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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Action: no action X-Rspamd-Server: rspamd2.dmz-prg2.suse.org X-Spamd-Result: default: False [-4.51 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; FUZZY_RATELIMITED(0.00)[rspamd.com]; FREEMAIL_TO(0.00)[collabora.com,gmail.com]; MIME_TRACE(0.00)[0:+]; ARC_NA(0.00)[]; FREEMAIL_CC(0.00)[linux.intel.com,kernel.org,gmail.com,ffwll.ch,lists.freedesktop.org,vger.kernel.org]; DKIM_TRACE(0.00)[suse.de:+]; TO_DN_SOME(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; RCVD_TLS_ALL(0.00)[]; DNSWL_BLOCKED(0.00)[2a07:de40:b281:106:10:150:64:167:received]; RCPT_COUNT_SEVEN(0.00)[8]; MID_RHS_MATCH_FROM(0.00)[]; ASN(0.00)[asn:32098, ipnet:2800::/6, country:US]; RCVD_VIA_SMTP_AUTH(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:dkim,suse.de:mid,suse.com:url] X-Rspamd-Queue-Id: 5A9064D202 X-Spam-Flag: NO X-Spam-Score: -4.51 X-Spam-Level: Hi Am 16.03.26 um 10:50 schrieb Boris Brezillon: >> Avoid this race by adding a huge_fault callback to drm_gem_shmem_vm_ops so that >> PMD-sized mappings are handled through the appropriate huge page fault path. This patch will conflict heavily with the folio-tracking patches that has been merged into upstream DRM. How do we deal with that? Best regards Thomas >> >> Fixes: 211b9a39f261 ("drm/shmem-helper: Map huge pages in fault handler") >> Signed-off-by: Pedro Demarchi Gomes >> --- >> >> Changes in v3: >> - Pass a try_pmd boolean parameter to drm_gem_shmem_any_fault >> - Compile drm_gem_shmem_huge_fault only if CONFIG_ARCH_SUPPORTS_PMD_PFNMAP >> is defined to avoid a build warning >> >> Changes in v2: https://lore.kernel.org/dri-devel/20260313141719.3949700-1-pedrodemargomes@gmail.com/ >> - Keep the #ifdef unindented >> - Create drm_gem_shmem_any_fault to handle faults of any order and use >> drm_gem_shmem_[huge_]fault() as wrappers >> >> v1: https://lore.kernel.org/all/20260312155027.1682606-1-pedrodemargomes@gmail.com/ >> >> --- >> drivers/gpu/drm/drm_gem_shmem_helper.c | 63 ++++++++++++++------------ >> 1 file changed, 35 insertions(+), 28 deletions(-) >> >> diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c >> index 7b5a49935ae4..9428c3ab7283 100644 >> --- a/drivers/gpu/drm/drm_gem_shmem_helper.c >> +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c >> @@ -550,36 +550,18 @@ int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev, >> } >> EXPORT_SYMBOL_GPL(drm_gem_shmem_dumb_create); >> >> -static bool drm_gem_shmem_try_map_pmd(struct vm_fault *vmf, unsigned long addr, >> - struct page *page) >> -{ >> -#ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP >> - unsigned long pfn = page_to_pfn(page); >> - unsigned long paddr = pfn << PAGE_SHIFT; >> - bool aligned = (addr & ~PMD_MASK) == (paddr & ~PMD_MASK); >> - >> - if (aligned && >> - pmd_none(*vmf->pmd) && >> - folio_test_pmd_mappable(page_folio(page))) { >> - pfn &= PMD_MASK >> PAGE_SHIFT; >> - if (vmf_insert_pfn_pmd(vmf, pfn, false) == VM_FAULT_NOPAGE) >> - return true; >> - } >> -#endif >> - >> - return false; >> -} >> - >> -static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) >> +static vm_fault_t drm_gem_shmem_any_fault(struct vm_fault *vmf, bool try_pmd) >> { >> struct vm_area_struct *vma = vmf->vma; >> struct drm_gem_object *obj = vma->vm_private_data; >> struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); >> loff_t num_pages = obj->size >> PAGE_SHIFT; >> - vm_fault_t ret; >> + vm_fault_t ret = VM_FAULT_FALLBACK; >> struct page **pages = shmem->pages; >> pgoff_t page_offset; >> unsigned long pfn; >> + unsigned long paddr; >> + bool aligned; > Those two variables can be moved to the `if (try_pmd)` branch. > >> /* Offset to faulty address in the VMA. */ >> page_offset = vmf->pgoff - vma->vm_pgoff; >> @@ -593,13 +575,19 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) >> goto out; >> } >> >> - if (drm_gem_shmem_try_map_pmd(vmf, vmf->address, pages[page_offset])) { >> - ret = VM_FAULT_NOPAGE; >> - goto out; >> - } >> - >> pfn = page_to_pfn(pages[page_offset]); >> - ret = vmf_insert_pfn(vma, vmf->address, pfn); >> + if (try_pmd) { >> + paddr = pfn << PAGE_SHIFT; >> + aligned = (vmf->address & ~PMD_MASK) == (paddr & ~PMD_MASK); >> + >> + if (aligned && >> + folio_test_pmd_mappable(page_folio(pages[page_offset]))) { >> + pfn &= PMD_MASK >> PAGE_SHIFT; >> + ret = vmf_insert_pfn_pmd(vmf, pfn, false); >> + } >> + } else { >> + ret = vmf_insert_pfn(vma, vmf->address, pfn); >> + } > Hm, if we get rid of drm_gem_shmem_try_map_pmd(), we probably > need something like > > if (!try_pmd) { > ret = vmf_insert_pfn(vma, vmf->address, pfn); > } else { > #ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP > unsigned long paddr = pfn << PAGE_SHIFT; > bool aligned = (vmf->address & ~PMD_MASK) == (paddr & ~PMD_MASK); > > if (aligned && > folio_test_pmd_mappable(page_folio(pages[page_offset]))) { > pfn &= PMD_MASK >> PAGE_SHIFT; > ret = vmf_insert_pfn_pmd(vmf, pfn, false); > } > #else > ret = VM_FAULT_FALLBACK; > #endif > } > > to make sure we're not calling helpers that might not > exist in some configs (the compile might optimize the > try_pmd==true branch out already, but better safe than sorry). > >> out: >> dma_resv_unlock(shmem->base.resv); >> @@ -607,6 +595,22 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) >> return ret; >> } >> >> +#ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP >> +static vm_fault_t drm_gem_shmem_huge_fault(struct vm_fault *vmf, >> + unsigned int order) >> +{ >> + if (order != PMD_ORDER) >> + return VM_FAULT_FALLBACK; >> + >> + return drm_gem_shmem_any_fault(vmf, true); >> +} >> +#endif >> + >> +static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) >> +{ >> + return drm_gem_shmem_any_fault(vmf, false); >> +} >> + >> static void drm_gem_shmem_vm_open(struct vm_area_struct *vma) >> { >> struct drm_gem_object *obj = vma->vm_private_data; >> @@ -643,6 +647,9 @@ static void drm_gem_shmem_vm_close(struct vm_area_struct *vma) >> >> const struct vm_operations_struct drm_gem_shmem_vm_ops = { >> .fault = drm_gem_shmem_fault, >> +#ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP >> + .huge_fault = drm_gem_shmem_huge_fault, >> +#endif >> .open = drm_gem_shmem_vm_open, >> .close = drm_gem_shmem_vm_close, >> }; >> -- >> 2.47.3 >> -- -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)