#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/mm.h>
+#include <linux/interrupt.h>
#include <asm/e820.h>
#include <asm/processor.h>
* or when the present bit is not set. Otherwise we would return a
* pointer to a nonexisting mapping.
*/
-pte_t *lookup_address(unsigned long address, int *level)
+pte_t *lookup_address(unsigned long address, unsigned int *level)
{
pgd_t *pgd = pgd_offset_k(address);
pud_t *pud;
try_preserve_large_page(pte_t *kpte, unsigned long address,
struct cpa_data *cpa)
{
- unsigned long nextpage_addr, numpages, pmask, psize, flags;
+ unsigned long nextpage_addr, numpages, pmask, psize, flags, addr;
pte_t new_pte, old_pte, *tmp;
pgprot_t old_prot, new_prot;
- int level, do_split = 1;
+ int i, do_split = 1;
+ unsigned int level;
spin_lock_irqsave(&pgd_lock, flags);
/*
pgprot_val(new_prot) |= pgprot_val(cpa->mask_set);
new_prot = static_protections(new_prot, address);
+ /*
+ * We need to check the full range, whether
+ * static_protection() requires a different pgprot for one of
+ * the pages in the range we try to preserve:
+ */
+ addr = address + PAGE_SIZE;
+ for (i = 1; i < cpa->numpages; i++, addr += PAGE_SIZE) {
+ pgprot_t chk_prot = static_protections(new_prot, addr);
+
+ if (pgprot_val(chk_prot) != pgprot_val(new_prot))
+ goto out_unlock;
+ }
+
/*
* If there are no changes, return. maxpages has been updated
* above:
return do_split;
}
+static LIST_HEAD(page_pool);
+static unsigned long pool_size, pool_pages, pool_low;
+static unsigned long pool_used, pool_failed, pool_refill;
+
+static void cpa_fill_pool(void)
+{
+ struct page *p;
+ gfp_t gfp = GFP_KERNEL;
+
+ /* Do not allocate from interrupt context */
+ if (in_irq() || irqs_disabled())
+ return;
+ /*
+ * Check unlocked. I does not matter when we have one more
+ * page in the pool. The bit lock avoids recursive pool
+ * allocations:
+ */
+ if (pool_pages >= pool_size || test_and_set_bit_lock(0, &pool_refill))
+ return;
+
+#ifdef CONFIG_DEBUG_PAGEALLOC
+ /*
+ * We could do:
+ * gfp = in_atomic() ? GFP_ATOMIC : GFP_KERNEL;
+ * but this fails on !PREEMPT kernels
+ */
+ gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
+#endif
+
+ while (pool_pages < pool_size) {
+ p = alloc_pages(gfp, 0);
+ if (!p) {
+ pool_failed++;
+ break;
+ }
+ spin_lock_irq(&pgd_lock);
+ list_add(&p->lru, &page_pool);
+ pool_pages++;
+ spin_unlock_irq(&pgd_lock);
+ }
+ clear_bit_unlock(0, &pool_refill);
+}
+
+#define SHIFT_MB (20 - PAGE_SHIFT)
+#define ROUND_MB_GB ((1 << 10) - 1)
+#define SHIFT_MB_GB 10
+#define POOL_PAGES_PER_GB 16
+
+void __init cpa_init(void)
+{
+ struct sysinfo si;
+ unsigned long gb;
+
+ si_meminfo(&si);
+ /*
+ * Calculate the number of pool pages:
+ *
+ * Convert totalram (nr of pages) to MiB and round to the next
+ * GiB. Shift MiB to Gib and multiply the result by
+ * POOL_PAGES_PER_GB:
+ */
+ gb = ((si.totalram >> SHIFT_MB) + ROUND_MB_GB) >> SHIFT_MB_GB;
+ pool_size = POOL_PAGES_PER_GB * gb;
+ pool_low = pool_size;
+
+ cpa_fill_pool();
+ printk(KERN_DEBUG
+ "CPA: page pool initialized %lu of %lu pages preallocated\n",
+ pool_pages, pool_size);
+}
+
static int split_large_page(pte_t *kpte, unsigned long address)
{
unsigned long flags, pfn, pfninc = 1;
- gfp_t gfp_flags = GFP_KERNEL;
unsigned int i, level;
pte_t *pbase, *tmp;
pgprot_t ref_prot;
struct page *base;
-#ifdef CONFIG_DEBUG_PAGEALLOC
- gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
-#endif
- base = alloc_pages(gfp_flags, 0);
- if (!base)
+ /*
+ * Get a page from the pool. The pool list is protected by the
+ * pgd_lock, which we have to take anyway for the split
+ * operation:
+ */
+ spin_lock_irqsave(&pgd_lock, flags);
+ if (list_empty(&page_pool)) {
+ spin_unlock_irqrestore(&pgd_lock, flags);
return -ENOMEM;
+ }
+
+ base = list_first_entry(&page_pool, struct page, lru);
+ list_del(&base->lru);
+ pool_pages--;
+
+ if (pool_pages < pool_low)
+ pool_low = pool_pages;
- spin_lock_irqsave(&pgd_lock, flags);
/*
* Check for races, another CPU might have split this page
* up for us already:
base = NULL;
out_unlock:
+ /*
+ * If we dropped out via the lookup_address check under
+ * pgd_lock then stick the page back into the pool:
+ */
+ if (base) {
+ list_add(&base->lru, &page_pool);
+ pool_pages++;
+ } else
+ pool_used++;
spin_unlock_irqrestore(&pgd_lock, flags);
- if (base)
- __free_pages(base, 0);
-
return 0;
}
static int __change_page_attr(unsigned long address, struct cpa_data *cpa)
{
- int level, do_split, err;
+ int do_split, err;
+ unsigned int level;
struct page *kpte_page;
pte_t *kpte;
* Check whether we really changed something:
*/
if (!cpa.flushtlb)
- return ret;
+ goto out;
/*
* No need to flush, when we did not set any of the caching
else
cpa_flush_all(cache);
+out:
+ cpa_fill_pool();
return ret;
}
* but that can deadlock->flush only current cpu:
*/
__flush_tlb_all();
+
+ /*
+ * Try to refill the page pool here. We can do this only after
+ * the tlb flush.
+ */
+ cpa_fill_pool();
}
#endif
git.samba.org / sfrench / cifs-2.6.git / blobdiff