[PATCH 18/20] percpu: kill lpage first chunk allocator

Tejun Heo
2009-07-21T10:27:58Z

With x86 converted to embedding allocator, lpage doesn't have any user
left. Kill it along with cpa handling code.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jan Beulich <JBeulich@novell.com>
---
Documentation/kernel-parameters.txt | 10 +-
arch/x86/mm/pageattr.c | 20 +---
include/linux/percpu.h | 16 ---
mm/percpu.c | 241 -----------------------------------
4 files changed, 6 insertions(+), 281 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 89b7568..720b758 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1916,11 +1916,11 @@ and is between 256 and 4096 characters. It is defined in the file
See arch/parisc/kernel/pdc_chassis.c

percpu_alloc= Select which percpu first chunk allocator to use.
- Currently supported values are "embed", "page" and
- "lpage". Archs may support subset or none of the
- selections. See comments in mm/percpu.c for details
- on each allocator. This parameter is primarily for
- debugging and performance comparison.
+ Currently supported values are "embed" and "page".
+ Archs may support subset or none of the selections.
+ See comments in mm/percpu.c for details on each
+ allocator. This parameter is primarily for debugging
+ and performance comparison.

pf. [PARIDE]
See Documentation/blockdev/paride.txt.
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index c106f78..b0a09ba 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -684,7 +684,7 @@ static int cpa_process_alias(struct cpa_data *cpa)
{
struct cpa_data alias_cpa;
unsigned long laddr = (unsigned long)__va(cpa->pfn << PAGE_SHIFT);
- unsigned long vaddr, remapped;
+ unsigned long vaddr;
int ret;

if (cpa->pfn >= max_pfn_mapped)
@@ -739,24 +739,6 @@ static int cpa_process_alias(struct cpa_data *cpa)
}
#endif

- /*
- * If the PMD page was partially used for per-cpu remapping,
- * the recycled area needs to be split and modified. Because
- * the area is always proper subset of a PMD page
- * cpa->numpages is guaranteed to be 1 for these areas, so
- * there's no need to loop over and check for further remaps.
- */
- remapped = (unsigned long)pcpu_lpage_remapped((void *)laddr);
- if (remapped) {
- WARN_ON(cpa->numpages > 1);
- alias_cpa = *cpa;
- alias_cpa.vaddr = &remapped;
- alias_cpa.flags &= ~(CPA_PAGES_ARRAY | CPA_ARRAY);
- ret = __change_page_attr_set_clr(&alias_cpa, 0);
- if (ret)
- return ret;
- }
-
return 0;
}

diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index 2535993..878836c 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -82,7 +82,6 @@ enum pcpu_fc {
PCPU_FC_AUTO,
PCPU_FC_EMBED,
PCPU_FC_PAGE,
- PCPU_FC_LPAGE,

PCPU_FC_NR,
};
@@ -95,7 +94,6 @@ typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size,
typedef void (*pcpu_fc_free_fn_t)(void *ptr, size_t size);
typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr);
typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
-typedef void (*pcpu_fc_map_fn_t)(void *ptr, size_t size, void *addr);

extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
int nr_units);
@@ -124,20 +122,6 @@ extern int __init pcpu_page_first_chunk(size_t reserved_size,
pcpu_fc_populate_pte_fn_t populate_pte_fn);
#endif

-#ifdef CONFIG_NEED_PER_CPU_LPAGE_FIRST_CHUNK
-extern int __init pcpu_lpage_first_chunk(const struct pcpu_alloc_info *ai,
- pcpu_fc_alloc_fn_t alloc_fn,
- pcpu_fc_free_fn_t free_fn,
- pcpu_fc_map_fn_t map_fn);
-
-extern void *pcpu_lpage_remapped(void *kaddr);
-#else
-static inline void *pcpu_lpage_remapped(void *kaddr)
-{
- return NULL;
-}
-#endif
-
/*
* Use this to get to a cpu's version of the per-cpu object
* dynamically allocated. Non-atomic access to the current CPU's
diff --git a/mm/percpu.c b/mm/percpu.c
index c2826d0..7793392 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1713,7 +1713,6 @@ const char *pcpu_fc_names[PCPU_FC_NR] __initdata = {
[PCPU_FC_AUTO] = "auto",
[PCPU_FC_EMBED] = "embed",
[PCPU_FC_PAGE] = "page",
- [PCPU_FC_LPAGE] = "lpage",
};

enum pcpu_fc pcpu_chosen_fc __initdata = PCPU_FC_AUTO;
@@ -1730,10 +1729,6 @@ static int __init percpu_alloc_setup(char *str)
else if (!strcmp(str, "page"))
pcpu_chosen_fc = PCPU_FC_PAGE;
#endif
-#ifdef CONFIG_NEED_PER_CPU_LPAGE_FIRST_CHUNK
- else if (!strcmp(str, "lpage"))
- pcpu_chosen_fc = PCPU_FC_LPAGE;
-#endif
else
pr_warning("PERCPU: unknown allocator %s specified\n", str);

@@ -1970,242 +1965,6 @@ out_free_ar:
}
#endif /* CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK */

-#ifdef CONFIG_NEED_PER_CPU_LPAGE_FIRST_CHUNK
-struct pcpul_ent {
- void *ptr;
- void *map_addr;
-};
-
-static size_t pcpul_size;
-static size_t pcpul_lpage_size;
-static int pcpul_nr_lpages;
-static struct pcpul_ent *pcpul_map;
-
-static bool __init pcpul_unit_to_cpu(int unit, const struct pcpu_alloc_info *ai,
- unsigned int *cpup)
-{
- int group, cunit;
-
- for (group = 0, cunit = 0; group < ai->nr_groups; group++) {
- const struct pcpu_group_info *gi = &ai->groups[group];
-
- if (unit < cunit + gi->nr_units) {
- if (cpup)
- *cpup = gi->cpu_map[unit - cunit];
- return true;
- }
- cunit += gi->nr_units;
- }
-
- return false;
-}
-
-static int __init pcpul_cpu_to_unit(int cpu, const struct pcpu_alloc_info *ai)
-{
- int group, unit, i;
-
- for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
- const struct pcpu_group_info *gi = &ai->groups[group];
-
- for (i = 0; i < gi->nr_units; i++)
- if (gi->cpu_map[i] == cpu)
- return unit + i;
- }
- BUG();
-}
-
-/**
- * pcpu_lpage_first_chunk - remap the first percpu chunk using large page
- * @ai: pcpu_alloc_info
- * @alloc_fn: function to allocate percpu lpage, always called with lpage_size
- * @free_fn: function to free percpu memory, @size <= lpage_size
- * @map_fn: function to map percpu lpage, always called with lpage_size
- *
- * This allocator uses large page to build and map the first chunk.
- * Unlike other helpers, the caller should provide fully initialized
- * @ai. This can be done using pcpu_build_alloc_info(). This two
- * stage initialization is to allow arch code to evaluate the
- * parameters before committing to it.
- *
- * Large pages are allocated as directed by @unit_map and other
- * parameters and mapped to vmalloc space. Unused holes are returned
- * to the page allocator. Note that these holes end up being actively
- * mapped twice - once to the physical mapping and to the vmalloc area
- * for the first percpu chunk. Depending on architecture, this might
- * cause problem when changing page attributes of the returned area.
- * These double mapped areas can be detected using
- * pcpu_lpage_remapped().
- *
- * RETURNS:
- * 0 on success, -errno on failure.
- */
-int __init pcpu_lpage_first_chunk(const struct pcpu_alloc_info *ai,
- pcpu_fc_alloc_fn_t alloc_fn,
- pcpu_fc_free_fn_t free_fn,
- pcpu_fc_map_fn_t map_fn)
-{
- static struct vm_struct vm;
- const size_t lpage_size = ai->atom_size;
- size_t chunk_size, map_size;
- unsigned int cpu;
- int i, j, unit, nr_units, rc;
-
- nr_units = 0;
- for (i = 0; i < ai->nr_groups; i++)
- nr_units += ai->groups[i].nr_units;
-
- chunk_size = ai->unit_size * nr_units;
- BUG_ON(chunk_size % lpage_size);
-
- pcpul_size = ai->static_size + ai->reserved_size + ai->dyn_size;
- pcpul_lpage_size = lpage_size;
- pcpul_nr_lpages = chunk_size / lpage_size;
-
- /* allocate pointer array and alloc large pages */
- map_size = pcpul_nr_lpages * sizeof(pcpul_map[0]);
- pcpul_map = alloc_bootmem(map_size);
-
- /* allocate all pages */
- for (i = 0; i < pcpul_nr_lpages; i++) {
- size_t offset = i * lpage_size;
- int first_unit = offset / ai->unit_size;
- int last_unit = (offset + lpage_size - 1) / ai->unit_size;
- void *ptr;
-
- /* find out which cpu is mapped to this unit */
- for (unit = first_unit; unit <= last_unit; unit++)
- if (pcpul_unit_to_cpu(unit, ai, &cpu))
- goto found;
- continue;
- found:
- ptr = alloc_fn(cpu, lpage_size, lpage_size);
- if (!ptr) {
- pr_warning("PERCPU: failed to allocate large page "
- "for cpu%u\n", cpu);
- goto enomem;
- }
-
- pcpul_map[i].ptr = ptr;
- }
-
- /* return unused holes */
- for (unit = 0; unit < nr_units; unit++) {
- size_t start = unit * ai->unit_size;
- size_t end = start + ai->unit_size;
- size_t off, next;
-
- /* don't free used part of occupied unit */
- if (pcpul_unit_to_cpu(unit, ai, NULL))
- start += pcpul_size;
-
- /* unit can span more than one page, punch the holes */
- for (off = start; off < end; off = next) {
- void *ptr = pcpul_map[off / lpage_size].ptr;
- next = min(roundup(off + 1, lpage_size), end);
- if (ptr)
- free_fn(ptr + off % lpage_size, next - off);
- }
- }
-
- /* allocate address, map and copy */
- vm.flags = VM_ALLOC;
- vm.size = chunk_size;
- vm_area_register_early(&vm, ai->unit_size);
-
- for (i = 0; i < pcpul_nr_lpages; i++) {
- if (!pcpul_map[i].ptr)
- continue;
- pcpul_map[i].map_addr = vm.addr + i * lpage_size;
- map_fn(pcpul_map[i].ptr, lpage_size, pcpul_map[i].map_addr);
- }
-
- for_each_possible_cpu(cpu)
- memcpy(vm.addr + pcpul_cpu_to_unit(cpu, ai) * ai->unit_size,
- __per_cpu_load, ai->static_size);
-
- /* we're ready, commit */
- pr_info("PERCPU: large pages @%p s%zu r%zu d%zu u%zu\n",
- vm.addr, ai->static_size, ai->reserved_size, ai->dyn_size,
- ai->unit_size);
-
- rc = pcpu_setup_first_chunk(ai, vm.addr);
-
- /*
- * Sort pcpul_map array for pcpu_lpage_remapped(). Unmapped
- * lpages are pushed to the end and trimmed.
- */
- for (i = 0; i < pcpul_nr_lpages - 1; i++)
- for (j = i + 1; j < pcpul_nr_lpages; j++) {
- struct pcpul_ent tmp;
-
- if (!pcpul_map[j].ptr)
- continue;
- if (pcpul_map[i].ptr &&
- pcpul_map[i].ptr < pcpul_map[j].ptr)
- continue;
-
- tmp = pcpul_map[i];
- pcpul_map[i] = pcpul_map[j];
- pcpul_map[j] = tmp;
- }
-
- while (pcpul_nr_lpages && !pcpul_map[pcpul_nr_lpages - 1].ptr)
- pcpul_nr_lpages--;
-
- return rc;
-
-enomem:
- for (i = 0; i < pcpul_nr_lpages; i++)
- if (pcpul_map[i].ptr)
- free_fn(pcpul_map[i].ptr, lpage_size);
- free_bootmem(__pa(pcpul_map), map_size);
- return -ENOMEM;
-}
-
-/**
- * pcpu_lpage_remapped - determine whether a kaddr is in pcpul recycled area
- * @kaddr: the kernel address in question
- *
- * Determine whether @kaddr falls in the pcpul recycled area. This is
- * used by pageattr to detect VM aliases and break up the pcpu large
- * page mapping such that the same physical page is not mapped under
- * different attributes.
- *
- * The recycled area is always at the tail of a partially used large
- * page.
- *
- * RETURNS:
- * Address of corresponding remapped pcpu address if match is found;
- * otherwise, NULL.
- */
-void *pcpu_lpage_remapped(void *kaddr)
-{
- unsigned long lpage_mask = pcpul_lpage_size - 1;
- void *lpage_addr = (void *)((unsigned long)kaddr & ~lpage_mask);
- unsigned long offset = (unsigned long)kaddr & lpage_mask;
- int left = 0, right = pcpul_nr_lpages - 1;
- int pos;
-
- /* pcpul in use at all? */
- if (!pcpul_map)
- return NULL;
-
- /* okay, perform binary search */
- while (left <= right) {
- pos = (left + right) / 2;
-
- if (pcpul_map[pos].ptr < lpage_addr)
- left = pos + 1;
- else if (pcpul_map[pos].ptr > lpage_addr)
- right = pos - 1;
- else
- return pcpul_map[pos].map_addr + offset;
- }
-
- return NULL;
-}
-#endif /* CONFIG_NEED_PER_CPU_LPAGE_FIRST_CHUNK */
-
/*
* Generic percpu area setup.
*
--
1.6.0.2