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[209.85.220.65]) by mx.google.com with SMTPS id g5sor33927445pgs.55.2019.07.29.00.10.45 for (Google Transport Security); Mon, 29 Jul 2019 00:10:45 -0700 (PDT) Received-SPF: pass (google.com: domain of minchan.kim@gmail.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=GbpKZO+1; spf=pass (google.com: domain of minchan.kim@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=minchan.kim@gmail.com; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=MP9bWqLglik/G7ydzgpH6qxtoOPjTnKjIEZbq35U0w8=; b=GbpKZO+1qWJF5PiJfpJI+X1d49LQDhRSEjabzM4QoQoxyPC/ykpjviHT067xaP4ur9 Q8obYhARMbKPZN2+MUi7KS43dNzPuKR0TZprepoLgqL8dD+kKWF7yA9cJNsgLDuWAebQ 0gfhz135PdhcmBO/tQ+4kqQB0rCDV9+w4pqCBPOlGYoT71nY1o7yaEyjkMRD7hBR1P5C yhPQ3G7yavjMpqxRD9NSxGBh3X0PbYCwpznGkB3NPHVGfrc0PBFT5fj7o+pFYkL6z117 bVr0nUhG4ri8CNjgE/N7liJe66keFa5uc+KTxXZUTrXVXIUPyjeXYn3corPlUzoq8C+Z tqKg== X-Google-Smtp-Source: APXvYqxnzOd4PuafCgb1AfLhTACUQYfJQLs65HMwphdh3OAlLdZAE/tGNxyoyJ+8bK3MjIY85KClhg== X-Received: by 2002:a63:2784:: with SMTP id n126mr99458545pgn.92.1564384245259; Mon, 29 Jul 2019 00:10:45 -0700 (PDT) Received: from bbox-2.seo.corp.google.com ([2401:fa00:d:0:98f1:8b3d:1f37:3e8]) by smtp.gmail.com with ESMTPSA id i124sm111028139pfe.61.2019.07.29.00.10.41 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Mon, 29 Jul 2019 00:10:44 -0700 (PDT) From: Minchan Kim To: Andrew Morton Cc: LKML , linux-mm , Minchan Kim , Miguel de Dios , Wei Wang , Michal Hocko , Johannes Weiner , Mel Gorman Subject: [PATCH] mm: release the spinlock on zap_pte_range Date: Mon, 29 Jul 2019 16:10:37 +0900 Message-Id: <20190729071037.241581-1-minchan@kernel.org> X-Mailer: git-send-email 2.22.0.709.g102302147b-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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: In our testing(carmera recording), Miguel and Wei found unmap_page_range takes above 6ms with preemption disabled easily. When I see that, the reason is it holds page table spinlock during entire 512 page operation in a PMD. 6.2ms is never trivial for user experince if RT task couldn't run in the time because it could make frame drop or glitch audio problem. This patch adds preemption point like coyp_pte_range. Reported-by: Miguel de Dios Reported-by: Wei Wang Cc: Michal Hocko Cc: Johannes Weiner Cc: Mel Gorman Signed-off-by: Minchan Kim --- mm/memory.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 2e796372927fd..bc3e0c5e4f89b 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1007,6 +1007,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, struct zap_details *details) { struct mm_struct *mm = tlb->mm; + int progress = 0; int force_flush = 0; int rss[NR_MM_COUNTERS]; spinlock_t *ptl; @@ -1022,7 +1023,16 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, flush_tlb_batched_pending(mm); arch_enter_lazy_mmu_mode(); do { - pte_t ptent = *pte; + pte_t ptent; + + if (progress >= 32) { + progress = 0; + if (need_resched()) + break; + } + progress += 8; + + ptent = *pte; if (pte_none(ptent)) continue; @@ -1123,8 +1133,11 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, if (force_flush) { force_flush = 0; tlb_flush_mmu(tlb); - if (addr != end) - goto again; + } + + if (addr != end) { + progress = 0; + goto again; } return addr; -- 2.22.0.709.g102302147b-goog