From patchwork Fri Jul 19 09:33:32 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yunsheng Lin X-Patchwork-Id: 13737077 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B5343143873; Fri, 19 Jul 2024 09:37:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.188 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721381838; cv=none; b=jhQQpLymZVwBiQPW5n9QadQM0fPM4NKG72AZ93lbgjz2PGZIwgqYGj+QWrqxdrv6xTW7JpIbVbMOZbsvWtqPhJs4XrysMRW+BYCLSypILHzDr8mLsewAY+25uyvqOTde27ipmUI/5FZ3VQfHm/bNK9FppGR5zqndQp9IiAYSB1g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721381838; c=relaxed/simple; bh=f3LPo32DUMQnM//iCcEBtNZDHv2SGhH2nfljeci44pA=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=U56+JBDli1lW6wFQ4K/aHIqWwoRGXt2A926p4HddVqlmMsCJnPI7r5abS6Fl2tVIhbSVkBPD3gEDJNnGOADpkAQNz/6ryHbqoErn9GasfFWcPkykqmYH+OSb3WIlgDAc9Fo5eYIeKrMmfSuhQYhmxb0ypMrp0tA3FcnvZ5S0oVE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.188 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.88.105]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4WQPfp0vF1zdjHW; Fri, 19 Jul 2024 17:35:30 +0800 (CST) Received: from dggpemf200006.china.huawei.com (unknown [7.185.36.61]) by mail.maildlp.com (Postfix) with ESMTPS id CBF561400C9; Fri, 19 Jul 2024 17:37:14 +0800 (CST) Received: from localhost.localdomain (10.69.192.56) by dggpemf200006.china.huawei.com (7.185.36.61) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Fri, 19 Jul 2024 17:37:14 +0800 From: Yunsheng Lin To: , , CC: , , Yunsheng Lin , Alexander Duyck , Andrew Morton , Subject: [RFC v11 08/14] mm: page_frag: some minor refactoring before adding new API Date: Fri, 19 Jul 2024 17:33:32 +0800 Message-ID: <20240719093338.55117-9-linyunsheng@huawei.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20240719093338.55117-1-linyunsheng@huawei.com> References: <20240719093338.55117-1-linyunsheng@huawei.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggpemf200006.china.huawei.com (7.185.36.61) X-Patchwork-State: RFC Refactor common codes from __page_frag_alloc_va_align() to __page_frag_cache_refill(), so that the new API can make use of them. CC: Alexander Duyck Signed-off-by: Yunsheng Lin --- include/linux/page_frag_cache.h | 2 +- mm/page_frag_cache.c | 93 +++++++++++++++++---------------- 2 files changed, 49 insertions(+), 46 deletions(-) diff --git a/include/linux/page_frag_cache.h b/include/linux/page_frag_cache.h index 12a16f8e8ad0..5aa45de7a9a5 100644 --- a/include/linux/page_frag_cache.h +++ b/include/linux/page_frag_cache.h @@ -50,7 +50,7 @@ static inline void *encoded_page_address(unsigned long encoded_va) static inline void page_frag_cache_init(struct page_frag_cache *nc) { - nc->encoded_va = 0; + memset(nc, 0, sizeof(*nc)); } static inline bool page_frag_cache_is_pfmemalloc(struct page_frag_cache *nc) diff --git a/mm/page_frag_cache.c b/mm/page_frag_cache.c index 7928e5d50711..d9c9cad17af7 100644 --- a/mm/page_frag_cache.c +++ b/mm/page_frag_cache.c @@ -19,6 +19,28 @@ #include #include "internal.h" +static struct page *__page_frag_cache_recharge(struct page_frag_cache *nc) +{ + unsigned long encoded_va = nc->encoded_va; + struct page *page; + + page = virt_to_page((void *)encoded_va); + if (!page_ref_sub_and_test(page, nc->pagecnt_bias)) + return NULL; + + if (unlikely(encoded_page_pfmemalloc(encoded_va))) { + VM_BUG_ON(compound_order(page) != + encoded_page_order(encoded_va)); + free_unref_page(page, encoded_page_order(encoded_va)); + return NULL; + } + + /* OK, page count is 0, we can safely set it */ + set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1); + + return page; +} + static struct page *__page_frag_cache_refill(struct page_frag_cache *nc, gfp_t gfp_mask) { @@ -26,6 +48,14 @@ static struct page *__page_frag_cache_refill(struct page_frag_cache *nc, struct page *page = NULL; gfp_t gfp = gfp_mask; + if (likely(nc->encoded_va)) { + page = __page_frag_cache_recharge(nc); + if (page) { + order = encoded_page_order(nc->encoded_va); + goto out; + } + } + #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) gfp_mask = (gfp_mask & ~__GFP_DIRECT_RECLAIM) | __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC; @@ -35,7 +65,7 @@ static struct page *__page_frag_cache_refill(struct page_frag_cache *nc, if (unlikely(!page)) { page = alloc_pages_node(NUMA_NO_NODE, gfp, 0); if (unlikely(!page)) { - nc->encoded_va = 0; + memset(nc, 0, sizeof(*nc)); return NULL; } @@ -45,6 +75,16 @@ static struct page *__page_frag_cache_refill(struct page_frag_cache *nc, nc->encoded_va = encode_aligned_va(page_address(page), order, page_is_pfmemalloc(page)); + /* 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); + +out: + /* reset page count bias and remaining to start of new frag */ + nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; + nc->remaining = PAGE_SIZE << order; + return page; } @@ -55,7 +95,7 @@ void page_frag_cache_drain(struct page_frag_cache *nc) __page_frag_cache_drain(virt_to_head_page((void *)nc->encoded_va), nc->pagecnt_bias); - nc->encoded_va = 0; + memset(nc, 0, sizeof(*nc)); } EXPORT_SYMBOL(page_frag_cache_drain); @@ -72,31 +112,9 @@ void *__page_frag_alloc_va_align(struct page_frag_cache *nc, unsigned int fragsz, gfp_t gfp_mask, unsigned int align_mask) { - unsigned long encoded_va = nc->encoded_va; - unsigned int size, remaining; - struct page *page; - - if (unlikely(!encoded_va)) { -refill: - page = __page_frag_cache_refill(nc, gfp_mask); - if (!page) - return NULL; - - encoded_va = nc->encoded_va; - size = page_frag_cache_page_size(encoded_va); + unsigned int size = page_frag_cache_page_size(nc->encoded_va); + unsigned int remaining = nc->remaining & align_mask; - /* 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); - - /* reset page count bias and remaining to start of new frag */ - nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; - nc->remaining = size; - } - - size = page_frag_cache_page_size(encoded_va); - remaining = nc->remaining & align_mask; if (unlikely(remaining < fragsz)) { if (unlikely(fragsz > PAGE_SIZE)) { /* @@ -111,32 +129,17 @@ void *__page_frag_alloc_va_align(struct page_frag_cache *nc, return NULL; } - page = virt_to_page((void *)encoded_va); - - if (!page_ref_sub_and_test(page, nc->pagecnt_bias)) - goto refill; - - if (unlikely(encoded_page_pfmemalloc(encoded_va))) { - VM_BUG_ON(compound_order(page) != - encoded_page_order(encoded_va)); - free_unref_page(page, encoded_page_order(encoded_va)); - goto refill; - } - - /* OK, page count is 0, we can safely set it */ - set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1); - - /* reset page count bias and remaining to start of new frag */ - nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; - nc->remaining = size; + if (unlikely(!__page_frag_cache_refill(nc, gfp_mask))) + return NULL; + size = page_frag_cache_page_size(nc->encoded_va); remaining = size; } nc->pagecnt_bias--; nc->remaining = remaining - fragsz; - return encoded_page_address(encoded_va) + (size - remaining); + return encoded_page_address(nc->encoded_va) + (size - remaining); } EXPORT_SYMBOL(__page_frag_alloc_va_align);