mirror of
https://github.com/torvalds/linux.git
synced 2025-11-04 02:30:34 +02:00
mm/gup: cache dev_pagemap while pinning pages
Getting pages from ZONE_DEVICE memory needs to check the backing device's live-ness, which is tracked in the device's dev_pagemap metadata. This metadata is stored in a radix tree and looking it up adds measurable software overhead. This patch avoids repeating this relatively costly operation when dev_pagemap is used by caching the last dev_pagemap while getting user pages. The gup_benchmark kernel self test reports this reduces time to get user pages to as low as 1/3 of the previous time. Link: http://lkml.kernel.org/r/20181012173040.15669-1-keith.busch@intel.com Signed-off-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Keith Busch
Linus Torvalds
parent
9fd61bc951
commit
df06b37ffe
5 changed files with 79 additions and 73 deletions
|
|
@ -213,9 +213,9 @@ static inline int hpage_nr_pages(struct page *page)
|
|||
}
|
||||
|
||||
struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
|
||||
pmd_t *pmd, int flags);
|
||||
pmd_t *pmd, int flags, struct dev_pagemap **pgmap);
|
||||
struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr,
|
||||
pud_t *pud, int flags);
|
||||
pud_t *pud, int flags, struct dev_pagemap **pgmap);
|
||||
|
||||
extern vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t orig_pmd);
|
||||
|
||||
|
|
@ -344,13 +344,13 @@ static inline void mm_put_huge_zero_page(struct mm_struct *mm)
|
|||
}
|
||||
|
||||
static inline struct page *follow_devmap_pmd(struct vm_area_struct *vma,
|
||||
unsigned long addr, pmd_t *pmd, int flags)
|
||||
unsigned long addr, pmd_t *pmd, int flags, struct dev_pagemap **pgmap)
|
||||
{
|
||||
return NULL;
|
||||
}
|
||||
|
||||
static inline struct page *follow_devmap_pud(struct vm_area_struct *vma,
|
||||
unsigned long addr, pud_t *pud, int flags)
|
||||
unsigned long addr, pud_t *pud, int flags, struct dev_pagemap **pgmap)
|
||||
{
|
||||
return NULL;
|
||||
}
|
||||
|
|
|
|||
|
|
@ -2536,16 +2536,8 @@ static inline vm_fault_t vmf_error(int err)
|
|||
return VM_FAULT_SIGBUS;
|
||||
}
|
||||
|
||||
struct page *follow_page_mask(struct vm_area_struct *vma,
|
||||
unsigned long address, unsigned int foll_flags,
|
||||
unsigned int *page_mask);
|
||||
|
||||
static inline struct page *follow_page(struct vm_area_struct *vma,
|
||||
unsigned long address, unsigned int foll_flags)
|
||||
{
|
||||
unsigned int unused_page_mask;
|
||||
return follow_page_mask(vma, address, foll_flags, &unused_page_mask);
|
||||
}
|
||||
struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
|
||||
unsigned int foll_flags);
|
||||
|
||||
#define FOLL_WRITE 0x01 /* check pte is writable */
|
||||
#define FOLL_TOUCH 0x02 /* mark page accessed */
|
||||
|
|
|
|||
110
mm/gup.c
110
mm/gup.c
|
|
@ -20,6 +20,11 @@
|
|||
|
||||
#include "internal.h"
|
||||
|
||||
struct follow_page_context {
|
||||
struct dev_pagemap *pgmap;
|
||||
unsigned int page_mask;
|
||||
};
|
||||
|
||||
static struct page *no_page_table(struct vm_area_struct *vma,
|
||||
unsigned int flags)
|
||||
{
|
||||
|
|
@ -71,10 +76,10 @@ static inline bool can_follow_write_pte(pte_t pte, unsigned int flags)
|
|||
}
|
||||
|
||||
static struct page *follow_page_pte(struct vm_area_struct *vma,
|
||||
unsigned long address, pmd_t *pmd, unsigned int flags)
|
||||
unsigned long address, pmd_t *pmd, unsigned int flags,
|
||||
struct dev_pagemap **pgmap)
|
||||
{
|
||||
struct mm_struct *mm = vma->vm_mm;
|
||||
struct dev_pagemap *pgmap = NULL;
|
||||
struct page *page;
|
||||
spinlock_t *ptl;
|
||||
pte_t *ptep, pte;
|
||||
|
|
@ -116,8 +121,8 @@ static struct page *follow_page_pte(struct vm_area_struct *vma,
|
|||
* Only return device mapping pages in the FOLL_GET case since
|
||||
* they are only valid while holding the pgmap reference.
|
||||
*/
|
||||
pgmap = get_dev_pagemap(pte_pfn(pte), NULL);
|
||||
if (pgmap)
|
||||
*pgmap = get_dev_pagemap(pte_pfn(pte), *pgmap);
|
||||
if (*pgmap)
|
||||
page = pte_page(pte);
|
||||
else
|
||||
goto no_page;
|
||||
|
|
@ -152,15 +157,8 @@ static struct page *follow_page_pte(struct vm_area_struct *vma,
|
|||
goto retry;
|
||||
}
|
||||
|
||||
if (flags & FOLL_GET) {
|
||||
if (flags & FOLL_GET)
|
||||
get_page(page);
|
||||
|
||||
/* drop the pgmap reference now that we hold the page */
|
||||
if (pgmap) {
|
||||
put_dev_pagemap(pgmap);
|
||||
pgmap = NULL;
|
||||
}
|
||||
}
|
||||
if (flags & FOLL_TOUCH) {
|
||||
if ((flags & FOLL_WRITE) &&
|
||||
!pte_dirty(pte) && !PageDirty(page))
|
||||
|
|
@ -210,7 +208,8 @@ static struct page *follow_page_pte(struct vm_area_struct *vma,
|
|||
|
||||
static struct page *follow_pmd_mask(struct vm_area_struct *vma,
|
||||
unsigned long address, pud_t *pudp,
|
||||
unsigned int flags, unsigned int *page_mask)
|
||||
unsigned int flags,
|
||||
struct follow_page_context *ctx)
|
||||
{
|
||||
pmd_t *pmd, pmdval;
|
||||
spinlock_t *ptl;
|
||||
|
|
@ -258,13 +257,13 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma,
|
|||
}
|
||||
if (pmd_devmap(pmdval)) {
|
||||
ptl = pmd_lock(mm, pmd);
|
||||
page = follow_devmap_pmd(vma, address, pmd, flags);
|
||||
page = follow_devmap_pmd(vma, address, pmd, flags, &ctx->pgmap);
|
||||
spin_unlock(ptl);
|
||||
if (page)
|
||||
return page;
|
||||
}
|
||||
if (likely(!pmd_trans_huge(pmdval)))
|
||||
return follow_page_pte(vma, address, pmd, flags);
|
||||
return follow_page_pte(vma, address, pmd, flags, &ctx->pgmap);
|
||||
|
||||
if ((flags & FOLL_NUMA) && pmd_protnone(pmdval))
|
||||
return no_page_table(vma, flags);
|
||||
|
|
@ -284,7 +283,7 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma,
|
|||
}
|
||||
if (unlikely(!pmd_trans_huge(*pmd))) {
|
||||
spin_unlock(ptl);
|
||||
return follow_page_pte(vma, address, pmd, flags);
|
||||
return follow_page_pte(vma, address, pmd, flags, &ctx->pgmap);
|
||||
}
|
||||
if (flags & FOLL_SPLIT) {
|
||||
int ret;
|
||||
|
|
@ -307,18 +306,18 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma,
|
|||
}
|
||||
|
||||
return ret ? ERR_PTR(ret) :
|
||||
follow_page_pte(vma, address, pmd, flags);
|
||||
follow_page_pte(vma, address, pmd, flags, &ctx->pgmap);
|
||||
}
|
||||
page = follow_trans_huge_pmd(vma, address, pmd, flags);
|
||||
spin_unlock(ptl);
|
||||
*page_mask = HPAGE_PMD_NR - 1;
|
||||
ctx->page_mask = HPAGE_PMD_NR - 1;
|
||||
return page;
|
||||
}
|
||||
|
||||
|
||||
static struct page *follow_pud_mask(struct vm_area_struct *vma,
|
||||
unsigned long address, p4d_t *p4dp,
|
||||
unsigned int flags, unsigned int *page_mask)
|
||||
unsigned int flags,
|
||||
struct follow_page_context *ctx)
|
||||
{
|
||||
pud_t *pud;
|
||||
spinlock_t *ptl;
|
||||
|
|
@ -344,7 +343,7 @@ static struct page *follow_pud_mask(struct vm_area_struct *vma,
|
|||
}
|
||||
if (pud_devmap(*pud)) {
|
||||
ptl = pud_lock(mm, pud);
|
||||
page = follow_devmap_pud(vma, address, pud, flags);
|
||||
page = follow_devmap_pud(vma, address, pud, flags, &ctx->pgmap);
|
||||
spin_unlock(ptl);
|
||||
if (page)
|
||||
return page;
|
||||
|
|
@ -352,13 +351,13 @@ static struct page *follow_pud_mask(struct vm_area_struct *vma,
|
|||
if (unlikely(pud_bad(*pud)))
|
||||
return no_page_table(vma, flags);
|
||||
|
||||
return follow_pmd_mask(vma, address, pud, flags, page_mask);
|
||||
return follow_pmd_mask(vma, address, pud, flags, ctx);
|
||||
}
|
||||
|
||||
|
||||
static struct page *follow_p4d_mask(struct vm_area_struct *vma,
|
||||
unsigned long address, pgd_t *pgdp,
|
||||
unsigned int flags, unsigned int *page_mask)
|
||||
unsigned int flags,
|
||||
struct follow_page_context *ctx)
|
||||
{
|
||||
p4d_t *p4d;
|
||||
struct page *page;
|
||||
|
|
@ -378,7 +377,7 @@ static struct page *follow_p4d_mask(struct vm_area_struct *vma,
|
|||
return page;
|
||||
return no_page_table(vma, flags);
|
||||
}
|
||||
return follow_pud_mask(vma, address, p4d, flags, page_mask);
|
||||
return follow_pud_mask(vma, address, p4d, flags, ctx);
|
||||
}
|
||||
|
||||
/**
|
||||
|
|
@ -396,13 +395,13 @@ static struct page *follow_p4d_mask(struct vm_area_struct *vma,
|
|||
*/
|
||||
struct page *follow_page_mask(struct vm_area_struct *vma,
|
||||
unsigned long address, unsigned int flags,
|
||||
unsigned int *page_mask)
|
||||
struct follow_page_context *ctx)
|
||||
{
|
||||
pgd_t *pgd;
|
||||
struct page *page;
|
||||
struct mm_struct *mm = vma->vm_mm;
|
||||
|
||||
*page_mask = 0;
|
||||
ctx->page_mask = 0;
|
||||
|
||||
/* make this handle hugepd */
|
||||
page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
|
||||
|
|
@ -431,7 +430,19 @@ struct page *follow_page_mask(struct vm_area_struct *vma,
|
|||
return no_page_table(vma, flags);
|
||||
}
|
||||
|
||||
return follow_p4d_mask(vma, address, pgd, flags, page_mask);
|
||||
return follow_p4d_mask(vma, address, pgd, flags, ctx);
|
||||
}
|
||||
|
||||
struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
|
||||
unsigned int foll_flags)
|
||||
{
|
||||
struct follow_page_context ctx = { NULL };
|
||||
struct page *page;
|
||||
|
||||
page = follow_page_mask(vma, address, foll_flags, &ctx);
|
||||
if (ctx.pgmap)
|
||||
put_dev_pagemap(ctx.pgmap);
|
||||
return page;
|
||||
}
|
||||
|
||||
static int get_gate_page(struct mm_struct *mm, unsigned long address,
|
||||
|
|
@ -659,9 +670,9 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
|
|||
unsigned int gup_flags, struct page **pages,
|
||||
struct vm_area_struct **vmas, int *nonblocking)
|
||||
{
|
||||
long i = 0;
|
||||
unsigned int page_mask;
|
||||
long ret = 0, i = 0;
|
||||
struct vm_area_struct *vma = NULL;
|
||||
struct follow_page_context ctx = { NULL };
|
||||
|
||||
if (!nr_pages)
|
||||
return 0;
|
||||
|
|
@ -691,12 +702,14 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
|
|||
pages ? &pages[i] : NULL);
|
||||
if (ret)
|
||||
return i ? : ret;
|
||||
page_mask = 0;
|
||||
ctx.page_mask = 0;
|
||||
goto next_page;
|
||||
}
|
||||
|
||||
if (!vma || check_vma_flags(vma, gup_flags))
|
||||
return i ? : -EFAULT;
|
||||
if (!vma || check_vma_flags(vma, gup_flags)) {
|
||||
ret = -EFAULT;
|
||||
goto out;
|
||||
}
|
||||
if (is_vm_hugetlb_page(vma)) {
|
||||
i = follow_hugetlb_page(mm, vma, pages, vmas,
|
||||
&start, &nr_pages, i,
|
||||
|
|
@ -709,23 +722,26 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
|
|||
* If we have a pending SIGKILL, don't keep faulting pages and
|
||||
* potentially allocating memory.
|
||||
*/
|
||||
if (unlikely(fatal_signal_pending(current)))
|
||||
return i ? i : -ERESTARTSYS;
|
||||
if (unlikely(fatal_signal_pending(current))) {
|
||||
ret = -ERESTARTSYS;
|
||||
goto out;
|
||||
}
|
||||
cond_resched();
|
||||
page = follow_page_mask(vma, start, foll_flags, &page_mask);
|
||||
|
||||
page = follow_page_mask(vma, start, foll_flags, &ctx);
|
||||
if (!page) {
|
||||
int ret;
|
||||
ret = faultin_page(tsk, vma, start, &foll_flags,
|
||||
nonblocking);
|
||||
switch (ret) {
|
||||
case 0:
|
||||
goto retry;
|
||||
case -EBUSY:
|
||||
ret = 0;
|
||||
/* FALLTHRU */
|
||||
case -EFAULT:
|
||||
case -ENOMEM:
|
||||
case -EHWPOISON:
|
||||
return i ? i : ret;
|
||||
case -EBUSY:
|
||||
return i;
|
||||
goto out;
|
||||
case -ENOENT:
|
||||
goto next_page;
|
||||
}
|
||||
|
|
@ -737,27 +753,31 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
|
|||
*/
|
||||
goto next_page;
|
||||
} else if (IS_ERR(page)) {
|
||||
return i ? i : PTR_ERR(page);
|
||||
ret = PTR_ERR(page);
|
||||
goto out;
|
||||
}
|
||||
if (pages) {
|
||||
pages[i] = page;
|
||||
flush_anon_page(vma, page, start);
|
||||
flush_dcache_page(page);
|
||||
page_mask = 0;
|
||||
ctx.page_mask = 0;
|
||||
}
|
||||
next_page:
|
||||
if (vmas) {
|
||||
vmas[i] = vma;
|
||||
page_mask = 0;
|
||||
ctx.page_mask = 0;
|
||||
}
|
||||
page_increm = 1 + (~(start >> PAGE_SHIFT) & page_mask);
|
||||
page_increm = 1 + (~(start >> PAGE_SHIFT) & ctx.page_mask);
|
||||
if (page_increm > nr_pages)
|
||||
page_increm = nr_pages;
|
||||
i += page_increm;
|
||||
start += page_increm * PAGE_SIZE;
|
||||
nr_pages -= page_increm;
|
||||
} while (nr_pages);
|
||||
return i;
|
||||
out:
|
||||
if (ctx.pgmap)
|
||||
put_dev_pagemap(ctx.pgmap);
|
||||
return i ? i : ret;
|
||||
}
|
||||
|
||||
static bool vma_permits_fault(struct vm_area_struct *vma,
|
||||
|
|
|
|||
|
|
@ -852,11 +852,10 @@ static void touch_pmd(struct vm_area_struct *vma, unsigned long addr,
|
|||
}
|
||||
|
||||
struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
|
||||
pmd_t *pmd, int flags)
|
||||
pmd_t *pmd, int flags, struct dev_pagemap **pgmap)
|
||||
{
|
||||
unsigned long pfn = pmd_pfn(*pmd);
|
||||
struct mm_struct *mm = vma->vm_mm;
|
||||
struct dev_pagemap *pgmap;
|
||||
struct page *page;
|
||||
|
||||
assert_spin_locked(pmd_lockptr(mm, pmd));
|
||||
|
|
@ -886,12 +885,11 @@ struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
|
|||
return ERR_PTR(-EEXIST);
|
||||
|
||||
pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT;
|
||||
pgmap = get_dev_pagemap(pfn, NULL);
|
||||
if (!pgmap)
|
||||
*pgmap = get_dev_pagemap(pfn, *pgmap);
|
||||
if (!*pgmap)
|
||||
return ERR_PTR(-EFAULT);
|
||||
page = pfn_to_page(pfn);
|
||||
get_page(page);
|
||||
put_dev_pagemap(pgmap);
|
||||
|
||||
return page;
|
||||
}
|
||||
|
|
@ -1000,11 +998,10 @@ static void touch_pud(struct vm_area_struct *vma, unsigned long addr,
|
|||
}
|
||||
|
||||
struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr,
|
||||
pud_t *pud, int flags)
|
||||
pud_t *pud, int flags, struct dev_pagemap **pgmap)
|
||||
{
|
||||
unsigned long pfn = pud_pfn(*pud);
|
||||
struct mm_struct *mm = vma->vm_mm;
|
||||
struct dev_pagemap *pgmap;
|
||||
struct page *page;
|
||||
|
||||
assert_spin_locked(pud_lockptr(mm, pud));
|
||||
|
|
@ -1028,12 +1025,11 @@ struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr,
|
|||
return ERR_PTR(-EEXIST);
|
||||
|
||||
pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT;
|
||||
pgmap = get_dev_pagemap(pfn, NULL);
|
||||
if (!pgmap)
|
||||
*pgmap = get_dev_pagemap(pfn, *pgmap);
|
||||
if (!*pgmap)
|
||||
return ERR_PTR(-EFAULT);
|
||||
page = pfn_to_page(pfn);
|
||||
get_page(page);
|
||||
put_dev_pagemap(pgmap);
|
||||
|
||||
return page;
|
||||
}
|
||||
|
|
|
|||
|
|
@ -1709,11 +1709,9 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
|
|||
return ret;
|
||||
}
|
||||
|
||||
struct page *follow_page_mask(struct vm_area_struct *vma,
|
||||
unsigned long address, unsigned int flags,
|
||||
unsigned int *page_mask)
|
||||
struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
|
||||
unsigned int foll_flags)
|
||||
{
|
||||
*page_mask = 0;
|
||||
return NULL;
|
||||
}
|
||||
|
||||
|
|
|
|||
Loading…
Reference in a new issue