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Fri, 23 Aug 2024 09:42:52 -0700 (PDT) Received: from pc638.lan ([84.217.131.213]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-5334ea5d6e4sm590346e87.225.2024.08.23.09.42.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 23 Aug 2024 09:42:51 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Fri, 23 Aug 2024 18:42:47 +0200 To: Michal Hocko Cc: Hailong Liu , Uladzislau Rezki , Andrew Morton , Barry Song <21cnbao@gmail.com>, Christoph Hellwig , Vlastimil Babka , Tangquan Zheng , stable@vger.kernel.org, Baoquan He , Matthew Wilcox , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RESEND PATCH v1] mm/vmalloc: fix page mapping if vm_area_alloc_pages() with high order fallback to order 0 Message-ID: References: <20240808122019.3361-1-hailong.liu@oppo.com> <20240815220709.47f66f200fd0a072777cc348@linux-foundation.org> <20240816091232.fsliktqgza5o5x6t@oppo.com> <20240816114626.jmhqh5ducbk7qeur@oppo.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Hello, Michal. > > Let me clarify what I would like to have clarified: > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 6b783baf12a1..fea90a39f5c5 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -3510,13 +3510,13 @@ void *vmap_pfn(unsigned long *pfns, unsigned int count, pgprot_t prot) > EXPORT_SYMBOL_GPL(vmap_pfn); > #endif /* CONFIG_VMAP_PFN */ > > +/* GFP_NOFAIL semantic is implemented by __vmalloc_node_range_noprof */ > static inline unsigned int > vm_area_alloc_pages(gfp_t gfp, int nid, > unsigned int order, unsigned int nr_pages, struct page **pages) > { > unsigned int nr_allocated = 0; > - gfp_t alloc_gfp = gfp; > - bool nofail = gfp & __GFP_NOFAIL; > + gfp_t alloc_gfp = gfp & ~ __GFP_NOFAIL; > struct page *page; > int i; > > @@ -3527,9 +3527,6 @@ vm_area_alloc_pages(gfp_t gfp, int nid, > * more permissive. > */ > if (!order) { > - /* bulk allocator doesn't support nofail req. officially */ > - gfp_t bulk_gfp = gfp & ~__GFP_NOFAIL; > - > while (nr_allocated < nr_pages) { > unsigned int nr, nr_pages_request; > > @@ -3547,12 +3544,12 @@ vm_area_alloc_pages(gfp_t gfp, int nid, > * but mempolicy wants to alloc memory by interleaving. > */ > if (IS_ENABLED(CONFIG_NUMA) && nid == NUMA_NO_NODE) > - nr = alloc_pages_bulk_array_mempolicy_noprof(bulk_gfp, > + nr = alloc_pages_bulk_array_mempolicy_noprof(alloc_gfp, > nr_pages_request, > pages + nr_allocated); > > else > - nr = alloc_pages_bulk_array_node_noprof(bulk_gfp, nid, > + nr = alloc_pages_bulk_array_node_noprof(alloc_gfp, nid, > nr_pages_request, > pages + nr_allocated); > > @@ -3566,13 +3563,6 @@ vm_area_alloc_pages(gfp_t gfp, int nid, > if (nr != nr_pages_request) > break; > } > - } else if (gfp & __GFP_NOFAIL) { > - /* > - * Higher order nofail allocations are really expensive and > - * potentially dangerous (pre-mature OOM, disruptive reclaim > - * and compaction etc. > - */ > - alloc_gfp &= ~__GFP_NOFAIL; > } > > /* High-order pages or fallback path if "bulk" fails. */ > -- > See below the change. It does not do any functional change and it is rather a small refactoring, which includes the comment i wanted to add and what you wanted to be clarified(if i got you correctly): diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 3f9b6bd707d2..24fad2e48799 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -3531,8 +3531,6 @@ vm_area_alloc_pages(gfp_t gfp, int nid, unsigned int order, unsigned int nr_pages, struct page **pages) { unsigned int nr_allocated = 0; - gfp_t alloc_gfp = gfp; - bool nofail = gfp & __GFP_NOFAIL; struct page *page; int i; @@ -3543,9 +3541,6 @@ vm_area_alloc_pages(gfp_t gfp, int nid, * more permissive. */ if (!order) { - /* bulk allocator doesn't support nofail req. officially */ - gfp_t bulk_gfp = gfp & ~__GFP_NOFAIL; - while (nr_allocated < nr_pages) { unsigned int nr, nr_pages_request; @@ -3563,12 +3558,12 @@ vm_area_alloc_pages(gfp_t gfp, int nid, * but mempolicy wants to alloc memory by interleaving. */ if (IS_ENABLED(CONFIG_NUMA) && nid == NUMA_NO_NODE) - nr = alloc_pages_bulk_array_mempolicy_noprof(bulk_gfp, + nr = alloc_pages_bulk_array_mempolicy_noprof(gfp & ~__GFP_NOFAIL, nr_pages_request, pages + nr_allocated); - else - nr = alloc_pages_bulk_array_node_noprof(bulk_gfp, nid, + /* bulk allocator doesn't support nofail req. officially */ + nr = alloc_pages_bulk_array_node_noprof(gfp & ~__GFP_NOFAIL, nid, nr_pages_request, pages + nr_allocated); @@ -3582,24 +3577,18 @@ vm_area_alloc_pages(gfp_t gfp, int nid, if (nr != nr_pages_request) break; } - } else if (gfp & __GFP_NOFAIL) { - /* - * Higher order nofail allocations are really expensive and - * potentially dangerous (pre-mature OOM, disruptive reclaim - * and compaction etc. - */ - alloc_gfp &= ~__GFP_NOFAIL; } /* High-order pages or fallback path if "bulk" fails. */ while (nr_allocated < nr_pages) { - if (!nofail && fatal_signal_pending(current)) + if (!(gfp & __GFP_NOFAIL) && fatal_signal_pending(current)) break; if (nid == NUMA_NO_NODE) - page = alloc_pages_noprof(alloc_gfp, order); + page = alloc_pages_noprof(gfp, order); else - page = alloc_pages_node_noprof(nid, alloc_gfp, order); + page = alloc_pages_node_noprof(nid, gfp, order); + if (unlikely(!page)) break; @@ -3666,7 +3655,16 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, set_vm_area_page_order(area, page_shift - PAGE_SHIFT); page_order = vm_area_page_order(area); - area->nr_pages = vm_area_alloc_pages(gfp_mask | __GFP_NOWARN, + /* + * Higher order nofail allocations are really expensive and + * potentially dangerous (pre-mature OOM, disruptive reclaim + * and compaction etc. + * + * Please note, the __vmalloc_node_range_noprof() falls-back + * to order-0 pages if high-order attempt has been unsuccessful. + */ + area->nr_pages = vm_area_alloc_pages(page_order ? + gfp_mask &= ~__GFP_NOFAIL : gfp_mask | __GFP_NOWARN, node, page_order, nr_small_pages, area->pages); atomic_long_add(area->nr_pages, &nr_vmalloc_pages); Is that aligned with your wish? Thanks! -- Uladzislau Rezki