Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752136AbaKUSZU (ORCPT ); Fri, 21 Nov 2014 13:25:20 -0500 Received: from g4t3426.houston.hp.com ([15.201.208.54]:37557 "EHLO g4t3426.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750852AbaKUSZQ (ORCPT ); Fri, 21 Nov 2014 13:25:16 -0500 From: Toshi Kani To: hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com, akpm@linux-foundation.org, arnd@arndb.de Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, jgross@suse.com, stefan.bader@canonical.com, luto@amacapital.net, hmh@hmh.eng.br, yigal@plexistor.com, konrad.wilk@oracle.com, Toshi Kani Subject: [PATCH v6 6/7] x86, mm, asm: Add WT support to set_page_memtype() Date: Fri, 21 Nov 2014 11:10:39 -0700 Message-Id: <1416593440-23083-7-git-send-email-toshi.kani@hp.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1416593440-23083-1-git-send-email-toshi.kani@hp.com> References: <1416593440-23083-1-git-send-email-toshi.kani@hp.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As set_memory_wb() calls set_page_memtype() with -1, _PGMT_DEFAULT is solely used for tracking the WB type. _PGMT_WB is defined but unused. Hence, this patch renames _PGMT_DEFAULT to _PGMT_WB to clarify its usage, and releases the slot used by _PGMT_WB before. As a result, set_memory_wb() is changed to call set_page_memtype() with _PGMT_WB, and get_page_memtype() returns _PAGE_CACHE_MODE_WB for _PGMT_WB. This patch then defines _PGMT_WT to the released slot. This enables set_page_memtype() to track the WT type. Signed-off-by: Toshi Kani --- arch/x86/mm/pat.c | 48 +++++++++++++++++++++--------------------------- 1 file changed, 21 insertions(+), 27 deletions(-) diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index 1271533..1c7a5f5 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -69,18 +69,18 @@ static u64 __read_mostly boot_pat_state; #ifdef CONFIG_X86_PAT /* - * X86 PAT uses page flags WC and Uncached together to keep track of - * memory type of pages that have backing page struct. X86 PAT supports 3 - * different memory types, _PAGE_CACHE_MODE_WB, _PAGE_CACHE_MODE_WC and - * _PAGE_CACHE_MODE_UC_MINUS and fourth state where page's memory type has not - * been changed from its default (value of -1 used to denote this). + * X86 PAT uses page flags arch_1 and uncached together to keep track of + * memory type of pages that have backing page struct. X86 PAT supports 4 + * different memory types, _PAGE_CACHE_MODE_WT, _PAGE_CACHE_MODE_WC, + * _PAGE_CACHE_MODE_UC_MINUS and _PAGE_CACHE_MODE_WB where page's memory + * type has not been changed from its default. * Note we do not support _PAGE_CACHE_MODE_UC here. */ -#define _PGMT_DEFAULT 0 +#define _PGMT_WB 0 /* default */ #define _PGMT_WC (1UL << PG_arch_1) #define _PGMT_UC_MINUS (1UL << PG_uncached) -#define _PGMT_WB (1UL << PG_uncached | 1UL << PG_arch_1) +#define _PGMT_WT (1UL << PG_uncached | 1UL << PG_arch_1) #define _PGMT_MASK (1UL << PG_uncached | 1UL << PG_arch_1) #define _PGMT_CLEAR_MASK (~_PGMT_MASK) @@ -88,14 +88,14 @@ static inline enum page_cache_mode get_page_memtype(struct page *pg) { unsigned long pg_flags = pg->flags & _PGMT_MASK; - if (pg_flags == _PGMT_DEFAULT) - return -1; + if (pg_flags == _PGMT_WB) + return _PAGE_CACHE_MODE_WB; else if (pg_flags == _PGMT_WC) return _PAGE_CACHE_MODE_WC; else if (pg_flags == _PGMT_UC_MINUS) return _PAGE_CACHE_MODE_UC_MINUS; else - return _PAGE_CACHE_MODE_WB; + return _PAGE_CACHE_MODE_WT; } static inline void set_page_memtype(struct page *pg, @@ -112,11 +112,12 @@ static inline void set_page_memtype(struct page *pg, case _PAGE_CACHE_MODE_UC_MINUS: memtype_flags = _PGMT_UC_MINUS; break; - case _PAGE_CACHE_MODE_WB: - memtype_flags = _PGMT_WB; + case _PAGE_CACHE_MODE_WT: + memtype_flags = _PGMT_WT; break; + case _PAGE_CACHE_MODE_WB: default: - memtype_flags = _PGMT_DEFAULT; + memtype_flags = _PGMT_WB; /* default */ break; } @@ -382,8 +383,9 @@ static int pat_pagerange_is_ram(resource_size_t start, resource_size_t end) /* * For RAM pages, we use page flags to mark the pages with appropriate type. - * The page flags are limited to three types, WB, WC and UC-. - * WT and WP requests fail with -EINVAL, and UC gets redirected to UC-. + * The page flags are limited to four types, WB (default), WC, WT and UC-. + * WP request fails with -EINVAL, and UC gets redirected to UC-. + * A new memtype can only be set to the default memtype WB. * Here we do two pass: * - Find the memtype of all the pages in the range, look for any conflicts * - In case of no conflicts, set the new memtype for pages in the range @@ -395,8 +397,7 @@ static int reserve_ram_pages_type(u64 start, u64 end, struct page *page; u64 pfn; - if ((req_type == _PAGE_CACHE_MODE_WT) || - (req_type == _PAGE_CACHE_MODE_WP)) { + if (req_type == _PAGE_CACHE_MODE_WP) { if (new_type) *new_type = _PAGE_CACHE_MODE_UC_MINUS; return -EINVAL; @@ -413,7 +414,7 @@ static int reserve_ram_pages_type(u64 start, u64 end, page = pfn_to_page(pfn); type = get_page_memtype(page); - if (type != -1) { + if (type != _PAGE_CACHE_MODE_WB) { pr_info("reserve_ram_pages_type failed [mem %#010Lx-%#010Lx], track 0x%x, req 0x%x\n", start, end - 1, type, req_type); if (new_type) @@ -440,7 +441,7 @@ static int free_ram_pages_type(u64 start, u64 end) for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) { page = pfn_to_page(pfn); - set_page_memtype(page, -1); + set_page_memtype(page, _PAGE_CACHE_MODE_WB); } return 0; } @@ -580,7 +581,7 @@ int free_memtype(u64 start, u64 end) * Only to be called when PAT is enabled * * Returns _PAGE_CACHE_MODE_WB, _PAGE_CACHE_MODE_WC, _PAGE_CACHE_MODE_UC_MINUS - * or _PAGE_CACHE_MODE_UC + * or _PAGE_CACHE_MODE_WT. */ static enum page_cache_mode lookup_memtype(u64 paddr) { @@ -594,13 +595,6 @@ static enum page_cache_mode lookup_memtype(u64 paddr) struct page *page; page = pfn_to_page(paddr >> PAGE_SHIFT); rettype = get_page_memtype(page); - /* - * -1 from get_page_memtype() implies RAM page is in its - * default state and not reserved, and hence of type WB - */ - if (rettype == -1) - rettype = _PAGE_CACHE_MODE_WB; - return rettype; } -- 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/