Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752258AbaKKFoE (ORCPT ); Tue, 11 Nov 2014 00:44:04 -0500 Received: from cantor2.suse.de ([195.135.220.15]:59308 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751825AbaKKFoA (ORCPT ); Tue, 11 Nov 2014 00:44:00 -0500 From: Juergen Gross To: linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com, konrad.wilk@oracle.com, david.vrabel@citrix.com, boris.ostrovsky@oracle.com, x86@kernel.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com Cc: Juergen Gross Subject: [PATCH V3 6/8] xen: Hide get_phys_to_machine() to be able to tune common path Date: Tue, 11 Nov 2014 06:43:44 +0100 Message-Id: <1415684626-18590-7-git-send-email-jgross@suse.com> X-Mailer: git-send-email 2.1.2 In-Reply-To: <1415684626-18590-1-git-send-email-jgross@suse.com> References: <1415684626-18590-1-git-send-email-jgross@suse.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Today get_phys_to_machine() is always called when the mfn for a pfn is to be obtained. Add a wrapper __pfn_to_mfn() as inline function to be able to avoid calling get_phys_to_machine() when possible as soon as the switch to a linear mapped p2m list has been done. Signed-off-by: Juergen Gross --- arch/x86/include/asm/xen/page.h | 27 +++++++++++++++++++++------ arch/x86/xen/mmu.c | 2 +- arch/x86/xen/p2m.c | 6 +++--- 3 files changed, 25 insertions(+), 10 deletions(-) diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h index 28fa795..07d8a7b 100644 --- a/arch/x86/include/asm/xen/page.h +++ b/arch/x86/include/asm/xen/page.h @@ -59,6 +59,22 @@ extern int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, struct page **pages, unsigned int count); extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn); +/* + * When to use pfn_to_mfn(), __pfn_to_mfn() or get_phys_to_machine(): + * - pfn_to_mfn() returns either INVALID_P2M_ENTRY or the mfn. In case of an + * identity entry the identity indicator will be cleared. + * - __pfn_to_mfn() returns the found entry of the p2m table. A possibly set + * identity indicator will be still set. __pfn_to_mfn() is encapsulating + * get_phys_to_machine() and might skip that function if possible to speed + * up the common path. + * - get_phys_to_machine() is basically the same as __pfn_to_mfn(), but + * without any short cuts for the common fast path. + */ +static inline unsigned long __pfn_to_mfn(unsigned long pfn) +{ + return get_phys_to_machine(pfn); +} + static inline unsigned long pfn_to_mfn(unsigned long pfn) { unsigned long mfn; @@ -66,7 +82,7 @@ static inline unsigned long pfn_to_mfn(unsigned long pfn) if (xen_feature(XENFEAT_auto_translated_physmap)) return pfn; - mfn = get_phys_to_machine(pfn); + mfn = __pfn_to_mfn(pfn); if (mfn != INVALID_P2M_ENTRY) mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT); @@ -79,7 +95,7 @@ static inline int phys_to_machine_mapping_valid(unsigned long pfn) if (xen_feature(XENFEAT_auto_translated_physmap)) return 1; - return get_phys_to_machine(pfn) != INVALID_P2M_ENTRY; + return __pfn_to_mfn(pfn) != INVALID_P2M_ENTRY; } static inline unsigned long mfn_to_pfn_no_overrides(unsigned long mfn) @@ -113,7 +129,7 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn) return mfn; pfn = mfn_to_pfn_no_overrides(mfn); - if (get_phys_to_machine(pfn) != mfn) { + if (__pfn_to_mfn(pfn) != mfn) { /* * If this appears to be a foreign mfn (because the pfn * doesn't map back to the mfn), then check the local override @@ -129,8 +145,7 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn) * entry doesn't map back to the mfn and m2p_override doesn't have a * valid entry for it. */ - if (pfn == ~0 && - get_phys_to_machine(mfn) == IDENTITY_FRAME(mfn)) + if (pfn == ~0 && __pfn_to_mfn(mfn) == IDENTITY_FRAME(mfn)) pfn = mfn; return pfn; @@ -176,7 +191,7 @@ static inline unsigned long mfn_to_local_pfn(unsigned long mfn) return mfn; pfn = mfn_to_pfn(mfn); - if (get_phys_to_machine(pfn) != mfn) + if (__pfn_to_mfn(pfn) != mfn) return -1; /* force !pfn_valid() */ return pfn; } diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index d3e492b..31ca515 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -387,7 +387,7 @@ static pteval_t pte_pfn_to_mfn(pteval_t val) unsigned long mfn; if (!xen_feature(XENFEAT_auto_translated_physmap)) - mfn = get_phys_to_machine(pfn); + mfn = __pfn_to_mfn(pfn); else mfn = pfn; /* diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index 6a9dfa6..328875a 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -785,7 +785,7 @@ static int m2p_add_override(unsigned long mfn, struct page *page, * because mfn_to_pfn (that ends up being called by GUPF) will * return the backend pfn rather than the frontend pfn. */ pfn = mfn_to_pfn_no_overrides(mfn); - if (get_phys_to_machine(pfn) == mfn) + if (__pfn_to_mfn(pfn) == mfn) set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)); return 0; @@ -965,7 +965,7 @@ static int m2p_remove_override(struct page *page, * pfn again. */ mfn &= ~FOREIGN_FRAME_BIT; pfn = mfn_to_pfn_no_overrides(mfn); - if (get_phys_to_machine(pfn) == FOREIGN_FRAME(mfn) && + if (__pfn_to_mfn(pfn) == FOREIGN_FRAME(mfn) && m2p_find_override(mfn) == NULL) set_phys_to_machine(pfn, mfn); @@ -990,7 +990,7 @@ int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, } for (i = 0; i < count; i++) { - unsigned long mfn = get_phys_to_machine(page_to_pfn(pages[i])); + unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i])); unsigned long pfn = page_to_pfn(pages[i]); if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) { -- 2.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/