From patchwork Wed May 24 15:33:03 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 13254222 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 95805C77B73 for ; Wed, 24 May 2023 15:34:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=4cVE4wHEEWCL68QiPzZKdcyF1OvKpu+xUzzVsiFHhuc=; b=Nue5pYI9rxrw8b 2Obrje5CutxOE+TD8irCYAYGrCKSiwNbeof8ivBVDa0jxxTD5ZiYnqPdwZjmtkSh3ciDLPkYIKP7r Np9M+GpYPsW1LaM0FdvjQ6RKLaiav4C8H4h8m6IVaNvEhWb9YS+U1GQJ2jzQliaBoLlKKCJCH8a1U ibkXEXD6QnQdMzFhRhBqcvRwX64ITwJVaqbQ0d8odcvMepLfpA6oROiU1VJqIFvCJHSWnk4KOKUUV qmSrsq+7I6xY44XIlSVOdc4HhKaPtMG7l9UT+mIrU4WZ/iHkFtsKAgnZoeT5Y7a1ZbskcWWmjc8rJ YWlxbcj28JfumgzDHxqA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1q1qUk-00Dqlq-1y; Wed, 24 May 2023 15:33:46 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1q1qUb-00DqfY-2D for linux-arm-kernel@lists.infradead.org; Wed, 24 May 2023 15:33:39 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1684942416; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=E/mkzJ+c6qr7yPOsPF9NXbENxWjJthPNWT3mBurv3yc=; b=ad4CnB4dMF57kwsg/xU7UcpF5Jr3YIO6MFWbAJFIHsMsLrY+dvXUEJu9368HSfKt7l63e/ mYZddq5p0LpSTsxBtsjCIkKSol+gXKTW+JwUMw6hcBhhGSlJXsHKMUMOv82RK5qm/u4zq2 cr5W1Q8QkTKnUe79DBM6Cnua5gKrLgg= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-617-ozOdLk_aN02TMJY6p7EiVg-1; Wed, 24 May 2023 11:33:33 -0400 X-MC-Unique: ozOdLk_aN02TMJY6p7EiVg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id B040C280BC80; Wed, 24 May 2023 15:33:31 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.39.192.68]) by smtp.corp.redhat.com (Postfix) with ESMTP id C783840CFD45; Wed, 24 May 2023 15:33:27 +0000 (UTC) From: David Howells To: netdev@vger.kernel.org Cc: David Howells , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Willem de Bruijn , David Ahern , Matthew Wilcox , Jens Axboe , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Jeroen de Borst , Catherine Sullivan , Shailend Chand , Felix Fietkau , John Crispin , Sean Wang , Mark Lee , Lorenzo Bianconi , Matthias Brugger , AngeloGioacchino Del Regno , Keith Busch , Jens Axboe , Christoph Hellwig , Sagi Grimberg , Chaitanya Kulkarni , Andrew Morton , linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-nvme@lists.infradead.org Subject: [PATCH net-next 04/12] mm: Make the page_frag_cache allocator use multipage folios Date: Wed, 24 May 2023 16:33:03 +0100 Message-Id: <20230524153311.3625329-5-dhowells@redhat.com> In-Reply-To: <20230524153311.3625329-1-dhowells@redhat.com> References: <20230524153311.3625329-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230524_083337_801694_3059D19A X-CRM114-Status: GOOD ( 28.87 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Change the page_frag_cache allocator to use multipage folios rather than groups of pages. This reduces page_frag_free to just a folio_put() or put_page(). Signed-off-by: David Howells cc: "David S. Miller" cc: Eric Dumazet cc: Jakub Kicinski cc: Paolo Abeni cc: Jens Axboe cc: Jeroen de Borst cc: Catherine Sullivan cc: Shailend Chand cc: Felix Fietkau cc: John Crispin cc: Sean Wang cc: Mark Lee cc: Lorenzo Bianconi cc: Matthias Brugger cc: AngeloGioacchino Del Regno cc: Keith Busch cc: Jens Axboe cc: Christoph Hellwig cc: Sagi Grimberg cc: Chaitanya Kulkarni cc: Andrew Morton cc: Matthew Wilcox cc: netdev@vger.kernel.org cc: linux-arm-kernel@lists.infradead.org cc: linux-mediatek@lists.infradead.org cc: linux-nvme@lists.infradead.org cc: linux-mm@kvack.org --- include/linux/mm_types.h | 13 ++---- mm/page_frag_alloc.c | 99 +++++++++++++++++++--------------------- 2 files changed, 52 insertions(+), 60 deletions(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 306a3d1a0fa6..d7c52a5979cc 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -420,18 +420,13 @@ static inline void *folio_get_private(struct folio *folio) } struct page_frag_cache { - void * va; -#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) - __u16 offset; - __u16 size; -#else - __u32 offset; -#endif + struct folio *folio; + unsigned int offset; /* we maintain a pagecount bias, so that we dont dirty cache line * containing page->_refcount every time we allocate a fragment. */ - unsigned int pagecnt_bias; - bool pfmemalloc; + unsigned int pagecnt_bias; + bool pfmemalloc; }; typedef unsigned long vm_flags_t; diff --git a/mm/page_frag_alloc.c b/mm/page_frag_alloc.c index 9d3f6fbd9a07..ffd68bfb677d 100644 --- a/mm/page_frag_alloc.c +++ b/mm/page_frag_alloc.c @@ -16,33 +16,34 @@ #include #include -static struct page *__page_frag_cache_refill(struct page_frag_cache *nc, - gfp_t gfp_mask) +/* + * Allocate a new folio for the frag cache. + */ +static struct folio *page_frag_cache_refill(struct page_frag_cache *nc, + gfp_t gfp_mask) { - struct page *page = NULL; + struct folio *folio = NULL; gfp_t gfp = gfp_mask; #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) - gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY | - __GFP_NOMEMALLOC; - page = alloc_pages_node(NUMA_NO_NODE, gfp_mask, - PAGE_FRAG_CACHE_MAX_ORDER); - nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE; + gfp_mask |= __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC; + folio = folio_alloc(gfp_mask, PAGE_FRAG_CACHE_MAX_ORDER); #endif - if (unlikely(!page)) - page = alloc_pages_node(NUMA_NO_NODE, gfp, 0); + if (unlikely(!folio)) + folio = folio_alloc(gfp, 0); - nc->va = page ? page_address(page) : NULL; - - return page; + if (folio) + nc->folio = folio; + return folio; } void __page_frag_cache_drain(struct page *page, unsigned int count) { - VM_BUG_ON_PAGE(page_ref_count(page) == 0, page); + struct folio *folio = page_folio(page); + + VM_BUG_ON_FOLIO(folio_ref_count(folio) == 0, folio); - if (page_ref_sub_and_test(page, count - 1)) - __free_pages(page, compound_order(page)); + folio_put_refs(folio, count); } EXPORT_SYMBOL(__page_frag_cache_drain); @@ -54,11 +55,12 @@ EXPORT_SYMBOL(__page_frag_cache_drain); */ void page_frag_cache_clear(struct page_frag_cache *nc) { - if (nc->va) { - struct page *page = virt_to_head_page(nc->va); + struct folio *folio = nc->folio; - __page_frag_cache_drain(page, nc->pagecnt_bias); - nc->va = NULL; + if (folio) { + VM_BUG_ON_FOLIO(folio_ref_count(folio) == 0, folio); + folio_put_refs(folio, nc->pagecnt_bias); + nc->folio = NULL; } } EXPORT_SYMBOL(page_frag_cache_clear); @@ -67,56 +69,51 @@ void *page_frag_alloc_align(struct page_frag_cache *nc, unsigned int fragsz, gfp_t gfp_mask, unsigned int align) { - unsigned int size = PAGE_SIZE; - struct page *page; - int offset; + struct folio *folio = nc->folio; + size_t offset; WARN_ON_ONCE(!is_power_of_2(align)); - if (unlikely(!nc->va)) { + if (unlikely(!folio)) { refill: - page = __page_frag_cache_refill(nc, gfp_mask); - if (!page) + folio = page_frag_cache_refill(nc, gfp_mask); + if (!folio) return NULL; -#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) - /* if size can vary use size else just use PAGE_SIZE */ - size = nc->size; -#endif /* Even if we own the page, we do not use atomic_set(). * This would break get_page_unless_zero() users. */ - page_ref_add(page, PAGE_FRAG_CACHE_MAX_SIZE); + folio_ref_add(folio, PAGE_FRAG_CACHE_MAX_SIZE); /* reset page count bias and offset to start of new frag */ - nc->pfmemalloc = page_is_pfmemalloc(page); + nc->pfmemalloc = folio_is_pfmemalloc(folio); nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; - nc->offset = size; + nc->offset = folio_size(folio); } - offset = nc->offset - fragsz; - if (unlikely(offset < 0)) { - page = virt_to_page(nc->va); - - if (page_ref_count(page) != nc->pagecnt_bias) + offset = nc->offset; + if (unlikely(fragsz > offset)) { + /* Reuse the folio if everyone we gave it to has finished with + * it. + */ + if (!folio_ref_sub_and_test(folio, nc->pagecnt_bias)) { + nc->folio = NULL; goto refill; + } + if (unlikely(nc->pfmemalloc)) { - page_ref_sub(page, nc->pagecnt_bias - 1); - __free_pages(page, compound_order(page)); + __folio_put(folio); + nc->folio = NULL; goto refill; } -#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) - /* if size can vary use size else just use PAGE_SIZE */ - size = nc->size; -#endif /* OK, page count is 0, we can safely set it */ - set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1); + folio_set_count(folio, PAGE_FRAG_CACHE_MAX_SIZE + 1); /* reset page count bias and offset to start of new frag */ nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; - offset = size - fragsz; - if (unlikely(offset < 0)) { + offset = folio_size(folio); + if (unlikely(fragsz > offset)) { /* * The caller is trying to allocate a fragment * with fragsz > PAGE_SIZE but the cache isn't big @@ -126,15 +123,17 @@ void *page_frag_alloc_align(struct page_frag_cache *nc, * it could make memory pressure worse * so we simply return NULL here. */ + nc->offset = offset; return NULL; } } nc->pagecnt_bias--; + offset -= fragsz; offset &= ~(align - 1); nc->offset = offset; - return nc->va + offset; + return folio_address(folio) + offset; } EXPORT_SYMBOL(page_frag_alloc_align); @@ -143,8 +142,6 @@ EXPORT_SYMBOL(page_frag_alloc_align); */ void page_frag_free(void *addr) { - struct page *page = virt_to_head_page(addr); - - __free_pages(page, compound_order(page)); + folio_put(virt_to_folio(addr)); } EXPORT_SYMBOL(page_frag_free);