kernel/linux.git/sound/core/memalloc.c, branch v6.1.168

ALSA: memalloc: Workaround for Xen PV

2023-02-09T10:28:02+00:00

[ Upstream commit 53466ebdec614f915c691809b0861acecb941e30 ] We change recently the memalloc helper to use dma_alloc_noncontiguous() and the fallback to get_pages(). Although lots of issues with IOMMU (or non-IOMMU) have been addressed, but there seems still a regression on Xen PV. Interestingly, the only proper way to work is use dma_alloc_coherent(). The use of dma_alloc_coherent() for SG buffer was dropped as it's problematic on IOMMU systems. OTOH, Xen PV has a different way, and it's fine to use the dma_alloc_coherent(). This patch is a workaround for Xen PV. It consists of the following changes: - For Xen PV, use only the fallback allocation without dma_alloc_noncontiguous() - In the fallback allocation, use dma_alloc_coherent(); the DMA address from dma_alloc_coherent() is returned in get_addr ops - The DMA addresses are stored in an array; the first entry stores the number of allocated pages in lower bits, which are referred at releasing pages again Reported-by: Marek Marczykowski-Górecki Tested-by: Marek Marczykowski-Górecki Fixes: a8d302a0b770 ("ALSA: memalloc: Revive x86-specific WC page allocations again") Fixes: 9736a325137b ("ALSA: memalloc: Don't fall back for SG-buffer with IOMMU") Link: https://lore.kernel.org/r/87tu256lqs.wl-tiwai@suse.de Link: https://lore.kernel.org/r/20230125153104.5527-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin

ALSA: memalloc: Allocate more contiguous pages for fallback case

2022-12-31T12:32:11+00:00

[ Upstream commit cc26516374065a34e10c9a8bf3e940e42cd96e2a ] Currently the fallback SG allocation tries to allocate each single page, and this tends to result in the reverse order of memory addresses when large space is available at boot, as the kernel takes a free page from the top to the bottom in the zone. The end result looks as if non-contiguous (although it actually is). What's worse is that it leads to an overflow of BDL entries for HD-audio. For avoiding such a problem, this patch modifies the allocation code slightly; now it tries to allocate the larger contiguous chunks as much as possible, then reduces to the smaller chunks only if the allocation failed -- a similar strategy as the existing snd_dma_alloc_pages_fallback() function. Along with the trick, drop the unused address array from snd_dma_sg_fallback object. It was needed in the past when dma_alloc_coherent() was used, but with the standard page allocator, it became superfluous and never referred. Fixes: a8d302a0b770 ("ALSA: memalloc: Revive x86-specific WC page allocations again") Reviewed-by: Kai Vehmanen Link: https://lore.kernel.org/r/20221114141658.29620-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin

ALSA: memalloc: Try dma_alloc_noncontiguous() at first

2022-11-12T08:48:51+00:00

The latest fix for the non-contiguous memalloc helper changed the allocation method for a non-IOMMU system to use only the fallback allocator. This should have worked, but it caused a problem sometimes when too many non-contiguous pages are allocated that can't be treated by HD-audio controller. As a quirk workaround, go back to the original strategy: use dma_alloc_noncontiguous() at first, and apply the fallback only when it fails, but only for non-IOMMU case. We'll need a better fix in the fallback code as well, but this workaround should paper over most cases. Fixes: 9736a325137b ("ALSA: memalloc: Don't fall back for SG-buffer with IOMMU") Reported-by: Linus Torvalds Link: https://lore.kernel.org/r/CAHk-=wgSH5ubdvt76gNwa004ooZAEJL_1Q-Fyw5M2FDdqL==dg@mail.gmail.com Link: https://lore.kernel.org/r/20221112084718.3305-1-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: memalloc: Don't fall back for SG-buffer with IOMMU

2022-11-10T13:23:03+00:00

When the non-contiguous page allocation for SG buffer allocation fails, the memalloc helper tries to fall back to the old page allocation methods. This would, however, result in the bogus page addresses when IOMMU is enabled. Usually in such a case, the fallback allocation should fail as well, but occasionally it succeeds and hitting a bad access. The fallback was thought for non-IOMMU case, and as the error from dma_alloc_noncontiguous() with IOMMU essentially implies a fatal memory allocation error, we should return the error straightforwardly without fallback. This avoids the corner case like the above. The patch also renames the local variable "dma_ops" with snd_ prefix for avoiding the name conflict. Fixes: a8d302a0b770 ("ALSA: memalloc: Revive x86-specific WC page allocations again") Reported-by: Kai Vehmanen Reviewed-by: Kai Vehmanen Link: https://lore.kernel.org/r/alpine.DEB.2.22.394.2211041541090.3532114@eliteleevi.tm.intel.com Link: https://lore.kernel.org/r/20221110132216.30605-1-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: memalloc: use __GFP_RETRY_MAYFAIL for DMA mem allocs

2022-09-26T06:23:37+00:00

Use __GFP_RETRY_MAYFAIL instead of __GFP__NORETRY in snd_dma_dev_alloc(), snd_dma_wc_alloc() and friends, to allocate pages for device memory. The MAYFAIL flag retains the semantics of not triggering the OOM killer, but lowers the risk of alloc failure. MAYFAIL flag was added in commit dcda9b04713c3 ("mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic"). This change addresses recurring failures with SOF audio driver in test cases where a system suspend-resume stress test is run, combined with an active high memory-load use-case. The failure typically shows up as: [ 379.480229] sof-audio-pci-intel-tgl 0000:00:1f.3: booting DSP firmware [ 379.484803] sof-audio-pci-intel-tgl 0000:00:1f.3: error: memory alloc failed: -12 [ 379.484810] sof-audio-pci-intel-tgl 0000:00:1f.3: error: dma prepare for ICCMAX stream failed Multiple fixes to reduce the memory usage of DSP boot have been identified in SOF driver, but even with those fixes, debug on affected systems has shown that even a single page alloc may fail with __GFP_NORETRY. When this occurs, system is under significant load on physical memory, but a lot of reclaimable pages are available, so the system has not run out of memory. With __GFP_RETRY_MAYFAIL, the errors are not hit in these stress tests. The alloc failure is severe as audio capability is completely lost if alloc failure is hit at system resume. An alternative solution was considered where the resources for DSP boot would be kept allocated until driver is unbound. This would avoid the allocation failure, but consume memory that is only needed temporarily at probe and resume time. It seems better to not hang on to the memory, but rather work a bit harder for allocating the pages at resume. BugLink: https://github.com/thesofproject/linux/issues/3844 Signed-off-by: Kai Vehmanen Reviewed-by: Pierre-Louis Bossart Link: https://lore.kernel.org/r/20220923153501.3326041-1-kai.vehmanen@linux.intel.com Signed-off-by: Takashi Iwai

Merge branch 'for-linus' into for-next

2022-09-06T09:04:15+00:00

Once again back-merge the 6.0-rc devel branch for further USB-audio and HD-audio developments. Signed-off-by: Takashi Iwai

ALSA: hda: Once again fix regression of page allocations with IOMMU

2022-09-06T09:03:48+00:00

The last fix for trying to recover the regression on AMD platforms, unfortunately, leaded to yet another regression: it turned out that IOMMUs don't like the usage of raw page allocations. This is yet another attempt for addressing the log saga; at this time, we re-use the existing buffer allocation mechanism with SG-pages although we require only single pages. The SG buffer allocation itself was confirmed to work for stream buffers, so it's relatively easy to adapt for other places. The only problem is: although the HD-audio code is accessing the address directly via dmab->address field, SG-pages don't set up it. For the ease of adaption, we now set up the dmab->addr field from the address of the first page as default, so that it can run with the HD-audio driver code as-is without the excessive call of snd_sgbuf_get_addr() multiple times; that's the only change in the memalloc helper side. The rest is nothing but a flip of the dma_type field in the HD-audio side. Fixes: a8d302a0b770 ("ALSA: memalloc: Revive x86-specific WC page allocations again") Reported-by: Mikhail Gavrilov Tested-by: Mikhail Gavrilov Cc: Link: https://lore.kernel.org/r/CABXGCsO+kB2t5QyHY-rUe76npr1m0-5JOtt8g8SiHUo34ur7Ww@mail.gmail.com Link: https://bugzilla.kernel.org/show_bug.cgi?id=216112 Link: https://bugzilla.kernel.org/show_bug.cgi?id=216363 Link: https://lore.kernel.org/r/20220906090319.23358-1-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: memalloc: Drop special handling of GFP for CONTINUOUS allocation

2022-08-24T06:00:26+00:00

Now that all users of snd_dma_continuous_data() is gone, let's drop this ugly (and dangerous) way. After this commit, SNDRV_DMA_TYPE_CONTINUOUS may take the standard device pointer instead of the hacked pointer by the macro above, and the memalloc core refers to the coherent_dma_mask of the given device like other SNDRV_DMA_TYPE. It's still allowed to pass NULL there, and in that case, the allocation is performed always in the normal zone. For SNDRV_DMA_TYPE_VMALLOC, the device pointer is simply ignored. Link: https://lore.kernel.org/r/20220823115740.14123-5-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: memalloc: Revive x86-specific WC page allocations again

2022-08-22T11:01:27+00:00

We dropped the x86-specific hack for WC-page allocations with a hope that the standard dma_alloc_wc() works nowadays. Alas, it doesn't, and we need to take back some workaround again, but in a different form, as the previous one was broken for some platforms. This patch re-introduces the x86-specific WC-page allocations, but it uses rather the manual page allocations instead of dma_alloc_coherent(). The use of dma_alloc_coherent() was also a potential problem in the recent addition of the fallback allocation for noncontig pages, and this patch eliminates both at once. Fixes: 9882d63bea14 ("ALSA: memalloc: Drop x86-specific hack for WC allocations") Cc: BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=216363 Link: https://lore.kernel.org/r/20220821155911.10715-1-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: memalloc: Fix missing return value comments for kernel docs

2022-07-13T11:42:37+00:00

Each kernel doc comment expects the definition of the return value in a proper format. This patch adds or fixes the missing entries for memory allocation helpers. Link: https://lore.kernel.org/r/20220713104759.4365-7-tiwai@suse.de Signed-off-by: Takashi Iwai