| Message ID | 20240125164256.4147-11-alexandru.elisei@arm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Add support for arm64 MTE dynamic tag storage reuse | expand |
On 1/25/24 22:12, Alexandru Elisei wrote: > If the pages to be allocated are free, take them directly off the buddy > allocator, instead of going through alloc_contig_range() and avoiding > costly calls to lru_cache_disable(). > > Only allocations of the same size as the CMA region order are considered, > to avoid taking the zone spinlock for too long. > > Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> This patch seems to be improving standard cma_alloc() as well as the previously added new allocator i.e cma_alloc_range() - via a new helper cma_alloc_pages_fastpath(). Should not any standard cma_alloc() improvement be discussed as an independent patch separately irrespective of this series. OR it is some how related to this series which I might be missing ? > --- > > Changes since rfc v2: > > * New patch. Reworked from the rfc v2 patch #26 ("arm64: mte: Fast track > reserving tag storage when the block is free") (David Hildenbrand). > > include/linux/page-flags.h | 15 ++++++++++++-- > mm/Kconfig | 5 +++++ > mm/cma.c | 42 ++++++++++++++++++++++++++++++++++---- > mm/memory-failure.c | 8 ++++---- > mm/page_alloc.c | 23 ++++++++++++--------- > 5 files changed, 73 insertions(+), 20 deletions(-) > > diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h > index 735cddc13d20..b7237bce7446 100644 > --- a/include/linux/page-flags.h > +++ b/include/linux/page-flags.h > @@ -575,11 +575,22 @@ TESTSCFLAG(HWPoison, hwpoison, PF_ANY) > #define MAGIC_HWPOISON 0x48575053U /* HWPS */ > extern void SetPageHWPoisonTakenOff(struct page *page); > extern void ClearPageHWPoisonTakenOff(struct page *page); > -extern bool take_page_off_buddy(struct page *page); > -extern bool put_page_back_buddy(struct page *page); > +extern bool PageHWPoisonTakenOff(struct page *page); > #else > PAGEFLAG_FALSE(HWPoison, hwpoison) > +TESTSCFLAG_FALSE(HWPoison, hwpoison) > #define __PG_HWPOISON 0 > +static inline void SetPageHWPoisonTakenOff(struct page *page) { } > +static inline void ClearPageHWPoisonTakenOff(struct page *page) { } > +static inline bool PageHWPoisonTakenOff(struct page *page) > +{ > + return false; > +} > +#endif > + > +#ifdef CONFIG_WANTS_TAKE_PAGE_OFF_BUDDY > +extern bool take_page_off_buddy(struct page *page, bool poison); > +extern bool put_page_back_buddy(struct page *page, bool unpoison); > #endif > > #if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT) > diff --git a/mm/Kconfig b/mm/Kconfig > index ffc3a2ba3a8c..341cf53898db 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -745,12 +745,16 @@ config DEFAULT_MMAP_MIN_ADDR > config ARCH_SUPPORTS_MEMORY_FAILURE > bool > > +config WANTS_TAKE_PAGE_OFF_BUDDY > + bool> + > config MEMORY_FAILURE > depends on MMU > depends on ARCH_SUPPORTS_MEMORY_FAILURE > bool "Enable recovery from hardware memory errors" > select MEMORY_ISOLATION > select RAS > + select WANTS_TAKE_PAGE_OFF_BUDDY > help > Enables code to recover from some memory failures on systems > with MCA recovery. This allows a system to continue running > @@ -891,6 +895,7 @@ config CMA > depends on MMU > select MIGRATION > select MEMORY_ISOLATION > + select WANTS_TAKE_PAGE_OFF_BUDDY > help > This enables the Contiguous Memory Allocator which allows other > subsystems to allocate big physically-contiguous blocks of memory. > diff --git a/mm/cma.c b/mm/cma.c > index 2881bab12b01..15663f95d77b 100644 > --- a/mm/cma.c > +++ b/mm/cma.c > @@ -444,6 +444,34 @@ static void cma_debug_show_areas(struct cma *cma) > static inline void cma_debug_show_areas(struct cma *cma) { } > #endif > > +/* Called with the cma mutex held. */ > +static int cma_alloc_pages_fastpath(struct cma *cma, unsigned long start, > + unsigned long end) > +{ > + bool success = false; > + unsigned long i, j; > + > + /* Avoid contention on the zone lock. */ > + if (start - end != 1 << cma->order_per_bit) > + return -EINVAL; > + > + for (i = start; i < end; i++) { > + if (!is_free_buddy_page(pfn_to_page(i))) > + break; > + success = take_page_off_buddy(pfn_to_page(i), false); > + if (!success) > + break; > + } > + > + if (success) > + return 0; > + > + for (j = start; j < i; j++) > + put_page_back_buddy(pfn_to_page(j), false); > + > + return -EBUSY; > +} > + > /** > * cma_alloc_range() - allocate pages in a specific range > * @cma: Contiguous memory region for which the allocation is performed. > @@ -493,7 +521,11 @@ int cma_alloc_range(struct cma *cma, unsigned long start, unsigned long count, > > for (i = 0; i < tries; i++) { > mutex_lock(&cma_mutex); > - err = alloc_contig_range(start, start + count, MIGRATE_CMA, gfp); > + err = cma_alloc_pages_fastpath(cma, start, start + count); > + if (err) { > + err = alloc_contig_range(start, start + count, > + MIGRATE_CMA, gfp); > + } > mutex_unlock(&cma_mutex); > > if (err != -EBUSY) > @@ -529,7 +561,6 @@ int cma_alloc_range(struct cma *cma, unsigned long start, unsigned long count, > return err; > } > > - > /** > * cma_alloc() - allocate pages from contiguous area > * @cma: Contiguous memory region for which the allocation is performed. > @@ -589,8 +620,11 @@ struct page *cma_alloc(struct cma *cma, unsigned long count, > > pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit); > mutex_lock(&cma_mutex); > - ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, > - GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0)); > + ret = cma_alloc_pages_fastpath(cma, pfn, pfn + count); > + if (ret) { > + ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, > + GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0)); > + } > mutex_unlock(&cma_mutex); > if (ret == 0) { > page = pfn_to_page(pfn); > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index 4f9b61f4a668..b87b533a9871 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -157,7 +157,7 @@ static int __page_handle_poison(struct page *page) > zone_pcp_disable(page_zone(page)); > ret = dissolve_free_huge_page(page); > if (!ret) > - ret = take_page_off_buddy(page); > + ret = take_page_off_buddy(page, true); > zone_pcp_enable(page_zone(page)); > > return ret; > @@ -1353,7 +1353,7 @@ static int page_action(struct page_state *ps, struct page *p, > return action_result(pfn, ps->type, result); > } > > -static inline bool PageHWPoisonTakenOff(struct page *page) > +bool PageHWPoisonTakenOff(struct page *page) > { > return PageHWPoison(page) && page_private(page) == MAGIC_HWPOISON; > } > @@ -2247,7 +2247,7 @@ int memory_failure(unsigned long pfn, int flags) > res = get_hwpoison_page(p, flags); > if (!res) { > if (is_free_buddy_page(p)) { > - if (take_page_off_buddy(p)) { > + if (take_page_off_buddy(p, true)) { > page_ref_inc(p); > res = MF_RECOVERED; > } else { > @@ -2578,7 +2578,7 @@ int unpoison_memory(unsigned long pfn) > ret = folio_test_clear_hwpoison(folio) ? 0 : -EBUSY; > } else if (ghp < 0) { > if (ghp == -EHWPOISON) { > - ret = put_page_back_buddy(p) ? 0 : -EBUSY; > + ret = put_page_back_buddy(p, true) ? 0 : -EBUSY; > } else { > ret = ghp; > unpoison_pr_info("Unpoison: failed to grab page %#lx\n", > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 0fa34bcfb1af..502ee3eb8583 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -6655,7 +6655,7 @@ bool is_free_buddy_page(struct page *page) > } > EXPORT_SYMBOL(is_free_buddy_page); > > -#ifdef CONFIG_MEMORY_FAILURE > +#ifdef CONFIG_WANTS_TAKE_PAGE_OFF_BUDDY > /* > * Break down a higher-order page in sub-pages, and keep our target out of > * buddy allocator. > @@ -6687,9 +6687,9 @@ static void break_down_buddy_pages(struct zone *zone, struct page *page, > } > > /* > - * Take a page that will be marked as poisoned off the buddy allocator. > + * Take a page off the buddy allocator, and optionally mark it as poisoned. > */ > -bool take_page_off_buddy(struct page *page) > +bool take_page_off_buddy(struct page *page, bool poison) > { > struct zone *zone = page_zone(page); > unsigned long pfn = page_to_pfn(page); > @@ -6710,7 +6710,8 @@ bool take_page_off_buddy(struct page *page) > del_page_from_free_list(page_head, zone, page_order); > break_down_buddy_pages(zone, page_head, page, 0, > page_order, migratetype); > - SetPageHWPoisonTakenOff(page); > + if (poison) > + SetPageHWPoisonTakenOff(page); > if (!is_migrate_isolate(migratetype)) > __mod_zone_freepage_state(zone, -1, migratetype); > ret = true; > @@ -6724,9 +6725,10 @@ bool take_page_off_buddy(struct page *page) > } > > /* > - * Cancel takeoff done by take_page_off_buddy(). > + * Cancel takeoff done by take_page_off_buddy(), and optionally unpoison the > + * page. > */ > -bool put_page_back_buddy(struct page *page) > +bool put_page_back_buddy(struct page *page, bool unpoison) > { > struct zone *zone = page_zone(page); > unsigned long pfn = page_to_pfn(page); > @@ -6736,17 +6738,18 @@ bool put_page_back_buddy(struct page *page) > > spin_lock_irqsave(&zone->lock, flags); > if (put_page_testzero(page)) { > - ClearPageHWPoisonTakenOff(page); > + VM_WARN_ON_ONCE(PageHWPoisonTakenOff(page) && !unpoison); > + if (unpoison) > + ClearPageHWPoisonTakenOff(page); > __free_one_page(page, pfn, zone, 0, migratetype, FPI_NONE); > - if (TestClearPageHWPoison(page)) { > + if (!unpoison || (unpoison && TestClearPageHWPoison(page))) > ret = true; > - } > } > spin_unlock_irqrestore(&zone->lock, flags); > > return ret; > } > -#endif > +#endif /* CONFIG_WANTS_TAKE_PAGE_OFF_BUDDY */ > > #ifdef CONFIG_ZONE_DMA > bool has_managed_dma(void)
Hi, On Tue, Jan 30, 2024 at 02:48:53PM +0530, Anshuman Khandual wrote: > > > On 1/25/24 22:12, Alexandru Elisei wrote: > > If the pages to be allocated are free, take them directly off the buddy > > allocator, instead of going through alloc_contig_range() and avoiding > > costly calls to lru_cache_disable(). > > > > Only allocations of the same size as the CMA region order are considered, > > to avoid taking the zone spinlock for too long. > > > > Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> > > This patch seems to be improving standard cma_alloc() as well as > the previously added new allocator i.e cma_alloc_range() - via a > new helper cma_alloc_pages_fastpath(). Yes, that's correct. > > Should not any standard cma_alloc() improvement be discussed as > an independent patch separately irrespective of this series. OR > it is some how related to this series which I might be missing ? Yes, it's related to this series. I wrote this patch because it fixes a performance regression with Chrome when dynamic tag storage management is enabled [1]. I will bring back the commit message explaining that. [1] https://lore.kernel.org/linux-fsdevel/20231119165721.9849-27-alexandru.elisei@arm.com/ Thanks, Alex > > > --- > > > > Changes since rfc v2: > > > > * New patch. Reworked from the rfc v2 patch #26 ("arm64: mte: Fast track > > reserving tag storage when the block is free") (David Hildenbrand). > > > > include/linux/page-flags.h | 15 ++++++++++++-- > > mm/Kconfig | 5 +++++ > > mm/cma.c | 42 ++++++++++++++++++++++++++++++++++---- > > mm/memory-failure.c | 8 ++++---- > > mm/page_alloc.c | 23 ++++++++++++--------- > > 5 files changed, 73 insertions(+), 20 deletions(-) > > > > diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h > > index 735cddc13d20..b7237bce7446 100644 > > --- a/include/linux/page-flags.h > > +++ b/include/linux/page-flags.h > > @@ -575,11 +575,22 @@ TESTSCFLAG(HWPoison, hwpoison, PF_ANY) > > #define MAGIC_HWPOISON 0x48575053U /* HWPS */ > > extern void SetPageHWPoisonTakenOff(struct page *page); > > extern void ClearPageHWPoisonTakenOff(struct page *page); > > -extern bool take_page_off_buddy(struct page *page); > > -extern bool put_page_back_buddy(struct page *page); > > +extern bool PageHWPoisonTakenOff(struct page *page); > > #else > > PAGEFLAG_FALSE(HWPoison, hwpoison) > > +TESTSCFLAG_FALSE(HWPoison, hwpoison) > > #define __PG_HWPOISON 0 > > +static inline void SetPageHWPoisonTakenOff(struct page *page) { } > > +static inline void ClearPageHWPoisonTakenOff(struct page *page) { } > > +static inline bool PageHWPoisonTakenOff(struct page *page) > > +{ > > + return false; > > +} > > +#endif > > + > > +#ifdef CONFIG_WANTS_TAKE_PAGE_OFF_BUDDY > > +extern bool take_page_off_buddy(struct page *page, bool poison); > > +extern bool put_page_back_buddy(struct page *page, bool unpoison); > > #endif > > > > #if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT) > > diff --git a/mm/Kconfig b/mm/Kconfig > > index ffc3a2ba3a8c..341cf53898db 100644 > > --- a/mm/Kconfig > > +++ b/mm/Kconfig > > @@ -745,12 +745,16 @@ config DEFAULT_MMAP_MIN_ADDR > > config ARCH_SUPPORTS_MEMORY_FAILURE > > bool > > > > +config WANTS_TAKE_PAGE_OFF_BUDDY > > + bool> + > > config MEMORY_FAILURE > > depends on MMU > > depends on ARCH_SUPPORTS_MEMORY_FAILURE > > bool "Enable recovery from hardware memory errors" > > select MEMORY_ISOLATION > > select RAS > > + select WANTS_TAKE_PAGE_OFF_BUDDY > > help > > Enables code to recover from some memory failures on systems > > with MCA recovery. This allows a system to continue running > > @@ -891,6 +895,7 @@ config CMA > > depends on MMU > > select MIGRATION > > select MEMORY_ISOLATION > > + select WANTS_TAKE_PAGE_OFF_BUDDY > > help > > This enables the Contiguous Memory Allocator which allows other > > subsystems to allocate big physically-contiguous blocks of memory. > > diff --git a/mm/cma.c b/mm/cma.c > > index 2881bab12b01..15663f95d77b 100644 > > --- a/mm/cma.c > > +++ b/mm/cma.c > > @@ -444,6 +444,34 @@ static void cma_debug_show_areas(struct cma *cma) > > static inline void cma_debug_show_areas(struct cma *cma) { } > > #endif > > > > +/* Called with the cma mutex held. */ > > +static int cma_alloc_pages_fastpath(struct cma *cma, unsigned long start, > > + unsigned long end) > > +{ > > + bool success = false; > > + unsigned long i, j; > > + > > + /* Avoid contention on the zone lock. */ > > + if (start - end != 1 << cma->order_per_bit) > > + return -EINVAL; > > + > > + for (i = start; i < end; i++) { > > + if (!is_free_buddy_page(pfn_to_page(i))) > > + break; > > + success = take_page_off_buddy(pfn_to_page(i), false); > > + if (!success) > > + break; > > + } > > + > > + if (success) > > + return 0; > > + > > + for (j = start; j < i; j++) > > + put_page_back_buddy(pfn_to_page(j), false); > > + > > + return -EBUSY; > > +} > > + > > /** > > * cma_alloc_range() - allocate pages in a specific range > > * @cma: Contiguous memory region for which the allocation is performed. > > @@ -493,7 +521,11 @@ int cma_alloc_range(struct cma *cma, unsigned long start, unsigned long count, > > > > for (i = 0; i < tries; i++) { > > mutex_lock(&cma_mutex); > > - err = alloc_contig_range(start, start + count, MIGRATE_CMA, gfp); > > + err = cma_alloc_pages_fastpath(cma, start, start + count); > > + if (err) { > > + err = alloc_contig_range(start, start + count, > > + MIGRATE_CMA, gfp); > > + } > > mutex_unlock(&cma_mutex); > > > > if (err != -EBUSY) > > @@ -529,7 +561,6 @@ int cma_alloc_range(struct cma *cma, unsigned long start, unsigned long count, > > return err; > > } > > > > - > > /** > > * cma_alloc() - allocate pages from contiguous area > > * @cma: Contiguous memory region for which the allocation is performed. > > @@ -589,8 +620,11 @@ struct page *cma_alloc(struct cma *cma, unsigned long count, > > > > pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit); > > mutex_lock(&cma_mutex); > > - ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, > > - GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0)); > > + ret = cma_alloc_pages_fastpath(cma, pfn, pfn + count); > > + if (ret) { > > + ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, > > + GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0)); > > + } > > mutex_unlock(&cma_mutex); > > if (ret == 0) { > > page = pfn_to_page(pfn); > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > > index 4f9b61f4a668..b87b533a9871 100644 > > --- a/mm/memory-failure.c > > +++ b/mm/memory-failure.c > > @@ -157,7 +157,7 @@ static int __page_handle_poison(struct page *page) > > zone_pcp_disable(page_zone(page)); > > ret = dissolve_free_huge_page(page); > > if (!ret) > > - ret = take_page_off_buddy(page); > > + ret = take_page_off_buddy(page, true); > > zone_pcp_enable(page_zone(page)); > > > > return ret; > > @@ -1353,7 +1353,7 @@ static int page_action(struct page_state *ps, struct page *p, > > return action_result(pfn, ps->type, result); > > } > > > > -static inline bool PageHWPoisonTakenOff(struct page *page) > > +bool PageHWPoisonTakenOff(struct page *page) > > { > > return PageHWPoison(page) && page_private(page) == MAGIC_HWPOISON; > > } > > @@ -2247,7 +2247,7 @@ int memory_failure(unsigned long pfn, int flags) > > res = get_hwpoison_page(p, flags); > > if (!res) { > > if (is_free_buddy_page(p)) { > > - if (take_page_off_buddy(p)) { > > + if (take_page_off_buddy(p, true)) { > > page_ref_inc(p); > > res = MF_RECOVERED; > > } else { > > @@ -2578,7 +2578,7 @@ int unpoison_memory(unsigned long pfn) > > ret = folio_test_clear_hwpoison(folio) ? 0 : -EBUSY; > > } else if (ghp < 0) { > > if (ghp == -EHWPOISON) { > > - ret = put_page_back_buddy(p) ? 0 : -EBUSY; > > + ret = put_page_back_buddy(p, true) ? 0 : -EBUSY; > > } else { > > ret = ghp; > > unpoison_pr_info("Unpoison: failed to grab page %#lx\n", > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index 0fa34bcfb1af..502ee3eb8583 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -6655,7 +6655,7 @@ bool is_free_buddy_page(struct page *page) > > } > > EXPORT_SYMBOL(is_free_buddy_page); > > > > -#ifdef CONFIG_MEMORY_FAILURE > > +#ifdef CONFIG_WANTS_TAKE_PAGE_OFF_BUDDY > > /* > > * Break down a higher-order page in sub-pages, and keep our target out of > > * buddy allocator. > > @@ -6687,9 +6687,9 @@ static void break_down_buddy_pages(struct zone *zone, struct page *page, > > } > > > > /* > > - * Take a page that will be marked as poisoned off the buddy allocator. > > + * Take a page off the buddy allocator, and optionally mark it as poisoned. > > */ > > -bool take_page_off_buddy(struct page *page) > > +bool take_page_off_buddy(struct page *page, bool poison) > > { > > struct zone *zone = page_zone(page); > > unsigned long pfn = page_to_pfn(page); > > @@ -6710,7 +6710,8 @@ bool take_page_off_buddy(struct page *page) > > del_page_from_free_list(page_head, zone, page_order); > > break_down_buddy_pages(zone, page_head, page, 0, > > page_order, migratetype); > > - SetPageHWPoisonTakenOff(page); > > + if (poison) > > + SetPageHWPoisonTakenOff(page); > > if (!is_migrate_isolate(migratetype)) > > __mod_zone_freepage_state(zone, -1, migratetype); > > ret = true; > > @@ -6724,9 +6725,10 @@ bool take_page_off_buddy(struct page *page) > > } > > > > /* > > - * Cancel takeoff done by take_page_off_buddy(). > > + * Cancel takeoff done by take_page_off_buddy(), and optionally unpoison the > > + * page. > > */ > > -bool put_page_back_buddy(struct page *page) > > +bool put_page_back_buddy(struct page *page, bool unpoison) > > { > > struct zone *zone = page_zone(page); > > unsigned long pfn = page_to_pfn(page); > > @@ -6736,17 +6738,18 @@ bool put_page_back_buddy(struct page *page) > > > > spin_lock_irqsave(&zone->lock, flags); > > if (put_page_testzero(page)) { > > - ClearPageHWPoisonTakenOff(page); > > + VM_WARN_ON_ONCE(PageHWPoisonTakenOff(page) && !unpoison); > > + if (unpoison) > > + ClearPageHWPoisonTakenOff(page); > > __free_one_page(page, pfn, zone, 0, migratetype, FPI_NONE); > > - if (TestClearPageHWPoison(page)) { > > + if (!unpoison || (unpoison && TestClearPageHWPoison(page))) > > ret = true; > > - } > > } > > spin_unlock_irqrestore(&zone->lock, flags); > > > > return ret; > > } > > -#endif > > +#endif /* CONFIG_WANTS_TAKE_PAGE_OFF_BUDDY */ > > > > #ifdef CONFIG_ZONE_DMA > > bool has_managed_dma(void)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 735cddc13d20..b7237bce7446 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -575,11 +575,22 @@ TESTSCFLAG(HWPoison, hwpoison, PF_ANY) #define MAGIC_HWPOISON 0x48575053U /* HWPS */ extern void SetPageHWPoisonTakenOff(struct page *page); extern void ClearPageHWPoisonTakenOff(struct page *page); -extern bool take_page_off_buddy(struct page *page); -extern bool put_page_back_buddy(struct page *page); +extern bool PageHWPoisonTakenOff(struct page *page); #else PAGEFLAG_FALSE(HWPoison, hwpoison) +TESTSCFLAG_FALSE(HWPoison, hwpoison) #define __PG_HWPOISON 0 +static inline void SetPageHWPoisonTakenOff(struct page *page) { } +static inline void ClearPageHWPoisonTakenOff(struct page *page) { } +static inline bool PageHWPoisonTakenOff(struct page *page) +{ + return false; +} +#endif + +#ifdef CONFIG_WANTS_TAKE_PAGE_OFF_BUDDY +extern bool take_page_off_buddy(struct page *page, bool poison); +extern bool put_page_back_buddy(struct page *page, bool unpoison); #endif #if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT) diff --git a/mm/Kconfig b/mm/Kconfig index ffc3a2ba3a8c..341cf53898db 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -745,12 +745,16 @@ config DEFAULT_MMAP_MIN_ADDR config ARCH_SUPPORTS_MEMORY_FAILURE bool +config WANTS_TAKE_PAGE_OFF_BUDDY + bool + config MEMORY_FAILURE depends on MMU depends on ARCH_SUPPORTS_MEMORY_FAILURE bool "Enable recovery from hardware memory errors" select MEMORY_ISOLATION select RAS + select WANTS_TAKE_PAGE_OFF_BUDDY help Enables code to recover from some memory failures on systems with MCA recovery. This allows a system to continue running @@ -891,6 +895,7 @@ config CMA depends on MMU select MIGRATION select MEMORY_ISOLATION + select WANTS_TAKE_PAGE_OFF_BUDDY help This enables the Contiguous Memory Allocator which allows other subsystems to allocate big physically-contiguous blocks of memory. diff --git a/mm/cma.c b/mm/cma.c index 2881bab12b01..15663f95d77b 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -444,6 +444,34 @@ static void cma_debug_show_areas(struct cma *cma) static inline void cma_debug_show_areas(struct cma *cma) { } #endif +/* Called with the cma mutex held. */ +static int cma_alloc_pages_fastpath(struct cma *cma, unsigned long start, + unsigned long end) +{ + bool success = false; + unsigned long i, j; + + /* Avoid contention on the zone lock. */ + if (start - end != 1 << cma->order_per_bit) + return -EINVAL; + + for (i = start; i < end; i++) { + if (!is_free_buddy_page(pfn_to_page(i))) + break; + success = take_page_off_buddy(pfn_to_page(i), false); + if (!success) + break; + } + + if (success) + return 0; + + for (j = start; j < i; j++) + put_page_back_buddy(pfn_to_page(j), false); + + return -EBUSY; +} + /** * cma_alloc_range() - allocate pages in a specific range * @cma: Contiguous memory region for which the allocation is performed. @@ -493,7 +521,11 @@ int cma_alloc_range(struct cma *cma, unsigned long start, unsigned long count, for (i = 0; i < tries; i++) { mutex_lock(&cma_mutex); - err = alloc_contig_range(start, start + count, MIGRATE_CMA, gfp); + err = cma_alloc_pages_fastpath(cma, start, start + count); + if (err) { + err = alloc_contig_range(start, start + count, + MIGRATE_CMA, gfp); + } mutex_unlock(&cma_mutex); if (err != -EBUSY) @@ -529,7 +561,6 @@ int cma_alloc_range(struct cma *cma, unsigned long start, unsigned long count, return err; } - /** * cma_alloc() - allocate pages from contiguous area * @cma: Contiguous memory region for which the allocation is performed. @@ -589,8 +620,11 @@ struct page *cma_alloc(struct cma *cma, unsigned long count, pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit); mutex_lock(&cma_mutex); - ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, - GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0)); + ret = cma_alloc_pages_fastpath(cma, pfn, pfn + count); + if (ret) { + ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, + GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0)); + } mutex_unlock(&cma_mutex); if (ret == 0) { page = pfn_to_page(pfn); diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 4f9b61f4a668..b87b533a9871 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -157,7 +157,7 @@ static int __page_handle_poison(struct page *page) zone_pcp_disable(page_zone(page)); ret = dissolve_free_huge_page(page); if (!ret) - ret = take_page_off_buddy(page); + ret = take_page_off_buddy(page, true); zone_pcp_enable(page_zone(page)); return ret; @@ -1353,7 +1353,7 @@ static int page_action(struct page_state *ps, struct page *p, return action_result(pfn, ps->type, result); } -static inline bool PageHWPoisonTakenOff(struct page *page) +bool PageHWPoisonTakenOff(struct page *page) { return PageHWPoison(page) && page_private(page) == MAGIC_HWPOISON; } @@ -2247,7 +2247,7 @@ int memory_failure(unsigned long pfn, int flags) res = get_hwpoison_page(p, flags); if (!res) { if (is_free_buddy_page(p)) { - if (take_page_off_buddy(p)) { + if (take_page_off_buddy(p, true)) { page_ref_inc(p); res = MF_RECOVERED; } else { @@ -2578,7 +2578,7 @@ int unpoison_memory(unsigned long pfn) ret = folio_test_clear_hwpoison(folio) ? 0 : -EBUSY; } else if (ghp < 0) { if (ghp == -EHWPOISON) { - ret = put_page_back_buddy(p) ? 0 : -EBUSY; + ret = put_page_back_buddy(p, true) ? 0 : -EBUSY; } else { ret = ghp; unpoison_pr_info("Unpoison: failed to grab page %#lx\n", diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 0fa34bcfb1af..502ee3eb8583 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6655,7 +6655,7 @@ bool is_free_buddy_page(struct page *page) } EXPORT_SYMBOL(is_free_buddy_page); -#ifdef CONFIG_MEMORY_FAILURE +#ifdef CONFIG_WANTS_TAKE_PAGE_OFF_BUDDY /* * Break down a higher-order page in sub-pages, and keep our target out of * buddy allocator. @@ -6687,9 +6687,9 @@ static void break_down_buddy_pages(struct zone *zone, struct page *page, } /* - * Take a page that will be marked as poisoned off the buddy allocator. + * Take a page off the buddy allocator, and optionally mark it as poisoned. */ -bool take_page_off_buddy(struct page *page) +bool take_page_off_buddy(struct page *page, bool poison) { struct zone *zone = page_zone(page); unsigned long pfn = page_to_pfn(page); @@ -6710,7 +6710,8 @@ bool take_page_off_buddy(struct page *page) del_page_from_free_list(page_head, zone, page_order); break_down_buddy_pages(zone, page_head, page, 0, page_order, migratetype); - SetPageHWPoisonTakenOff(page); + if (poison) + SetPageHWPoisonTakenOff(page); if (!is_migrate_isolate(migratetype)) __mod_zone_freepage_state(zone, -1, migratetype); ret = true; @@ -6724,9 +6725,10 @@ bool take_page_off_buddy(struct page *page) } /* - * Cancel takeoff done by take_page_off_buddy(). + * Cancel takeoff done by take_page_off_buddy(), and optionally unpoison the + * page. */ -bool put_page_back_buddy(struct page *page) +bool put_page_back_buddy(struct page *page, bool unpoison) { struct zone *zone = page_zone(page); unsigned long pfn = page_to_pfn(page); @@ -6736,17 +6738,18 @@ bool put_page_back_buddy(struct page *page) spin_lock_irqsave(&zone->lock, flags); if (put_page_testzero(page)) { - ClearPageHWPoisonTakenOff(page); + VM_WARN_ON_ONCE(PageHWPoisonTakenOff(page) && !unpoison); + if (unpoison) + ClearPageHWPoisonTakenOff(page); __free_one_page(page, pfn, zone, 0, migratetype, FPI_NONE); - if (TestClearPageHWPoison(page)) { + if (!unpoison || (unpoison && TestClearPageHWPoison(page))) ret = true; - } } spin_unlock_irqrestore(&zone->lock, flags); return ret; } -#endif +#endif /* CONFIG_WANTS_TAKE_PAGE_OFF_BUDDY */ #ifdef CONFIG_ZONE_DMA bool has_managed_dma(void)
If the pages to be allocated are free, take them directly off the buddy allocator, instead of going through alloc_contig_range() and avoiding costly calls to lru_cache_disable(). Only allocations of the same size as the CMA region order are considered, to avoid taking the zone spinlock for too long. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> --- Changes since rfc v2: * New patch. Reworked from the rfc v2 patch #26 ("arm64: mte: Fast track reserving tag storage when the block is free") (David Hildenbrand). include/linux/page-flags.h | 15 ++++++++++++-- mm/Kconfig | 5 +++++ mm/cma.c | 42 ++++++++++++++++++++++++++++++++++---- mm/memory-failure.c | 8 ++++---- mm/page_alloc.c | 23 ++++++++++++--------- 5 files changed, 73 insertions(+), 20 deletions(-)