From: Christoffer Dall <christoffer.dall@linaro.org> To: Mario Smarduch <m.smarduch@samsung.com> Cc: kvmarm@lists.cs.columbia.edu, marc.zyngier@arm.com, pbonzini@redhat.com, gleb@kernel.org, agraf@suse.de, xiantao.zhang@intel.com, borntraeger@de.ibm.com, cornelia.huck@de.ibm.com, xiaoguangrong@linux.vnet.ibm.com, steve.capper@arm.com, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, jays.lee@samsung.com, sungjinn.chung@samsung.com Subject: Re: [PATCH v9 2/4] arm: ARMv7 dirty page logging inital mem region write protect (w/no huge PUD support) Date: Tue, 12 Aug 2014 11:36:18 +0200 [thread overview] Message-ID: <20140812093618.GM10550@cbox> (raw) In-Reply-To: <53E96F8E.3070905@samsung.com> On Mon, Aug 11, 2014 at 06:36:14PM -0700, Mario Smarduch wrote: > On 08/11/2014 12:12 PM, Christoffer Dall wrote: [...] > >> +/** > >> + * stage2_wp_range() - write protect stage2 memory region range > >> + * @kvm: The KVM pointer > >> + * @start: Start address of range > >> + * &end: End address of range > >> + */ > >> +static void stage2_wp_range(struct kvm *kvm, phys_addr_t addr, phys_addr_t end) > >> +{ > >> + pgd_t *pgd; > >> + phys_addr_t next; > >> + > >> + pgd = kvm->arch.pgd + pgd_index(addr); > >> + do { > >> + /* > >> + * Release kvm_mmu_lock periodically if the memory region is > >> + * large features like detect hung task, lock detector or lock > > large. Otherwise, we may see panics due to.. > >> + * dep may panic. In addition holding the lock this long will > > extra white space ^^ Additionally, holding the lock for a > > long timer will > >> + * also starve other vCPUs. Applies to huge VM memory regions. > > ^^^ I don't understand this > > last remark. > Sorry overlooked this. > > While testing - VM regions that were small (~1GB) holding the mmu_lock > caused not problems, but when I was running memory regions around 2GB large > some kernel lockup detection/lock contention options (some selected by default) > caused deadlock warnings/panics in host kernel. > > This was in one my previous review comments sometime ago, I can go back > and find the options. > Just drop the last part of the comment, so the whole thing reads: /* * Release kvm_mmu_lock periodically if the memory region is * large. Otherwise, we may see kernel panics from debugging features * such as "detect hung task", "lock detector" or "lock dep checks". * Additionally, holding the lock too long will also starve other vCPUs. */ And check the actual names of those debugging features or use the CONFIG_<WHATEVER> names and say "we may see kernel panics with CONFIG_X, CONFIG_Y, and CONFIG_Z. Makes sense? -Christoffer
WARNING: multiple messages have this Message-ID (diff)
From: christoffer.dall@linaro.org (Christoffer Dall) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v9 2/4] arm: ARMv7 dirty page logging inital mem region write protect (w/no huge PUD support) Date: Tue, 12 Aug 2014 11:36:18 +0200 [thread overview] Message-ID: <20140812093618.GM10550@cbox> (raw) In-Reply-To: <53E96F8E.3070905@samsung.com> On Mon, Aug 11, 2014 at 06:36:14PM -0700, Mario Smarduch wrote: > On 08/11/2014 12:12 PM, Christoffer Dall wrote: [...] > >> +/** > >> + * stage2_wp_range() - write protect stage2 memory region range > >> + * @kvm: The KVM pointer > >> + * @start: Start address of range > >> + * &end: End address of range > >> + */ > >> +static void stage2_wp_range(struct kvm *kvm, phys_addr_t addr, phys_addr_t end) > >> +{ > >> + pgd_t *pgd; > >> + phys_addr_t next; > >> + > >> + pgd = kvm->arch.pgd + pgd_index(addr); > >> + do { > >> + /* > >> + * Release kvm_mmu_lock periodically if the memory region is > >> + * large features like detect hung task, lock detector or lock > > large. Otherwise, we may see panics due to.. > >> + * dep may panic. In addition holding the lock this long will > > extra white space ^^ Additionally, holding the lock for a > > long timer will > >> + * also starve other vCPUs. Applies to huge VM memory regions. > > ^^^ I don't understand this > > last remark. > Sorry overlooked this. > > While testing - VM regions that were small (~1GB) holding the mmu_lock > caused not problems, but when I was running memory regions around 2GB large > some kernel lockup detection/lock contention options (some selected by default) > caused deadlock warnings/panics in host kernel. > > This was in one my previous review comments sometime ago, I can go back > and find the options. > Just drop the last part of the comment, so the whole thing reads: /* * Release kvm_mmu_lock periodically if the memory region is * large. Otherwise, we may see kernel panics from debugging features * such as "detect hung task", "lock detector" or "lock dep checks". * Additionally, holding the lock too long will also starve other vCPUs. */ And check the actual names of those debugging features or use the CONFIG_<WHATEVER> names and say "we may see kernel panics with CONFIG_X, CONFIG_Y, and CONFIG_Z. Makes sense? -Christoffer
next prev parent reply other threads:[~2014-08-12 9:36 UTC|newest] Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-07-25 0:56 [PATCH v9 0/4] arm: dirty page logging support for ARMv7 Mario Smarduch 2014-07-25 0:56 ` Mario Smarduch 2014-07-25 0:56 ` [PATCH v9 1/4] arm: add ARMv7 HYP API to flush VM TLBs, change generic TLB flush to support arch flush Mario Smarduch 2014-07-25 0:56 ` Mario Smarduch 2014-07-25 6:12 ` Alexander Graf 2014-07-25 6:12 ` Alexander Graf 2014-07-25 17:37 ` Mario Smarduch 2014-07-25 17:37 ` Mario Smarduch 2014-08-08 17:50 ` [PATCH v9 1/4] arm: add ARMv7 HYP API to flush VM TLBs ... - looking for comments Mario Smarduch 2014-08-08 17:50 ` Mario Smarduch 2014-08-11 19:12 ` [PATCH v9 1/4] arm: add ARMv7 HYP API to flush VM TLBs, change generic TLB flush to support arch flush Christoffer Dall 2014-08-11 19:12 ` Christoffer Dall 2014-08-11 23:54 ` Mario Smarduch 2014-08-11 23:54 ` Mario Smarduch 2014-07-25 0:56 ` [PATCH v9 2/4] arm: ARMv7 dirty page logging inital mem region write protect (w/no huge PUD support) Mario Smarduch 2014-07-25 0:56 ` Mario Smarduch 2014-07-25 6:16 ` Alexander Graf 2014-07-25 6:16 ` Alexander Graf 2014-07-25 17:45 ` Mario Smarduch 2014-07-25 17:45 ` Mario Smarduch 2014-08-11 19:12 ` Christoffer Dall 2014-08-11 19:12 ` Christoffer Dall 2014-08-12 0:16 ` Mario Smarduch 2014-08-12 0:16 ` Mario Smarduch 2014-08-12 9:32 ` Christoffer Dall 2014-08-12 9:32 ` Christoffer Dall 2014-08-12 23:17 ` Mario Smarduch 2014-08-12 23:17 ` Mario Smarduch 2014-08-12 1:36 ` Mario Smarduch 2014-08-12 1:36 ` Mario Smarduch 2014-08-12 9:36 ` Christoffer Dall [this message] 2014-08-12 9:36 ` Christoffer Dall 2014-08-12 21:08 ` Mario Smarduch 2014-08-12 21:08 ` Mario Smarduch 2014-07-25 0:56 ` [PATCH v9 3/4] arm: dirty log write protect mgmt. Moved x86, armv7 to generic, set armv8 ia64 mips powerpc s390 arch specific Mario Smarduch 2014-07-25 0:56 ` Mario Smarduch 2014-08-11 19:13 ` Christoffer Dall 2014-08-11 19:13 ` Christoffer Dall 2014-08-12 0:24 ` Mario Smarduch 2014-08-12 0:24 ` Mario Smarduch 2014-07-25 0:56 ` [PATCH v9 4/4] arm: ARMv7 dirty page logging 2nd stage page fault handling support Mario Smarduch 2014-07-25 0:56 ` Mario Smarduch 2014-08-11 19:13 ` Christoffer Dall 2014-08-11 19:13 ` Christoffer Dall 2014-08-12 1:25 ` Mario Smarduch 2014-08-12 1:25 ` Mario Smarduch 2014-08-12 9:50 ` Christoffer Dall 2014-08-12 9:50 ` Christoffer Dall 2014-08-13 1:27 ` Mario Smarduch 2014-08-13 1:27 ` Mario Smarduch 2014-08-13 7:30 ` Christoffer Dall 2014-08-13 7:30 ` Christoffer Dall 2014-08-14 1:20 ` Mario Smarduch 2014-08-14 1:20 ` Mario Smarduch 2014-08-15 0:01 ` Mario Smarduch 2014-08-15 0:01 ` Mario Smarduch 2014-08-18 12:51 ` Christoffer Dall 2014-08-18 12:51 ` Christoffer Dall 2014-08-18 17:42 ` Mario Smarduch 2014-08-18 17:42 ` Mario Smarduch
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