On 12/25/21 at 05:53am, Hyeonggon Yoo wrote: > On Thu, Dec 23, 2021 at 05:44:35PM +0800, Baoquan He wrote: ...... > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index 7c7a0b5de2ff..843bc8e5550a 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -4204,7 +4204,8 @@ void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...) > > va_list args; > > static DEFINE_RATELIMIT_STATE(nopage_rs, 10*HZ, 1); > > > > - if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs)) > > + if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs) || > > + (gfp_mask & __GFP_DMA) && !has_managed_dma()) > > return; > > > > Warning when there's always no page in DMA zone is unnecessary > and it confuses user. > > The patch looks good. > Reviewed-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx> > > And there is some driers that allocate memory with GFP_DMA > even if that flag is unnecessary. We need to do cleanup later. Thanks for reviewing and giving out some awesome suggestions. > > Baoquan Are you planning to do it soon? > I want to help that. Yes, I had the plan and have done a little part. I talked to Christoph about my thought. I planned to collect all kmalloc(GFP_DMA) callsite and post a RFC mail, CC mailing list and maintainers related. Anyone interested or know one or several callsites well can help. Now, Christoph has handled all under drviers/scsi, and post patches to fix them. I have gone throug those places and found out below callsites where we can remove GFP_DMA directly when calling kmalloc() since not necessary. And even found one place kmalloc(GFP_DMA32). (HEAD -> master) vxge: don't use GFP_DMA mtd: rawnand: marvell: don't use GFP_DMA HID: intel-ish-hid: remove wrong GFP_DMA32 flag ps3disk: don't use GFP_DMA atm: iphase: don't use GFP_DMA Next, I will send a RFC mail to contain those suspect callsites. We can track them and can help if needed. Suggest to change them with: 1) using dma_alloc_xx , or dma_map_xx after kmalloc() 2) using alloc_pages(GFP_DMA) instead When we fix, we all post patch with subject key words as 'xxxx: don't use GFP_DMA'. Christoph has posted patch with the similar subject, we can search subject to get all related patches for later back porting. I will add you to CC when sending. Could be tomorrow. Any suggestion or thought? Thanks Baoquan
