From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76797C433EF for ; Mon, 4 Apr 2022 21:50:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1381422AbiDDVt5 (ORCPT ); Mon, 4 Apr 2022 17:49:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43720 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1380409AbiDDUFH (ORCPT ); Mon, 4 Apr 2022 16:05:07 -0400 Received: from mail-pl1-x632.google.com (mail-pl1-x632.google.com [IPv6:2607:f8b0:4864:20::632]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BE01530576; Mon, 4 Apr 2022 13:03:10 -0700 (PDT) Received: by mail-pl1-x632.google.com with SMTP id m18so9046697plx.3; Mon, 04 Apr 2022 13:03:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=s/lBuFlDBU1GRGFU9YRcAqT+yGPT0++0CD70PJQOVug=; b=jV2+yjJwu1XGCS/IRhjcd4DZs/IJskOYfgOFxua1OeyC9E1XiBQ1wmird8bypPrcZd MoGBN5NQmHruIHbraHzI416gKP9u1Rk/wCKqGnIARi5LArpYMbo9qrGE7m+wZIrMYgB7 sQCOXxRoKp6iGqfMZBH/dbXVaI7kIT84aRYJK1SkaC2+vsBgI3iSqVcH8CfF7R8x9LgO WnRl0woQcCgIkuorfpvG3+oj8JjHG/unaFUIs1HTA9jTUoUOhNUCfrzFgi9TP0Lbt06K Ut85ccYdHygANYMcQX+k3Qz+za4rSK9z6yduraH5Uf2d5HYFHkA6SkVP4GD+n5IbvCPJ UC2A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=s/lBuFlDBU1GRGFU9YRcAqT+yGPT0++0CD70PJQOVug=; b=B+guag9GMmgsdMyNDdnW9ymXyMqp1yv8qw5DL8C7a1QOWsXzYDBIj8Ei795WuNVxze /SEOchA4bT7rjl6PdiF+9AFyiS3Xg0IUHlHIMKkkoA7NnaKSxtaK2x+x9pl0Oh46n1iV KyNjciiBzWEfTmoSEne6fJ21AdaEEGTbCTmKkYMzkQF6Ud4CjYWetzJ1SXCgKjMfHUDu ImQpqot+A39ehmQNVXhqEA3wjVqoSbqJpWuIQ/A/Fpx17BQmU7zQMXTHP4ahAXRtIXyu 5SbEbHJHpJCP976hl6PULDjHspuwOW2FNfpt4dxwPXDns0yPbiSZCEH06mF/r6OHPqRw UVeA== X-Gm-Message-State: AOAM530d58xQHA6ydf+T65Me3tmkJkru11/hBRpqq1pQexQj6qjnp078 MAB7fy/AbPSVmbQdaRo7QsI= X-Google-Smtp-Source: ABdhPJzg9Vfz5QEnjinv2EOkeMGgWfDWMGTZSI+KOlHEC65AKTLMoaowQLItcjuPWMR/DDhthX79vA== X-Received: by 2002:a17:902:7245:b0:156:20aa:1534 with SMTP id c5-20020a170902724500b0015620aa1534mr1673619pll.94.1649102590218; Mon, 04 Apr 2022 13:03:10 -0700 (PDT) Received: from localhost.localdomain (c-67-174-241-145.hsd1.ca.comcast.net. [67.174.241.145]) by smtp.gmail.com with ESMTPSA id bw17-20020a056a00409100b004fadad3b93esm12779295pfb.142.2022.04.04.13.03.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 Apr 2022 13:03:09 -0700 (PDT) From: Yang Shi To: vbabka@suse.cz, kirill.shutemov@linux.intel.com, linmiaohe@huawei.com, songliubraving@fb.com, riel@surriel.com, willy@infradead.org, ziy@nvidia.com, tytso@mit.edu, akpm@linux-foundation.org Cc: shy828301@gmail.com, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [v3 PATCH 5/8] mm: khugepaged: make khugepaged_enter() void function Date: Mon, 4 Apr 2022 13:02:47 -0700 Message-Id: <20220404200250.321455-6-shy828301@gmail.com> X-Mailer: git-send-email 2.26.3 In-Reply-To: <20220404200250.321455-1-shy828301@gmail.com> References: <20220404200250.321455-1-shy828301@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The most callers of khugepaged_enter() don't care about the return value. Only dup_mmap(), anonymous THP page fault and MADV_HUGEPAGE handle the error by returning -ENOMEM. Actually it is not harmful for them to ignore the error case either. It also sounds overkilling to fail fork() and page fault early due to khugepaged_enter() error, and MADV_HUGEPAGE does set VM_HUGEPAGE flag regardless of the error. Acked-by: Song Liu Signed-off-by: Yang Shi --- include/linux/khugepaged.h | 30 ++++++++++++------------------ kernel/fork.c | 4 +--- mm/huge_memory.c | 4 ++-- mm/khugepaged.c | 18 +++++++----------- 4 files changed, 22 insertions(+), 34 deletions(-) diff --git a/include/linux/khugepaged.h b/include/linux/khugepaged.h index 2fcc01891b47..0423d3619f26 100644 --- a/include/linux/khugepaged.h +++ b/include/linux/khugepaged.h @@ -12,10 +12,10 @@ extern struct attribute_group khugepaged_attr_group; extern int khugepaged_init(void); extern void khugepaged_destroy(void); extern int start_stop_khugepaged(void); -extern int __khugepaged_enter(struct mm_struct *mm); +extern void __khugepaged_enter(struct mm_struct *mm); extern void __khugepaged_exit(struct mm_struct *mm); -extern int khugepaged_enter_vma_merge(struct vm_area_struct *vma, - unsigned long vm_flags); +extern void khugepaged_enter_vma_merge(struct vm_area_struct *vma, + unsigned long vm_flags); extern void khugepaged_min_free_kbytes_update(void); #ifdef CONFIG_SHMEM extern void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr); @@ -40,11 +40,10 @@ static inline void collapse_pte_mapped_thp(struct mm_struct *mm, (transparent_hugepage_flags & \ (1<flags)) - return __khugepaged_enter(mm); - return 0; + __khugepaged_enter(mm); } static inline void khugepaged_exit(struct mm_struct *mm) @@ -53,7 +52,7 @@ static inline void khugepaged_exit(struct mm_struct *mm) __khugepaged_exit(mm); } -static inline int khugepaged_enter(struct vm_area_struct *vma, +static inline void khugepaged_enter(struct vm_area_struct *vma, unsigned long vm_flags) { if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags)) @@ -62,27 +61,22 @@ static inline int khugepaged_enter(struct vm_area_struct *vma, (khugepaged_req_madv() && (vm_flags & VM_HUGEPAGE))) && !(vm_flags & VM_NOHUGEPAGE) && !test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) - if (__khugepaged_enter(vma->vm_mm)) - return -ENOMEM; - return 0; + __khugepaged_enter(vma->vm_mm); } #else /* CONFIG_TRANSPARENT_HUGEPAGE */ -static inline int khugepaged_fork(struct mm_struct *mm, struct mm_struct *oldmm) +static inline void khugepaged_fork(struct mm_struct *mm, struct mm_struct *oldmm) { - return 0; } static inline void khugepaged_exit(struct mm_struct *mm) { } -static inline int khugepaged_enter(struct vm_area_struct *vma, - unsigned long vm_flags) +static inline void khugepaged_enter(struct vm_area_struct *vma, + unsigned long vm_flags) { - return 0; } -static inline int khugepaged_enter_vma_merge(struct vm_area_struct *vma, - unsigned long vm_flags) +static inline void khugepaged_enter_vma_merge(struct vm_area_struct *vma, + unsigned long vm_flags) { - return 0; } static inline void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr) diff --git a/kernel/fork.c b/kernel/fork.c index 9796897560ab..0d13baf86650 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -612,9 +612,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, retval = ksm_fork(mm, oldmm); if (retval) goto out; - retval = khugepaged_fork(mm, oldmm); - if (retval) - goto out; + khugepaged_fork(mm, oldmm); prev = NULL; for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 183b793fd28e..4fd5a6a79d44 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -725,8 +725,8 @@ vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) return VM_FAULT_FALLBACK; if (unlikely(anon_vma_prepare(vma))) return VM_FAULT_OOM; - if (unlikely(khugepaged_enter(vma, vma->vm_flags))) - return VM_FAULT_OOM; + khugepaged_enter(vma, vma->vm_flags); + if (!(vmf->flags & FAULT_FLAG_WRITE) && !mm_forbids_zeropage(vma->vm_mm) && transparent_hugepage_use_zero_page()) { diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 609c1bc0a027..b69eda934d70 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -365,8 +365,7 @@ int hugepage_madvise(struct vm_area_struct *vma, * register it here without waiting a page fault that * may not happen any time soon. */ - if (khugepaged_enter_vma_merge(vma, *vm_flags)) - return -ENOMEM; + khugepaged_enter_vma_merge(vma, *vm_flags); break; case MADV_NOHUGEPAGE: *vm_flags &= ~VM_HUGEPAGE; @@ -475,20 +474,20 @@ static bool hugepage_vma_check(struct vm_area_struct *vma, return true; } -int __khugepaged_enter(struct mm_struct *mm) +void __khugepaged_enter(struct mm_struct *mm) { struct mm_slot *mm_slot; int wakeup; mm_slot = alloc_mm_slot(); if (!mm_slot) - return -ENOMEM; + return; /* __khugepaged_exit() must not run from under us */ VM_BUG_ON_MM(khugepaged_test_exit(mm), mm); if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) { free_mm_slot(mm_slot); - return 0; + return; } spin_lock(&khugepaged_mm_lock); @@ -504,11 +503,9 @@ int __khugepaged_enter(struct mm_struct *mm) mmgrab(mm); if (wakeup) wake_up_interruptible(&khugepaged_wait); - - return 0; } -int khugepaged_enter_vma_merge(struct vm_area_struct *vma, +void khugepaged_enter_vma_merge(struct vm_area_struct *vma, unsigned long vm_flags) { unsigned long hstart, hend; @@ -519,13 +516,12 @@ int khugepaged_enter_vma_merge(struct vm_area_struct *vma, * file-private shmem THP is not supported. */ if (!hugepage_vma_check(vma, vm_flags)) - return 0; + return; hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; hend = vma->vm_end & HPAGE_PMD_MASK; if (hstart < hend) - return khugepaged_enter(vma, vm_flags); - return 0; + khugepaged_enter(vma, vm_flags); } void __khugepaged_exit(struct mm_struct *mm) -- 2.26.3