On Fri, 18 Oct 2019 11:40:49 +0200 Uladzislau Rezki <urezki@xxxxxxxxx> wrote: > > > alloc_vmap_area() is given a gfp_mask for the page allocator. > > > Let's respect that mask and consider it even in the case when > > > doing regular CPU preloading, i.e. where a context can sleep. > > > > This is explaining what but it doesn't say why. I would go with > > " > > Allocation functions should comply with the given gfp_mask as much as > > possible. The preallocation code in alloc_vmap_area doesn't follow that > > pattern and it is using a hardcoded GFP_KERNEL. Although this doesn't > > really make much difference because vmalloc is not GFP_NOWAIT compliant > > in general (e.g. page table allocations are GFP_KERNEL) there is no > > reason to spread that bad habit and it is good to fix the antipattern. > > " > I can go with that, agree. I am not sure if i need to update the patch > and send v4. Or maybe Andrew can directly update it in his tree. > > Andrew, should i send or can update? I updated the changelog with Michal's words prior to committing. You were cc'ed :) From: "Uladzislau Rezki (Sony)" <urezki@xxxxxxxxx> Subject: mm/vmalloc: respect passed gfp_mask when doing preloading Allocation functions should comply with the given gfp_mask as much as possible. The preallocation code in alloc_vmap_area doesn't follow that pattern and it is using a hardcoded GFP_KERNEL. Although this doesn't really make much difference because vmalloc is not GFP_NOWAIT compliant in general (e.g. page table allocations are GFP_KERNEL) there is no reason to spread that bad habit and it is good to fix the antipattern. [mhocko@xxxxxxxx: rewrite changelog] Link: http://lkml.kernel.org/r/20191016095438.12391-2-urezki@xxxxxxxxx Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Cc: Daniel Wagner <dwagner@xxxxxxx> Cc: Hillf Danton <hdanton@xxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Oleksiy Avramchenko <oleksiy.avramchenko@xxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/vmalloc.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/mm/vmalloc.c~mm-vmalloc-respect-passed-gfp_mask-when-do-preloading +++ a/mm/vmalloc.c @@ -1063,9 +1063,9 @@ static struct vmap_area *alloc_vmap_area return ERR_PTR(-EBUSY); might_sleep(); + gfp_mask = gfp_mask & GFP_RECLAIM_MASK; - va = kmem_cache_alloc_node(vmap_area_cachep, - gfp_mask & GFP_RECLAIM_MASK, node); + va = kmem_cache_alloc_node(vmap_area_cachep, gfp_mask, node); if (unlikely(!va)) return ERR_PTR(-ENOMEM); @@ -1073,7 +1073,7 @@ static struct vmap_area *alloc_vmap_area * Only scan the relevant parts containing pointers to other objects * to avoid false negatives. */ - kmemleak_scan_area(&va->rb_node, SIZE_MAX, gfp_mask & GFP_RECLAIM_MASK); + kmemleak_scan_area(&va->rb_node, SIZE_MAX, gfp_mask); retry: /* @@ -1099,7 +1099,7 @@ retry: * Just proceed as it is. If needed "overflow" path * will refill the cache we allocate from. */ - pva = kmem_cache_alloc_node(vmap_area_cachep, GFP_KERNEL, node); + pva = kmem_cache_alloc_node(vmap_area_cachep, gfp_mask, node); spin_lock(&vmap_area_lock); _
