| Message ID | 20210121175502.274391-2-minchan@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Chunk Heap Support on DMA-HEAP | expand |
On 21.01.21 18:54, Minchan Kim wrote: > The upcoming patch will introduce __GFP_NORETRY semantic > in alloc_contig_range which is a failfast mode of the API. > Instead of adding a additional parameter for gfp, replace > no_warn with gfp flag. > > To keep old behaviors, it follows the rule below. > > no_warn gfp_flags > > false GFP_KERNEL > true GFP_KERNEL|__GFP_NOWARN > gfp & __GFP_NOWARN GFP_KERNEL | (gfp & __GFP_NOWARN) > > Reviewed-by: Suren Baghdasaryan <surenb@google.com> > Signed-off-by: Minchan Kim <minchan@kernel.org> > --- > drivers/dma-buf/heaps/cma_heap.c | 2 +- > drivers/s390/char/vmcp.c | 2 +- > include/linux/cma.h | 2 +- > kernel/dma/contiguous.c | 3 ++- > mm/cma.c | 12 ++++++------ > mm/cma_debug.c | 2 +- > mm/hugetlb.c | 6 ++++-- > mm/secretmem.c | 3 ++- > 8 files changed, 18 insertions(+), 14 deletions(-) > > diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c > index 364fc2f3e499..0afc1907887a 100644 > --- a/drivers/dma-buf/heaps/cma_heap.c > +++ b/drivers/dma-buf/heaps/cma_heap.c > @@ -298,7 +298,7 @@ static int cma_heap_allocate(struct dma_heap *heap, > if (align > CONFIG_CMA_ALIGNMENT) > align = CONFIG_CMA_ALIGNMENT; > > - cma_pages = cma_alloc(cma_heap->cma, pagecount, align, false); > + cma_pages = cma_alloc(cma_heap->cma, pagecount, align, GFP_KERNEL); > if (!cma_pages) > goto free_buffer; > > diff --git a/drivers/s390/char/vmcp.c b/drivers/s390/char/vmcp.c > index 9e066281e2d0..78f9adf56456 100644 > --- a/drivers/s390/char/vmcp.c > +++ b/drivers/s390/char/vmcp.c > @@ -70,7 +70,7 @@ static void vmcp_response_alloc(struct vmcp_session *session) > * anymore the system won't work anyway. > */ > if (order > 2) > - page = cma_alloc(vmcp_cma, nr_pages, 0, false); > + page = cma_alloc(vmcp_cma, nr_pages, 0, GFP_KERNEL); > if (page) { > session->response = (char *)page_to_phys(page); > session->cma_alloc = 1; > diff --git a/include/linux/cma.h b/include/linux/cma.h > index 217999c8a762..d6c02d08ddbc 100644 > --- a/include/linux/cma.h > +++ b/include/linux/cma.h > @@ -45,7 +45,7 @@ extern int cma_init_reserved_mem(phys_addr_t base, phys_addr_t size, > const char *name, > struct cma **res_cma); > extern struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, > - bool no_warn); > + gfp_t gfp_mask); > extern bool cma_release(struct cma *cma, const struct page *pages, unsigned int count); > > extern int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data); > diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c > index 3d63d91cba5c..552ed531c018 100644 > --- a/kernel/dma/contiguous.c > +++ b/kernel/dma/contiguous.c > @@ -260,7 +260,8 @@ struct page *dma_alloc_from_contiguous(struct device *dev, size_t count, > if (align > CONFIG_CMA_ALIGNMENT) > align = CONFIG_CMA_ALIGNMENT; > > - return cma_alloc(dev_get_cma_area(dev), count, align, no_warn); > + return cma_alloc(dev_get_cma_area(dev), count, align, GFP_KERNEL | > + (no_warn ? __GFP_NOWARN : 0)); > } > > /** > diff --git a/mm/cma.c b/mm/cma.c > index 0ba69cd16aeb..d50627686fec 100644 > --- a/mm/cma.c > +++ b/mm/cma.c > @@ -419,13 +419,13 @@ static inline void cma_debug_show_areas(struct cma *cma) { } > * @cma: Contiguous memory region for which the allocation is performed. > * @count: Requested number of pages. > * @align: Requested alignment of pages (in PAGE_SIZE order). > - * @no_warn: Avoid printing message about failed allocation > + * @gfp_mask: GFP mask to use during the cma allocation. > * > * This function allocates part of contiguous memory on specific > * contiguous memory area. > */ > struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, > - bool no_warn) > + gfp_t gfp_mask) > { > unsigned long mask, offset; > unsigned long pfn = -1; > @@ -438,8 +438,8 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, > if (!cma || !cma->count || !cma->bitmap) > return NULL; > > - pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma, > - count, align); > + pr_debug("%s(cma %p, count %zu, align %d gfp_mask 0x%x)\n", __func__, > + (void *)cma, count, align, gfp_mask); > > if (!count) > return NULL; > @@ -471,7 +471,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, > > pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit); > ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, > - GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0)); > + gfp_mask); > > if (ret == 0) { > page = pfn_to_page(pfn); > @@ -500,7 +500,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, > page_kasan_tag_reset(page + i); > } > > - if (ret && !no_warn) { > + if (ret && !(gfp_mask & __GFP_NOWARN)) { > pr_err("%s: alloc failed, req-size: %zu pages, ret: %d\n", > __func__, count, ret); > cma_debug_show_areas(cma); > diff --git a/mm/cma_debug.c b/mm/cma_debug.c > index d5bf8aa34fdc..00170c41cf81 100644 > --- a/mm/cma_debug.c > +++ b/mm/cma_debug.c > @@ -137,7 +137,7 @@ static int cma_alloc_mem(struct cma *cma, int count) > if (!mem) > return -ENOMEM; > > - p = cma_alloc(cma, count, 0, false); > + p = cma_alloc(cma, count, 0, GFP_KERNEL); > if (!p) { > kfree(mem); > return -ENOMEM; > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index a6bad1f686c5..4209a2ed1e1b 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -1266,7 +1266,8 @@ static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask, > > if (hugetlb_cma[nid]) { > page = cma_alloc(hugetlb_cma[nid], nr_pages, > - huge_page_order(h), true); > + huge_page_order(h), > + GFP_KERNEL | __GFP_NOWARN); > if (page) > return page; > } > @@ -1277,7 +1278,8 @@ static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask, > continue; > > page = cma_alloc(hugetlb_cma[node], nr_pages, > - huge_page_order(h), true); > + huge_page_order(h), > + GFP_KERNEL | __GFP_NOWARN); > if (page) > return page; > } > diff --git a/mm/secretmem.c b/mm/secretmem.c > index b8a32954ac68..585d55b9f9d8 100644 > --- a/mm/secretmem.c > +++ b/mm/secretmem.c > @@ -86,7 +86,8 @@ static int secretmem_pool_increase(struct secretmem_ctx *ctx, gfp_t gfp) > struct page *page; > int err; > > - page = cma_alloc(secretmem_cma, nr_pages, PMD_SIZE, gfp & __GFP_NOWARN); > + page = cma_alloc(secretmem_cma, nr_pages, PMD_SIZE, > + GFP_KERNEL | (gfp & __GFP_NOWARN)); > if (!page) > return -ENOMEM; > > Acked-by: David Hildenbrand <david@redhat.com>
On Thu, Jan 21, 2021 at 09:54:59AM -0800, Minchan Kim wrote: > The upcoming patch will introduce __GFP_NORETRY semantic > in alloc_contig_range which is a failfast mode of the API. > Instead of adding a additional parameter for gfp, replace > no_warn with gfp flag. > > To keep old behaviors, it follows the rule below. > > no_warn gfp_flags > > false GFP_KERNEL > true GFP_KERNEL|__GFP_NOWARN > gfp & __GFP_NOWARN GFP_KERNEL | (gfp & __GFP_NOWARN) > > Reviewed-by: Suren Baghdasaryan <surenb@google.com> > Signed-off-by: Minchan Kim <minchan@kernel.org> Found one missing piece : cma_alloc_alinged Resend with fixing From 54f5de059636d2178bf5f716239a4a1ea9cbdc52 Mon Sep 17 00:00:00 2001 From: Minchan Kim <minchan@kernel.org> Date: Mon, 21 Dec 2020 17:55:37 -0800 Subject: [PATCH v4 1/4] mm: cma: introduce gfp flag in cma_alloc instead The upcoming patch will introduce __GFP_NORETRY semantic in alloc_contig_range which is a failfast mode of the API. Instead of adding a additional parameter for gfp, replace no_warn with gfp flag. To keep old behaviors, it follows the rule below. no_warn gfp_flags false GFP_KERNEL true GFP_KERNEL|__GFP_NOWARN gfp & __GFP_NOWARN GFP_KERNEL | (gfp & __GFP_NOWARN) Reviewed-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Minchan Kim <minchan@kernel.org> --- drivers/dma-buf/heaps/cma_heap.c | 2 +- drivers/s390/char/vmcp.c | 2 +- include/linux/cma.h | 2 +- kernel/dma/contiguous.c | 6 ++++-- mm/cma.c | 12 ++++++------ mm/cma_debug.c | 2 +- mm/hugetlb.c | 6 ++++-- mm/secretmem.c | 3 ++- 8 files changed, 20 insertions(+), 15 deletions(-) diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c index 364fc2f3e499..0afc1907887a 100644 --- a/drivers/dma-buf/heaps/cma_heap.c +++ b/drivers/dma-buf/heaps/cma_heap.c @@ -298,7 +298,7 @@ static int cma_heap_allocate(struct dma_heap *heap, if (align > CONFIG_CMA_ALIGNMENT) align = CONFIG_CMA_ALIGNMENT; - cma_pages = cma_alloc(cma_heap->cma, pagecount, align, false); + cma_pages = cma_alloc(cma_heap->cma, pagecount, align, GFP_KERNEL); if (!cma_pages) goto free_buffer; diff --git a/drivers/s390/char/vmcp.c b/drivers/s390/char/vmcp.c index 9e066281e2d0..78f9adf56456 100644 --- a/drivers/s390/char/vmcp.c +++ b/drivers/s390/char/vmcp.c @@ -70,7 +70,7 @@ static void vmcp_response_alloc(struct vmcp_session *session) * anymore the system won't work anyway. */ if (order > 2) - page = cma_alloc(vmcp_cma, nr_pages, 0, false); + page = cma_alloc(vmcp_cma, nr_pages, 0, GFP_KERNEL); if (page) { session->response = (char *)page_to_phys(page); session->cma_alloc = 1; diff --git a/include/linux/cma.h b/include/linux/cma.h index 217999c8a762..d6c02d08ddbc 100644 --- a/include/linux/cma.h +++ b/include/linux/cma.h @@ -45,7 +45,7 @@ extern int cma_init_reserved_mem(phys_addr_t base, phys_addr_t size, const char *name, struct cma **res_cma); extern struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, - bool no_warn); + gfp_t gfp_mask); extern bool cma_release(struct cma *cma, const struct page *pages, unsigned int count); extern int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data); diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c index 3d63d91cba5c..f5a6fcaa9876 100644 --- a/kernel/dma/contiguous.c +++ b/kernel/dma/contiguous.c @@ -260,7 +260,8 @@ struct page *dma_alloc_from_contiguous(struct device *dev, size_t count, if (align > CONFIG_CMA_ALIGNMENT) align = CONFIG_CMA_ALIGNMENT; - return cma_alloc(dev_get_cma_area(dev), count, align, no_warn); + return cma_alloc(dev_get_cma_area(dev), count, align, GFP_KERNEL | + (no_warn ? __GFP_NOWARN : 0)); } /** @@ -283,7 +284,8 @@ static struct page *cma_alloc_aligned(struct cma *cma, size_t size, gfp_t gfp) { unsigned int align = min(get_order(size), CONFIG_CMA_ALIGNMENT); - return cma_alloc(cma, size >> PAGE_SHIFT, align, gfp & __GFP_NOWARN); + return cma_alloc(cma, size >> PAGE_SHIFT, align, + GFP_KERNEL | (gfp & __GFP_NOWARN)); } /** diff --git a/mm/cma.c b/mm/cma.c index 0ba69cd16aeb..d50627686fec 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -419,13 +419,13 @@ static inline void cma_debug_show_areas(struct cma *cma) { } * @cma: Contiguous memory region for which the allocation is performed. * @count: Requested number of pages. * @align: Requested alignment of pages (in PAGE_SIZE order). - * @no_warn: Avoid printing message about failed allocation + * @gfp_mask: GFP mask to use during the cma allocation. * * This function allocates part of contiguous memory on specific * contiguous memory area. */ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, - bool no_warn) + gfp_t gfp_mask) { unsigned long mask, offset; unsigned long pfn = -1; @@ -438,8 +438,8 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, if (!cma || !cma->count || !cma->bitmap) return NULL; - pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma, - count, align); + pr_debug("%s(cma %p, count %zu, align %d gfp_mask 0x%x)\n", __func__, + (void *)cma, count, align, gfp_mask); if (!count) return NULL; @@ -471,7 +471,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit); ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, - GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0)); + gfp_mask); if (ret == 0) { page = pfn_to_page(pfn); @@ -500,7 +500,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, page_kasan_tag_reset(page + i); } - if (ret && !no_warn) { + if (ret && !(gfp_mask & __GFP_NOWARN)) { pr_err("%s: alloc failed, req-size: %zu pages, ret: %d\n", __func__, count, ret); cma_debug_show_areas(cma); diff --git a/mm/cma_debug.c b/mm/cma_debug.c index d5bf8aa34fdc..00170c41cf81 100644 --- a/mm/cma_debug.c +++ b/mm/cma_debug.c @@ -137,7 +137,7 @@ static int cma_alloc_mem(struct cma *cma, int count) if (!mem) return -ENOMEM; - p = cma_alloc(cma, count, 0, false); + p = cma_alloc(cma, count, 0, GFP_KERNEL); if (!p) { kfree(mem); return -ENOMEM; diff --git a/mm/hugetlb.c b/mm/hugetlb.c index a6bad1f686c5..4209a2ed1e1b 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1266,7 +1266,8 @@ static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask, if (hugetlb_cma[nid]) { page = cma_alloc(hugetlb_cma[nid], nr_pages, - huge_page_order(h), true); + huge_page_order(h), + GFP_KERNEL | __GFP_NOWARN); if (page) return page; } @@ -1277,7 +1278,8 @@ static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask, continue; page = cma_alloc(hugetlb_cma[node], nr_pages, - huge_page_order(h), true); + huge_page_order(h), + GFP_KERNEL | __GFP_NOWARN); if (page) return page; } diff --git a/mm/secretmem.c b/mm/secretmem.c index b8a32954ac68..585d55b9f9d8 100644 --- a/mm/secretmem.c +++ b/mm/secretmem.c @@ -86,7 +86,8 @@ static int secretmem_pool_increase(struct secretmem_ctx *ctx, gfp_t gfp) struct page *page; int err; - page = cma_alloc(secretmem_cma, nr_pages, PMD_SIZE, gfp & __GFP_NOWARN); + page = cma_alloc(secretmem_cma, nr_pages, PMD_SIZE, + GFP_KERNEL | (gfp & __GFP_NOWARN)); if (!page) return -ENOMEM;
On Thu 21-01-21 09:54:59, Minchan Kim wrote: > The upcoming patch will introduce __GFP_NORETRY semantic > in alloc_contig_range which is a failfast mode of the API. > Instead of adding a additional parameter for gfp, replace > no_warn with gfp flag. > > To keep old behaviors, it follows the rule below. > > no_warn gfp_flags > > false GFP_KERNEL > true GFP_KERNEL|__GFP_NOWARN > gfp & __GFP_NOWARN GFP_KERNEL | (gfp & __GFP_NOWARN) > > Reviewed-by: Suren Baghdasaryan <surenb@google.com> > Signed-off-by: Minchan Kim <minchan@kernel.org> [...] > diff --git a/mm/cma.c b/mm/cma.c > index 0ba69cd16aeb..d50627686fec 100644 > --- a/mm/cma.c > +++ b/mm/cma.c > @@ -419,13 +419,13 @@ static inline void cma_debug_show_areas(struct cma *cma) { } > * @cma: Contiguous memory region for which the allocation is performed. > * @count: Requested number of pages. > * @align: Requested alignment of pages (in PAGE_SIZE order). > - * @no_warn: Avoid printing message about failed allocation > + * @gfp_mask: GFP mask to use during the cma allocation. Call out supported gfp flags explicitly. Have a look at kvmalloc_node for a guidance.
On Mon, Jan 25, 2021 at 02:07:01PM +0100, Michal Hocko wrote: > On Thu 21-01-21 09:54:59, Minchan Kim wrote: > > The upcoming patch will introduce __GFP_NORETRY semantic > > in alloc_contig_range which is a failfast mode of the API. > > Instead of adding a additional parameter for gfp, replace > > no_warn with gfp flag. > > > > To keep old behaviors, it follows the rule below. > > > > no_warn gfp_flags > > > > false GFP_KERNEL > > true GFP_KERNEL|__GFP_NOWARN > > gfp & __GFP_NOWARN GFP_KERNEL | (gfp & __GFP_NOWARN) > > > > Reviewed-by: Suren Baghdasaryan <surenb@google.com> > > Signed-off-by: Minchan Kim <minchan@kernel.org> > [...] > > diff --git a/mm/cma.c b/mm/cma.c > > index 0ba69cd16aeb..d50627686fec 100644 > > --- a/mm/cma.c > > +++ b/mm/cma.c > > @@ -419,13 +419,13 @@ static inline void cma_debug_show_areas(struct cma *cma) { } > > * @cma: Contiguous memory region for which the allocation is performed. > > * @count: Requested number of pages. > > * @align: Requested alignment of pages (in PAGE_SIZE order). > > - * @no_warn: Avoid printing message about failed allocation > > + * @gfp_mask: GFP mask to use during the cma allocation. > > Call out supported gfp flags explicitly. Have a look at kvmalloc_node > for a guidance. How about this? diff --git a/mm/cma.c b/mm/cma.c index d50627686fec..b94727b694d6 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -423,6 +423,10 @@ static inline void cma_debug_show_areas(struct cma *cma) { } * * This function allocates part of contiguous memory on specific * contiguous memory area. + * + * For gfp_mask, GFP_KERNEL and __GFP_NORETRY are supported. __GFP_NORETRY + * will avoid costly functions(e.g., waiting on page_writeback and locking) + * at current implementaion during the page migration. */ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, gfp_t gfp_mask)
On Mon 25-01-21 11:42:34, Minchan Kim wrote: > On Mon, Jan 25, 2021 at 02:07:01PM +0100, Michal Hocko wrote: > > On Thu 21-01-21 09:54:59, Minchan Kim wrote: > > > The upcoming patch will introduce __GFP_NORETRY semantic > > > in alloc_contig_range which is a failfast mode of the API. > > > Instead of adding a additional parameter for gfp, replace > > > no_warn with gfp flag. > > > > > > To keep old behaviors, it follows the rule below. > > > > > > no_warn gfp_flags > > > > > > false GFP_KERNEL > > > true GFP_KERNEL|__GFP_NOWARN > > > gfp & __GFP_NOWARN GFP_KERNEL | (gfp & __GFP_NOWARN) > > > > > > Reviewed-by: Suren Baghdasaryan <surenb@google.com> > > > Signed-off-by: Minchan Kim <minchan@kernel.org> > > [...] > > > diff --git a/mm/cma.c b/mm/cma.c > > > index 0ba69cd16aeb..d50627686fec 100644 > > > --- a/mm/cma.c > > > +++ b/mm/cma.c > > > @@ -419,13 +419,13 @@ static inline void cma_debug_show_areas(struct cma *cma) { } > > > * @cma: Contiguous memory region for which the allocation is performed. > > > * @count: Requested number of pages. > > > * @align: Requested alignment of pages (in PAGE_SIZE order). > > > - * @no_warn: Avoid printing message about failed allocation > > > + * @gfp_mask: GFP mask to use during the cma allocation. > > > > Call out supported gfp flags explicitly. Have a look at kvmalloc_node > > for a guidance. > > How about this? > > > diff --git a/mm/cma.c b/mm/cma.c > index d50627686fec..b94727b694d6 100644 > --- a/mm/cma.c > +++ b/mm/cma.c > @@ -423,6 +423,10 @@ static inline void cma_debug_show_areas(struct cma *cma) { } > * > * This function allocates part of contiguous memory on specific > * contiguous memory area. > + * > + * For gfp_mask, GFP_KERNEL and __GFP_NORETRY are supported. __GFP_NORETRY > + * will avoid costly functions(e.g., waiting on page_writeback and locking) > + * at current implementaion during the page migration. rather than explicitly mentioning what the flag implies I think it would be more useful to state the intended usecase. See how kvmalloc_node says "__GFP_RETRY_MAYFAIL is supported, and it should be used only if kmalloc is preferable to the vmalloc fallback, due to visible performance drawbacks. __GFP_NOWARN is also supported to suppress allocation failure messages." This would help people not familiar with internals to see whether this flag is a good fit for them. In this case I woul go with " @flags: gfp mask. Must be compatible (superset) with GFP_KERNEL. [...] Reclaim modifiers (__GFP_RETRY_MAYFAIL, __GFP_NOFAIL) are not supported. __GFP_NORETRY is supported, and it should be used for opportunistic allocation attempts that should rather fail quickly when the caller has a fallback strategy. " Obviously for this patch you will go with a simple statement that Reclaim modifiers are not supported at all. > */ > struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, > gfp_t gfp_mask) >
On Tue, Jan 26, 2021 at 08:38:08AM +0100, Michal Hocko wrote: > On Mon 25-01-21 11:42:34, Minchan Kim wrote: > > On Mon, Jan 25, 2021 at 02:07:01PM +0100, Michal Hocko wrote: > > > On Thu 21-01-21 09:54:59, Minchan Kim wrote: > > > > The upcoming patch will introduce __GFP_NORETRY semantic > > > > in alloc_contig_range which is a failfast mode of the API. > > > > Instead of adding a additional parameter for gfp, replace > > > > no_warn with gfp flag. > > > > > > > > To keep old behaviors, it follows the rule below. > > > > > > > > no_warn gfp_flags > > > > > > > > false GFP_KERNEL > > > > true GFP_KERNEL|__GFP_NOWARN > > > > gfp & __GFP_NOWARN GFP_KERNEL | (gfp & __GFP_NOWARN) > > > > > > > > Reviewed-by: Suren Baghdasaryan <surenb@google.com> > > > > Signed-off-by: Minchan Kim <minchan@kernel.org> > > > [...] > > > > diff --git a/mm/cma.c b/mm/cma.c > > > > index 0ba69cd16aeb..d50627686fec 100644 > > > > --- a/mm/cma.c > > > > +++ b/mm/cma.c > > > > @@ -419,13 +419,13 @@ static inline void cma_debug_show_areas(struct cma *cma) { } > > > > * @cma: Contiguous memory region for which the allocation is performed. > > > > * @count: Requested number of pages. > > > > * @align: Requested alignment of pages (in PAGE_SIZE order). > > > > - * @no_warn: Avoid printing message about failed allocation > > > > + * @gfp_mask: GFP mask to use during the cma allocation. > > > > > > Call out supported gfp flags explicitly. Have a look at kvmalloc_node > > > for a guidance. > > > > How about this? > > > > > > diff --git a/mm/cma.c b/mm/cma.c > > index d50627686fec..b94727b694d6 100644 > > --- a/mm/cma.c > > +++ b/mm/cma.c > > @@ -423,6 +423,10 @@ static inline void cma_debug_show_areas(struct cma *cma) { } > > * > > * This function allocates part of contiguous memory on specific > > * contiguous memory area. > > + * > > + * For gfp_mask, GFP_KERNEL and __GFP_NORETRY are supported. __GFP_NORETRY > > + * will avoid costly functions(e.g., waiting on page_writeback and locking) > > + * at current implementaion during the page migration. > > rather than explicitly mentioning what the flag implies I think it would > be more useful to state the intended usecase. See how kvmalloc_node says > "__GFP_RETRY_MAYFAIL is supported, and it should be used only if kmalloc is > preferable to the vmalloc fallback, due to visible performance > drawbacks. > __GFP_NOWARN is also supported to suppress allocation failure messages." > > This would help people not familiar with internals to see whether this > flag is a good fit for them. > > In this case I woul go with > " > @flags: gfp mask. Must be compatible (superset) with GFP_KERNEL. > [...] > Reclaim modifiers (__GFP_RETRY_MAYFAIL, __GFP_NOFAIL) are not supported. > __GFP_NORETRY is supported, and it should be used for opportunistic > allocation attempts that should rather fail quickly when the caller has > a fallback strategy. > " > > Obviously for this patch you will go with a simple statement that > Reclaim modifiers are not supported at all. After more discussion for gfp_flags in thread of next patch, let me changes a bit more based on it. Thanks for the suggestion, Michal.
On Tue, Jan 26, 2021 at 11:12:14AM -0800, Minchan Kim wrote: > On Tue, Jan 26, 2021 at 08:38:08AM +0100, Michal Hocko wrote: > > On Mon 25-01-21 11:42:34, Minchan Kim wrote: > > > On Mon, Jan 25, 2021 at 02:07:01PM +0100, Michal Hocko wrote: > > > > On Thu 21-01-21 09:54:59, Minchan Kim wrote: > > > > > The upcoming patch will introduce __GFP_NORETRY semantic > > > > > in alloc_contig_range which is a failfast mode of the API. > > > > > Instead of adding a additional parameter for gfp, replace > > > > > no_warn with gfp flag. > > > > > > > > > > To keep old behaviors, it follows the rule below. > > > > > > > > > > no_warn gfp_flags > > > > > > > > > > false GFP_KERNEL > > > > > true GFP_KERNEL|__GFP_NOWARN > > > > > gfp & __GFP_NOWARN GFP_KERNEL | (gfp & __GFP_NOWARN) > > > > > > > > > > Reviewed-by: Suren Baghdasaryan <surenb@google.com> > > > > > Signed-off-by: Minchan Kim <minchan@kernel.org> > > > > [...] > > > > > diff --git a/mm/cma.c b/mm/cma.c > > > > > index 0ba69cd16aeb..d50627686fec 100644 > > > > > --- a/mm/cma.c > > > > > +++ b/mm/cma.c > > > > > @@ -419,13 +419,13 @@ static inline void cma_debug_show_areas(struct cma *cma) { } > > > > > * @cma: Contiguous memory region for which the allocation is performed. > > > > > * @count: Requested number of pages. > > > > > * @align: Requested alignment of pages (in PAGE_SIZE order). > > > > > - * @no_warn: Avoid printing message about failed allocation > > > > > + * @gfp_mask: GFP mask to use during the cma allocation. > > > > > > > > Call out supported gfp flags explicitly. Have a look at kvmalloc_node > > > > for a guidance. > > > > > > How about this? > > > > > > > > > diff --git a/mm/cma.c b/mm/cma.c > > > index d50627686fec..b94727b694d6 100644 > > > --- a/mm/cma.c > > > +++ b/mm/cma.c > > > @@ -423,6 +423,10 @@ static inline void cma_debug_show_areas(struct cma *cma) { } > > > * > > > * This function allocates part of contiguous memory on specific > > > * contiguous memory area. > > > + * > > > + * For gfp_mask, GFP_KERNEL and __GFP_NORETRY are supported. __GFP_NORETRY > > > + * will avoid costly functions(e.g., waiting on page_writeback and locking) > > > + * at current implementaion during the page migration. > > > > rather than explicitly mentioning what the flag implies I think it would > > be more useful to state the intended usecase. See how kvmalloc_node says > > "__GFP_RETRY_MAYFAIL is supported, and it should be used only if kmalloc is > > preferable to the vmalloc fallback, due to visible performance > > drawbacks. > > __GFP_NOWARN is also supported to suppress allocation failure messages." > > > > This would help people not familiar with internals to see whether this > > flag is a good fit for them. > > > > In this case I woul go with > > " > > @flags: gfp mask. Must be compatible (superset) with GFP_KERNEL. > > [...] > > Reclaim modifiers (__GFP_RETRY_MAYFAIL, __GFP_NOFAIL) are not supported. > > __GFP_NORETRY is supported, and it should be used for opportunistic > > allocation attempts that should rather fail quickly when the caller has > > a fallback strategy. > > " > > > > Obviously for this patch you will go with a simple statement that > > Reclaim modifiers are not supported at all. > > After more discussion for gfp_flags in thread of next patch, let me > changes a bit more based on it. > > Thanks for the suggestion, Michal. Based on the discussion in other thread, I want to go with __GFP_NORETRY to indicate "opportunistic-easy-to-fail attempt" so suggestion words Michal is valid so I will carry it on next version. Thank you.
diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c index 364fc2f3e499..0afc1907887a 100644 --- a/drivers/dma-buf/heaps/cma_heap.c +++ b/drivers/dma-buf/heaps/cma_heap.c @@ -298,7 +298,7 @@ static int cma_heap_allocate(struct dma_heap *heap, if (align > CONFIG_CMA_ALIGNMENT) align = CONFIG_CMA_ALIGNMENT; - cma_pages = cma_alloc(cma_heap->cma, pagecount, align, false); + cma_pages = cma_alloc(cma_heap->cma, pagecount, align, GFP_KERNEL); if (!cma_pages) goto free_buffer; diff --git a/drivers/s390/char/vmcp.c b/drivers/s390/char/vmcp.c index 9e066281e2d0..78f9adf56456 100644 --- a/drivers/s390/char/vmcp.c +++ b/drivers/s390/char/vmcp.c @@ -70,7 +70,7 @@ static void vmcp_response_alloc(struct vmcp_session *session) * anymore the system won't work anyway. */ if (order > 2) - page = cma_alloc(vmcp_cma, nr_pages, 0, false); + page = cma_alloc(vmcp_cma, nr_pages, 0, GFP_KERNEL); if (page) { session->response = (char *)page_to_phys(page); session->cma_alloc = 1; diff --git a/include/linux/cma.h b/include/linux/cma.h index 217999c8a762..d6c02d08ddbc 100644 --- a/include/linux/cma.h +++ b/include/linux/cma.h @@ -45,7 +45,7 @@ extern int cma_init_reserved_mem(phys_addr_t base, phys_addr_t size, const char *name, struct cma **res_cma); extern struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, - bool no_warn); + gfp_t gfp_mask); extern bool cma_release(struct cma *cma, const struct page *pages, unsigned int count); extern int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data); diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c index 3d63d91cba5c..552ed531c018 100644 --- a/kernel/dma/contiguous.c +++ b/kernel/dma/contiguous.c @@ -260,7 +260,8 @@ struct page *dma_alloc_from_contiguous(struct device *dev, size_t count, if (align > CONFIG_CMA_ALIGNMENT) align = CONFIG_CMA_ALIGNMENT; - return cma_alloc(dev_get_cma_area(dev), count, align, no_warn); + return cma_alloc(dev_get_cma_area(dev), count, align, GFP_KERNEL | + (no_warn ? __GFP_NOWARN : 0)); } /** diff --git a/mm/cma.c b/mm/cma.c index 0ba69cd16aeb..d50627686fec 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -419,13 +419,13 @@ static inline void cma_debug_show_areas(struct cma *cma) { } * @cma: Contiguous memory region for which the allocation is performed. * @count: Requested number of pages. * @align: Requested alignment of pages (in PAGE_SIZE order). - * @no_warn: Avoid printing message about failed allocation + * @gfp_mask: GFP mask to use during the cma allocation. * * This function allocates part of contiguous memory on specific * contiguous memory area. */ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, - bool no_warn) + gfp_t gfp_mask) { unsigned long mask, offset; unsigned long pfn = -1; @@ -438,8 +438,8 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, if (!cma || !cma->count || !cma->bitmap) return NULL; - pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma, - count, align); + pr_debug("%s(cma %p, count %zu, align %d gfp_mask 0x%x)\n", __func__, + (void *)cma, count, align, gfp_mask); if (!count) return NULL; @@ -471,7 +471,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit); ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, - GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0)); + gfp_mask); if (ret == 0) { page = pfn_to_page(pfn); @@ -500,7 +500,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, page_kasan_tag_reset(page + i); } - if (ret && !no_warn) { + if (ret && !(gfp_mask & __GFP_NOWARN)) { pr_err("%s: alloc failed, req-size: %zu pages, ret: %d\n", __func__, count, ret); cma_debug_show_areas(cma); diff --git a/mm/cma_debug.c b/mm/cma_debug.c index d5bf8aa34fdc..00170c41cf81 100644 --- a/mm/cma_debug.c +++ b/mm/cma_debug.c @@ -137,7 +137,7 @@ static int cma_alloc_mem(struct cma *cma, int count) if (!mem) return -ENOMEM; - p = cma_alloc(cma, count, 0, false); + p = cma_alloc(cma, count, 0, GFP_KERNEL); if (!p) { kfree(mem); return -ENOMEM; diff --git a/mm/hugetlb.c b/mm/hugetlb.c index a6bad1f686c5..4209a2ed1e1b 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1266,7 +1266,8 @@ static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask, if (hugetlb_cma[nid]) { page = cma_alloc(hugetlb_cma[nid], nr_pages, - huge_page_order(h), true); + huge_page_order(h), + GFP_KERNEL | __GFP_NOWARN); if (page) return page; } @@ -1277,7 +1278,8 @@ static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask, continue; page = cma_alloc(hugetlb_cma[node], nr_pages, - huge_page_order(h), true); + huge_page_order(h), + GFP_KERNEL | __GFP_NOWARN); if (page) return page; } diff --git a/mm/secretmem.c b/mm/secretmem.c index b8a32954ac68..585d55b9f9d8 100644 --- a/mm/secretmem.c +++ b/mm/secretmem.c @@ -86,7 +86,8 @@ static int secretmem_pool_increase(struct secretmem_ctx *ctx, gfp_t gfp) struct page *page; int err; - page = cma_alloc(secretmem_cma, nr_pages, PMD_SIZE, gfp & __GFP_NOWARN); + page = cma_alloc(secretmem_cma, nr_pages, PMD_SIZE, + GFP_KERNEL | (gfp & __GFP_NOWARN)); if (!page) return -ENOMEM;