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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A0C93CAC583 for ; Tue, 9 Sep 2025 16:30:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id EF7048E0009; Tue, 9 Sep 2025 12:30:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id EA6758E0001; Tue, 9 Sep 2025 12:30:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D96138E0009; Tue, 9 Sep 2025 12:30:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id C775F8E0001 for ; Tue, 9 Sep 2025 12:30:21 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 7C5FD160566 for ; Tue, 9 Sep 2025 16:30:21 +0000 (UTC) X-FDA: 83870249442.10.022F757 Received: from mail-ed1-f43.google.com (mail-ed1-f43.google.com [209.85.208.43]) by imf11.hostedemail.com (Postfix) with ESMTP id 7D4194001B for ; Tue, 9 Sep 2025 16:30:19 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=v5LjQQev; spf=pass (imf11.hostedemail.com: domain of surenb@google.com designates 209.85.208.43 as permitted sender) smtp.mailfrom=surenb@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1757435419; 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-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=FHJHNlNOaMOyVoBAHvHo+maMOWkTYnhe6QXua4Kxw8s=; b=KPfTWR5vumU38JystjP3VXsAzpOfXGS8Vfew5PneM9+eElSeFGGxwRCr8BgwSP4P6ldV68 GVUSg7m0GUOXz+pGPjejxdSGF/u/Ko7P9q77ReXhbHOjDCx8gAG/mfqY7EJwrHO+0KAebQ TsGUR95xxDQNoycbohB/9CGGcxNNe10= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=v5LjQQev; spf=pass (imf11.hostedemail.com: domain of surenb@google.com designates 209.85.208.43 as permitted sender) smtp.mailfrom=surenb@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1757435419; a=rsa-sha256; cv=none; b=vPBhEGpRJQN0fAzGv/sI8iSd27zVOn2GgZ2OnnReIO1YOR+QTaU8NNeSH8KYImqGllpphF rSdmvVBi6lrLBGq4o39OTV6VE6uisxbm7UPu9E4UfumbG4V/LwgIRflMAJXFRu1ISaK2Ce ORjcKWCwIUNkybSi6uZ02T0p35+qAew= Received: by mail-ed1-f43.google.com with SMTP id 4fb4d7f45d1cf-621c6ae39b5so50a12.0 for ; Tue, 09 Sep 2025 09:30:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1757435418; x=1758040218; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=FHJHNlNOaMOyVoBAHvHo+maMOWkTYnhe6QXua4Kxw8s=; b=v5LjQQevBzlKiKkhi6tgGZFUpi2nqAs/q29eIPwuW62DEKvFT0fTqOJh7r+T/2fNvF xVTyxov0u3WDfwDArLZM+kh6yDLzX8x1r1he+lxbWzqVtjVlTsNJgnaTB0N4FnbuGBZW s3xhNFTVVO0uCBSKZxCYj3TuSpdj684zu5kJsW1eubJ6vgeH1s2umrqgHx24kH4Nx/OD f37nbkT58oOAoX1Cyst28l9GzLCeynAVdkkAX3vCLqC7y233TpkIS3TrvyBqPFc2duun E75g+76ZfHF/I1FoZdMspK6DiMsonw7ueLDYNCPpwEP4Fze6tnLL/xvoIsovswBDg92L Vhww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757435418; x=1758040218; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=FHJHNlNOaMOyVoBAHvHo+maMOWkTYnhe6QXua4Kxw8s=; b=v+y187iIbERej4/1VVQU8Y9y4BWbCHqMUeRyXc7TSemAR16PVjUmyENW6mIlfjyb1Q 5nJ9u7W9g7ZjKSxVtVUbN+kyylx8GnxlX92F7FqsHyxdcNLYKsVz5Ync6z4wtzk3aqzQ daz5B1lhprVoXwycA2ENJuOcCuCBW7Mc05UXRJbM8fp9KNgm+ZMpKYw7TbjIJW2GF5um VUwVqJG6p6Z4WhAi9XQLcjD6FYPNOJlJaMrJ27V1f2hQs0dxtI1yzn+7uC+Kxe+Sk9Ju yFZmeBeFHSY6XDoDlQW6khkQa31/xq8QmGSopJc8r7yCUGr3OoJuxhXYJrVq0NDqWQGh fXCA== X-Forwarded-Encrypted: i=1; AJvYcCX6c91o7JbSKrTWHXPtn/8/QxN3hk3RNMem1P/Vz3a3IJGflroBTkvSHz2EydCmWwSSuAUxlkFZZQ==@kvack.org X-Gm-Message-State: AOJu0Yxv1sHz9CgNel6nY2zvSABJzQRNx1owp3Zyp7ynrbp/MhpZXKY/ nIuY8H036ctEQu0uEm9RXl1noHdzq7fag2xu1diDpEGMBy4Q6VaoWBBwp6saqHYAL7bwke9od16 Pu4UuZ0XXvyZPRXO9ok+u64gEU2UEjXdAOT3bh4Vh X-Gm-Gg: ASbGncvSe38rGgYMu+FA5Bf7AS8RsOBbFpK2F1njKnkWdYOG6hx3b//d8Iynpf2eTV7 gWE5cQPoIjiO/1lSc95ajyAYEOARSFOnt/nls8rbMfurRVnn2psSnEvEweGiEvBKAyZb7Z52k9W jK5tlqVLCcjvGerMN/c9la3urr3oPC0c+Aumxt4X41621Tx8il0hlT+fVyxLfH1flgTemMfVqa4 ah5P8wnBQZgmmmwFCp3KqyE86+7qLzhqEdV+A7DxUkS X-Google-Smtp-Source: AGHT+IFbWAiDVlID1hnyzgk511dH5neUI5OLeqIjJ12rVpIAxmuNfaLD/tbpY5u2JY5Vm3Sgx+0SMd1CXr4QkvXrU5o= X-Received: by 2002:a05:6402:4541:b0:61e:c6ae:7a58 with SMTP id 4fb4d7f45d1cf-626a1f9b6a2mr267968a12.0.1757435417828; Tue, 09 Sep 2025 09:30:17 -0700 (PDT) MIME-Version: 1.0 References: <20250909090659.26400-1-zhongjinji@honor.com> <20250909090659.26400-4-zhongjinji@honor.com> In-Reply-To: From: Suren Baghdasaryan Date: Tue, 9 Sep 2025 09:30:04 -0700 X-Gm-Features: AS18NWAA3gXYcKcu6BJyCASw1JY2Tg5yKdBcwtKDAMzJA7pfY6LSVb0ENi0HJp8 Message-ID: Subject: Re: [PATCH v8 3/3] mm/oom_kill: The OOM reaper traverses the VMA maple tree in reverse order To: zhongjinji Cc: mhocko@suse.com, rientjes@google.com, shakeel.butt@linux.dev, akpm@linux-foundation.org, tglx@linutronix.de, liam.howlett@oracle.com, lorenzo.stoakes@oracle.com, lenb@kernel.org, rafael@kernel.org, pavel@kernel.org, linux-mm@kvack.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, liulu.liu@honor.com, feng.han@honor.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 7D4194001B X-Stat-Signature: pryi7w58ujdqxpkdj8ej69uhb5y8ew3r X-HE-Tag: 1757435419-664418 X-HE-Meta: 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 +WmkFIXk HWUrTTy5xuSAaceeq5KUsdHHVES9Zyd/acpVNB3i4U0lfOshSE0VuEb+nhD6BoQqCVI1CSnX9XOaTUNfu/fQ6ybWntEiP04xIS+TSSnPdqAF3jZaZJZjtLRMF4uYoo0P366pGV93Wu8T67AZfDIdFR67uG4eITmcAK7dgClez4HN3IiThUDxgbAkjzC0lJdmGSCeyu+xS6/TDluJ1ljkJXxOsTzcZwZwv4JJEqEeAm0w5u1dURbWk8OUCkQUwCO+Fe5weqOCmbFxKi+V7yVJZ/L7Og5Skn4CCncGDQnmYOFc0/XqxIDZvjETIytrEDd+QoMIb7ZCAea4zjE0dcSMH3q0e5lxAh1/ckJw+l+St69mhxnPdc8A5cZ0yCzPnLaPjNjwLk5WO/uPF/vdO7be4Io37Eg== 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: On Tue, Sep 9, 2025 at 9:29=E2=80=AFAM Suren Baghdasaryan wrote: > > On Tue, Sep 9, 2025 at 2:07=E2=80=AFAM zhongjinji = wrote: > > > > Although the oom_reaper is delayed and it gives the oom victim chance t= o > > clean up its address space this might take a while especially for > > processes with a large address space footprint. In those cases > > oom_reaper might start racing with the dying task and compete for share= d > > resources - e.g. page table lock contention has been observed. > > > > Reduce those races by reaping the oom victim from the other end of the > > address space. > > > > It is also a significant improvement for process_mrelease(). When a pro= cess > > is killed, process_mrelease is used to reap the killed process and ofte= n > > runs concurrently with the dying task. The test data shows that after > > applying the patch, lock contention is greatly reduced during the proce= dure > > of reaping the killed process. > > > > The test is based on arm64. > > > > Without the patch: > > |--99.57%-- oom_reaper > > | |--0.28%-- [hit in function] > > | |--73.58%-- unmap_page_range > > | | |--8.67%-- [hit in function] > > | | |--41.59%-- __pte_offset_map_lock > > | | |--29.47%-- folio_remove_rmap_ptes > > | | |--16.11%-- tlb_flush_mmu > > | | |--1.66%-- folio_mark_accessed > > | | |--0.74%-- free_swap_and_cache_nr > > | | |--0.69%-- __tlb_remove_folio_pages > > | |--19.94%-- tlb_finish_mmu > > | |--3.21%-- folio_remove_rmap_ptes > > | |--1.16%-- __tlb_remove_folio_pages > > | |--1.16%-- folio_mark_accessed > > | |--0.36%-- __pte_offset_map_lock > > > > With the patch: > > |--99.53%-- oom_reaper > > | |--55.77%-- unmap_page_range > > | | |--20.49%-- [hit in function] > > | | |--58.30%-- folio_remove_rmap_ptes > > | | |--11.48%-- tlb_flush_mmu > > | | |--3.33%-- folio_mark_accessed > > | | |--2.65%-- __tlb_remove_folio_pages > > | | |--1.37%-- _raw_spin_lock > > | | |--0.68%-- __mod_lruvec_page_state > > | | |--0.51%-- __pte_offset_map_lock > > | |--32.21%-- tlb_finish_mmu > > | |--6.93%-- folio_remove_rmap_ptes > > | |--1.90%-- __tlb_remove_folio_pages > > | |--1.55%-- folio_mark_accessed > > | |--0.69%-- __pte_offset_map_lock > > > > Signed-off-by: zhongjinji > > Reviewed-by: Liam R. Howlett > > Reviewed-by: Lorenzo Stoakes > > Acked-by: Shakeel Butt > > Acked-by: Michal Hocko > > Reviewed-by: Suren Baghdsaryan Apparently I misspelled my own last name :) Reviewed-by: Suren Baghdasaryan > > > --- > > mm/oom_kill.c | 10 ++++++++-- > > 1 file changed, 8 insertions(+), 2 deletions(-) > > > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > > index ffa50a1f0132..52d285da5ba4 100644 > > --- a/mm/oom_kill.c > > +++ b/mm/oom_kill.c > > @@ -516,7 +516,7 @@ static bool __oom_reap_task_mm(struct mm_struct *mm= ) > > { > > struct vm_area_struct *vma; > > bool ret =3D true; > > - VMA_ITERATOR(vmi, mm, 0); > > + MA_STATE(mas, &mm->mm_mt, ULONG_MAX, ULONG_MAX); > > > > /* > > * Tell all users of get_user/copy_from_user etc... that the co= ntent > > @@ -526,7 +526,13 @@ static bool __oom_reap_task_mm(struct mm_struct *m= m) > > */ > > set_bit(MMF_UNSTABLE, &mm->flags); > > > > - for_each_vma(vmi, vma) { > > + /* > > + * It might start racing with the dying task and compete for sh= ared > > + * resources - e.g. page table lock contention has been observe= d. > > + * Reduce those races by reaping the oom victim from the other = end > > + * of the address space. > > + */ > > + mas_for_each_rev(&mas, vma, 0) { > > if (vma->vm_flags & (VM_HUGETLB|VM_PFNMAP)) > > continue; > > > > -- > > 2.17.1 > >