From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0043FC43219 for ; Tue, 1 Nov 2022 20:18:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230214AbiKAUSl (ORCPT ); Tue, 1 Nov 2022 16:18:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56988 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230219AbiKAUSh (ORCPT ); Tue, 1 Nov 2022 16:18:37 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 526631C41D for ; Tue, 1 Nov 2022 13:18:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=LAbynVx7FMpy2SHEr2MnqNJCSXJegM+g7qTkiXTDbYs=; b=nQV2BbG4nWqNIeWDgdHTHH+0Ss Vbdz/mRtS6teMi0P6LMJOT8R8P1n6gvZmN4HMoAp8k3S/RNIkPGdcPjJtD0OdxJMBJylHvyWLLtty DMmAcMBe+/vMtVyHcbolbCJowl5NXh8puzjKQW93tXc2PI5e7t6j/icmMMjZy0e3PzlaKnQh2Tsu3 fOS2q8fm3Nfahg5fGQb4HYXuf/IMuyhQR5o1o7r1bkFNUNtND2mjRpeXg6M6VpGCHGjB3gllBFKu4 m6jCOjYV4NjOlnYiCzwyyb38DJQJCcuIkYzpyoKkg16OshFpk7xCqn56UG0P/+qTND+ck6l/dmol0 TK0yrG3A==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1opxiP-004uUW-Pd; Tue, 01 Nov 2022 20:18:29 +0000 From: "Matthew Wilcox (Oracle)" To: linux-mm@kvack.org Cc: "Matthew Wilcox (Oracle)" , Uladzislau Rezki , David Howells , Dave Chinner , linux-fsdevel@vger.kernel.org, Thomas Gleixner , Ira Weiny , "Fabio M. De Francesco" , Luis Chamberlain Subject: [PATCH v2 2/2] mm: Add folio_map_local() Date: Tue, 1 Nov 2022 20:18:28 +0000 Message-Id: <20221101201828.1170455-3-willy@infradead.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20221101201828.1170455-1-willy@infradead.org> References: <20221101201828.1170455-1-willy@infradead.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Some filesystems benefit from being able to map the entire folio. On 32-bit platforms with HIGHMEM, we fall back to using vmap, which will be slow. If it proves to be a performance problem, we can look at optimising it in a number of ways. Signed-off-by: Matthew Wilcox (Oracle) --- include/linux/highmem.h | 40 ++++++++++++++++++++++++++++++++++++++++ include/linux/vmalloc.h | 6 ++++-- mm/vmalloc.c | 32 ++++++++++++++++++++++++++++++++ 3 files changed, 76 insertions(+), 2 deletions(-) diff --git a/include/linux/highmem.h b/include/linux/highmem.h index e9912da5441b..d56ae62db252 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -10,6 +10,7 @@ #include #include #include +#include #include "highmem-internal.h" @@ -132,6 +133,45 @@ static inline void *kmap_local_page(struct page *page); */ static inline void *kmap_local_folio(struct folio *folio, size_t offset); +/** + * folio_map_local - Map an entire folio. + * @folio: The folio to map. + * + * Unlike kmap_local_folio(), map an entire folio. This should be undone + * with folio_unmap_local(). The address returned should be treated as + * stack-based, and local to this CPU, like kmap_local_folio(). + * + * Context: May allocate memory using GFP_KERNEL if it takes the vmap path. + * Return: A kernel virtual address which can be used to access the folio, + * or NULL if the mapping fails. + */ +static inline __must_check void *folio_map_local(struct folio *folio) +{ + might_alloc(GFP_KERNEL); + + if (!IS_ENABLED(CONFIG_HIGHMEM)) + return folio_address(folio); + if (folio_test_large(folio)) + return vm_map_folio(folio); + return kmap_local_page(&folio->page); +} + +/** + * folio_unmap_local - Unmap an entire folio. + * @addr: Address returned from folio_map_local() + * + * Undo the result of a previous call to folio_map_local(). + */ +static inline void folio_unmap_local(const void *addr, unsigned long nr_pages) +{ + if (!IS_ENABLED(CONFIG_HIGHMEM)) + return; + if (is_vmalloc_addr(addr)) + vm_unmap_ram(addr, nr_pages); + else + kunmap_local(addr); +} + /** * kmap_atomic - Atomically map a page for temporary usage - Deprecated! * @page: Pointer to the page to be mapped diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 096d48aa3437..4bb34c939c01 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -13,6 +13,7 @@ #include struct vm_area_struct; /* vma defining user mapping in mm_types.h */ +struct folio; /* also mm_types.h */ struct notifier_block; /* in notifier.h */ /* bits in flags of vmalloc's vm_struct below */ @@ -163,8 +164,9 @@ extern void *vcalloc(size_t n, size_t size) __alloc_size(1, 2); extern void vfree(const void *addr); extern void vfree_atomic(const void *addr); -extern void *vmap(struct page **pages, unsigned int count, - unsigned long flags, pgprot_t prot); +void *vmap(struct page **pages, unsigned int count, unsigned long flags, + pgprot_t prot); +void *vm_map_folio(struct folio *folio); void *vmap_pfn(unsigned long *pfns, unsigned int count, pgprot_t prot); extern void vunmap(const void *addr); diff --git a/mm/vmalloc.c b/mm/vmalloc.c index dcab1d3cf185..c101b09d15d3 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2288,6 +2288,38 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node) } EXPORT_SYMBOL(vm_map_ram); +#ifdef CONFIG_HIGHMEM +/** + * vm_map_folio() - Map an entire folio into virtually contiguous space. + * @folio: The folio to map. + * + * Maps all pages in @folio into contiguous kernel virtual space. This + * function is only available in HIGHMEM builds; for !HIGHMEM, use + * folio_address(). The pages are mapped with PAGE_KERNEL permissions. + * + * Return: The address of the area or %NULL on failure + */ +void *vm_map_folio(struct folio *folio) +{ + size_t size = folio_size(folio); + void *mem = vmap_alloc(size, NUMA_NO_NODE); + unsigned long addr = (unsigned long)mem; + + if (vmap_range_noflush(addr, addr + size, + folio_pfn(folio) << PAGE_SHIFT, + PAGE_KERNEL, folio_shift(folio))) { + vm_unmap_ram(mem, folio_nr_pages(folio)); + return NULL; + } + flush_cache_vmap(addr, addr + size); + + mem = kasan_unpoison_vmalloc(mem, size, KASAN_VMALLOC_PROT_NORMAL); + + return mem; +} +EXPORT_SYMBOL(vm_map_folio); +#endif + static struct vm_struct *vmlist __initdata; static inline unsigned int vm_area_page_order(struct vm_struct *vm) -- 2.35.1