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Date: Wed, 3 Jan 2018 09:29:14 +0900
From: Minchan Kim <minchan@...nel.org>
To: linux-kernel@...r.kernel.org
Cc: hughd@...gle.com, ying.huang@...el.com, mm-commits@...r.kernel.org
Subject: Re: [wrecked]
mm-swap-unify-cluster-based-and-vma-based-swap-readahead.patch removed from
-mm tree
Hi Andrew,
I want to keep this patchset rather than wrecking.
It is needed to code more neat to fix a bug James reported.
https://marc.info/?l=linux-mm&m=151493906616938
On Tue, Jan 02, 2018 at 04:23:34PM -0800, akpm@...ux-foundation.org wrote:
>
> The patch titled
> Subject: mm: swap: unify cluster-based and vma-based swap readahead
> has been removed from the -mm tree. Its filename was
> mm-swap-unify-cluster-based-and-vma-based-swap-readahead.patch
>
> This patch was dropped because other changes were merged, which wrecked this patch
>
> ------------------------------------------------------
> From: Minchan Kim <minchan@...nel.org>
> Subject: mm: swap: unify cluster-based and vma-based swap readahead
>
> This patch makes do_swap_page() not need to be aware of two different swap
> readahead algorithms. Just unify cluster-based and vma-based readahead
> function call.
>
> Link: http://lkml.kernel.org/r/1509520520-32367-3-git-send-email-minchan@kernel.org
> Signed-off-by: Minchan Kim <minchan@...nel.org>
> Cc: Hugh Dickins <hughd@...gle.com>
> Cc: Huang Ying <ying.huang@...el.com>
> Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
> ---
>
> include/linux/swap.h | 27 ++++++-----------------
> mm/memory.c | 11 +++------
> mm/shmem.c | 5 +++-
> mm/swap_state.c | 48 +++++++++++++++++++++++++++++++----------
> 4 files changed, 53 insertions(+), 38 deletions(-)
>
> diff -puN include/linux/swap.h~mm-swap-unify-cluster-based-and-vma-based-swap-readahead include/linux/swap.h
> --- a/include/linux/swap.h~mm-swap-unify-cluster-based-and-vma-based-swap-readahead
> +++ a/include/linux/swap.h
> @@ -401,7 +401,6 @@ int generic_swapfile_activate(struct swa
> #define SWAP_ADDRESS_SPACE_SHIFT 14
> #define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT)
> extern struct address_space *swapper_spaces[];
> -extern bool swap_vma_readahead;
> #define swap_address_space(entry) \
> (&swapper_spaces[swp_type(entry)][swp_offset(entry) \
> >> SWAP_ADDRESS_SPACE_SHIFT])
> @@ -423,10 +422,10 @@ extern struct page *read_swap_cache_asyn
> extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t,
> struct vm_area_struct *vma, unsigned long addr,
> bool *new_page_allocated);
> -extern struct page *swapin_readahead(swp_entry_t, gfp_t,
> - struct vm_area_struct *vma, unsigned long addr);
> -extern struct page *do_swap_page_readahead(swp_entry_t fentry, gfp_t gfp_mask,
> - struct vm_fault *vmf);
> +extern struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
> + struct vm_fault *vmf);
> +extern struct page *swapin_readahead(swp_entry_t entry, gfp_t flag,
> + struct vm_fault *vmf);
>
> /* linux/mm/swapfile.c */
> extern atomic_long_t nr_swap_pages;
> @@ -434,11 +433,6 @@ extern long total_swap_pages;
> extern atomic_t nr_rotate_swap;
> extern bool has_usable_swap(void);
>
> -static inline bool swap_use_vma_readahead(void)
> -{
> - return READ_ONCE(swap_vma_readahead) && !atomic_read(&nr_rotate_swap);
> -}
> -
> /* Swap 50% full? Release swapcache more aggressively.. */
> static inline bool vm_swap_full(void)
> {
> @@ -534,19 +528,14 @@ static inline void put_swap_page(struct
> {
> }
>
> -static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
> - struct vm_area_struct *vma, unsigned long addr)
> +static inline struct page *swap_cluster_readahead(swp_entry_t entry,
> + gfp_t gfp_mask, struct vm_fault *vmf)
> {
> return NULL;
> }
>
> -static inline bool swap_use_vma_readahead(void)
> -{
> - return false;
> -}
> -
> -static inline struct page *do_swap_page_readahead(swp_entry_t fentry,
> - gfp_t gfp_mask, struct vm_fault *vmf)
> +static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
> + struct vm_fault *vmf)
> {
> return NULL;
> }
> diff -puN mm/memory.c~mm-swap-unify-cluster-based-and-vma-based-swap-readahead mm/memory.c
> --- a/mm/memory.c~mm-swap-unify-cluster-based-and-vma-based-swap-readahead
> +++ a/mm/memory.c
> @@ -2889,7 +2889,8 @@ int do_swap_page(struct vm_fault *vmf)
> if (si->flags & SWP_SYNCHRONOUS_IO &&
> __swap_count(si, entry) == 1) {
> /* skip swapcache */
> - page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vmf->address);
> + page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma,
> + vmf->address);
> if (page) {
> __SetPageLocked(page);
> __SetPageSwapBacked(page);
> @@ -2898,12 +2899,8 @@ int do_swap_page(struct vm_fault *vmf)
> swap_readpage(page, true);
> }
> } else {
> - if (swap_use_vma_readahead())
> - page = do_swap_page_readahead(entry,
> - GFP_HIGHUSER_MOVABLE, vmf);
> - else
> - page = swapin_readahead(entry,
> - GFP_HIGHUSER_MOVABLE, vma, vmf->address);
> + page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE,
> + vmf);
> swapcache = page;
> }
>
> diff -puN mm/shmem.c~mm-swap-unify-cluster-based-and-vma-based-swap-readahead mm/shmem.c
> --- a/mm/shmem.c~mm-swap-unify-cluster-based-and-vma-based-swap-readahead
> +++ a/mm/shmem.c
> @@ -1413,9 +1413,12 @@ static struct page *shmem_swapin(swp_ent
> {
> struct vm_area_struct pvma;
> struct page *page;
> + struct vm_fault vmf;
>
> shmem_pseudo_vma_init(&pvma, info, index);
> - page = swapin_readahead(swap, gfp, &pvma, 0);
> + vmf.vma = &pvma;
> + vmf.address = 0;
> + page = swap_cluster_readahead(swap, gfp, &vmf);
> shmem_pseudo_vma_destroy(&pvma);
>
> return page;
> diff -puN mm/swap_state.c~mm-swap-unify-cluster-based-and-vma-based-swap-readahead mm/swap_state.c
> --- a/mm/swap_state.c~mm-swap-unify-cluster-based-and-vma-based-swap-readahead
> +++ a/mm/swap_state.c
> @@ -38,7 +38,7 @@ static const struct address_space_operat
>
> struct address_space *swapper_spaces[MAX_SWAPFILES] __read_mostly;
> static unsigned int nr_swapper_spaces[MAX_SWAPFILES] __read_mostly;
> -bool swap_vma_readahead __read_mostly = true;
> +bool enable_vma_readahead __read_mostly = true;
>
> #define SWAP_RA_WIN_SHIFT (PAGE_SHIFT / 2)
> #define SWAP_RA_HITS_MASK ((1UL << SWAP_RA_WIN_SHIFT) - 1)
> @@ -322,6 +322,11 @@ void free_pages_and_swap_cache(struct pa
> release_pages(pagep, nr);
> }
>
> +static inline bool swap_use_vma_readahead(void)
> +{
> + return READ_ONCE(enable_vma_readahead) && !atomic_read(&nr_rotate_swap);
> +}
> +
> /*
> * Lookup a swap entry in the swap cache. A found page will be returned
> * unlocked and with its refcount incremented - we rely on the kernel
> @@ -539,11 +544,10 @@ static unsigned long swapin_nr_pages(uns
> }
>
> /**
> - * swapin_readahead - swap in pages in hope we need them soon
> + * swap_cluster_readahead - swap in pages in hope we need them soon
> * @entry: swap entry of this memory
> * @gfp_mask: memory allocation flags
> - * @vma: user vma this address belongs to
> - * @addr: target address for mempolicy
> + * @vmf: fault information
> *
> * Returns the struct page for entry and addr, after queueing swapin.
> *
> @@ -555,10 +559,10 @@ static unsigned long swapin_nr_pages(uns
> * This has been extended to use the NUMA policies from the mm triggering
> * the readahead.
> *
> - * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
> + * Caller must hold down_read on the vma->vm_mm if vmf->vma is not NULL.
> */
> -struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask,
> - struct vm_area_struct *vma, unsigned long addr)
> +struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask,
> + struct vm_fault *vmf)
> {
> struct page *page;
> unsigned long entry_offset = swp_offset(entry);
> @@ -568,6 +572,8 @@ struct page *swapin_readahead(swp_entry_
> struct swap_info_struct *si = swp_swap_info(entry);
> struct blk_plug plug;
> bool do_poll = true, page_allocated;
> + struct vm_area_struct *vma = vmf->vma;
> + unsigned long addr = vmf->address;
>
> mask = swapin_nr_pages(offset) - 1;
> if (!mask)
> @@ -723,7 +729,7 @@ static void swap_ra_info(struct vm_fault
> pte_unmap(orig_pte);
> }
>
> -struct page *do_swap_page_readahead(swp_entry_t fentry, gfp_t gfp_mask,
> +struct page *swap_vma_readahead(swp_entry_t fentry, gfp_t gfp_mask,
> struct vm_fault *vmf)
> {
> struct blk_plug plug;
> @@ -771,20 +777,40 @@ skip:
> ra_info.win == 1);
> }
>
> +/**
> + * swapin_readahead - swap in pages in hope we need them soon
> + * @entry: swap entry of this memory
> + * @gfp_mask: memory allocation flags
> + * @vmf: fault information
> + *
> + * Returns the struct page for entry and addr, after queueing swapin.
> + *
> + * It's a main entry function for swap readahead. By the configuration,
> + * it will read ahead blocks by cluster-based(ie, physical disk based)
> + * or vma-based(ie, virtual address based on faulty address) readahead.
> + */
> +struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask,
> + struct vm_fault *vmf)
> +{
> + return swap_use_vma_readahead() ?
> + swap_vma_readahead(entry, gfp_mask, vmf) :
> + swap_cluster_readahead(entry, gfp_mask, vmf);
> +}
> +
> #ifdef CONFIG_SYSFS
> static ssize_t vma_ra_enabled_show(struct kobject *kobj,
> struct kobj_attribute *attr, char *buf)
> {
> - return sprintf(buf, "%s\n", swap_vma_readahead ? "true" : "false");
> + return sprintf(buf, "%s\n", enable_vma_readahead ? "true" : "false");
> }
> static ssize_t vma_ra_enabled_store(struct kobject *kobj,
> struct kobj_attribute *attr,
> const char *buf, size_t count)
> {
> if (!strncmp(buf, "true", 4) || !strncmp(buf, "1", 1))
> - swap_vma_readahead = true;
> + enable_vma_readahead = true;
> else if (!strncmp(buf, "false", 5) || !strncmp(buf, "0", 1))
> - swap_vma_readahead = false;
> + enable_vma_readahead = false;
> else
> return -EINVAL;
>
> _
>
> Patches currently in -mm which might be from minchan@...nel.org are
>
> mm-release-locked-page-in-do_swap_page.patch
> mm-do-not-stall-register_shrinker.patch
>
> --
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