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X-IronPort-AV: E=McAfee;i="6500,9779,10604"; a="325043350" X-IronPort-AV: E=Sophos;i="5.97,254,1669104000"; d="scan'208";a="325043350" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jan 2023 16:40:22 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10604"; a="727085675" X-IronPort-AV: E=Sophos;i="5.97,254,1669104000"; d="scan'208";a="727085675" Received: from yhuang6-desk2.sh.intel.com (HELO yhuang6-desk2.ccr.corp.intel.com) ([10.238.208.55]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jan 2023 16:40:12 -0800 From: "Huang, Ying" To: Longlong Xia Cc: , , , , , Subject: Re: [PATCH] mm/swapfile: add cond_resched() in get_swap_pages() References: <20230128094757.1060525-1-xialonglong1@huawei.com> Date: Sun, 29 Jan 2023 08:39:21 +0800 In-Reply-To: <20230128094757.1060525-1-xialonglong1@huawei.com> (Longlong Xia's message of "Sat, 28 Jan 2023 09:47:57 +0000") Message-ID: <87a622cgxy.fsf@yhuang6-desk2.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii X-Rspamd-Queue-Id: B2686100007 X-Stat-Signature: rtqzbqm1tprnmida1twwn378gdeyqg8h X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1674952824-86364 X-HE-Meta: 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 jCOSIEkB wv6MX6ZvABZEN///KATIB9jTzqpbNqoSxwcz9ZWAX2EaAtEj8+HsJ3qQPA8fyA+BvKxJ+u0LfAV15XbdOFN38K97R3Q23R+prVeCmJ1WQkm5SC1rPXTMkzrhcy+NIQbmlKmN9+5J2fxJSv+Bl/K9QfDrBGX1CKYBtp53sHVXrvG7PWqtL8fAqrV+IZ/1jGrsoFtWSFQAgiyyctzTgrIWxwTv4menKFcG6f/kHj+sBgl3UOG+BnO7InMVL8Xtha8qRP3dB 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: Longlong Xia writes: > The softlockup still occurs in get_swap_pages() under memory pressure. > 64 CPU cores, 64GB memory, and 28 zram devices, the disksize of each > zram device is 50MB with same priority as si. Use the stress-ng tool > to increase memory pressure, causing the system to oom frequently. > > The plist_for_each_entry_safe() loops in get_swap_pages() could reach > tens of thousands of times to find available space (extreme case: > cond_resched() is not called in scan_swap_map_slots()). Let's add > cond_resched() into get_swap_pages() when failed to find available > space to avoid softlockup. > > Signed-off-by: Longlong Xia Looks good to me. Thanks! Reviewed-by: "Huang, Ying" > --- > mm/swapfile.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/swapfile.c b/mm/swapfile.c > index 908a529bca12..4fa440e87cd6 100644 > --- a/mm/swapfile.c > +++ b/mm/swapfile.c > @@ -1100,6 +1100,7 @@ int get_swap_pages(int n_goal, swp_entry_t swp_entries[], int entry_size) > goto check_out; > pr_debug("scan_swap_map of si %d failed to find offset\n", > si->type); > + cond_resched(); > > spin_lock(&swap_avail_lock); > nextsi: