| Message ID | 20100128090835.0d93e53a@nehalam |
|---|---|
| State | Not Applicable, archived |
| Delegated to: | David Miller |
| Headers | show |
On 1/28/2010 12:08 PM, Stephen Hemminger wrote: > On Thu, 28 Jan 2010 11:43:16 -0500 > Michael Breuer<mbreuer@majjas.com> wrote: > > >> Update: I played with dma-debug. Was being disabled due to lack of >> memory. I forced it back on while pumping traffic through and got this: >> Jan 28 11:39:30 mail kernel: ------------[ cut here ]------------ >> Jan 28 11:39:30 mail kernel: WARNING: at lib/dma-debug.c:902 >> check_sync+0xc1/0x43f() >> Jan 28 11:39:30 mail kernel: Hardware name: System Product Name >> Jan 28 11:39:30 mail kernel: sky2 0000:06:00.0: DMA-API: device driver >> tries to sync DMA memory it has not allocated [device >> > This test in dma-debug is bogus. Because the debug code matches > dma based on address and size; and is perfectly valid to sync a value > less than size. This is the patch I sent earlier, it isn't 100% > correct but it will let you keep testing > .................................... > > > This should fix the dma-debug API code (and documentation), to > avoid false positives when sync is done on a partial map. > > Signed-off-by: Stephen Hemminger<shemminger@vyatta.com> > > --- a/Documentation/DMA-API.txt 2010-01-20 15:17:01.390143729 -0800 > +++ b/Documentation/DMA-API.txt 2010-01-20 15:18:48.967875255 -0800 > @@ -377,9 +377,10 @@ void > pci_dma_sync_sg(struct pci_dev *hwdev, struct scatterlist *sg, > int nelems, int direction) > > -Synchronise a single contiguous or scatter/gather mapping. All the > -parameters must be the same as those passed into the single mapping > -API. > +Synchronise a single contiguous or scatter/gather mapping. The > +device and handle must be the same as those passed into the single mapping > +API. The size can be less than the original mapping if only part > +of the mapping needs to be accessed. > > Notes: You must do this: > > --- a/lib/dma-debug.c 2010-01-20 15:22:55.919519883 -0800 > +++ b/lib/dma-debug.c 2010-01-20 15:26:31.648895638 -0800 > @@ -285,11 +285,9 @@ static struct dma_debug_entry *hash_buck > } > > /* > - * If we have multiple matches but no perfect-fit, just return > - * NULL. > + * If we have multiple matches but no perfect-fit > + * return best value and let caller deal with it. > */ > - ret = (matches == 1) ? ret : NULL; > - > return ret; > } > > Ok - applied. Noise gone... however I'm not sure whether I'll be able to keep dma-debug going long enough to catch anything. num_free_entries keeps dropping... looks like entries are not freed. I'm running with a huge number for now & sky2 as the driver filter. Is there a reason that entries wouldn't be unmapped, or is dma-debug.c just not processing the unmap correctly? -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Jan 28, 2010 at 01:46:17PM -0500, Michael Breuer wrote: > On 1/28/2010 12:08 PM, Stephen Hemminger wrote: > >--- a/lib/dma-debug.c 2010-01-20 15:22:55.919519883 -0800 > >+++ b/lib/dma-debug.c 2010-01-20 15:26:31.648895638 -0800 > >@@ -285,11 +285,9 @@ static struct dma_debug_entry *hash_buck > > } > > > > /* > >- * If we have multiple matches but no perfect-fit, just return > >- * NULL. > >+ * If we have multiple matches but no perfect-fit > >+ * return best value and let caller deal with it. > > */ > >- ret = (matches == 1) ? ret : NULL; > >- > > return ret; > > } > > > Ok - applied. Noise gone... however I'm not sure whether I'll be > able to keep dma-debug going long enough to catch anything. > num_free_entries keeps dropping... looks like entries are not freed. > I'm running with a huge number for now & sky2 as the driver filter. > Is there a reason that entries wouldn't be unmapped, or is > dma-debug.c just not processing the unmap correctly? Do you mean it's after this patch or earlier too? I think you might use my sky2/receive_copy/pci_unmap_len patch instead to get rid of this warning. Btw, since 1000 was too much, maybe you could try copybreak=256 yet, plus additional ping or some other source of shorter packets. And how about trying this new switch? Jarek P. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 1/28/2010 5:34 PM, Jarek Poplawski wrote: > On Thu, Jan 28, 2010 at 01:46:17PM -0500, Michael Breuer wrote: > >> On 1/28/2010 12:08 PM, Stephen Hemminger wrote: >> >>> --- a/lib/dma-debug.c 2010-01-20 15:22:55.919519883 -0800 >>> +++ b/lib/dma-debug.c 2010-01-20 15:26:31.648895638 -0800 >>> @@ -285,11 +285,9 @@ static struct dma_debug_entry *hash_buck >>> } >>> >>> /* >>> - * If we have multiple matches but no perfect-fit, just return >>> - * NULL. >>> + * If we have multiple matches but no perfect-fit >>> + * return best value and let caller deal with it. >>> */ >>> - ret = (matches == 1) ? ret : NULL; >>> - >>> return ret; >>> } >>> >>> >> Ok - applied. Noise gone... however I'm not sure whether I'll be >> able to keep dma-debug going long enough to catch anything. >> num_free_entries keeps dropping... looks like entries are not freed. >> I'm running with a huge number for now& sky2 as the driver filter. >> Is there a reason that entries wouldn't be unmapped, or is >> dma-debug.c just not processing the unmap correctly? >> > Do you mean it's after this patch or earlier too? I think you might > use my sky2/receive_copy/pci_unmap_len patch instead to get rid of > this warning. > > Btw, since 1000 was too much, maybe you could try copybreak=256 yet, > plus additional ping or some other source of shorter packets. And how > about trying this new switch? > > Jarek P. > This is with the pci_unmap_len patch as well as the dma-debug patch. I'm not getting any warnings - but dma-debug num-free-entries drops until zero and then debugging is disabled. I started with 8,000,000 about three hours ago - without load I'm already down to less than half that. Again - only looking at sky2. Looks like the dma-debug hash table is reducing one entry for every packet, but never increasing the num_entries (no unmap perhaps). -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Jan 28, 2010 at 05:43:34PM -0500, Michael Breuer wrote: > This is with the pci_unmap_len patch as well as the dma-debug patch. > I'm not getting any warnings - but dma-debug num-free-entries drops > until zero and then debugging is disabled. I started with 8,000,000 > about three hours ago - without load I'm already down to less than > half that. Again - only looking at sky2. Looks like the dma-debug > hash table is reducing one entry for every packet, but never > increasing the num_entries (no unmap perhaps). OK, then, until there is some new fix you better turn it off. Jarek P. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 1/28/2010 5:56 PM, Jarek Poplawski wrote: > On Thu, Jan 28, 2010 at 05:43:34PM -0500, Michael Breuer wrote: > >> This is with the pci_unmap_len patch as well as the dma-debug patch. >> I'm not getting any warnings - but dma-debug num-free-entries drops >> until zero and then debugging is disabled. I started with 8,000,000 >> about three hours ago - without load I'm already down to less than >> half that. Again - only looking at sky2. Looks like the dma-debug >> hash table is reducing one entry for every packet, but never >> increasing the num_entries (no unmap perhaps). >> > OK, then, until there is some new fix you better turn it off. > > Jarek P. > :( any further suggestions for helping track this down? -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
--- a/Documentation/DMA-API.txt 2010-01-20 15:17:01.390143729 -0800 +++ b/Documentation/DMA-API.txt 2010-01-20 15:18:48.967875255 -0800 @@ -377,9 +377,10 @@ void pci_dma_sync_sg(struct pci_dev *hwdev, struct scatterlist *sg, int nelems, int direction) -Synchronise a single contiguous or scatter/gather mapping. All the -parameters must be the same as those passed into the single mapping -API. +Synchronise a single contiguous or scatter/gather mapping. The +device and handle must be the same as those passed into the single mapping +API. The size can be less than the original mapping if only part +of the mapping needs to be accessed. Notes: You must do this: --- a/lib/dma-debug.c 2010-01-20 15:22:55.919519883 -0800 +++ b/lib/dma-debug.c 2010-01-20 15:26:31.648895638 -0800 @@ -285,11 +285,9 @@ static struct dma_debug_entry *hash_buck } /* - * If we have multiple matches but no perfect-fit, just return - * NULL. + * If we have multiple matches but no perfect-fit + * return best value and let caller deal with it. */ - ret = (matches == 1) ? ret : NULL; - return ret; }