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charset=us-ascii Content-Disposition: inline In-Reply-To: <20250807075810.358714-8-urezki@gmail.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: D9E78180005 X-Stat-Signature: 54on8nnpgegtbyo5iksmqjgkac8q84y1 X-Rspam-User: X-HE-Tag: 1755491728-262580 X-HE-Meta: U2FsdGVkX1+h4v6qY/5YrbHvlcZyfJWJgsG5mSTMBxU/E9E4VIKcBsII0ZaLiWtIxsDajAFVqEeKqHJEqCT+xr0A9yEDW8zTusxO5xQ32Fc+vFsiZbuRpqTmx4HcnBPk8jwYoXGc4M6zV2LmlW68X4vKsM522uC3ok/kAZI8Kua7d6cZKcVkLlxxNiPZN1wQ6Z8DnXOSDkjeFJ38EmsFm7s4Vyjr0gnJzaRaLWeG13HXD0El7bFW64mvzdcohSq0RPrHXDym3TPwzqRdxmMpa2oZ8gphLJMpBjx5Yj6ddLPogYGuQyjVlRBvBge+KnNSqCTtg10Pigu2ZjskFRTNWFcrxU0DE5F0tbLyIrB1yhcNZrpO5IvfmKQpw+IfsphIOVnNDq+tr7CKAaQxSJWbWUvqHzKDgcpIeDPqZvCKq5UMj9N9o59w8+R7qlIuzTzFZMy1tzm2HlaCxOLeeCH7Y5ZvKlhtZfN+fmWMHNDlntO0WPD5L7ua3DsASHqfz4Du2O1VDCNtujK4e7Pz/1fh5HP9H2yj/CCkbhmcLkyU7rKx5WK90UmRaO+ZOJUkNt5EadMQr+A7CXz7qfV7wBiqSxbWj8hY7GqSm+mXKNuN+KzUPl2z5Rqbo8dWAi4qpVFMANgtRXjX+tFjjmNO86SZ+HU1bLR4yAq/bywGvD9RbVayQa9+fxh53d1glThwBHlu+wVNVxDfSRTrbairo3/0xlSVnjhikh35vyd1QGK78EOX9YXyKvyDjOf1TVKo7X5rX84kjCKE3nzdJtCuuvfiU43tAOXvXAU4c8uXT6aMvQeD/SO+xvpvmUF77RfLxB1aIE+vc0diq4ZCInp1go+X5GuffKvKjOcLWoddKzfz3YfYHzlRSh00W0kdnieGRPNCNudazO3J+F0OJO/4gPTW5aOn37867+RbGW4xZ6ULk5IbyC8mUY+A14I0s4jYnNUfoPDaKZXkUrmHH0eDs9O TLda7Y5v nDkva9zUTLdAUo3E2iZp2SniiyTFpCC6K7lVde0cib653BzPWb5TdZHG5OojcMN550immSNIhfvLZAyrmcZt62mdCoOLVX3jg6PekiDuqO/o8OO0LyZjssYW+F1C3aM8KzOj85g5v5CtqiDQ5iLa7LmoFY8KZ8NLenzgcLeT13mm+QaHZnuDv7ryK2vL7g80pUN4U0WUITjBV7WrTa0atmICrgPO5o8YjcAZr+YPo3J0y2Knjiuij5KmrYNrAj4358z0dhIjm9j3zA5RkeW2kTXXvSWQXDPveR2v4IaH9iRatbOPXaXpdigUuWMo0fuS28b0qkkXEF3fRplXmL9ewgU80V7fL1zpCC1UNLGqSJDNpOonyOXNqxmojFUTvKlZXqojJXyYrz4d4d0RGMT32X23hnO14xtet8dpMwHXQlDeR9uvIn+1iauLZTNSWkC5TRLIqdxaJi1ey3ul8KcBgoAQ26A== 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 08/07/25 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);