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charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 48DDE180003 X-Stat-Signature: x5icx1t55wqez79o6rgbpbtdhj9y61ar X-Rspam-User: X-HE-Tag: 1755593209-498465 X-HE-Meta: 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 Hhu2F24T YzSb4DkvankxF0wBUlJpNofrsEeXJgvG+JBFPbUHmmB97P0M59sQ9JwtZbyqC+94HGDdl8lsKFaJgT4dNuibth6xJZplY03rXjZ46PGI5OJtEpYGoJBeICBBIVB+fejq+CmwbT49BA1JfMgqsAalLsil3ZtmDbnslJs0EgaSSaNcURDx7PfUeEnjcwjhmzVqs+8r76LC/vGEiasso+FQOGk8HRE83ORYZKUSDIxYXQDXq1px7vNLOIYy+Og9qcwDQu2VcOROVvStPsKGIL9nrJg8MtW0IyoVnFeXZUHOLhgrev+3tOgfAuDwVMt1mDA2d29QoFyqJ226cJ8YUKEQNrlYgwi0DdrEvVxKwTkrOIsMH+knuULv3BqGJJWZ5Pj3Zq372++hD58UWaXNy/3GMbTo2BRH/+QWD+fyXg8YiH8ESaUMmdQHJyw6CU3Kq41CJ31cgSZqUCH8fJhM1RCi1BTV0+Q== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 08/18/25 at 03:08pm, Uladzislau Rezki wrote: > On Mon, Aug 18, 2025 at 12:35:16PM +0800, Baoquan He wrote: > > On 08/07/25 at 09:58am, Uladzislau Rezki (Sony) wrote: > > > This patch makes __vmalloc_area_node() to correctly handle non-blocking > > > allocation requests, such as GFP_ATOMIC and GFP_NOWAIT. Main changes: > > > > > > - Add a __GFP_HIGHMEM to gfp_mask only for blocking requests > > > if there are no DMA constraints. > > > > > > - vmap_page_range() is wrapped by memalloc_noreclaim_save/restore() > > > to avoid memory reclaim related operations that could sleep during > > > page table setup or mapping pages. > > > > > > This is particularly important for page table allocations that > > > internally use GFP_PGTABLE_KERNEL, which may sleep unless such > > > scope restrictions are applied. For example: > > > > > > > > > __pte_alloc_kernel() > > > pte_alloc_one_kernel(&init_mm); > > > pagetable_alloc_noprof(GFP_PGTABLE_KERNEL & ~__GFP_HIGHMEM, 0); > > > > > > > > > Note: in most cases, PTE entries are established only up to the level > > > required by current vmap space usage, meaning the page tables are typically > > > fully populated during the mapping process. > > > > > > Signed-off-by: Uladzislau Rezki (Sony) > > > --- > > > mm/vmalloc.c | 20 ++++++++++++++++---- > > > 1 file changed, 16 insertions(+), 4 deletions(-) > > > > > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > > > index 2424f80d524a..8a7eab810561 100644 > > > --- a/mm/vmalloc.c > > > +++ b/mm/vmalloc.c > > > @@ -3721,12 +3721,20 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, > > > unsigned int nr_small_pages = size >> PAGE_SHIFT; > > > unsigned int page_order; > > > unsigned int flags; > > > + bool noblock; > > > int ret; > > > > > > array_size = (unsigned long)nr_small_pages * sizeof(struct page *); > > > + noblock = !gfpflags_allow_blocking(gfp_mask); > > > > > > - if (!(gfp_mask & (GFP_DMA | GFP_DMA32))) > > > - gfp_mask |= __GFP_HIGHMEM; > > > + if (noblock) { > > > + /* __GFP_NOFAIL and "noblock" flags are mutually exclusive. */ > > > + nofail = false; > > > + } else { > > > + /* Allow highmem allocations if there are no DMA constraints. */ > > > + if (!(gfp_mask & (GFP_DMA | GFP_DMA32))) > > > + gfp_mask |= __GFP_HIGHMEM; > > > + } > > > > > > /* Please note that the recursion is strictly bounded. */ > > > if (array_size > PAGE_SIZE) { > > > @@ -3790,7 +3798,9 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, > > > * page tables allocations ignore external gfp mask, enforce it > > > * by the scope API > > > */ > > > - if ((gfp_mask & (__GFP_FS | __GFP_IO)) == __GFP_IO) > > > + if (noblock) > > > + flags = memalloc_noreclaim_save(); > > > + else if ((gfp_mask & (__GFP_FS | __GFP_IO)) == __GFP_IO) > > > flags = memalloc_nofs_save(); > > > else if ((gfp_mask & (__GFP_FS | __GFP_IO)) == 0) > > > flags = memalloc_noio_save(); > > > @@ -3802,7 +3812,9 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, > > > schedule_timeout_uninterruptible(1); > > > } while (nofail && (ret < 0)); > > > > > > - if ((gfp_mask & (__GFP_FS | __GFP_IO)) == __GFP_IO) > > > + if (noblock) > > > + memalloc_noreclaim_restore(flags); > > > + else if ((gfp_mask & (__GFP_FS | __GFP_IO)) == __GFP_IO) > > > memalloc_nofs_restore(flags); > > > else if ((gfp_mask & (__GFP_FS | __GFP_IO)) == 0) > > > memalloc_noio_restore(flags); > > > > Can we use memalloc_flags_restore(flags) directly to replace above if > > else checking? It can reduce LOC, might be not as readable as the change > > in patch surely. Not strong opinion. > > > > memalloc_flags_restore(flags); > > > I agree, those if/else cases looks ugly. Maybe adding two save/restore > functions are worth doing specifically for vmalloc part. Yeah, that is also great idea.