mm: extended batches for generic mmu_gather
Instead of using a single batch (the small on-stack, or an allocated page), try and extend the batch every time it runs out and only flush once either the extend fails or we're done. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Requested-by: Nick Piggin <npiggin@kernel.dk> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Miller <davem@davemloft.net> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Tony Luck <tony.luck@intel.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>hifive-unleashed-5.1
Peter Zijlstra
Linus Torvalds
parent
2672391169
commit
e303297e6c
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@ -19,16 +19,6 @@
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#include <asm/pgalloc.h>
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#include <asm/tlbflush.h>
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/*
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* For UP we don't need to worry about TLB flush
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* and page free order so much..
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*/
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#ifdef CONFIG_SMP
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#define tlb_fast_mode(tlb) ((tlb)->nr == ~0U)
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#else
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#define tlb_fast_mode(tlb) 1
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#endif
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#ifdef CONFIG_HAVE_RCU_TABLE_FREE
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/*
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* Semi RCU freeing of the page directories.
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@ -78,6 +68,16 @@ extern void tlb_remove_table(struct mmu_gather *tlb, void *table);
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*/
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#define MMU_GATHER_BUNDLE 8
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struct mmu_gather_batch {
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struct mmu_gather_batch *next;
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unsigned int nr;
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unsigned int max;
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struct page *pages[0];
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};
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#define MAX_GATHER_BATCH \
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((PAGE_SIZE - sizeof(struct mmu_gather_batch)) / sizeof(void *))
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/* struct mmu_gather is an opaque type used by the mm code for passing around
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* any data needed by arch specific code for tlb_remove_page.
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*/
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@ -86,22 +86,48 @@ struct mmu_gather {
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#ifdef CONFIG_HAVE_RCU_TABLE_FREE
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struct mmu_table_batch *batch;
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#endif
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unsigned int nr; /* set to ~0U means fast mode */
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unsigned int max; /* nr < max */
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unsigned int need_flush;/* Really unmapped some ptes? */
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unsigned int fullmm; /* non-zero means full mm flush */
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struct page **pages;
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struct page *local[MMU_GATHER_BUNDLE];
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unsigned int need_flush : 1, /* Did free PTEs */
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fast_mode : 1; /* No batching */
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unsigned int fullmm;
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struct mmu_gather_batch *active;
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struct mmu_gather_batch local;
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struct page *__pages[MMU_GATHER_BUNDLE];
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};
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static inline void __tlb_alloc_page(struct mmu_gather *tlb)
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{
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unsigned long addr = __get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
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/*
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* For UP we don't need to worry about TLB flush
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* and page free order so much..
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*/
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#ifdef CONFIG_SMP
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#define tlb_fast_mode(tlb) (tlb->fast_mode)
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#else
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#define tlb_fast_mode(tlb) 1
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#endif
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if (addr) {
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tlb->pages = (void *)addr;
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tlb->max = PAGE_SIZE / sizeof(struct page *);
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static inline int tlb_next_batch(struct mmu_gather *tlb)
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{
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struct mmu_gather_batch *batch;
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batch = tlb->active;
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if (batch->next) {
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tlb->active = batch->next;
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return 1;
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}
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batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
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if (!batch)
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return 0;
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batch->next = NULL;
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batch->nr = 0;
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batch->max = MAX_GATHER_BATCH;
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tlb->active->next = batch;
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tlb->active = batch;
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return 1;
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}
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/* tlb_gather_mmu
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@ -114,16 +140,13 @@ tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, bool fullmm)
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{
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tlb->mm = mm;
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tlb->max = ARRAY_SIZE(tlb->local);
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tlb->pages = tlb->local;
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if (num_online_cpus() > 1) {
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tlb->nr = 0;
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__tlb_alloc_page(tlb);
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} else /* Use fast mode if only one CPU is online */
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tlb->nr = ~0U;
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tlb->fullmm = fullmm;
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tlb->fullmm = fullmm;
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tlb->need_flush = 0;
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tlb->fast_mode = (num_possible_cpus() == 1);
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tlb->local.next = NULL;
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tlb->local.nr = 0;
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tlb->local.max = ARRAY_SIZE(tlb->__pages);
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tlb->active = &tlb->local;
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#ifdef CONFIG_HAVE_RCU_TABLE_FREE
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tlb->batch = NULL;
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@ -133,6 +156,8 @@ tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, bool fullmm)
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static inline void
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tlb_flush_mmu(struct mmu_gather *tlb)
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{
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struct mmu_gather_batch *batch;
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if (!tlb->need_flush)
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return;
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tlb->need_flush = 0;
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@ -140,17 +165,15 @@ tlb_flush_mmu(struct mmu_gather *tlb)
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#ifdef CONFIG_HAVE_RCU_TABLE_FREE
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tlb_table_flush(tlb);
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#endif
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if (!tlb_fast_mode(tlb)) {
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free_pages_and_swap_cache(tlb->pages, tlb->nr);
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tlb->nr = 0;
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/*
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* If we are using the local on-stack array of pages for MMU
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* gather, try allocating an off-stack array again as we have
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* recently freed pages.
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*/
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if (tlb->pages == tlb->local)
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__tlb_alloc_page(tlb);
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if (tlb_fast_mode(tlb))
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return;
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for (batch = &tlb->local; batch; batch = batch->next) {
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free_pages_and_swap_cache(batch->pages, batch->nr);
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batch->nr = 0;
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}
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tlb->active = &tlb->local;
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}
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/* tlb_finish_mmu
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@ -160,13 +183,18 @@ tlb_flush_mmu(struct mmu_gather *tlb)
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static inline void
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tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
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{
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struct mmu_gather_batch *batch, *next;
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tlb_flush_mmu(tlb);
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/* keep the page table cache within bounds */
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check_pgt_cache();
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if (tlb->pages != tlb->local)
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free_pages((unsigned long)tlb->pages, 0);
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for (batch = tlb->local.next; batch; batch = next) {
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next = batch->next;
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free_pages((unsigned long)batch, 0);
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}
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tlb->local.next = NULL;
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}
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/* __tlb_remove_page
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@ -177,15 +205,24 @@ tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
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*/
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static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
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{
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struct mmu_gather_batch *batch;
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tlb->need_flush = 1;
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if (tlb_fast_mode(tlb)) {
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free_page_and_swap_cache(page);
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return 1; /* avoid calling tlb_flush_mmu() */
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}
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tlb->pages[tlb->nr++] = page;
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VM_BUG_ON(tlb->nr > tlb->max);
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return tlb->max - tlb->nr;
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batch = tlb->active;
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batch->pages[batch->nr++] = page;
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VM_BUG_ON(batch->nr > batch->max);
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if (batch->nr == batch->max) {
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if (!tlb_next_batch(tlb))
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return 0;
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}
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return batch->max - batch->nr;
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}
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/* tlb_remove_page
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@ -994,8 +994,8 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
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spinlock_t *ptl;
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int rss[NR_MM_COUNTERS];
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init_rss_vec(rss);
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again:
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init_rss_vec(rss);
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pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
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arch_enter_lazy_mmu_mode();
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do {
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