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Thu, 06 May 2021 11:24:29 -0700 (PDT) MIME-Version: 1.0 References: <20210505003032.489164-1-rick.p.edgecombe@intel.com> <20210505003032.489164-6-rick.p.edgecombe@intel.com> In-Reply-To: <20210505003032.489164-6-rick.p.edgecombe@intel.com> From: Shakeel Butt Date: Thu, 6 May 2021 11:24:18 -0700 Message-ID: Subject: Re: [PATCH RFC 5/9] x86, mm: Use cache of page tables To: Rick Edgecombe Cc: Dave Hansen , Andy Lutomirski , "Peter Zijlstra (Intel)" , Linux MM , x86@kernel.org, Andrew Morton , linux-hardening@vger.kernel.org, kernel-hardening@lists.openwall.com, Ira Weiny , Mike Rapoport , Dan Williams , LKML Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 511E2600010A Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=google.com header.s=20161025 header.b=cwWL6QfD; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf25.hostedemail.com: domain of shakeelb@google.com designates 209.85.208.170 as permitted sender) smtp.mailfrom=shakeelb@google.com X-Rspamd-Server: rspam04 X-Stat-Signature: zh31i89qniipbuejzodun9tuebu78jin Received-SPF: none (google.com>: No applicable sender policy available) receiver=imf25; identity=mailfrom; envelope-from=""; helo=mail-lj1-f170.google.com; client-ip=209.85.208.170 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1620325464-440163 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: On Tue, May 4, 2021 at 5:36 PM Rick Edgecombe wrote: > [...] > +#ifdef CONFIG_PKS_PG_TABLES > +struct page *alloc_table(gfp_t gfp) > +{ > + struct page *table; > + > + if (!pks_page_en) > + return alloc_page(gfp); > + > + table = get_grouped_page(numa_node_id(), &gpc_pks); > + if (!table) > + return NULL; > + > + if (gfp & __GFP_ZERO) > + memset(page_address(table), 0, PAGE_SIZE); > + > + if (memcg_kmem_enabled() && > + gfp & __GFP_ACCOUNT && > + !__memcg_kmem_charge_page(table, gfp, 0)) { > + free_table(table); > + table = NULL; > + } > + > + VM_BUG_ON_PAGE(*(unsigned long *)&table->ptl, table); table can be NULL due to charge failure.