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X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Apr 2024 19:37:07.6121 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 70d47d83-3fd3-4d8d-f16f-08dc630398b2 X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.160];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: CO1PEPF000044F3.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR12MB8016 On 4/22/24 12:31 PM, David Hildenbrand wrote: > On 19.04.24 02:15, John Hubbard wrote: >> On 4/18/24 8:18 AM, David Hildenbrand wrote: ... >>>     * >>>     * Returns 0 if the huge page was split successfully. >>>     * >>> - * Returns -EBUSY if @page's folio is pinned, or if the anon_vma disappeared >>> - * from under us. >>> + * Returns -EAGAIN if the folio has unexpected reference (e.g., GUP). >> >> ...or if the folio was removed from the page cache before this routine >> got a chance to lock it, right? (See the "fail:" path.) > > Right, that is sneaky. Let me extend to cover that case as well. > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 824eff9211db8..a7406267323ed 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -2975,7 +2975,8 @@ bool can_split_folio(struct folio *folio, int *pextra_pins) >   * >   * Returns 0 if the huge page was split successfully. >   * > - * Returns -EAGAIN if the folio has unexpected reference (e.g., GUP). > + * Returns -EAGAIN if the folio has unexpected reference (e.g., GUP) or if > + * the folio was concurrently removed from the page cache. Looks good, Reviewed-by: John Hubbard thanks, -- John Hubbard NVIDIA