The patch titled
Subject: mm, highmem: makes flush_all_zero_pkmaps() return index of last flushed entry
has been removed from the -mm tree. Its filename was
mm-highmem-makes-flush_all_zero_pkmaps-return-index-of-last-flushed-entry.patch
This patch was dropped because it was withdrawn
------------------------------------------------------
From: Joonsoo Kim <js1304@xxxxxxxxx>
Subject: mm, highmem: makes flush_all_zero_pkmaps() return index of last flushed entry
In current code, after flush_all_zero_pkmaps() is invoked we re-iterate
all pkmaps. This can be optimized if flush_all_zero_pkmaps() returns an
index of flushed entry. With this index, we can immediately map highmem
page to virtual address represented by index. So change return type of
flush_all_zero_pkmaps() and return index of last flushed entry.
Additionally, update last_pkmap_nr to this index. It is certain that
entry which is below this index is occupied by other mapping, therefore
updating last_pkmap_nr to this index is reasonable optimization.
Signed-off-by: Joonsoo Kim <js1304@xxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/highmem.h | 1
mm/highmem.c | 75 ++++++++++++++++++++++----------------
2 files changed, 45 insertions(+), 31 deletions(-)
diff -puN include/linux/highmem.h~mm-highmem-makes-flush_all_zero_pkmaps-return-index-of-last-flushed-entry include/linux/highmem.h
--- a/include/linux/highmem.h~mm-highmem-makes-flush_all_zero_pkmaps-return-index-of-last-flushed-entry
+++ a/include/linux/highmem.h
@@ -32,6 +32,7 @@ static inline void invalidate_kernel_vma
#ifdef CONFIG_HIGHMEM
#include <asm/highmem.h>
+#define PKMAP_INVALID_INDEX (LAST_PKMAP)
/* declarations for linux/mm/highmem.c */
unsigned int nr_free_highpages(void);
diff -puN mm/highmem.c~mm-highmem-makes-flush_all_zero_pkmaps-return-index-of-last-flushed-entry mm/highmem.c
--- a/mm/highmem.c~mm-highmem-makes-flush_all_zero_pkmaps-return-index-of-last-flushed-entry
+++ a/mm/highmem.c
@@ -107,10 +107,10 @@ struct page *kmap_to_page(void *vaddr)
}
EXPORT_SYMBOL(kmap_to_page);
-static void flush_all_zero_pkmaps(void)
+static unsigned int flush_all_zero_pkmaps(void)
{
int i;
- int need_flush = 0;
+ unsigned int index = PKMAP_INVALID_INDEX;
flush_cache_kmaps();
@@ -142,10 +142,13 @@ static void flush_all_zero_pkmaps(void)
&pkmap_page_table[i]);
set_page_address(page, NULL);
- need_flush = 1;
+ if (index == PKMAP_INVALID_INDEX)
+ index = i;
}
- if (need_flush)
+ if (index != PKMAP_INVALID_INDEX)
flush_tlb_kernel_range(PKMAP_ADDR(0), PKMAP_ADDR(LAST_PKMAP));
+
+ return index;
}
/**
@@ -153,14 +156,19 @@ static void flush_all_zero_pkmaps(void)
*/
void kmap_flush_unused(void)
{
+ unsigned int index;
+
lock_kmap();
- flush_all_zero_pkmaps();
+ index = flush_all_zero_pkmaps();
+ if (index != PKMAP_INVALID_INDEX && (index < last_pkmap_nr))
+ last_pkmap_nr = index;
unlock_kmap();
}
static inline unsigned long map_new_virtual(struct page *page)
{
unsigned long vaddr;
+ unsigned int index = PKMAP_INVALID_INDEX;
int count;
start:
@@ -169,40 +177,45 @@ start:
for (;;) {
last_pkmap_nr = (last_pkmap_nr + 1) & LAST_PKMAP_MASK;
if (!last_pkmap_nr) {
- flush_all_zero_pkmaps();
- count = LAST_PKMAP;
+ index = flush_all_zero_pkmaps();
+ break;
}
- if (!pkmap_count[last_pkmap_nr])
+ if (!pkmap_count[last_pkmap_nr]) {
+ index = last_pkmap_nr;
break; /* Found a usable entry */
- if (--count)
- continue;
+ }
+ if (--count == 0)
+ break;
+ }
- /*
- * Sleep for somebody else to unmap their entries
- */
- {
- DECLARE_WAITQUEUE(wait, current);
+ /*
+ * Sleep for somebody else to unmap their entries
+ */
+ if (index == PKMAP_INVALID_INDEX) {
+ DECLARE_WAITQUEUE(wait, current);
- __set_current_state(TASK_UNINTERRUPTIBLE);
- add_wait_queue(&pkmap_map_wait, &wait);
- unlock_kmap();
- schedule();
- remove_wait_queue(&pkmap_map_wait, &wait);
- lock_kmap();
-
- /* Somebody else might have mapped it while we slept */
- if (page_address(page))
- return (unsigned long)page_address(page);
+ __set_current_state(TASK_UNINTERRUPTIBLE);
+ add_wait_queue(&pkmap_map_wait, &wait);
+ unlock_kmap();
+ schedule();
+ remove_wait_queue(&pkmap_map_wait, &wait);
+ lock_kmap();
+
+ /* Somebody else might have mapped it while we slept */
+ vaddr = (unsigned long)page_address(page);
+ if (vaddr)
+ return vaddr;
- /* Re-start */
- goto start;
- }
+ /* Re-start */
+ goto start;
}
- vaddr = PKMAP_ADDR(last_pkmap_nr);
+
+ vaddr = PKMAP_ADDR(index);
set_pte_at(&init_mm, vaddr,
- &(pkmap_page_table[last_pkmap_nr]), mk_pte(page, kmap_prot));
+ &(pkmap_page_table[index]), mk_pte(page, kmap_prot));
- pkmap_count[last_pkmap_nr] = 1;
+ pkmap_count[index] = 1;
+ last_pkmap_nr = index;
set_page_address(page, (void *)vaddr);
return vaddr;
_
Patches currently in -mm which might be from js1304@xxxxxxxxx are
linux-next.patch
mm-highmem-use-pkmap_nr-to-calculate-an-index-of-pkmap.patch
mm-highmem-remove-useless-pool_lock.patch
mm-highmem-remove-page_address_pool-list.patch
mm-highmem-remove-page_address_pool-list-v2.patch
mm-highmem-get-virtual-address-of-the-page-using-pkmap_addr.patch
memcg-make-it-possible-to-use-the-stock-for-more-than-one-page.patch
memcg-reclaim-when-more-than-one-page-needed.patch
memcg-change-defines-to-an-enum.patch
memcg-kmem-accounting-basic-infrastructure.patch
mm-add-a-__gfp_kmemcg-flag.patch
memcg-kmem-controller-infrastructure.patch
mm-allocate-kernel-pages-to-the-right-memcg.patch
res_counter-return-amount-of-charges-after-res_counter_uncharge.patch
memcg-kmem-accounting-lifecycle-management.patch
memcg-use-static-branches-when-code-not-in-use.patch
memcg-allow-a-memcg-with-kmem-charges-to-be-destructed.patch
memcg-execute-the-whole-memcg-freeing-in-free_worker.patch
fork-protect-architectures-where-thread_size-=-page_size-against-fork-bombs.patch
memcg-add-documentation-about-the-kmem-controller.patch
slab-slub-struct-memcg_params.patch
slab-annotate-on-slab-caches-nodelist-locks.patch
slab-slub-consider-a-memcg-parameter-in-kmem_create_cache.patch
memcg-allocate-memory-for-memcg-caches-whenever-a-new-memcg-appears.patch
memcg-infrastructure-to-match-an-allocation-to-the-right-cache.patch
memcg-skip-memcg-kmem-allocations-in-specified-code-regions.patch
slb-always-get-the-cache-from-its-page-in-kmem_cache_free.patch
slb-allocate-objects-from-memcg-cache.patch
memcg-destroy-memcg-caches.patch
memcg-slb-track-all-the-memcg-children-of-a-kmem_cache.patch
memcg-slb-shrink-dead-caches.patch
memcg-aggregate-memcg-cache-values-in-slabinfo.patch
slab-propagate-tunable-values.patch
slub-slub-specific-propagation-changes.patch
slub-slub-specific-propagation-changes-fix.patch
kmem-add-slab-specific-documentation-about-the-kmem-controller.patch
bootmem-remove-not-implemented-function-call-bootmem_arch_preferred_node.patch
avr32-kconfig-remove-have_arch_bootmem.patch
bootmem-remove-alloc_arch_preferred_bootmem.patch
bootmem-fix-wrong-call-parameter-for-free_bootmem.patch
bootmem-fix-wrong-call-parameter-for-free_bootmem-fix.patch
mm-warn_on_once-if-f_op-mmap-change-vmas-start-address.patch
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