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 X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_NEOMUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DDC4AC04E87 for ; Mon, 20 May 2019 14:26:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AC08D214AE for ; Mon, 20 May 2019 14:26:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733065AbfETO0i (ORCPT ); Mon, 20 May 2019 10:26:38 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:46257 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730445AbfETO0h (ORCPT ); Mon, 20 May 2019 10:26:37 -0400 Received: by mail-wr1-f65.google.com with SMTP id r7so14813264wrr.13 for ; Mon, 20 May 2019 07:26:35 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=6iQOSKIYW9UJpBK8lU1MTIA5BRMtl8//awGT4QEdgQU=; b=AaRDAJRTuVzSHKNXcpKmHm1GKyHYkuA5J/tBuapdDPRbwolRJyaD3dSFafHVVNy4gE ZSVIYDwc/GFOX53z6F2ef/eBwgC1mhBttll/rFvT5odEQm7oo2dCkA/F29Gmj/4fZ3Qu RNyeREWHYVhFrdM3b281rXNsBSxV7+IoVfp+OZJdB/aGGzKARYKBHoHqFeQ/Kzwaxl0W iuneixDInG3zSecef3yyWBWoBM2CI2kwkEMDEHHaAn1sceSissH6FLFCcULFRbT1WO5P qDgs5cDl6IZC3B2qhX6ZPUx10Z0KGIm+0FxG8BaBpLQde62DuZpRTahWbUGBi/QwCB60 /W8Q== X-Gm-Message-State: APjAAAWpZXWeD6p5s1DIpGxJtH3m0V3jo0hY8meh4Nn75j5TCTiNpWyx Vn8TkGrflD/DKRfzS0889nPCpg== X-Google-Smtp-Source: APXvYqySOkxSj8JyFEtIzQCgWBXM331B+o90vzDQn3uePg6N3fyz2EtpbrXMGg7VhCP1H1/7sHYsSg== X-Received: by 2002:a5d:468b:: with SMTP id u11mr9131773wrq.276.1558362394873; Mon, 20 May 2019 07:26:34 -0700 (PDT) Received: from localhost (nat-pool-brq-t.redhat.com. [213.175.37.10]) by smtp.gmail.com with ESMTPSA id 16sm10265202wmx.45.2019.05.20.07.26.33 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 20 May 2019 07:26:34 -0700 (PDT) Date: Mon, 20 May 2019 16:26:33 +0200 From: Oleksandr Natalenko To: Minchan Kim Cc: Andrew Morton , LKML , linux-mm , Michal Hocko , Johannes Weiner , Tim Murray , Joel Fernandes , Suren Baghdasaryan , Daniel Colascione , Shakeel Butt , Sonny Rao , Brian Geffon Subject: Re: [RFC 4/7] mm: factor out madvise's core functionality Message-ID: <20190520142633.x5d27gk454qruc4o@butterfly.localdomain> References: <20190520035254.57579-1-minchan@kernel.org> <20190520035254.57579-5-minchan@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190520035254.57579-5-minchan@kernel.org> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi. On Mon, May 20, 2019 at 12:52:51PM +0900, Minchan Kim wrote: > This patch factor out madvise's core functionality so that upcoming > patch can reuse it without duplication. > > It shouldn't change any behavior. > > Signed-off-by: Minchan Kim > --- > mm/madvise.c | 168 +++++++++++++++++++++++++++------------------------ > 1 file changed, 89 insertions(+), 79 deletions(-) > > diff --git a/mm/madvise.c b/mm/madvise.c > index 9a6698b56845..119e82e1f065 100644 > --- a/mm/madvise.c > +++ b/mm/madvise.c > @@ -742,7 +742,8 @@ static long madvise_dontneed_single_vma(struct vm_area_struct *vma, > return 0; > } > > -static long madvise_dontneed_free(struct vm_area_struct *vma, > +static long madvise_dontneed_free(struct task_struct *tsk, > + struct vm_area_struct *vma, > struct vm_area_struct **prev, > unsigned long start, unsigned long end, > int behavior) > @@ -754,8 +755,8 @@ static long madvise_dontneed_free(struct vm_area_struct *vma, > if (!userfaultfd_remove(vma, start, end)) { > *prev = NULL; /* mmap_sem has been dropped, prev is stale */ > > - down_read(¤t->mm->mmap_sem); > - vma = find_vma(current->mm, start); > + down_read(&tsk->mm->mmap_sem); > + vma = find_vma(tsk->mm, start); > if (!vma) > return -ENOMEM; > if (start < vma->vm_start) { > @@ -802,7 +803,8 @@ static long madvise_dontneed_free(struct vm_area_struct *vma, > * Application wants to free up the pages and associated backing store. > * This is effectively punching a hole into the middle of a file. > */ > -static long madvise_remove(struct vm_area_struct *vma, > +static long madvise_remove(struct task_struct *tsk, > + struct vm_area_struct *vma, > struct vm_area_struct **prev, > unsigned long start, unsigned long end) > { > @@ -836,13 +838,13 @@ static long madvise_remove(struct vm_area_struct *vma, > get_file(f); > if (userfaultfd_remove(vma, start, end)) { > /* mmap_sem was not released by userfaultfd_remove() */ > - up_read(¤t->mm->mmap_sem); > + up_read(&tsk->mm->mmap_sem); > } > error = vfs_fallocate(f, > FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, > offset, end - start); > fput(f); > - down_read(¤t->mm->mmap_sem); > + down_read(&tsk->mm->mmap_sem); > return error; > } > > @@ -916,12 +918,13 @@ static int madvise_inject_error(int behavior, > #endif What about madvise_inject_error() and get_user_pages_fast() in it please? > > static long > -madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev, > - unsigned long start, unsigned long end, int behavior) > +madvise_vma(struct task_struct *tsk, struct vm_area_struct *vma, > + struct vm_area_struct **prev, unsigned long start, > + unsigned long end, int behavior) > { > switch (behavior) { > case MADV_REMOVE: > - return madvise_remove(vma, prev, start, end); > + return madvise_remove(tsk, vma, prev, start, end); > case MADV_WILLNEED: > return madvise_willneed(vma, prev, start, end); > case MADV_COOL: > @@ -930,7 +933,8 @@ madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev, > return madvise_cold(vma, start, end); > case MADV_FREE: > case MADV_DONTNEED: > - return madvise_dontneed_free(vma, prev, start, end, behavior); > + return madvise_dontneed_free(tsk, vma, prev, start, > + end, behavior); > default: > return madvise_behavior(vma, prev, start, end, behavior); > } > @@ -974,68 +978,8 @@ madvise_behavior_valid(int behavior) > } > } > > -/* > - * The madvise(2) system call. > - * > - * Applications can use madvise() to advise the kernel how it should > - * handle paging I/O in this VM area. The idea is to help the kernel > - * use appropriate read-ahead and caching techniques. The information > - * provided is advisory only, and can be safely disregarded by the > - * kernel without affecting the correct operation of the application. > - * > - * behavior values: > - * MADV_NORMAL - the default behavior is to read clusters. This > - * results in some read-ahead and read-behind. > - * MADV_RANDOM - the system should read the minimum amount of data > - * on any access, since it is unlikely that the appli- > - * cation will need more than what it asks for. > - * MADV_SEQUENTIAL - pages in the given range will probably be accessed > - * once, so they can be aggressively read ahead, and > - * can be freed soon after they are accessed. > - * MADV_WILLNEED - the application is notifying the system to read > - * some pages ahead. > - * MADV_DONTNEED - the application is finished with the given range, > - * so the kernel can free resources associated with it. > - * MADV_FREE - the application marks pages in the given range as lazy free, > - * where actual purges are postponed until memory pressure happens. > - * MADV_REMOVE - the application wants to free up the given range of > - * pages and associated backing store. > - * MADV_DONTFORK - omit this area from child's address space when forking: > - * typically, to avoid COWing pages pinned by get_user_pages(). > - * MADV_DOFORK - cancel MADV_DONTFORK: no longer omit this area when forking. > - * MADV_WIPEONFORK - present the child process with zero-filled memory in this > - * range after a fork. > - * MADV_KEEPONFORK - undo the effect of MADV_WIPEONFORK > - * MADV_HWPOISON - trigger memory error handler as if the given memory range > - * were corrupted by unrecoverable hardware memory failure. > - * MADV_SOFT_OFFLINE - try to soft-offline the given range of memory. > - * MADV_MERGEABLE - the application recommends that KSM try to merge pages in > - * this area with pages of identical content from other such areas. > - * MADV_UNMERGEABLE- cancel MADV_MERGEABLE: no longer merge pages with others. > - * MADV_HUGEPAGE - the application wants to back the given range by transparent > - * huge pages in the future. Existing pages might be coalesced and > - * new pages might be allocated as THP. > - * MADV_NOHUGEPAGE - mark the given range as not worth being backed by > - * transparent huge pages so the existing pages will not be > - * coalesced into THP and new pages will not be allocated as THP. > - * MADV_DONTDUMP - the application wants to prevent pages in the given range > - * from being included in its core dump. > - * MADV_DODUMP - cancel MADV_DONTDUMP: no longer exclude from core dump. > - * > - * return values: > - * zero - success > - * -EINVAL - start + len < 0, start is not page-aligned, > - * "behavior" is not a valid value, or application > - * is attempting to release locked or shared pages, > - * or the specified address range includes file, Huge TLB, > - * MAP_SHARED or VMPFNMAP range. > - * -ENOMEM - addresses in the specified range are not currently > - * mapped, or are outside the AS of the process. > - * -EIO - an I/O error occurred while paging in data. > - * -EBADF - map exists, but area maps something that isn't a file. > - * -EAGAIN - a kernel resource was temporarily unavailable. > - */ > -SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior) > +static int madvise_core(struct task_struct *tsk, unsigned long start, > + size_t len_in, int behavior) > { > unsigned long end, tmp; > struct vm_area_struct *vma, *prev; > @@ -1071,10 +1015,10 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior) > > write = madvise_need_mmap_write(behavior); > if (write) { > - if (down_write_killable(¤t->mm->mmap_sem)) > + if (down_write_killable(&tsk->mm->mmap_sem)) > return -EINTR; > } else { > - down_read(¤t->mm->mmap_sem); > + down_read(&tsk->mm->mmap_sem); > } > > /* > @@ -1082,7 +1026,7 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior) > * ranges, just ignore them, but return -ENOMEM at the end. > * - different from the way of handling in mlock etc. > */ > - vma = find_vma_prev(current->mm, start, &prev); > + vma = find_vma_prev(tsk->mm, start, &prev); > if (vma && start > vma->vm_start) > prev = vma; > > @@ -1107,7 +1051,7 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior) > tmp = end; > > /* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */ > - error = madvise_vma(vma, &prev, start, tmp, behavior); > + error = madvise_vma(tsk, vma, &prev, start, tmp, behavior); > if (error) > goto out; > start = tmp; > @@ -1119,14 +1063,80 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior) > if (prev) > vma = prev->vm_next; > else /* madvise_remove dropped mmap_sem */ > - vma = find_vma(current->mm, start); > + vma = find_vma(tsk->mm, start); > } > out: > blk_finish_plug(&plug); > if (write) > - up_write(¤t->mm->mmap_sem); > + up_write(&tsk->mm->mmap_sem); > else > - up_read(¤t->mm->mmap_sem); > + up_read(&tsk->mm->mmap_sem); > > return error; > } > + > +/* > + * The madvise(2) system call. > + * > + * Applications can use madvise() to advise the kernel how it should > + * handle paging I/O in this VM area. The idea is to help the kernel > + * use appropriate read-ahead and caching techniques. The information > + * provided is advisory only, and can be safely disregarded by the > + * kernel without affecting the correct operation of the application. > + * > + * behavior values: > + * MADV_NORMAL - the default behavior is to read clusters. This > + * results in some read-ahead and read-behind. > + * MADV_RANDOM - the system should read the minimum amount of data > + * on any access, since it is unlikely that the appli- > + * cation will need more than what it asks for. > + * MADV_SEQUENTIAL - pages in the given range will probably be accessed > + * once, so they can be aggressively read ahead, and > + * can be freed soon after they are accessed. > + * MADV_WILLNEED - the application is notifying the system to read > + * some pages ahead. > + * MADV_DONTNEED - the application is finished with the given range, > + * so the kernel can free resources associated with it. > + * MADV_FREE - the application marks pages in the given range as lazy free, > + * where actual purges are postponed until memory pressure happens. > + * MADV_REMOVE - the application wants to free up the given range of > + * pages and associated backing store. > + * MADV_DONTFORK - omit this area from child's address space when forking: > + * typically, to avoid COWing pages pinned by get_user_pages(). > + * MADV_DOFORK - cancel MADV_DONTFORK: no longer omit this area when forking. > + * MADV_WIPEONFORK - present the child process with zero-filled memory in this > + * range after a fork. > + * MADV_KEEPONFORK - undo the effect of MADV_WIPEONFORK > + * MADV_HWPOISON - trigger memory error handler as if the given memory range > + * were corrupted by unrecoverable hardware memory failure. > + * MADV_SOFT_OFFLINE - try to soft-offline the given range of memory. > + * MADV_MERGEABLE - the application recommends that KSM try to merge pages in > + * this area with pages of identical content from other such areas. > + * MADV_UNMERGEABLE- cancel MADV_MERGEABLE: no longer merge pages with others. > + * MADV_HUGEPAGE - the application wants to back the given range by transparent > + * huge pages in the future. Existing pages might be coalesced and > + * new pages might be allocated as THP. > + * MADV_NOHUGEPAGE - mark the given range as not worth being backed by > + * transparent huge pages so the existing pages will not be > + * coalesced into THP and new pages will not be allocated as THP. > + * MADV_DONTDUMP - the application wants to prevent pages in the given range > + * from being included in its core dump. > + * MADV_DODUMP - cancel MADV_DONTDUMP: no longer exclude from core dump. > + * > + * return values: > + * zero - success > + * -EINVAL - start + len < 0, start is not page-aligned, > + * "behavior" is not a valid value, or application > + * is attempting to release locked or shared pages, > + * or the specified address range includes file, Huge TLB, > + * MAP_SHARED or VMPFNMAP range. > + * -ENOMEM - addresses in the specified range are not currently > + * mapped, or are outside the AS of the process. > + * -EIO - an I/O error occurred while paging in data. > + * -EBADF - map exists, but area maps something that isn't a file. > + * -EAGAIN - a kernel resource was temporarily unavailable. > + */ > +SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior) > +{ > + return madvise_core(current, start, len_in, behavior); > +} > -- > 2.21.0.1020.gf2820cf01a-goog > -- Best regards, Oleksandr Natalenko (post-factum) Senior Software Maintenance Engineer