock_ptr(ptdesc)) at: > [ 50.447635] [] > madvise_cold_or_pageout_pte_range+0x80c/0xea0 > [ 50.449066] but there are no more locks to release! > [ 50.449535] > [ 50.449535] other info that might help us debug this: > [ 50.450140] 1 lock held by singlethread/102: > [ 50.450688] #0: ffff0000c001f208 (&mm->mmap_lock){++++}-{4:4}, at: > do_madvise.part.0+0x178/0x518 > [ 50.452321] > [ 50.452321] stack backtrace: > [ 50.452959] CPU: 3 PID: 102 Comm: singlethread Not tainted > 6.9.0-rc2-00257-g2d9f63c285db #128 > [ 50.453812] Hardware name: linux,dummy-virt (DT) > [ 50.454373] Call trace: > [ 50.454755] dump_backtrace+0x9c/0x100 > [ 50.455246] show_stack+0x20/0x38 > [ 50.455667] dump_stack_lvl+0xec/0x150 > [ 50.456111] dump_stack+0x18/0x28 > [ 50.456533] print_unlock_imbalance_bug+0x130/0x148 > [ 50.457014] lock_release+0x2e0/0x360 > [ 50.457487] _raw_spin_unlock+0x2c/0x78 > [ 50.457997] madvise_cold_or_pageout_pte_range+0x80c/0xea0 > [ 50.458635] walk_pgd_range+0x388/0x7d8 > [ 50.459168] __walk_page_range+0x1e0/0x1f0 > [ 50.459682] walk_page_range+0x1f0/0x2c8 > [ 50.460225] madvise_pageout+0xf8/0x280 > [ 50.460711] madvise_vma_behavior+0x310/0x9b8 > [ 50.461169] madvise_walk_vmas+0xc0/0x128 > [ 50.461605] do_madvise.part.0+0xf8/0x518 > [ 50.462041] __arm64_sys_madvise+0x68/0x88 > [ 50.462529] invoke_syscall+0x50/0x128 > [ 50.463001] el0_svc_common.constprop.0+0x48/0xf8 > [ 50.463508] do_el0_svc+0x28/0x40 > [ 50.464004] el0_svc+0x50/0x150 > [ 50.464492] el0t_64_sync_handler+0x13c/0x158 > [ 50.465021] el0t_64_sync+0x1a4/0x1a8 > [ 50.466959] ------------[ cut here ]------------ > [ 50.467451] WARNING: CPU: 3 PID: 102 at > kernel/rcu/tree_plugin.h:431 __rcu_read_unlock+0x74/0x218 > [ 50.468160] Modules linked in: > [ 50.468803] CPU: 3 PID: 102 Comm: singlethread Not tainted > 6.9.0-rc2-00257-g2d9f63c285db #128 > [ 50.469658] Hardware name: linux,dummy-virt (DT) > [ 50.470293] pstate: a3400005 (NzCv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--) > [ 50.470991] pc : __rcu_read_unlock+0x74/0x218 > [ 50.471594] lr : madvise_cold_or_pageout_pte_range+0x828/0xea0 > [ 50.472236] sp : ffff800080abb7e0 > [ 50.472622] pmr_save: 000000e0 > [ 50.473010] x29: ffff800080abb7e0 x28: 0000ffffa467a000 x27: fffffdffc3128c00 > [ 50.474006] x26: 0010000000000001 x25: 000000000000001b x24: ffff0000c32d73d0 > [ 50.474971] x23: 0060000104a3afc3 x22: ffff0000c2492840 x21: 0400000000000001 > [ 50.475943] x20: ff77fffffffffbff x19: ffff0000c3230000 x18: ffffffffffffffff > [ 50.477286] x17: 672d37353230302d x16: 3263722d302e392e x15: ffff800100abb227 > [ 50.478373] x14: 0000000000000001 x13: 38613178302f3461 x12: 3178302b636e7973 > [ 50.479354] x11: fffffffffffe0000 x10: ffffb03159697d08 x9 : ffffb03155fe3048 > [ 50.480265] x8 : 00000000ffffefff x7 : ffffb03159697d08 x6 : 0000000000000000 > [ 50.481154] x5 : 0000000000000001 x4 : ffff800080abbfe0 x3 : 0000000000000000 > [ 50.482035] x2 : ffff4fd055074000 x1 : 00000000ffffffff x0 : 000000003fffffff > [ 50.483163] Call trace: > [ 50.483599] __rcu_read_unlock+0x74/0x218 > [ 50.484152] madvise_cold_or_pageout_pte_range+0x828/0xea0 > [ 50.484780] walk_pgd_range+0x388/0x7d8 > [ 50.485328] __walk_page_range+0x1e0/0x1f0 > [ 50.485725] walk_page_range+0x1f0/0x2c8 > [ 50.486117] madvise_pageout+0xf8/0x280 > [ 50.486547] madvise_vma_behavior+0x310/0x9b8 > [ 50.486975] madvise_walk_vmas+0xc0/0x128 > [ 50.487403] do_madvise.part.0+0xf8/0x518 > [ 50.487845] __arm64_sys_madvise+0x68/0x88 > [ 50.488374] invoke_syscall+0x50/0x128 > [ 50.488946] el0_svc_common.constprop.0+0x48/0xf8 > [ 50.489732] do_el0_svc+0x28/0x40 > [ 50.490210] el0_svc+0x50/0x150 > [ 50.490674] el0t_64_sync_handler+0x13c/0x158 > [ 50.491257] el0t_64_sync+0x1a4/0x1a8 > [ 50.491793] irq event stamp: 3087 > [ 50.492243] hardirqs last enabled at (3087): [] > _raw_spin_unlock_irq+0x38/0x90 > [ 50.492917] hardirqs last disabled at (3086): [] > _raw_spin_lock_irq+0x9c/0xc0 > [ 50.493742] softirqs last enabled at (2470): [] > __do_softirq+0x534/0x588 > [ 50.494567] softirqs last disabled at (2461): [] > ____do_softirq+0x18/0x30 > [ 50.495328] ---[ end trace 0000000000000000 ]--- > [ 50.497110] BUG: sleeping function called from invalid context at > kernel/locking/rwsem.c:1578 > [ 50.497544] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: > 102, name: singlethread > [ 50.497652] preempt_count: ffffffff, expected: 0 > [ 50.497728] RCU nest depth: -1, expected: 0 > [ 50.497851] INFO: lockdep is turned off. > [ 50.498023] CPU: 3 PID: 102 Comm: singlethread Tainted: G W > 6.9.0-rc2-00257-g2d9f63c285db #128 > [ 50.498166] Hardware name: linux,dummy-virt (DT) > [ 50.498221] Call trace: > [ 50.498260] dump_backtrace+0x9c/0x100 > [ 50.498378] show_stack+0x20/0x38 > [ 50.498487] dump_stack_lvl+0xec/0x150 > [ 50.498574] dump_stack+0x18/0x28 > [ 50.498659] __might_resched+0x158/0x278 > [ 50.498741] __might_sleep+0x50/0xa0 > [ 50.498849] down_write+0x30/0x1a8 > [ 50.498950] split_huge_page_to_list_to_order+0x3c8/0x1130 > [ 50.499052] madvise_cold_or_pageout_pte_range+0x84c/0xea0 > [ 50.499138] walk_pgd_range+0x388/0x7d8 > [ 50.499224] __walk_page_range+0x1e0/0x1f0 > [ 50.499334] walk_page_range+0x1f0/0x2c8 > [ 50.499458] madvise_pageout+0xf8/0x280 > [ 50.499554] madvise_vma_behavior+0x310/0x9b8 > [ 50.499657] madvise_walk_vmas+0xc0/0x128 > [ 50.499739] do_madvise.part.0+0xf8/0x518 > [ 50.499851] __arm64_sys_madvise+0x68/0x88 > [ 50.499953] invoke_syscall+0x50/0x128 > [ 50.500037] el0_svc_common.constprop.0+0x48/0xf8 > [ 50.500121] do_el0_svc+0x28/0x40 > [ 50.500203] el0_svc+0x50/0x150 > [ 50.500322] el0t_64_sync_handler+0x13c/0x158 > [ 50.500422] el0t_64_sync+0x1a4/0x1a8 > [ 50.501378] BUG: scheduling while atomic: singlethread/102/0x00000000 > [ 50.517641] INFO: lockdep is turned off. > [ 50.518206] Modules linked in: > [ 50.521135] CPU: 2 PID: 102 Comm: singlethread Tainted: G W > 6.9.0-rc2-00257-g2d9f63c285db #128 > [ 50.522026] Hardware name: linux,dummy-virt (DT) > [ 50.522623] Call trace: > [ 50.522993] dump_backtrace+0x9c/0x100 > [ 50.523527] show_stack+0x20/0x38 > [ 50.523950] dump_stack_lvl+0xec/0x150 > [ 50.524405] dump_stack+0x18/0x28 > [ 50.524849] __schedule_bug+0x80/0xe0 > [ 50.525309] __schedule+0xb1c/0xc00 > [ 50.525750] schedule+0x58/0x170 > [ 50.526227] schedule_preempt_disabled+0x2c/0x50 > [ 50.526762] rwsem_down_write_slowpath+0x1ac/0x718 > [ 50.527342] down_write+0xf8/0x1a8 > [ 50.527857] split_huge_page_to_list_to_order+0x3c8/0x1130 > [ 50.528437] madvise_cold_or_pageout_pte_range+0x84c/0xea0 > [ 50.529012] walk_pgd_range+0x388/0x7d8 > [ 50.529442] __walk_page_range+0x1e0/0x1f0 > [ 50.529896] walk_page_range+0x1f0/0x2c8 > [ 50.530342] madvise_pageout+0xf8/0x280 > [ 50.530878] madvise_vma_behavior+0x310/0x9b8 > [ 50.531395] madvise_walk_vmas+0xc0/0x128 > [ 50.531849] do_madvise.part.0+0xf8/0x518 > [ 50.532330] __arm64_sys_madvise+0x68/0x88 > [ 50.532829] invoke_syscall+0x50/0x128 > [ 50.533374] el0_svc_common.constprop.0+0x48/0xf8 > [ 50.533992] do_el0_svc+0x28/0x40 > [ 50.534498] el0_svc+0x50/0x150 > [ 50.535029] el0t_64_sync_handler+0x13c/0x158 > [ 50.535588] el0t_64_sync+0x1a4/0x1a8 > > > >> include/linux/pgtable.h | 30 ++++++++++++++ >> mm/internal.h | 12 +++++- >> mm/madvise.c | 88 ++++++++++++++++++++++++----------------- >> mm/memory.c | 4 +- >> 4 files changed, 93 insertions(+), 41 deletions(-) >> >> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h >> index 8185939df1e8..391f56a1b188 100644 >> --- a/include/linux/pgtable.h >> +++ b/include/linux/pgtable.h >> @@ -361,6 +361,36 @@ static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, >> } >> #endif >> >> +#ifndef mkold_ptes >> +/** >> + * mkold_ptes - Mark PTEs that map consecutive pages of the same folio as old. >> + * @vma: VMA the pages are mapped into. >> + * @addr: Address the first page is mapped at. >> + * @ptep: Page table pointer for the first entry. >> + * @nr: Number of entries to mark old. >> + * >> + * May be overridden by the architecture; otherwise, implemented as a simple >> + * loop over ptep_test_and_clear_young(). >> + * >> + * Note that PTE bits in the PTE range besides the PFN can differ. For example, >> + * some PTEs might be write-protected. >> + * >> + * Context: The caller holds the page table lock. The PTEs map consecutive >> + * pages that belong to the same folio. The PTEs are all in the same PMD. >> + */ >> +static inline void mkold_ptes(struct vm_area_struct *vma, unsigned long addr, >> + pte_t *ptep, unsigned int nr) >> +{ >> + for (;;) { >> + ptep_test_and_clear_young(vma, addr, ptep); >> + if (--nr == 0) >> + break; >> + ptep++; >> + addr += PAGE_SIZE; >> + } >> +} >> +#endif >> + >> #ifndef __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG >> #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG) >> static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma, >> diff --git a/mm/internal.h b/mm/internal.h >> index eadb79c3a357..efee8e4cd2af 100644 >> --- a/mm/internal.h >> +++ b/mm/internal.h >> @@ -130,6 +130,8 @@ static inline pte_t __pte_batch_clear_ignored(pte_t pte, fpb_t flags) >> * @flags: Flags to modify the PTE batch semantics. >> * @any_writable: Optional pointer to indicate whether any entry except the >> * first one is writable. >> + * @any_young: Optional pointer to indicate whether any entry except the >> + * first one is young. >> * >> * Detect a PTE batch: consecutive (present) PTEs that map consecutive >> * pages of the same large folio. >> @@ -145,16 +147,18 @@ static inline pte_t __pte_batch_clear_ignored(pte_t pte, fpb_t flags) >> */ >> static inline int folio_pte_batch(struct folio *folio, unsigned long addr, >> pte_t *start_ptep, pte_t pte, int max_nr, fpb_t flags, >> - bool *any_writable) >> + bool *any_writable, bool *any_young) >> { >> unsigned long folio_end_pfn = folio_pfn(folio) + folio_nr_pages(folio); >> const pte_t *end_ptep = start_ptep + max_nr; >> pte_t expected_pte, *ptep; >> - bool writable; >> + bool writable, young; >> int nr; >> >> if (any_writable) >> *any_writable = false; >> + if (any_young) >> + *any_young = false; >> >> VM_WARN_ON_FOLIO(!pte_present(pte), folio); >> VM_WARN_ON_FOLIO(!folio_test_large(folio) || max_nr < 1, folio); >> @@ -168,6 +172,8 @@ static inline int folio_pte_batch(struct folio *folio, unsigned long addr, >> pte = ptep_get(ptep); >> if (any_writable) >> writable = !!pte_write(pte); >> + if (any_young) >> + young = !!pte_young(pte); >> pte = __pte_batch_clear_ignored(pte, flags); >> >> if (!pte_same(pte, expected_pte)) >> @@ -183,6 +189,8 @@ static inline int folio_pte_batch(struct folio *folio, unsigned long addr, >> >> if (any_writable) >> *any_writable |= writable; >> + if (any_young) >> + *any_young |= young; >> >> nr = pte_batch_hint(ptep, pte); >> expected_pte = pte_advance_pfn(expected_pte, nr); >> diff --git a/mm/madvise.c b/mm/madvise.c >> index 070bedb4996e..bd00b83e7c50 100644 >> --- a/mm/madvise.c >> +++ b/mm/madvise.c >> @@ -336,6 +336,7 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd, >> LIST_HEAD(folio_list); >> bool pageout_anon_only_filter; >> unsigned int batch_count = 0; >> + int nr; >> >> if (fatal_signal_pending(current)) >> return -EINTR; >> @@ -423,7 +424,8 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd, >> return 0; >> flush_tlb_batched_pending(mm); >> arch_enter_lazy_mmu_mode(); >> - for (; addr < end; pte++, addr += PAGE_SIZE) { >> + for (; addr < end; pte += nr, addr += nr * PAGE_SIZE) { >> + nr = 1; >> ptent = ptep_get(pte); >> >> if (++batch_count == SWAP_CLUSTER_MAX) { >> @@ -447,55 +449,67 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd, >> continue; >> >> /* >> - * Creating a THP page is expensive so split it only if we >> - * are sure it's worth. Split it if we are only owner. >> + * If we encounter a large folio, only split it if it is not >> + * fully mapped within the range we are operating on. Otherwise >> + * leave it as is so that it can be swapped out whole. If we >> + * fail to split a folio, leave it in place and advance to the >> + * next pte in the range. >> */ >> if (folio_test_large(folio)) { >> - int err; >> - >> - if (folio_likely_mapped_shared(folio)) >> - break; >> - if (pageout_anon_only_filter && !folio_test_anon(folio)) >> - break; >> - if (!folio_trylock(folio)) >> - break; >> - folio_get(folio); >> - arch_leave_lazy_mmu_mode(); >> - pte_unmap_unlock(start_pte, ptl); >> - start_pte = NULL; >> - err = split_folio(folio); >> - folio_unlock(folio); >> - folio_put(folio); >> - if (err) >> - break; >> - start_pte = pte = >> - pte_offset_map_lock(mm, pmd, addr, &ptl); >> - if (!start_pte) >> - break; >> - arch_enter_lazy_mmu_mode(); >> - pte--; >> - addr -= PAGE_SIZE; >> - continue; >> + const fpb_t fpb_flags = FPB_IGNORE_DIRTY | >> + FPB_IGNORE_SOFT_DIRTY; >> + int max_nr = (end - addr) / PAGE_SIZE; >> + bool any_young; >> + >> + nr = folio_pte_batch(folio, addr, pte, ptent, max_nr, >> + fpb_flags, NULL, &any_young); >> + if (any_young) >> + ptent = pte_mkyoung(ptent); >> + >> + if (nr < folio_nr_pages(folio)) { >> + int err; >> + >> + if (folio_likely_mapped_shared(folio)) >> + continue; >> + if (pageout_anon_only_filter && !folio_test_anon(folio)) >> + continue; >> + if (!folio_trylock(folio)) >> + continue; >> + folio_get(folio); >> + arch_leave_lazy_mmu_mode(); >> + pte_unmap_unlock(start_pte, ptl); >> + start_pte = NULL; >> + err = split_folio(folio); >> + folio_unlock(folio); >> + folio_put(folio); >> + if (err) >> + continue; The ptl is unlocked at this point. This used to break, but now it continues without the lock held! >> + start_pte = pte = >> + pte_offset_map_lock(mm, pmd, addr, &ptl); >> + if (!start_pte) >> + break; I think we would want to move the condition to here: if (err) continue; I'll fix it in the next version. Thanks, Ryan >> + arch_enter_lazy_mmu_mode(); >> + nr = 0; >> + continue; >> + } >> } >> >> /* >> * Do not interfere with other mappings of this folio and >> - * non-LRU folio. >> + * non-LRU folio. If we have a large folio at this point, we >> + * know it is fully mapped so if its mapcount is the same as its >> + * number of pages, it must be exclusive. >> */ >> - if (!folio_test_lru(folio) || folio_mapcount(folio) != 1) >> + if (!folio_test_lru(folio) || >> + folio_mapcount(folio) != folio_nr_pages(folio)) >> continue; >> >> if (pageout_anon_only_filter && !folio_test_anon(folio)) >> continue; >> >> - VM_BUG_ON_FOLIO(folio_test_large(folio), folio); >> - >> if (!pageout && pte_young(ptent)) { >> - ptent = ptep_get_and_clear_full(mm, addr, pte, >> - tlb->fullmm); >> - ptent = pte_mkold(ptent); >> - set_pte_at(mm, addr, pte, ptent); >> - tlb_remove_tlb_entry(tlb, pte, addr); >> + mkold_ptes(vma, addr, pte, nr); >> + tlb_remove_tlb_entries(tlb, pte, nr, addr); >> } >> >> /* >> diff --git a/mm/memory.c b/mm/memory.c >> index 9d844582ba38..b5b48f4cf2af 100644 >> --- a/mm/memory.c >> +++ b/mm/memory.c >> @@ -989,7 +989,7 @@ copy_present_ptes(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma >> flags |= FPB_IGNORE_SOFT_DIRTY; >> >> nr = folio_pte_batch(folio, addr, src_pte, pte, max_nr, flags, >> - &any_writable); >> + &any_writable, NULL); >> folio_ref_add(folio, nr); >> if (folio_test_anon(folio)) { >> if (unlikely(folio_try_dup_anon_rmap_ptes(folio, page, >> @@ -1553,7 +1553,7 @@ static inline int zap_present_ptes(struct mmu_gather *tlb, >> */ >> if (unlikely(folio_test_large(folio) && max_nr != 1)) { >> nr = folio_pte_batch(folio, addr, pte, ptent, max_nr, fpb_flags, >> - NULL); >> + NULL, NULL); >> >> zap_present_folio_ptes(tlb, vma, folio, page, pte, ptent, nr, >> addr, details, rss, force_flush, >> -- >> 2.25.1 >>