lkml.org 
[lkml]   [2011]   [Apr]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
SubjectRe: [PATCH 01/20] mm: mmu_gather rework
From
Date
On Wed, 2011-04-20 at 10:47 +0200, Peter Zijlstra wrote:
>
> But I guess I can have asm-generic/tlb.h define HAVE_GENERIC_MMU_GATHER
> and make the compilation in mm/memory.c conditional on that (or generate
> lots of Kconfig churn).

Something like so:

---
Subject: mm: Uninline large generic tlb.h functions
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Wed Apr 20 11:04:42 CEST 2011

Some of these functions have grown beyond inline sanity, move them
out-of-line.

Requested-by: Andrew Morton <akpm@linux-foundation.org>
Requested-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
include/asm-generic/tlb.h | 135 ++++------------------------------------------
mm/memory.c | 124 +++++++++++++++++++++++++++++++++++++++++-
2 files changed, 135 insertions(+), 124 deletions(-)

Index: linux-2.6/include/asm-generic/tlb.h
===================================================================
--- linux-2.6.orig/include/asm-generic/tlb.h
+++ linux-2.6/include/asm-generic/tlb.h
@@ -96,134 +96,25 @@ struct mmu_gather {
struct page *__pages[MMU_GATHER_BUNDLE];
};

-/*
- * For UP we don't need to worry about TLB flush
- * and page free order so much..
- */
-#ifdef CONFIG_SMP
- #define tlb_fast_mode(tlb) (tlb->fast_mode)
-#else
- #define tlb_fast_mode(tlb) 1
-#endif
+#define HAVE_GENERIC_MMU_GATHER

-static inline int tlb_next_batch(struct mmu_gather *tlb)
+static inline int tlb_fast_mode(struct mmu_gather *tlb)
{
- struct mmu_gather_batch *batch;
-
- batch = tlb->active;
- if (batch->next) {
- tlb->active = batch->next;
- return 1;
- }
-
- batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
- if (!batch)
- return 0;
-
- batch->next = NULL;
- batch->nr = 0;
- batch->max = MAX_GATHER_BATCH;
-
- tlb->active->next = batch;
- tlb->active = batch;
-
+#ifdef CONFIG_SMP
+ return tlb->fast_mode;
+#else
+ /*
+ * For UP we don't need to worry about TLB flush
+ * and page free order so much..
+ */
return 1;
-}
-
-/* tlb_gather_mmu
- * Called to initialize an (on-stack) mmu_gather structure for page-table
- * tear-down from @mm. The @fullmm argument is used when @mm is without
- * users and we're going to destroy the full address space (exit/execve).
- */
-static inline void
-tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, bool fullmm)
-{
- tlb->mm = mm;
-
- tlb->fullmm = fullmm;
- tlb->need_flush = 0;
- tlb->fast_mode = (num_possible_cpus() == 1);
- tlb->local.next = NULL;
- tlb->local.nr = 0;
- tlb->local.max = ARRAY_SIZE(tlb->__pages);
- tlb->active = &tlb->local;
-
-#ifdef CONFIG_HAVE_RCU_TABLE_FREE
- tlb->batch = NULL;
#endif
}

-static inline void
-tlb_flush_mmu(struct mmu_gather *tlb)
-{
- struct mmu_gather_batch *batch;
-
- if (!tlb->need_flush)
- return;
- tlb->need_flush = 0;
- tlb_flush(tlb);
-#ifdef CONFIG_HAVE_RCU_TABLE_FREE
- tlb_table_flush(tlb);
-#endif
-
- if (tlb_fast_mode(tlb))
- return;
-
- for (batch = &tlb->local; batch; batch = batch->next) {
- free_pages_and_swap_cache(batch->pages, batch->nr);
- batch->nr = 0;
- }
- tlb->active = &tlb->local;
-}
-
-/* tlb_finish_mmu
- * Called at the end of the shootdown operation to free up any resources
- * that were required.
- */
-static inline void
-tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
-{
- struct mmu_gather_batch *batch, *next;
-
- tlb_flush_mmu(tlb);
-
- /* keep the page table cache within bounds */
- check_pgt_cache();
-
- for (batch = tlb->local.next; batch; batch = next) {
- next = batch->next;
- free_pages((unsigned long)batch, 0);
- }
- tlb->local.next = NULL;
-}
-
-/* __tlb_remove_page
- * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
- * handling the additional races in SMP caused by other CPUs caching valid
- * mappings in their TLBs. Returns the number of free page slots left.
- * When out of page slots we must call tlb_flush_mmu().
- */
-static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
-{
- struct mmu_gather_batch *batch;
-
- tlb->need_flush = 1;
-
- if (tlb_fast_mode(tlb)) {
- free_page_and_swap_cache(page);
- return 1; /* avoid calling tlb_flush_mmu() */
- }
-
- batch = tlb->active;
- batch->pages[batch->nr++] = page;
- VM_BUG_ON(batch->nr > batch->max);
- if (batch->nr == batch->max) {
- if (!tlb_next_batch(tlb))
- return 0;
- }
-
- return batch->max - batch->nr;
-}
+void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, bool fullmm);
+void tlb_flush_mmu(struct mmu_gather *tlb);
+void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end);
+int __tlb_remove_page(struct mmu_gather *tlb, struct page *page);

/* tlb_remove_page
* Similar to __tlb_remove_page but will call tlb_flush_mmu() itself when
Index: linux-2.6/mm/memory.c
===================================================================
--- linux-2.6.orig/mm/memory.c
+++ linux-2.6/mm/memory.c
@@ -182,7 +182,7 @@ void sync_mm_rss(struct task_struct *tas
{
__sync_task_rss_stat(task, mm);
}
-#else
+#else /* SPLIT_RSS_COUNTING */

#define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member)
#define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member)
@@ -191,7 +191,127 @@ static void check_sync_rss_stat(struct t
{
}

+#endif /* SPLIT_RSS_COUNTING */
+
+#ifdef HAVE_GENERIC_MMU_GATHER
+
+static int tlb_next_batch(struct mmu_gather *tlb)
+{
+ struct mmu_gather_batch *batch;
+
+ batch = tlb->active;
+ if (batch->next) {
+ tlb->active = batch->next;
+ return 1;
+ }
+
+ batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
+ if (!batch)
+ return 0;
+
+ batch->next = NULL;
+ batch->nr = 0;
+ batch->max = MAX_GATHER_BATCH;
+
+ tlb->active->next = batch;
+ tlb->active = batch;
+
+ return 1;
+}
+
+/* tlb_gather_mmu
+ * Called to initialize an (on-stack) mmu_gather structure for page-table
+ * tear-down from @mm. The @fullmm argument is used when @mm is without
+ * users and we're going to destroy the full address space (exit/execve).
+ */
+void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, bool fullmm)
+{
+ tlb->mm = mm;
+
+ tlb->fullmm = fullmm;
+ tlb->need_flush = 0;
+ tlb->fast_mode = (num_possible_cpus() == 1);
+ tlb->local.next = NULL;
+ tlb->local.nr = 0;
+ tlb->local.max = ARRAY_SIZE(tlb->__pages);
+ tlb->active = &tlb->local;
+
+#ifdef CONFIG_HAVE_RCU_TABLE_FREE
+ tlb->batch = NULL;
#endif
+}
+
+void tlb_flush_mmu(struct mmu_gather *tlb)
+{
+ struct mmu_gather_batch *batch;
+
+ if (!tlb->need_flush)
+ return;
+ tlb->need_flush = 0;
+ tlb_flush(tlb);
+#ifdef CONFIG_HAVE_RCU_TABLE_FREE
+ tlb_table_flush(tlb);
+#endif
+
+ if (tlb_fast_mode(tlb))
+ return;
+
+ for (batch = &tlb->local; batch; batch = batch->next) {
+ free_pages_and_swap_cache(batch->pages, batch->nr);
+ batch->nr = 0;
+ }
+ tlb->active = &tlb->local;
+}
+
+/* tlb_finish_mmu
+ * Called at the end of the shootdown operation to free up any resources
+ * that were required.
+ */
+void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
+{
+ struct mmu_gather_batch *batch, *next;
+
+ tlb_flush_mmu(tlb);
+
+ /* keep the page table cache within bounds */
+ check_pgt_cache();
+
+ for (batch = tlb->local.next; batch; batch = next) {
+ next = batch->next;
+ free_pages((unsigned long)batch, 0);
+ }
+ tlb->local.next = NULL;
+}
+
+/* __tlb_remove_page
+ * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
+ * handling the additional races in SMP caused by other CPUs caching valid
+ * mappings in their TLBs. Returns the number of free page slots left.
+ * When out of page slots we must call tlb_flush_mmu().
+ */
+int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
+{
+ struct mmu_gather_batch *batch;
+
+ tlb->need_flush = 1;
+
+ if (tlb_fast_mode(tlb)) {
+ free_page_and_swap_cache(page);
+ return 1; /* avoid calling tlb_flush_mmu() */
+ }
+
+ batch = tlb->active;
+ batch->pages[batch->nr++] = page;
+ if (batch->nr == batch->max) {
+ if (!tlb_next_batch(tlb))
+ return 0;
+ }
+ VM_BUG_ON(batch->nr > batch->max);
+
+ return batch->max - batch->nr;
+}
+
+#endif /* HAVE_GENERIC_MMU_GATHER */

#ifdef CONFIG_HAVE_RCU_TABLE_FREE

@@ -268,7 +388,7 @@ void tlb_remove_table(struct mmu_gather
tlb_table_flush(tlb);
}

-#endif
+#endif /* CONFIG_HAVE_RCU_TABLE_FREE */

/*
* If a p?d_bad entry is found while walking page tables, report


\
 
 \ /
  Last update: 2011-04-20 11:13    [W:0.069 / U:1.756 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site