Date: Thu, 1 Aug 2013 16:19:52 +0200 From: Zbigniew Bodek <zbb@semihalf.com> To: "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org> Cc: ray@freebsd.org, Alan Cox <alc@cs.rice.edu> Subject: Re: New pmap-v6.c features and improvements Message-ID: <CAG7dG%2BwoHUZp8M_KSMkDy_YNyoC3sLT9qwY_orVqk%2BAoeFpNEA@mail.gmail.com> In-Reply-To: <51F68F58.8060600@semihalf.com> References: <519B6B1C.9060008@semihalf.com> <20130522184232.GA437@jail.io> <519E0D62.5030708@semihalf.com> <51CC4CC1.4020509@semihalf.com> <51D57456.9080504@semihalf.com> <B6F68E56-7452-44D4-9C9D-195221B06380@bsdimp.com> <51F68F58.8060600@semihalf.com>
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[-- Attachment #1 --] 2013/7/29 Zbyszek Bodek <zbb@semihalf.com> > On 04.07.2013 19:34, Warner Losh wrote: > > > > On Jul 4, 2013, at 7:10 AM, Zbyszek Bodek wrote: > > > >> On 27.06.2013 16:31, Zbyszek Bodek wrote: > >>> On 23.05.2013 14:36, Zbyszek Bodek wrote: > >>>> On 22.05.2013 20:42, Ruslan Bukin wrote: > >>>>> On Tue, May 21, 2013 at 02:39:56PM +0200, Zbyszek Bodek wrote: > >>>>>> Hello Everyone, > >>>>>> > >>>>>> I would like to introduce another pack of patches for pmap-v6.c and > >>>>>> related, that we created as a part of Semihalf work on Superpages > >>>>>> support. > >>>>>> > >>>>>> The patches include some major changes like: > >>>>>> > >>>>>> - Switch to AP[1:0] access permissions model > >>>>>> - Transition of the mapping related flags to PTE (stop using PVF_ > flags > >>>>>> in pv_entry) > >>>>>> - Rework of the pmap_enter_locked() function > >>>>>> - pmap code optimizations > >>>>>> > >>>>>> And some minor clean-ups: > >>>>>> > >>>>>> - Get rid of the VERBOSE_INIT_ARM option > >>>>>> - Clean-ups, style and naming improvements to pmap > >>>>>> > >>>>>> Please check out the attachment for details. > >>>>>> > >>>>>> I will be happy to answer your questions and doubts if any. > >>>>>> > >>>>>> Best regards > >>>>>> Zbyszek Bodek > >>>>> > >>>>> I tested new patches with exynos5 and everything is OK. > >>>>> (I mean all works as usual) > >>>>> > >>>> > >>>> Hello. > >>>> > >>>> I'm happy to announce that code has been integrated to the FreeBSD > HEAD. > >>>> Great thanks your help! > >>>> > >>> > >>> Hello Everyone, > >>> > >>> We have two micro patches for pmap-v6.c containing fix for 'modified' > >>> bit emulation and removal of the redundant PGA_WRITEABLE clearing. > >>> > >>> Please check out the attachment. > >>> > >>> These two are minimal changes and we would like to commit them soon, so > >>> we would be grateful if you could test them on your ARMv6/v7 platforms > >>> and give us your remarks. > >>> > >> > >> Hello, > >> > >> Because there were no objections, we've integrated the patches: > >> > >> http://svnweb.freebsd.org/base?view=revision&revision=252694 > >> http://svnweb.freebsd.org/base?view=revision&revision=252695 > > > Hello Everyone, > > I'm sending another set of fixes for pmap-v6.c > Please see attachment. > > 0012 - Removal of the costly, frequent sweeping through the > pv_entries whenever pmap_nuke_pv(), pmap_modify_pv(), etc. > are called. This also makes order with clearing PGA_WRITEABLE > aflag as well as with the pmap_statistics related to the > wired_count. > 0013 - Fix for pamp_set_prot() where not all of the protection bits were > cleared before the actual configuration. L2_XN is not icluded to > the L2_S_PROT mask to maintain consistency between PROT_MASKS for > L2 and L1 descriptors - contain only kernel/user and > read/write permissions bits. > 0014 - Fix for pmap_change_wiring() where "wired" indicator of type > boolean was being used as a "wired flag" passed to > pmap_modify_pv() which was obviously not a valid PVF_WIRED flag. > > Please test those patches on your ARM-based machines and send your > feedback. We will also appreciate your reviews and remarks. > > Thank you in advance for your help. > > Hello, Are there any updates in this topic? In addition, I'm attaching two more minor improvements, this time: 0015 - small clean-ups in pmap_clearbit() that in general gives one relevant improvement which is to skip redundant "dirty" setting for a page. 0016 - removal of the unused pv_kva field from the md_page structure If there are no objections to that and earlier presented changes we would like to integrate them to the HEAD soon. Best regards Zbyszek Bodek [-- Attachment #2 --] From f92f68202d6dae4b30d6bd88ca79b3b226ea0cda Mon Sep 17 00:00:00 2001 From: Zbigniew Bodek <zbb@semihalf.com> Date: Mon, 29 Jul 2013 19:18:22 +0200 Subject: [PATCH 1/2] Simplify and clean-up redundant statements from ARMv6/v7 pmap_clearbit() PVF_MOD is an unused flag kept just to indicate what is to be cleared since PTE's L2_APX shows modification status. What more, there is no need for calling vm_page_dirty() when clearing "modified" flag as it is already set for that page in pmap_fault_fixup() or pmap_enter() thanks to "modified" bit emulation. There is also no need for checking PTE's "referenced" or "writeable" flags. If there is a request to clear a particular flag, just do it. Submitted by: Zbigniew Bodek <zbb@semihalf.com> Sponsored by: The FreeBSD Foundation, Semihalf --- sys/arm/arm/pmap-v6.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/sys/arm/arm/pmap-v6.c b/sys/arm/arm/pmap-v6.c index 3142f56..2852f12 100644 --- a/sys/arm/arm/pmap-v6.c +++ b/sys/arm/arm/pmap-v6.c @@ -900,9 +900,6 @@ pmap_clearbit(struct vm_page *m, u_int maskbits) rw_wlock(&pvh_global_lock); - if (maskbits & PVF_WRITE) - maskbits |= PVF_MOD; - if (TAILQ_EMPTY(&m->md.pv_list)) { rw_wunlock(&pvh_global_lock); return (0); @@ -924,14 +921,12 @@ pmap_clearbit(struct vm_page *m, u_int maskbits) ptep = &l2b->l2b_kva[l2pte_index(va)]; npte = opte = *ptep; - if ((maskbits & (PVF_WRITE|PVF_MOD)) && L2_S_WRITABLE(opte)) { - vm_page_dirty(m); - + if (maskbits & (PVF_WRITE | PVF_MOD)) { /* make the pte read only */ npte |= L2_APX; } - if ((maskbits & PVF_REF) && L2_S_REFERENCED(opte)) { + if (maskbits & PVF_REF) { /* * Clear referenced flag in PTE so that we * will take a flag fault the next time the mapping -- 1.8.2 [-- Attachment #3 --] From 278d58c41d24147428e1a9b91af48de92d0071a6 Mon Sep 17 00:00:00 2001 From: Zbigniew Bodek <zbb@semihalf.com> Date: Wed, 31 Jul 2013 19:19:28 +0200 Subject: [PATCH 2/2] Stop using redundant pv_kva field in md_page structure for ARMv6/v7 This variable is complitely useless in current pmap-v6.c implementation, hence delete it to save some space on each vm_page. Submitted by: Zbigniew Bodek <zbb@semihalf.com> Sponsored by: The FreeBSD Foundation, Semihalf --- sys/arm/arm/pmap-v6.c | 2 +- sys/arm/include/pmap.h | 2 ++ 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/sys/arm/arm/pmap-v6.c b/sys/arm/arm/pmap-v6.c index 2852f12..aef4ce3 100644 --- a/sys/arm/arm/pmap-v6.c +++ b/sys/arm/arm/pmap-v6.c @@ -4368,6 +4368,6 @@ pmap_page_set_memattr(vm_page_t m, vm_memattr_t ma) * uncacheable, being careful to sync caches and PTEs (and maybe * invalidate TLB?) for any current mapping it modifies. */ - if (m->md.pv_kva != 0 || TAILQ_FIRST(&m->md.pv_list) != NULL) + if (TAILQ_FIRST(&m->md.pv_list) != NULL) panic("Can't change memattr on page with existing mappings"); } diff --git a/sys/arm/include/pmap.h b/sys/arm/include/pmap.h index b416169..780ed9b 100644 --- a/sys/arm/include/pmap.h +++ b/sys/arm/include/pmap.h @@ -121,7 +121,9 @@ struct pv_chunk; struct md_page { int pvh_attrs; vm_memattr_t pv_memattr; +#if (ARM_MMU_V6 + ARM_MMU_V7) == 0 vm_offset_t pv_kva; /* first kernel VA mapping */ +#endif TAILQ_HEAD(,pv_entry) pv_list; }; -- 1.8.2home | help
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