Hi, This series try to add support for high order folios in shmem write and fallocate paths when swap is disabled (noswap option). This is part of the Large Block Size (LBS) effort [1][2] and a continuation of the shmem work from Luis here [3] following Matthew Wilcox's suggestion [4] regarding the path to take for the folio allocation order calculation. [1] https://kernelnewbies.org/KernelProjects/large-block-size [2] https://docs.google.com/spreadsheets/d/e/2PACX-1vS7sQfw90S00l2rfOKm83Jlg0px8KxMQE4HHp_DKRGbAGcAV-xu6LITHBEc4xzVh9wLH6WM2lR0cZS8/pubhtml# [3] RFC v2 add support for blocksize > PAGE_SIZE https://lore.kernel.org/all/ZHBowMEDfyrAAOWH@bombadil.infradead.org/T/#md3e93ab46ce2ad9254e1eb54ffe71211988b5632 [4] https://lore.kernel.org/all/ZHD9zmIeNXICDaRJ@casper.infradead.org/ I went from the latest v2 to an RFC because my current implementation is broken the moment large folios is enabled in the fallocate path. So this is a work in progress RFC patch series (and therefore incomplete). The issue was identified when running this series on fstests for tmpfs and fail on generic/285 and generic/436 tests (lseek DATA/HOLE) [5][6] with large folios support in the fallocate path. To fix these regressions I try adding support for per-block tracking of the uptodate flag instead of doing it per folio. I borrowed this implementation from iomap but I may not integrated it correctly. I think this was introduced in iomap few years back to address the problem when block size < PS [7], and recently being optimized [8] and added the ability of tracking per-block dirty flag. With large folios, per-block (page) uptodate is needed, otherwise the entire large folio is marked as uptodate in shmem_write_end() making the lseek HOLE and DATA tests fail (above tests). These per-block uptodate tracking support [9] fixes the above mentioned generic tests but introduces new errors easily reproducible with fsx [10]. In addition, this other thread [11] explains the performance problem with XFS for high order folios in iomap write path but I think here we need at least the uptodate only because of the above reasoning. Please, find below the logs [5][6] for lseek DATA/HOLE before and after the fixes. And the logs [10] for the fsx failure. I'm looking forward for your comments for error correction and to determine the overall vailidty of the approach. Note: In case people are interested in testing, we've added testing support for tmpfs in kdevops using (x)fstests. Please find the link to the baseline results in the below changes section. Available profiles are: * default (no mount options) * huge=always * huge=within_size * huge=advise * noswap, huge=never * noswap, huge=always * noswap, huge=within_size * noswap, huge=advise Changes since v2 * Rebased onto next-20231027 including latests changes for shmem and mempolicy. * Testing tmpfs using fstests with kdevops. Baseline results for different linux-next tags can be found here: https://github.com/linux-kdevops/kdevops/tree/master/workflows/fstests/expunges/6.6.0-rc6-next-20231019/tmpfs/unassigned https://github.com/linux-kdevops/kdevops/tree/master/workflows/fstests/expunges/6.6.0-rc4-next-20231006/tmpfs/unassigned https://github.com/linux-kdevops/kdevops/tree/master/workflows/fstests/expunges/6.6.0-rc4-next-20231004/tmpfs/unassigned * Added XArray tests to prove order is not kept when replacing an entry with NULL when using cmpxchg. Required for patch 'shmem: return number of pages beeing freed in shmem_free_swap' * Added XArray test for multi-index use. * Drop huge argument in shmem_alloc_and_add_folio() and make use of VM_HUGEPAGE instead. * Increase max order from PMD_ORDER-1 to PMD_ORDER (MAX_PAGECACHE_ORDER). * Add/fix shmem_free_swap conversion to return (properly) the number of pages freed. * Fix order patch being changed in further patch. However, I do initialize order = 0 in patch [patch-order] and then updated to the mapping size in patch [patch-high-order]. I can merge both patches if necessary to avoid this change in the series. [patch-order]: shmem: add order arg to shmem_alloc_folio() [patch-high-order]: shmem: add large folio support to the write path * Folio order tracing when added to page cache. * THP vs large folios in the write path: if huge flag is passed and kernel has support for THP, then allocation will use huge the path, otherwise folio order will be used, based on the file size without using huge_gfp flags. * Add patch to remove huge flag argument from shmem_alloc_and_add_folio. We can check for the huge flag being set as part of gfp flags (VM_HUGEPAGE). Check patch: 'shmem: remove huge arg from shmem_alloc_and_add_folio()'. * Add high order folios in fallocate path. * Add per-block uptodate tracking based on iomap implementation (work in progress). Changes since v1 * Order handling code simplified in shmem_get_folio_gfp after Matthew Willcox's review. * Drop patch 1/6 [filemap] and merge mapping_size_order code directly in shmem. [filemap] filemap: make the folio order calculation shareable * Added MAX_SHMEM_ORDER to make it explicit we don't have the same max order as in pagecache (MAX_PAGECACHE_ORDER). * Use HPAGE_PMD_ORDER-1 as MAX_SHMEM_ORDER to respect huge mount option. * Update cover letter: drop huge strategy question and add more context regarding LBS project. Add fsx and fstests summary with new baseline. * Add fixes found by Matthew in patch 3/6 [acct]. [acct] shmem: account for large order folios * Fix length (i_size_read -> PAGE_SIZE) that is passed to shmem_get_folio_gfp in shmem_fault and shmem_read_folio_gfp to PAGE_SIZE. * Add patch as suggested by Matthew to return the number of pages freed in shmem_free_swap (instead of errno). When no pages are freed, return 0 (pages). Note: As an alternative, we can embed -ENOENT and make use of IS_ERR_VALUE. Approach discarded because little value was added. If this method is preferred, please let discuss it. [5] (x)ftests regression with large folios in the fallocate path: generic/285: src/seek_sanity_test/test09() generic/436: src/seek_sanity_test/test13() [6] (x)ftests, how to check/reproduce regressions: ```sh mkdir -p /mnt/test-tmpfs ./src/seek_sanity_test -s 9 -e 9 /mnt/test-tmpfs/file ./src/seek_sanity_test -s 13 -e 13 /mnt/test-tmpfs/file umount /mnt/test-tmpfs ``` [7] iomap per-block uptodate tracking in iomap: 9dc55f1389f9 iomap: add support for sub-pagesize buffered I/O without buffer heads 1cea335d1db1 iomap: fix sub-page uptodate handling [8] iomap per-block dirty and uptodate flags optimizations in iomap 4ce02c679722 iomap: Add per-block dirty state tracking to improve performance 35d30c9cf127 iomap: don't skip reading in !uptodate folios when unsharing a range a01b8f225248 iomap: Allocate ifs in ->write_begin() early 7f79d85b525b iomap: Refactor iomap_write_delalloc_punch() function out 0af2b37d8e7a iomap: Use iomap_punch_t typedef eee2d2e6ea55 iomap: Fix possible overflow condition in iomap_write_delalloc_scan cc86181a3b76 iomap: Add some uptodate state handling helpers for ifs state bitmap 3ea5c76cadee iomap: Drop ifs argument from iomap_set_range_uptodate() 04f52c4e6f80 iomap: Rename iomap_page to iomap_folio_state and others [9] Patch: shmem: add per-block uptodate tracking [10] fsx up to 633 ops (or up to 1200 without -X). ```sh mkdir -p /mnt/test-tmpfs mount -t tmpfs -o size=1G -o noswap tmpfs /mnt/test-tmpfs /root/xfstests-dev/ltp/fsx /mnt/test-tmpfs/file -d -N 1200 -X umount /mnt/test-tmpfs ``` Logs: ```logs READ BAD DATA: offset = 0x0, size = 0x3364c, fname = /mnt/test-tmpfs/file OFFSET GOOD BAD RANGE 0x28000 0x79d0 0x0000 0x0 operation# (mod 256) for the bad data unknown, check HOLE and EXTEND ops 0x28001 0xd079 0x0000 0x1 operation# (mod 256) for the bad data unknown, check HOLE and EXTEND ops 0x28002 0x7914 0x0000 0x2 operation# (mod 256) for the bad data unknown, check HOLE and EXTEND ops 0x28003 0x1479 0x0000 0x3 operation# (mod 256) for the bad data unknown, check HOLE and EXTEND ops 0x28004 0x79ec 0x0000 0x4 operation# (mod 256) for the bad data unknown, check HOLE and EXTEND ops 0x28005 0xec79 0x0000 0x5 operation# (mod 256) for the bad data unknown, check HOLE and EXTEND ops 0x28006 0x7929 0x0000 0x6 operation# (mod 256) for the bad data unknown, check HOLE and EXTEND ops 0x28007 0x2979 0x0000 0x7 operation# (mod 256) for the bad data unknown, check HOLE and EXTEND ops 0x28008 0x7935 0x0000 0x8 operation# (mod 256) for the bad data unknown, check HOLE and EXTEND ops 0x28009 0x3579 0x0000 0x9 operation# (mod 256) for the bad data unknown, check HOLE and EXTEND ops 0x2800a 0x7968 0x0000 0xa operation# (mod 256) for the bad data unknown, check HOLE and EXTEND ops 0x2800b 0x6879 0x0000 0xb operation# (mod 256) for the bad data unknown, check HOLE and EXTEND ops 0x2800c 0x79d3 0x0000 0xc operation# (mod 256) for the bad data unknown, check HOLE and EXTEND ops 0x2800d 0xd379 0x0000 0xd operation# (mod 256) for the bad data unknown, check HOLE and EXTEND ops 0x2800e 0x79f2 0x0000 0xe operation# (mod 256) for the bad data unknown, check HOLE and EXTEND ops 0x2800f 0xf279 0x0000 0xf operation# (mod 256) for the bad data unknown, check HOLE and EXTEND ops LOG DUMP (633 total operations): 1( 1 mod 256): SKIPPED (no operation) 2( 2 mod 256): TRUNCATE UP from 0x0 to 0x3aea7 ******WWWW 3( 3 mod 256): COPY 0x1a3d6 thru 0x26607 (0xc232 bytes) to 0x2ea8c thru 0x3acbd 4( 4 mod 256): READ 0x2f6d2 thru 0x3853e (0x8e6d bytes) 5( 5 mod 256): READ 0x2d6d3 thru 0x310f5 (0x3a23 bytes) ***RRRR*** 6( 6 mod 256): SKIPPED (no operation) 7( 7 mod 256): WRITE 0x341a2 thru 0x3fafc (0xb95b bytes) EXTEND ... 625(113 mod 256): PUNCH 0x8f01 thru 0x9806 (0x906 bytes) 626(114 mod 256): MAPREAD 0xe517 thru 0x11396 (0x2e80 bytes) 627(115 mod 256): SKIPPED (no operation) 628(116 mod 256): SKIPPED (no operation) 629(117 mod 256): FALLOC 0x284fe thru 0x32480 (0x9f82 bytes) EXTENDING ******FFFF 630(118 mod 256): WRITE 0x333ac thru 0x3364b (0x2a0 bytes) HOLE 631(119 mod 256): SKIPPED (no operation) 632(120 mod 256): SKIPPED (no operation) 633(121 mod 256): WRITE 0x1f876 thru 0x2d86a (0xdff5 bytes) ***WWWW ``` Daniel Gomez (9): XArray: add cmpxchg order test shmem: drop BLOCKS_PER_PAGE macro shmem: return number of pages beeing freed in shmem_free_swap shmem: trace shmem_add_to_page_cache folio order shmem: remove huge arg from shmem_alloc_and_add_folio() shmem: add file length arg in shmem_get_folio() path shmem: add order arg to shmem_alloc_folio() shmem: add large folio support to the write path shmem: add per-block uptodate tracking Luis Chamberlain (2): test_xarray: add tests for advanced multi-index use shmem: account for large order folios MAINTAINERS | 1 + include/linux/shmem_fs.h | 2 +- include/trace/events/shmem.h | 52 ++++++ lib/test_xarray.c | 155 +++++++++++++++++ mm/khugepaged.c | 3 +- mm/shmem.c | 325 ++++++++++++++++++++++++++++------- mm/userfaultfd.c | 2 +- 7 files changed, 472 insertions(+), 68 deletions(-) create mode 100644 include/trace/events/shmem.h -- 2.39.2 XArray multi-index entries do not keep track of the order stored once the entry is being marked as used (replaced with NULL). Add a test to check the order is actually lost. Signed-off-by: Daniel Gomez <da.gomez@samsung.com> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> --- lib/test_xarray.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/lib/test_xarray.c b/lib/test_xarray.c index XXXXXXX..XXXXXXX 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -XXX,XX +XXX,XX @@ static noinline void check_cmpxchg(struct xarray *xa) XA_BUG_ON(xa, !xa_empty(xa)); } +static noinline void check_cmpxchg_order(struct xarray *xa) +{ + void *FIVE = xa_mk_value(5); + unsigned int order = IS_ENABLED(CONFIG_XARRAY_MULTI) ? 15 : 1; + void *old; + + XA_BUG_ON(xa, !xa_empty(xa)); + XA_BUG_ON(xa, xa_store_index(xa, 5, GFP_KERNEL) != NULL); + XA_BUG_ON(xa, xa_insert(xa, 5, FIVE, GFP_KERNEL) != -EBUSY); + XA_BUG_ON(xa, xa_store_order(xa, 5, order, FIVE, GFP_KERNEL)); + XA_BUG_ON(xa, xa_get_order(xa, 5) != order); + XA_BUG_ON(xa, xa_get_order(xa, xa_to_value(FIVE)) != order); + old = xa_cmpxchg(xa, 5, FIVE, NULL, GFP_KERNEL); + XA_BUG_ON(xa, old != FIVE); + XA_BUG_ON(xa, xa_get_order(xa, 5) != 0); + XA_BUG_ON(xa, xa_get_order(xa, xa_to_value(FIVE)) != 0); + XA_BUG_ON(xa, xa_get_order(xa, xa_to_value(old)) != 0); + XA_BUG_ON(xa, !xa_empty(xa)); +} + static noinline void check_reserve(struct xarray *xa) { void *entry; @@ -XXX,XX +XXX,XX @@ static int xarray_checks(void) check_xas_erase(&array); check_insert(&array); check_cmpxchg(&array); + check_cmpxchg_order(&array); check_reserve(&array); check_reserve(&xa0); check_multi_store(&array); -- 2.39.2 From: Luis Chamberlain <mcgrof@kernel.org> The multi index selftests are great but they don't replicate how we deal with the page cache exactly, which makes it a bit hard to follow as the page cache uses the advanced API. Add tests which use the advanced API, mimicking what we do in the page cache, while at it, extend the example to do what is needed for min order support. Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Tested-by: Daniel Gomez <da.gomez@samsung.com> --- lib/test_xarray.c | 134 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 134 insertions(+) diff --git a/lib/test_xarray.c b/lib/test_xarray.c index XXXXXXX..XXXXXXX 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -XXX,XX +XXX,XX @@ static noinline void check_multi_store(struct xarray *xa) #endif } +#ifdef CONFIG_XARRAY_MULTI +static noinline void check_xa_multi_store_adv_add(struct xarray *xa, + unsigned long index, + unsigned int order, + void *p) +{ + XA_STATE(xas, xa, index); + + xas_set_order(&xas, index, order); + + do { + xas_lock_irq(&xas); + + xas_store(&xas, p); + XA_BUG_ON(xa, xas_error(&xas)); + XA_BUG_ON(xa, xa_load(xa, index) != p); + + xas_unlock_irq(&xas); + } while (xas_nomem(&xas, GFP_KERNEL)); + + XA_BUG_ON(xa, xas_error(&xas)); +} + +static noinline void check_xa_multi_store_adv_delete(struct xarray *xa, + unsigned long index, + unsigned int order) +{ + unsigned int nrpages = 1UL << order; + unsigned long base = round_down(index, nrpages); + XA_STATE(xas, xa, base); + + xas_set_order(&xas, base, order); + xas_store(&xas, NULL); + xas_init_marks(&xas); +} + +static unsigned long some_val = 0xdeadbeef; +static unsigned long some_val_2 = 0xdeaddead; + +/* mimics the page cache */ +static noinline void check_xa_multi_store_adv(struct xarray *xa, + unsigned long pos, + unsigned int order) +{ + unsigned int nrpages = 1UL << order; + unsigned long index, base, next_index, next_next_index; + unsigned int i; + + index = pos >> PAGE_SHIFT; + base = round_down(index, nrpages); + next_index = round_down(base + nrpages, nrpages); + next_next_index = round_down(next_index + nrpages, nrpages); + + check_xa_multi_store_adv_add(xa, base, order, &some_val); + + for (i = 0; i < nrpages; i++) + XA_BUG_ON(xa, xa_load(xa, base + i) != &some_val); + + XA_BUG_ON(xa, xa_load(xa, next_index) != NULL); + + /* Use order 0 for the next item */ + check_xa_multi_store_adv_add(xa, next_index, 0, &some_val_2); + XA_BUG_ON(xa, xa_load(xa, next_index) != &some_val_2); + + /* Remove the next item */ + check_xa_multi_store_adv_delete(xa, next_index, 0); + + /* Now use order for a new pointer */ + check_xa_multi_store_adv_add(xa, next_index, order, &some_val_2); + + for (i = 0; i < nrpages; i++) + XA_BUG_ON(xa, xa_load(xa, next_index + i) != &some_val_2); + + check_xa_multi_store_adv_delete(xa, next_index, order); + check_xa_multi_store_adv_delete(xa, base, order); + XA_BUG_ON(xa, !xa_empty(xa)); + + /* starting fresh again */ + + /* let's test some holes now */ + + /* hole at base and next_next */ + check_xa_multi_store_adv_add(xa, next_index, order, &some_val_2); + + for (i = 0; i < nrpages; i++) + XA_BUG_ON(xa, xa_load(xa, base + i) != NULL); + + for (i = 0; i < nrpages; i++) + XA_BUG_ON(xa, xa_load(xa, next_index + i) != &some_val_2); + + for (i = 0; i < nrpages; i++) + XA_BUG_ON(xa, xa_load(xa, next_next_index + i) != NULL); + + check_xa_multi_store_adv_delete(xa, next_index, order); + XA_BUG_ON(xa, !xa_empty(xa)); + + /* hole at base and next */ + + check_xa_multi_store_adv_add(xa, next_next_index, order, &some_val_2); + + for (i = 0; i < nrpages; i++) + XA_BUG_ON(xa, xa_load(xa, base + i) != NULL); + + for (i = 0; i < nrpages; i++) + XA_BUG_ON(xa, xa_load(xa, next_index + i) != NULL); + + for (i = 0; i < nrpages; i++) + XA_BUG_ON(xa, xa_load(xa, next_next_index + i) != &some_val_2); + + check_xa_multi_store_adv_delete(xa, next_next_index, order); + XA_BUG_ON(xa, !xa_empty(xa)); +} +#endif + +static noinline void check_multi_store_advanced(struct xarray *xa) +{ +#ifdef CONFIG_XARRAY_MULTI + unsigned int max_order = IS_ENABLED(CONFIG_XARRAY_MULTI) ? 20 : 1; + unsigned long end = ULONG_MAX/2; + unsigned long pos, i; + + /* + * About 117 million tests below. + */ + for (pos = 7; pos < end; pos = (pos * pos) + 564) { + for (i = 0; i < max_order; i++) { + check_xa_multi_store_adv(xa, pos, i); + check_xa_multi_store_adv(xa, pos + 157, i); + } + } +#endif +} + static noinline void check_xa_alloc_1(struct xarray *xa, unsigned int base) { int i; @@ -XXX,XX +XXX,XX @@ static int xarray_checks(void) check_reserve(&array); check_reserve(&xa0); check_multi_store(&array); + check_multi_store_advanced(&array); check_get_order(&array); check_xa_alloc(); check_find(&array); -- 2.39.2 The commit [1] replaced all BLOCKS_PER_PAGE in favor of the generic PAGE_SECTORS but definition was not removed. Drop it as unused macro. [1] e09764cff44b5 ("shmem: quota support"). Signed-off-by: Daniel Gomez <da.gomez@samsung.com> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> --- mm/shmem.c | 1 - 1 file changed, 1 deletion(-) diff --git a/mm/shmem.c b/mm/shmem.c index XXXXXXX..XXXXXXX 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -XXX,XX +XXX,XX @@ static struct vfsmount *shm_mnt __ro_after_init; #include "internal.h" -#define BLOCKS_PER_PAGE (PAGE_SIZE/512) #define VM_ACCT(size) (PAGE_ALIGN(size) >> PAGE_SHIFT) /* Pretend that each entry is of this size in directory's i_size */ -- 2.39.2 Both shmem_free_swap callers expect the number of pages being freed. In the large folios context, this needs to support larger values other than 0 (used as 1 page being freed) and -ENOENT (used as 0 pages being freed). In preparation for large folios adoption, make shmem_free_swap routine return the number of pages being freed. So, returning 0 in this context, means 0 pages being freed. Suggested-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Daniel Gomez <da.gomez@samsung.com> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> --- mm/shmem.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index XXXXXXX..XXXXXXX 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -XXX,XX +XXX,XX @@ static void shmem_delete_from_page_cache(struct folio *folio, void *radswap) } /* - * Remove swap entry from page cache, free the swap and its page cache. + * Remove swap entry from page cache, free the swap and its page cache. Returns + * the number of pages being freed. 0 means entry not found in XArray (0 pages + * being freed). */ -static int shmem_free_swap(struct address_space *mapping, +static long shmem_free_swap(struct address_space *mapping, pgoff_t index, void *radswap) { void *old; + long swaps_freed = 1UL << xa_get_order(&mapping->i_pages, index); old = xa_cmpxchg_irq(&mapping->i_pages, index, radswap, NULL, 0); if (old != radswap) - return -ENOENT; + return 0; free_swap_and_cache(radix_to_swp_entry(radswap)); - return 0; + + return swaps_freed; } /* @@ -XXX,XX +XXX,XX @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend, if (xa_is_value(folio)) { if (unfalloc) continue; - nr_swaps_freed += !shmem_free_swap(mapping, + nr_swaps_freed += shmem_free_swap(mapping, indices[i], folio); continue; } @@ -XXX,XX +XXX,XX @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend, folio = fbatch.folios[i]; if (xa_is_value(folio)) { + long swaps_freed; + if (unfalloc) continue; - if (shmem_free_swap(mapping, indices[i], folio)) { + swaps_freed = shmem_free_swap(mapping, indices[i], folio); + if (!swaps_freed) { /* Swap was replaced by page: retry */ index = indices[i]; break; } - nr_swaps_freed++; + nr_swaps_freed += swaps_freed; continue; } -- 2.39.2 From: Luis Chamberlain <mcgrof@kernel.org> shmem uses the shem_info_inode alloced, swapped to account for allocated pages and swapped pages. In preparation for large order folios adjust the accounting to use folio_nr_pages(). This should produce no functional changes yet as larger order folios are not yet used or supported in shmem. Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Daniel Gomez <da.gomez@samsung.com> --- mm/shmem.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index XXXXXXX..XXXXXXX 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -XXX,XX +XXX,XX @@ unsigned long shmem_partial_swap_usage(struct address_space *mapping, pgoff_t start, pgoff_t end) { XA_STATE(xas, &mapping->i_pages, start); - struct page *page; + struct folio *folio; unsigned long swapped = 0; unsigned long max = end - 1; rcu_read_lock(); - xas_for_each(&xas, page, max) { - if (xas_retry(&xas, page)) + xas_for_each(&xas, folio, max) { + if (xas_retry(&xas, folio)) continue; - if (xa_is_value(page)) - swapped++; + if (xa_is_value(folio)) + swapped += folio_nr_pages(folio); if (xas.xa_index == max) break; if (need_resched()) { @@ -XXX,XX +XXX,XX @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) if (add_to_swap_cache(folio, swap, __GFP_HIGH | __GFP_NOMEMALLOC | __GFP_NOWARN, NULL) == 0) { - shmem_recalc_inode(inode, 0, 1); + shmem_recalc_inode(inode, 0, folio_nr_pages(folio)); swap_shmem_alloc(swap); shmem_delete_from_page_cache(folio, swp_to_radix_entry(swap)); @@ -XXX,XX +XXX,XX @@ static void shmem_set_folio_swapin_error(struct inode *inode, pgoff_t index, struct address_space *mapping = inode->i_mapping; swp_entry_t swapin_error; void *old; + long num_swap_pages; swapin_error = make_poisoned_swp_entry(); old = xa_cmpxchg_irq(&mapping->i_pages, index, @@ -XXX,XX +XXX,XX @@ static void shmem_set_folio_swapin_error(struct inode *inode, pgoff_t index, return; folio_wait_writeback(folio); + num_swap_pages = folio_nr_pages(folio); delete_from_swap_cache(folio); /* * Don't treat swapin error folio as alloced. Otherwise inode->i_blocks * won't be 0 when inode is released and thus trigger WARN_ON(i_blocks) * in shmem_evict_inode(). */ - shmem_recalc_inode(inode, -1, -1); + shmem_recalc_inode(inode, -num_swap_pages, -num_swap_pages); swap_free(swap); } @@ -XXX,XX +XXX,XX @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, if (error) goto failed; - shmem_recalc_inode(inode, 0, -1); + shmem_recalc_inode(inode, 0, -folio_nr_pages(folio)); if (sgp == SGP_WRITE) folio_mark_accessed(folio); @@ -XXX,XX +XXX,XX @@ int shmem_mfill_atomic_pte(pmd_t *dst_pmd, if (ret) goto out_delete_from_cache; - shmem_recalc_inode(inode, 1, 0); + shmem_recalc_inode(inode, folio_nr_pages(folio), 0); folio_unlock(folio); return 0; out_delete_from_cache: -- 2.39.2 To be able to trace and account for order of the folio. Based on include/trace/filemap.h. Update MAINTAINERS file list for SHMEM. Signed-off-by: Daniel Gomez <da.gomez@samsung.com> --- MAINTAINERS | 1 + include/trace/events/shmem.h | 52 ++++++++++++++++++++++++++++++++++++ mm/shmem.c | 4 +++ 3 files changed, 57 insertions(+) create mode 100644 include/trace/events/shmem.h diff --git a/MAINTAINERS b/MAINTAINERS index XXXXXXX..XXXXXXX 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -XXX,XX +XXX,XX @@ M: Hugh Dickins <hughd@google.com> L: linux-mm@kvack.org S: Maintained F: include/linux/shmem_fs.h +F: include/trace/events/shmem.h F: mm/shmem.c TOMOYO SECURITY MODULE diff --git a/include/trace/events/shmem.h b/include/trace/events/shmem.h new file mode 100644 index XXXXXXX..XXXXXXX --- /dev/null +++ b/include/trace/events/shmem.h @@ -XXX,XX +XXX,XX @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM shmem + +#if !defined(_TRACE_SHMEM_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_SHMEM_H + +#include <linux/types.h> +#include <linux/tracepoint.h> + +DECLARE_EVENT_CLASS(mm_shmem_op_page_cache, + + TP_PROTO(struct folio *folio), + + TP_ARGS(folio), + + TP_STRUCT__entry( + __field(unsigned long, pfn) + __field(unsigned long, i_ino) + __field(unsigned long, index) + __field(dev_t, s_dev) + __field(unsigned char, order) + ), + + TP_fast_assign( + __entry->pfn = folio_pfn(folio); + __entry->i_ino = folio->mapping->host->i_ino; + __entry->index = folio->index; + if (folio->mapping->host->i_sb) + __entry->s_dev = folio->mapping->host->i_sb->s_dev; + else + __entry->s_dev = folio->mapping->host->i_rdev; + __entry->order = folio_order(folio); + ), + + TP_printk("dev %d:%d ino %lx pfn=0x%lx ofs=%lu order=%u", + MAJOR(__entry->s_dev), MINOR(__entry->s_dev), + __entry->i_ino, + __entry->pfn, + __entry->index << PAGE_SHIFT, + __entry->order) +); + +DEFINE_EVENT(mm_shmem_op_page_cache, mm_shmem_add_to_page_cache, + TP_PROTO(struct folio *folio), + TP_ARGS(folio) + ); + +#endif /* _TRACE_SHMEM_H */ + +/* This part must be outside protection */ +#include <trace/define_trace.h> diff --git a/mm/shmem.c b/mm/shmem.c index XXXXXXX..XXXXXXX 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -XXX,XX +XXX,XX @@ static struct vfsmount *shm_mnt __ro_after_init; #include "internal.h" +#define CREATE_TRACE_POINTS +#include <trace/events/shmem.h> + #define VM_ACCT(size) (PAGE_ALIGN(size) >> PAGE_SHIFT) /* Pretend that each entry is of this size in directory's i_size */ @@ -XXX,XX +XXX,XX @@ static struct folio *shmem_alloc_and_add_folio(gfp_t gfp, } } + trace_mm_shmem_add_to_page_cache(folio); shmem_recalc_inode(inode, pages, 0); folio_add_lru(folio); return folio; -- 2.39.2 The huge flag is already part of of the memory allocation flag (gfp_t). Make use of the VM_HUGEPAGE bit set by vma_thp_gfp_mask() to know if the allocation must be a huge page. Drop CONFIG_TRANSPARENT_HUGEPAGE check in shmem_alloc_and_add_folio() as VM_HUGEPAGE won't be set unless THP config is enabled. Signed-off-by: Daniel Gomez <da.gomez@samsung.com> --- mm/shmem.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index XXXXXXX..XXXXXXX 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -XXX,XX +XXX,XX @@ static struct folio *shmem_alloc_folio(gfp_t gfp, static struct folio *shmem_alloc_and_add_folio(gfp_t gfp, struct inode *inode, pgoff_t index, - struct mm_struct *fault_mm, bool huge) + struct mm_struct *fault_mm) { struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); @@ -XXX,XX +XXX,XX @@ static struct folio *shmem_alloc_and_add_folio(gfp_t gfp, long pages; int error; - if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) - huge = false; - - if (huge) { + if (gfp & VM_HUGEPAGE) { pages = HPAGE_PMD_NR; index = round_down(index, HPAGE_PMD_NR); @@ -XXX,XX +XXX,XX @@ static struct folio *shmem_alloc_and_add_folio(gfp_t gfp, if (xa_find(&mapping->i_pages, &index, index + pages - 1, XA_PRESENT)) { error = -EEXIST; - } else if (huge) { + } else if (gfp & VM_HUGEPAGE) { count_vm_event(THP_FILE_FALLBACK); count_vm_event(THP_FILE_FALLBACK_CHARGE); } @@ -XXX,XX +XXX,XX @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, huge_gfp = vma_thp_gfp_mask(vma); huge_gfp = limit_gfp_mask(huge_gfp, gfp); folio = shmem_alloc_and_add_folio(huge_gfp, - inode, index, fault_mm, true); + inode, index, fault_mm); if (!IS_ERR(folio)) { count_vm_event(THP_FILE_ALLOC); goto alloced; @@ -XXX,XX +XXX,XX @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, goto repeat; } - folio = shmem_alloc_and_add_folio(gfp, inode, index, fault_mm, false); + folio = shmem_alloc_and_add_folio(gfp, inode, index, fault_mm); if (IS_ERR(folio)) { error = PTR_ERR(folio); if (error == -EEXIST) -- 2.39.2 In preparation for large folio in the write path, add file length argument in shmem_get_folio() path to be able to calculate the folio order based on the file size. Use of order-0 (PAGE_SIZE) for non write paths such as read, page cache read, and vm fault. This enables high order folios in the write and fallocate paths once the folio order is calculated based on the length. Signed-off-by: Daniel Gomez <da.gomez@samsung.com> --- include/linux/shmem_fs.h | 2 +- mm/khugepaged.c | 3 ++- mm/shmem.c | 33 ++++++++++++++++++--------------- mm/userfaultfd.c | 2 +- 4 files changed, 22 insertions(+), 18 deletions(-) diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index XXXXXXX..XXXXXXX 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -XXX,XX +XXX,XX @@ enum sgp_type { }; int shmem_get_folio(struct inode *inode, pgoff_t index, struct folio **foliop, - enum sgp_type sgp); + enum sgp_type sgp, size_t len); struct folio *shmem_read_folio_gfp(struct address_space *mapping, pgoff_t index, gfp_t gfp); diff --git a/mm/khugepaged.c b/mm/khugepaged.c index XXXXXXX..XXXXXXX 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -XXX,XX +XXX,XX @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, xas_unlock_irq(&xas); /* swap in or instantiate fallocated page */ if (shmem_get_folio(mapping->host, index, - &folio, SGP_NOALLOC)) { + &folio, SGP_NOALLOC, + PAGE_SIZE)) { result = SCAN_FAIL; goto xa_unlocked; } diff --git a/mm/shmem.c b/mm/shmem.c index XXXXXXX..XXXXXXX 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -XXX,XX +XXX,XX @@ static struct folio *shmem_get_partial_folio(struct inode *inode, pgoff_t index) * (although in some cases this is just a waste of time). */ folio = NULL; - shmem_get_folio(inode, index, &folio, SGP_READ); + shmem_get_folio(inode, index, &folio, SGP_READ, PAGE_SIZE); return folio; } @@ -XXX,XX +XXX,XX @@ static struct folio *shmem_alloc_folio(gfp_t gfp, static struct folio *shmem_alloc_and_add_folio(gfp_t gfp, struct inode *inode, pgoff_t index, - struct mm_struct *fault_mm) + struct mm_struct *fault_mm, size_t len) { struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); @@ -XXX,XX +XXX,XX @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, */ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, struct folio **foliop, enum sgp_type sgp, gfp_t gfp, - struct vm_fault *vmf, vm_fault_t *fault_type) + struct vm_fault *vmf, vm_fault_t *fault_type, size_t len) { struct vm_area_struct *vma = vmf ? vmf->vma : NULL; struct mm_struct *fault_mm; @@ -XXX,XX +XXX,XX @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, huge_gfp = vma_thp_gfp_mask(vma); huge_gfp = limit_gfp_mask(huge_gfp, gfp); folio = shmem_alloc_and_add_folio(huge_gfp, - inode, index, fault_mm); + inode, index, fault_mm, len); if (!IS_ERR(folio)) { count_vm_event(THP_FILE_ALLOC); goto alloced; @@ -XXX,XX +XXX,XX @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, goto repeat; } - folio = shmem_alloc_and_add_folio(gfp, inode, index, fault_mm); + folio = shmem_alloc_and_add_folio(gfp, inode, index, fault_mm, len); if (IS_ERR(folio)) { error = PTR_ERR(folio); if (error == -EEXIST) @@ -XXX,XX +XXX,XX @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, } int shmem_get_folio(struct inode *inode, pgoff_t index, struct folio **foliop, - enum sgp_type sgp) + enum sgp_type sgp, size_t len) { return shmem_get_folio_gfp(inode, index, foliop, sgp, - mapping_gfp_mask(inode->i_mapping), NULL, NULL); + mapping_gfp_mask(inode->i_mapping), NULL, NULL, len); } /* @@ -XXX,XX +XXX,XX @@ static vm_fault_t shmem_fault(struct vm_fault *vmf) WARN_ON_ONCE(vmf->page != NULL); err = shmem_get_folio_gfp(inode, vmf->pgoff, &folio, SGP_CACHE, - gfp, vmf, &ret); + gfp, vmf, &ret, PAGE_SIZE); if (err) return vmf_error(err); if (folio) { @@ -XXX,XX +XXX,XX @@ shmem_write_begin(struct file *file, struct address_space *mapping, struct folio *folio; int ret = 0; + if (!mapping_large_folio_support(mapping)) + len = min_t(size_t, len, PAGE_SIZE - offset_in_page(pos)); + /* i_rwsem is held by caller */ if (unlikely(info->seals & (F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_FUTURE_WRITE))) { @@ -XXX,XX +XXX,XX @@ shmem_write_begin(struct file *file, struct address_space *mapping, return -EPERM; } - ret = shmem_get_folio(inode, index, &folio, SGP_WRITE); + ret = shmem_get_folio(inode, index, &folio, SGP_WRITE, len); if (ret) return ret; @@ -XXX,XX +XXX,XX @@ static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to) break; } - error = shmem_get_folio(inode, index, &folio, SGP_READ); + error = shmem_get_folio(inode, index, &folio, SGP_READ, PAGE_SIZE); if (error) { if (error == -EINVAL) error = 0; @@ -XXX,XX +XXX,XX @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, break; error = shmem_get_folio(inode, *ppos / PAGE_SIZE, &folio, - SGP_READ); + SGP_READ, PAGE_SIZE); if (error) { if (error == -EINVAL) error = 0; @@ -XXX,XX +XXX,XX @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset, error = -ENOMEM; else error = shmem_get_folio(inode, index, &folio, - SGP_FALLOC); + SGP_FALLOC, (end - index) << PAGE_SHIFT); if (error) { info->fallocend = undo_fallocend; /* Remove the !uptodate folios we added */ @@ -XXX,XX +XXX,XX @@ static int shmem_symlink(struct mnt_idmap *idmap, struct inode *dir, inode->i_op = &shmem_short_symlink_operations; } else { inode_nohighmem(inode); - error = shmem_get_folio(inode, 0, &folio, SGP_WRITE); + error = shmem_get_folio(inode, 0, &folio, SGP_WRITE, PAGE_SIZE); if (error) goto out_remove_offset; inode->i_mapping->a_ops = &shmem_aops; @@ -XXX,XX +XXX,XX @@ static const char *shmem_get_link(struct dentry *dentry, struct inode *inode, return ERR_PTR(-ECHILD); } } else { - error = shmem_get_folio(inode, 0, &folio, SGP_READ); + error = shmem_get_folio(inode, 0, &folio, SGP_READ, PAGE_SIZE); if (error) return ERR_PTR(error); if (!folio) @@ -XXX,XX +XXX,XX @@ struct folio *shmem_read_folio_gfp(struct address_space *mapping, BUG_ON(!shmem_mapping(mapping)); error = shmem_get_folio_gfp(inode, index, &folio, SGP_CACHE, - gfp, NULL, NULL); + gfp, NULL, NULL, PAGE_SIZE); if (error) return ERR_PTR(error); diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index XXXXXXX..XXXXXXX 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -XXX,XX +XXX,XX @@ static int mfill_atomic_pte_continue(pmd_t *dst_pmd, struct page *page; int ret; - ret = shmem_get_folio(inode, pgoff, &folio, SGP_NOALLOC); + ret = shmem_get_folio(inode, pgoff, &folio, SGP_NOALLOC, PAGE_SIZE); /* Our caller expects us to return -EFAULT if we failed to find folio */ if (ret == -ENOENT) ret = -EFAULT; -- 2.39.2 Add folio order argument to the shmem_alloc_folio() and merge it with the shmem_alloc_folio_huge(). Return will make use of the new page_rmappable_folio() where order-0 and high order folios are both supported. Signed-off-by: Daniel Gomez <da.gomez@samsung.com> --- mm/shmem.c | 33 ++++++++++----------------------- 1 file changed, 10 insertions(+), 23 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index XXXXXXX..XXXXXXX 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -XXX,XX +XXX,XX @@ static gfp_t limit_gfp_mask(gfp_t huge_gfp, gfp_t limit_gfp) return result; } -static struct folio *shmem_alloc_hugefolio(gfp_t gfp, - struct shmem_inode_info *info, pgoff_t index) +static struct folio *shmem_alloc_folio(gfp_t gfp, struct shmem_inode_info *info, + pgoff_t index, unsigned int order) { struct mempolicy *mpol; pgoff_t ilx; struct page *page; - mpol = shmem_get_pgoff_policy(info, index, HPAGE_PMD_ORDER, &ilx); - page = alloc_pages_mpol(gfp, HPAGE_PMD_ORDER, mpol, ilx, numa_node_id()); + mpol = shmem_get_pgoff_policy(info, index, order, &ilx); + page = alloc_pages_mpol(gfp, order, mpol, ilx, numa_node_id()); mpol_cond_put(mpol); return page_rmappable_folio(page); } -static struct folio *shmem_alloc_folio(gfp_t gfp, - struct shmem_inode_info *info, pgoff_t index) -{ - struct mempolicy *mpol; - pgoff_t ilx; - struct page *page; - - mpol = shmem_get_pgoff_policy(info, index, 0, &ilx); - page = alloc_pages_mpol(gfp, 0, mpol, ilx, numa_node_id()); - mpol_cond_put(mpol); - - return (struct folio *)page; -} - static struct folio *shmem_alloc_and_add_folio(gfp_t gfp, struct inode *inode, pgoff_t index, struct mm_struct *fault_mm, size_t len) { struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); + unsigned int order = 0; struct folio *folio; long pages; int error; @@ -XXX,XX +XXX,XX @@ static struct folio *shmem_alloc_and_add_folio(gfp_t gfp, index + HPAGE_PMD_NR - 1, XA_PRESENT)) return ERR_PTR(-E2BIG); - folio = shmem_alloc_hugefolio(gfp, info, index); + folio = shmem_alloc_folio(gfp, info, index, HPAGE_PMD_ORDER); if (!folio) count_vm_event(THP_FILE_FALLBACK); } else { - pages = 1; - folio = shmem_alloc_folio(gfp, info, index); + pages = 1UL << order; + folio = shmem_alloc_folio(gfp, info, index, order); } if (!folio) return ERR_PTR(-ENOMEM); @@ -XXX,XX +XXX,XX @@ static int shmem_replace_folio(struct folio **foliop, gfp_t gfp, */ gfp &= ~GFP_CONSTRAINT_MASK; VM_BUG_ON_FOLIO(folio_test_large(old), old); - new = shmem_alloc_folio(gfp, info, index); + new = shmem_alloc_folio(gfp, info, index, 0); if (!new) return -ENOMEM; @@ -XXX,XX +XXX,XX @@ int shmem_mfill_atomic_pte(pmd_t *dst_pmd, if (!*foliop) { ret = -ENOMEM; - folio = shmem_alloc_folio(gfp, info, pgoff); + folio = shmem_alloc_folio(gfp, info, pgoff, 0); if (!folio) goto out_unacct_blocks; -- 2.39.2 Current work in progress. Large folios in the fallocate path makes regress fstests generic/285 and generic/436. Add large folio support for shmem write path matching the same high order preference mechanism used for iomap buffered IO path as used in __filemap_get_folio(). Add shmem_mapping_size_order to get a hint for the order of the folio based on the file size which takes care of the mapping requirements. Swap does not support high order folios for now, so make it order 0 in case swap is enabled. Add the __GFP_COMP flag for high order folios except when huge is enabled. This fixes a memory leak when allocating high order folios. Signed-off-by: Daniel Gomez <da.gomez@samsung.com> --- mm/shmem.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 48 insertions(+), 1 deletion(-) diff --git a/mm/shmem.c b/mm/shmem.c index XXXXXXX..XXXXXXX 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -XXX,XX +XXX,XX @@ static struct folio *shmem_alloc_folio(gfp_t gfp, struct shmem_inode_info *info, pgoff_t ilx; struct page *page; + if ((order != 0) && !(gfp & VM_HUGEPAGE)) + gfp |= __GFP_COMP; + mpol = shmem_get_pgoff_policy(info, index, order, &ilx); page = alloc_pages_mpol(gfp, order, mpol, ilx, numa_node_id()); mpol_cond_put(mpol); @@ -XXX,XX +XXX,XX @@ static struct folio *shmem_alloc_folio(gfp_t gfp, struct shmem_inode_info *info, return page_rmappable_folio(page); } +/** + * shmem_mapping_size_order - Get maximum folio order for the given file size. + * @mapping: Target address_space. + * @index: The page index. + * @size: The suggested size of the folio to create. + * + * This returns a high order for folios (when supported) based on the file size + * which the mapping currently allows at the given index. The index is relevant + * due to alignment considerations the mapping might have. The returned order + * may be less than the size passed. + * + * Like __filemap_get_folio order calculation. + * + * Return: The order. + */ +static inline unsigned int +shmem_mapping_size_order(struct address_space *mapping, pgoff_t index, + size_t size, struct shmem_sb_info *sbinfo) +{ + unsigned int order = ilog2(size); + + if ((order <= PAGE_SHIFT) || + (!mapping_large_folio_support(mapping) || !sbinfo->noswap)) + return 0; + + order -= PAGE_SHIFT; + + /* If we're not aligned, allocate a smaller folio */ + if (index & ((1UL << order) - 1)) + order = __ffs(index); + + order = min_t(size_t, order, MAX_PAGECACHE_ORDER); + + /* Order-1 not supported due to THP dependency */ + return (order == 1) ? 0 : order; +} + static struct folio *shmem_alloc_and_add_folio(gfp_t gfp, struct inode *inode, pgoff_t index, struct mm_struct *fault_mm, size_t len) { struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); - unsigned int order = 0; + unsigned int order = shmem_mapping_size_order(mapping, index, len, + SHMEM_SB(inode->i_sb)); struct folio *folio; long pages; int error; +neworder: if (gfp & VM_HUGEPAGE) { pages = HPAGE_PMD_NR; index = round_down(index, HPAGE_PMD_NR); @@ -XXX,XX +XXX,XX @@ static struct folio *shmem_alloc_and_add_folio(gfp_t gfp, unlock: folio_unlock(folio); folio_put(folio); + if (order != 0) { + if (--order == 1) + order = 0; + goto neworder; + } return ERR_PTR(error); } -- 2.39.2 Current work in progress due to fsx regression (check below). Based on iomap per-block dirty and uptodate state track, add support for shmem_folio_state struct to track uptodate per-block when a folio is larger than a block. In shmem, this is when large folios is used, as one block is equal to one page in this context. Add support for invalidate_folio, release_folio and is_partially_uptodate address space operations. The first two are needed to be able to free the new shmem_folio_state struct. The last callback is required for large folios when enabling per-block tracking. This was spotted when running fstests for tmpfs and regress on generic/285 and generic/436 tests [1] with large folios support in the fallocate path without having per-block uptodate tracking. [1] tests: generic/285: src/seek_sanity_test/test09() generic/436: src/seek_sanity_test/test13() How to reproduce: ```sh mkdir -p /mnt/test-tmpfs ./src/seek_sanity_test -s 9 -e 9 /mnt/test-tmpfs/file ./src/seek_sanity_test -s 13 -e 13 /mnt/test-tmpfs/file umount /mnt/test-tmpfs ``` After per-block uptodate support is added, fsx regresion is found when running the following: ```sh mkdir -p /mnt/test-tmpfs mount -t tmpfs -o size=1G -o noswap tmpfs /mnt/test-tmpfs /root/xfstests-dev/ltp/fsx /mnt/test-tmpfs/file -d -N 1200 -X umount /mnt/test-tmpfs ``` Signed-off-by: Daniel Gomez <da.gomez@samsung.com> --- mm/shmem.c | 169 +++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 159 insertions(+), 10 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index XXXXXXX..XXXXXXX 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -XXX,XX +XXX,XX @@ struct shmem_options { #define SHMEM_SEEN_QUOTA 32 }; +/* + * Structure allocated for each folio to track per-block uptodate state. + * + * Like buffered-io shmem_folio_state struct but only for uptodate. + */ +struct shmem_folio_state { + spinlock_t state_lock; + unsigned long state[]; +}; + +static inline bool sfs_is_fully_uptodate(struct folio *folio, + struct shmem_folio_state *sfs) +{ + struct inode *inode = folio->mapping->host; + + return bitmap_full(sfs->state, i_blocks_per_folio(inode, folio)); +} + +static inline bool sfs_block_is_uptodate(struct shmem_folio_state *sfs, + unsigned int block) +{ + return test_bit(block, sfs->state); +} + +static void sfs_set_range_uptodate(struct folio *folio, + struct shmem_folio_state *sfs, size_t off, + size_t len) +{ + struct inode *inode = folio->mapping->host; + unsigned int first_blk = off >> inode->i_blkbits; + unsigned int last_blk = (off + len - 1) >> inode->i_blkbits; + unsigned int nr_blks = last_blk - first_blk + 1; + unsigned long flags; + + spin_lock_irqsave(&sfs->state_lock, flags); + bitmap_set(sfs->state, first_blk, nr_blks); + if (sfs_is_fully_uptodate(folio, sfs)) + folio_mark_uptodate(folio); + spin_unlock_irqrestore(&sfs->state_lock, flags); +} + +static void shmem_set_range_uptodate(struct folio *folio, size_t off, + size_t len) +{ + struct shmem_folio_state *sfs = folio->private; + + if (sfs) + sfs_set_range_uptodate(folio, sfs, off, len); + else + folio_mark_uptodate(folio); +} + +static struct shmem_folio_state *sfs_alloc(struct inode *inode, + struct folio *folio, gfp_t gfp) +{ + struct shmem_folio_state *sfs = folio->private; + unsigned int nr_blocks = i_blocks_per_folio(inode, folio); + + if (sfs || nr_blocks <= 1) + return sfs; + + /* + * sfs->state tracks uptodate flag when the block size is smaller + * than the folio size. + */ + sfs = kzalloc(struct_size(sfs, state, BITS_TO_LONGS(nr_blocks)), gfp); + if (!sfs) + return sfs; + + spin_lock_init(&sfs->state_lock); + if (folio_test_uptodate(folio)) + bitmap_set(sfs->state, 0, nr_blocks); + folio_attach_private(folio, sfs); + + return sfs; +} + +static void sfs_free(struct folio *folio) +{ + struct shmem_folio_state *sfs = folio_detach_private(folio); + + if (!sfs) + return; + WARN_ON_ONCE(sfs_is_fully_uptodate(folio, sfs) != + folio_test_uptodate(folio)); + kfree(sfs); +} + #ifdef CONFIG_TMPFS static unsigned long shmem_default_max_blocks(void) { @@ -XXX,XX +XXX,XX @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) } folio_zero_range(folio, 0, folio_size(folio)); flush_dcache_folio(folio); - folio_mark_uptodate(folio); + shmem_set_range_uptodate(folio, 0, folio_size(folio)); } swap = folio_alloc_swap(folio); @@ -XXX,XX +XXX,XX @@ static struct folio *shmem_alloc_and_add_folio(gfp_t gfp, struct shmem_inode_info *info = SHMEM_I(inode); unsigned int order = shmem_mapping_size_order(mapping, index, len, SHMEM_SB(inode->i_sb)); + struct shmem_folio_state *sfs; struct folio *folio; long pages; int error; @@ -XXX,XX +XXX,XX @@ static struct folio *shmem_alloc_and_add_folio(gfp_t gfp, } } + sfs = sfs_alloc(inode, folio, gfp); + if (!sfs && i_blocks_per_folio(inode, folio) > 1) + goto unlock; + trace_mm_shmem_add_to_page_cache(folio); shmem_recalc_inode(inode, pages, 0); folio_add_lru(folio); @@ -XXX,XX +XXX,XX @@ static int shmem_replace_folio(struct folio **foliop, gfp_t gfp, __folio_set_locked(new); __folio_set_swapbacked(new); - folio_mark_uptodate(new); + shmem_set_range_uptodate(new, 0, folio_size(new)); new->swap = entry; folio_set_swapcache(new); @@ -XXX,XX +XXX,XX @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, for (i = 0; i < n; i++) clear_highpage(folio_page(folio, i)); flush_dcache_folio(folio); - folio_mark_uptodate(folio); + shmem_set_range_uptodate(folio, 0, folio_size(folio)); } /* Perhaps the file has been truncated since we checked */ @@ -XXX,XX +XXX,XX @@ shmem_write_end(struct file *file, struct address_space *mapping, if (pos + copied > inode->i_size) i_size_write(inode, pos + copied); + if (unlikely(copied < len && !folio_test_uptodate(folio))) + return 0; + if (!folio_test_uptodate(folio)) { - if (copied < folio_size(folio)) { - size_t from = offset_in_folio(folio, pos); - folio_zero_segments(folio, 0, from, - from + copied, folio_size(folio)); - } - folio_mark_uptodate(folio); + size_t from = offset_in_folio(folio, pos); + if (!folio_test_large(folio) && copied < folio_size(folio)) + folio_zero_segments(folio, 0, from, from + copied, + folio_size(folio)); + if (folio_test_large(folio) && copied < PAGE_SIZE) + folio_zero_segments(folio, from, from, from + copied, + folio_size(folio)); + shmem_set_range_uptodate(folio, from, len); } folio_mark_dirty(folio); folio_unlock(folio); @@ -XXX,XX +XXX,XX @@ shmem_write_end(struct file *file, struct address_space *mapping, return copied; } +void shmem_invalidate_folio(struct folio *folio, size_t offset, size_t len) +{ + /* + * If we're invalidating the entire folio, clear the dirty state + * from it and release it to avoid unnecessary buildup of the LRU. + */ + if (offset == 0 && len == folio_size(folio)) { + WARN_ON_ONCE(folio_test_writeback(folio)); + folio_cancel_dirty(folio); + sfs_free(folio); + } +} + +bool shmem_release_folio(struct folio *folio, gfp_t gfp_flags) +{ + sfs_free(folio); + return true; +} + +/* + * shmem_is_partially_uptodate checks whether blocks within a folio are + * uptodate or not. + * + * Returns true if all blocks which correspond to the specified part + * of the folio are uptodate. + */ +bool shmem_is_partially_uptodate(struct folio *folio, size_t from, size_t count) +{ + struct shmem_folio_state *sfs = folio->private; + struct inode *inode = folio->mapping->host; + unsigned first, last, i; + + if (!sfs) + return false; + + /* Caller's range may extend past the end of this folio */ + count = min(folio_size(folio) - from, count); + + /* First and last blocks in range within folio */ + first = from >> inode->i_blkbits; + last = (from + count - 1) >> inode->i_blkbits; + + for (i = first; i <= last; i++) + if (!sfs_block_is_uptodate(sfs, i)) + return false; + return true; +} + static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to) { struct file *file = iocb->ki_filp; @@ -XXX,XX +XXX,XX @@ static int shmem_symlink(struct mnt_idmap *idmap, struct inode *dir, inode->i_mapping->a_ops = &shmem_aops; inode->i_op = &shmem_symlink_inode_operations; memcpy(folio_address(folio), symname, len); - folio_mark_uptodate(folio); + shmem_set_range_uptodate(folio, 0, folio_size(folio)); folio_mark_dirty(folio); folio_unlock(folio); folio_put(folio); @@ -XXX,XX +XXX,XX @@ const struct address_space_operations shmem_aops = { #ifdef CONFIG_MIGRATION .migrate_folio = migrate_folio, #endif + .invalidate_folio = shmem_invalidate_folio, + .release_folio = shmem_release_folio, + .is_partially_uptodate = shmem_is_partially_uptodate, .error_remove_page = shmem_error_remove_page, }; EXPORT_SYMBOL(shmem_aops); -- 2.39.2 This series add support for high order folios in shmem write path when swap is disabled (noswap option). This is part of the Large Block Size (LBS) effort [1][2] and a continuation of the shmem work from Luis here [3] following Matthew Wilcox's suggestion [4] regarding the path to take for the folio allocation order calculation. [1] https://kernelnewbies.org/KernelProjects/large-block-size [2] https://docs.google.com/spreadsheets/d/e/2PACX-1vS7sQfw90S00l2rfOKm83Jlg0px8KxMQE4HHp_DKRGbAGcAV-xu6LITHBEc4xzVh9wLH6WM2lR0cZS8/pubhtml# [3] RFC v2 add support for blocksize > PAGE_SIZE https://lore.kernel.org/all/ZHBowMEDfyrAAOWH@bombadil.infradead.org/T/#md3e93ab46ce2ad9254e1eb54ffe71211988b5632 [4] https://lore.kernel.org/all/ZHD9zmIeNXICDaRJ@casper.infradead.org/ fsx and fstests has been performed on tmpfs with noswap with the following results: V2: - fsx: 4,9B - fstests: Same result as baseline for next-230918. V1: - fsx: 2d test, 21,5B - fstests: Same result as baseline for next-230911 [3][4][5] Patches have been tested and sent from next-230918. [3] Baseline next-230911 failures are: generic/080 generic/126 generic/193 generic/633 generic/689 [4] fstests logs baseline: https://gitlab.com/-/snippets/3598621 [5] fstests logs patches: https://gitlab.com/-/snippets/3598628 Note: because of next-230918 regression in rmap, patch [8] applied. [8] 20230918151729.5A1F4C32796@smtp.kernel.org Daniel Changes since v1 * Order handling code simplified in shmem_get_folio_gfp after Matthew Willcox's review. * Drop patch 1/6 [6] and merge mapping_size_order code directly in shmem. * Added MAX_SHMEM_ORDER to make it explicit we don't have the same max order as in pagecache (MAX_PAGECACHE_ORDER). * Use HPAGE_PMD_ORDER-1 as MAX_SHMEM_ORDER to respect huge mount option. * Update cover letter: drop huge strategy question and add more context regarding LBS project. Add fsx and fstests summary with new baseline. * Add fixes found by Matthew in patch 3/6 [7]. * Fix length (i_size_read -> PAGE_SIZE) that is passed to shmem_get_folio_gfp in shmem_fault and shmem_read_folio_gfp to PAGE_SIZE. * Add patch as suggested by Matthew to return the number of pages freed in shmem_free_swap (instead of errno). When no pages are freed, return 0 (pages). Note: As an alternative, we can embed -ENOENT and make use of IS_ERR_VALUE. Approach discarded because little value was added. If this method is preferred, please let discuss it. [6] filemap: make the folio order calculation shareable [7] shmem: account for large order folios Daniel Gomez (5): shmem: drop BLOCKS_PER_PAGE macro shmem: return freed pages in shmem_free_swap shmem: add order parameter support to shmem_alloc_folio shmem: add file length in shmem_get_folio path shmem: add large folios support to the write path Luis Chamberlain (1): shmem: account for large order folios include/linux/shmem_fs.h | 2 +- mm/khugepaged.c | 2 +- mm/shmem.c | 141 ++++++++++++++++++++++++++------------- 3 files changed, 97 insertions(+), 48 deletions(-) -- 2.39.2 The commit [1] replaced all BLOCKS_PER_PAGE in favor of the generic PAGE_SECTORS but definition was not removed. Drop it as unused macro. [1] e09764cff44b5 ("shmem: quota support"). Signed-off-by: Daniel Gomez <da.gomez@samsung.com> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> --- mm/shmem.c | 1 - 1 file changed, 1 deletion(-) diff --git a/mm/shmem.c b/mm/shmem.c index XXXXXXX..XXXXXXX 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -XXX,XX +XXX,XX @@ static struct vfsmount *shm_mnt; #include "internal.h" -#define BLOCKS_PER_PAGE (PAGE_SIZE/512) #define VM_ACCT(size) (PAGE_ALIGN(size) >> PAGE_SHIFT) /* Pretend that each entry is of this size in directory's i_size */ -- 2.39.2 Both shmem_free_swap callers require to get the number of pages in the folio after calling shmem_free_swap. Make shmem_free_swap return the expected value directly and return 0 number of pages being freed to avoid error handling in the external accounting. Suggested-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Daniel Gomez <da.gomez@samsung.com> --- mm/shmem.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index XXXXXXX..XXXXXXX 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -XXX,XX +XXX,XX @@ static void shmem_delete_from_page_cache(struct folio *folio, void *radswap) /* * Remove swap entry from page cache, free the swap and its page cache. */ -static int shmem_free_swap(struct address_space *mapping, +static long shmem_free_swap(struct address_space *mapping, pgoff_t index, void *radswap) { void *old; old = xa_cmpxchg_irq(&mapping->i_pages, index, radswap, NULL, 0); if (old != radswap) - return -ENOENT; + return 0; + free_swap_and_cache(radix_to_swp_entry(radswap)); - return 0; + + return folio_nr_pages((struct folio *)radswap); } /* @@ -XXX,XX +XXX,XX @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend, if (xa_is_value(folio)) { if (unfalloc) continue; - nr_swaps_freed += !shmem_free_swap(mapping, + nr_swaps_freed += shmem_free_swap(mapping, indices[i], folio); continue; } @@ -XXX,XX +XXX,XX @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend, if (xa_is_value(folio)) { if (unfalloc) continue; - if (shmem_free_swap(mapping, indices[i], folio)) { + nr_swaps_freed += shmem_free_swap(mapping, indices[i], folio); + if (!nr_swaps_freed) { /* Swap was replaced by page: retry */ index = indices[i]; break; } - nr_swaps_freed++; continue; } -- 2.39.2 From: Luis Chamberlain <mcgrof@kernel.org> shmem uses the shem_info_inode alloced, swapped to account for allocated pages and swapped pages. In preparation for large order folios adjust the accounting to use folio_nr_pages(). This should produce no functional changes yet as larger order folios are not yet used or supported in shmem. Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Daniel Gomez <da.gomez@samsung.com> --- mm/shmem.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index XXXXXXX..XXXXXXX 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -XXX,XX +XXX,XX @@ unsigned long shmem_partial_swap_usage(struct address_space *mapping, pgoff_t start, pgoff_t end) { XA_STATE(xas, &mapping->i_pages, start); - struct page *page; + struct folio *folio; unsigned long swapped = 0; unsigned long max = end - 1; rcu_read_lock(); - xas_for_each(&xas, page, max) { - if (xas_retry(&xas, page)) + xas_for_each(&xas, folio, max) { + if (xas_retry(&xas, folio)) continue; - if (xa_is_value(page)) - swapped++; + if (xa_is_value(folio)) + swapped += folio_nr_pages(folio); if (xas.xa_index == max) break; if (need_resched()) { @@ -XXX,XX +XXX,XX @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) if (add_to_swap_cache(folio, swap, __GFP_HIGH | __GFP_NOMEMALLOC | __GFP_NOWARN, NULL) == 0) { - shmem_recalc_inode(inode, 0, 1); + shmem_recalc_inode(inode, 0, folio_nr_pages(folio)); swap_shmem_alloc(swap); shmem_delete_from_page_cache(folio, swp_to_radix_entry(swap)); @@ -XXX,XX +XXX,XX @@ static void shmem_set_folio_swapin_error(struct inode *inode, pgoff_t index, struct address_space *mapping = inode->i_mapping; swp_entry_t swapin_error; void *old; + long num_swap_pages; swapin_error = make_poisoned_swp_entry(); old = xa_cmpxchg_irq(&mapping->i_pages, index, @@ -XXX,XX +XXX,XX @@ static void shmem_set_folio_swapin_error(struct inode *inode, pgoff_t index, return; folio_wait_writeback(folio); + num_swap_pages = folio_nr_pages(folio); delete_from_swap_cache(folio); /* * Don't treat swapin error folio as alloced. Otherwise inode->i_blocks * won't be 0 when inode is released and thus trigger WARN_ON(i_blocks) * in shmem_evict_inode(). */ - shmem_recalc_inode(inode, -1, -1); + shmem_recalc_inode(inode, -num_swap_pages, -num_swap_pages); swap_free(swap); } @@ -XXX,XX +XXX,XX @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, if (error) goto failed; - shmem_recalc_inode(inode, 0, -1); + shmem_recalc_inode(inode, 0, -folio_nr_pages(folio)); if (sgp == SGP_WRITE) folio_mark_accessed(folio); @@ -XXX,XX +XXX,XX @@ int shmem_mfill_atomic_pte(pmd_t *dst_pmd, if (ret) goto out_delete_from_cache; - shmem_recalc_inode(inode, 1, 0); + shmem_recalc_inode(inode, folio_nr_pages(folio), 0); folio_unlock(folio); return 0; out_delete_from_cache: -- 2.39.2 In preparation for high order folio support for the write path, add order parameter when allocating a folio. This is on the write path when huge support is not enabled or when it is but the huge page allocation fails, the fallback will take advantage of this too. Use order 0 for the non write paths such as reads or swap in as these currently lack high order folios support. Signed-off-by: Daniel Gomez <da.gomez@samsung.com> --- mm/shmem.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index XXXXXXX..XXXXXXX 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -XXX,XX +XXX,XX @@ static struct folio *shmem_alloc_hugefolio(gfp_t gfp, } static struct folio *shmem_alloc_folio(gfp_t gfp, - struct shmem_inode_info *info, pgoff_t index) + struct shmem_inode_info *info, pgoff_t index, + unsigned int order) { struct vm_area_struct pvma; struct folio *folio; shmem_pseudo_vma_init(&pvma, info, index); - folio = vma_alloc_folio(gfp, 0, &pvma, 0, false); + folio = vma_alloc_folio(gfp, order, &pvma, 0, false); shmem_pseudo_vma_destroy(&pvma); return folio; } static struct folio *shmem_alloc_and_acct_folio(gfp_t gfp, struct inode *inode, - pgoff_t index, bool huge) + pgoff_t index, bool huge, unsigned int *order) { struct shmem_inode_info *info = SHMEM_I(inode); struct folio *folio; @@ -XXX,XX +XXX,XX @@ static struct folio *shmem_alloc_and_acct_folio(gfp_t gfp, struct inode *inode, if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) huge = false; - nr = huge ? HPAGE_PMD_NR : 1; + nr = huge ? HPAGE_PMD_NR : 1U << *order; err = shmem_inode_acct_block(inode, nr); if (err) @@ -XXX,XX +XXX,XX @@ static struct folio *shmem_alloc_and_acct_folio(gfp_t gfp, struct inode *inode, if (huge) folio = shmem_alloc_hugefolio(gfp, info, index); else - folio = shmem_alloc_folio(gfp, info, index); + folio = shmem_alloc_folio(gfp, info, index, *order); if (folio) { __folio_set_locked(folio); __folio_set_swapbacked(folio); @@ -XXX,XX +XXX,XX @@ static int shmem_replace_folio(struct folio **foliop, gfp_t gfp, */ gfp &= ~GFP_CONSTRAINT_MASK; VM_BUG_ON_FOLIO(folio_test_large(old), old); - new = shmem_alloc_folio(gfp, info, index); + new = shmem_alloc_folio(gfp, info, index, 0); if (!new) return -ENOMEM; @@ -XXX,XX +XXX,XX @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, int error; int once = 0; int alloced = 0; + unsigned int order = 0; if (index > (MAX_LFS_FILESIZE >> PAGE_SHIFT)) return -EFBIG; @@ -XXX,XX +XXX,XX @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, huge_gfp = vma_thp_gfp_mask(vma); huge_gfp = limit_gfp_mask(huge_gfp, gfp); - folio = shmem_alloc_and_acct_folio(huge_gfp, inode, index, true); + folio = shmem_alloc_and_acct_folio(huge_gfp, inode, index, true, + &order); if (IS_ERR(folio)) { alloc_nohuge: - folio = shmem_alloc_and_acct_folio(gfp, inode, index, false); + folio = shmem_alloc_and_acct_folio(gfp, inode, index, false, + &order); } if (IS_ERR(folio)) { int retry = 5; @@ -XXX,XX +XXX,XX @@ int shmem_mfill_atomic_pte(pmd_t *dst_pmd, if (!*foliop) { ret = -ENOMEM; - folio = shmem_alloc_folio(gfp, info, pgoff); + folio = shmem_alloc_folio(gfp, info, pgoff, 0); if (!folio) goto out_unacct_blocks; -- 2.39.2 To be able to calculate folio order based on the file size when allocation occurs on the write path. Use of length 0 for non write paths and PAGE_SIZE for pagecache read and vm fault. Signed-off-by: Daniel Gomez <da.gomez@samsung.com> --- include/linux/shmem_fs.h | 2 +- mm/khugepaged.c | 2 +- mm/shmem.c | 32 ++++++++++++++++++-------------- 3 files changed, 20 insertions(+), 16 deletions(-) diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index XXXXXXX..XXXXXXX 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -XXX,XX +XXX,XX @@ enum sgp_type { }; int shmem_get_folio(struct inode *inode, pgoff_t index, struct folio **foliop, - enum sgp_type sgp); + enum sgp_type sgp, size_t len); struct folio *shmem_read_folio_gfp(struct address_space *mapping, pgoff_t index, gfp_t gfp); diff --git a/mm/khugepaged.c b/mm/khugepaged.c index XXXXXXX..XXXXXXX 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -XXX,XX +XXX,XX @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, xas_unlock_irq(&xas); /* swap in or instantiate fallocated page */ if (shmem_get_folio(mapping->host, index, - &folio, SGP_NOALLOC)) { + &folio, SGP_NOALLOC, 0)) { result = SCAN_FAIL; goto xa_unlocked; } diff --git a/mm/shmem.c b/mm/shmem.c index XXXXXXX..XXXXXXX 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -XXX,XX +XXX,XX @@ static struct folio *shmem_get_partial_folio(struct inode *inode, pgoff_t index) * (although in some cases this is just a waste of time). */ folio = NULL; - shmem_get_folio(inode, index, &folio, SGP_READ); + shmem_get_folio(inode, index, &folio, SGP_READ, 0); return folio; } @@ -XXX,XX +XXX,XX @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, struct folio **foliop, enum sgp_type sgp, gfp_t gfp, struct vm_area_struct *vma, struct vm_fault *vmf, - vm_fault_t *fault_type) + vm_fault_t *fault_type, size_t len) { struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); @@ -XXX,XX +XXX,XX @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, } int shmem_get_folio(struct inode *inode, pgoff_t index, struct folio **foliop, - enum sgp_type sgp) + enum sgp_type sgp, size_t len) { return shmem_get_folio_gfp(inode, index, foliop, sgp, - mapping_gfp_mask(inode->i_mapping), NULL, NULL, NULL); + mapping_gfp_mask(inode->i_mapping), + NULL, NULL, NULL, len); } /* @@ -XXX,XX +XXX,XX @@ static vm_fault_t shmem_fault(struct vm_fault *vmf) spin_unlock(&inode->i_lock); } - err = shmem_get_folio_gfp(inode, vmf->pgoff, &folio, SGP_CACHE, - gfp, vma, vmf, &ret); + err = shmem_get_folio_gfp(inode, vmf->pgoff, &folio, SGP_CACHE, gfp, + vma, vmf, &ret, PAGE_SIZE); if (err) return vmf_error(err); if (folio) @@ -XXX,XX +XXX,XX @@ shmem_write_begin(struct file *file, struct address_space *mapping, struct folio *folio; int ret = 0; + if (!mapping_large_folio_support(mapping)) + len = min_t(size_t, len, PAGE_SIZE - offset_in_page(pos)); + /* i_rwsem is held by caller */ if (unlikely(info->seals & (F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_FUTURE_WRITE))) { @@ -XXX,XX +XXX,XX @@ shmem_write_begin(struct file *file, struct address_space *mapping, return -EPERM; } - ret = shmem_get_folio(inode, index, &folio, SGP_WRITE); + ret = shmem_get_folio(inode, index, &folio, SGP_WRITE, len); if (ret) return ret; @@ -XXX,XX +XXX,XX @@ static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to) break; } - error = shmem_get_folio(inode, index, &folio, SGP_READ); + error = shmem_get_folio(inode, index, &folio, SGP_READ, 0); if (error) { if (error == -EINVAL) error = 0; @@ -XXX,XX +XXX,XX @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, break; error = shmem_get_folio(inode, *ppos / PAGE_SIZE, &folio, - SGP_READ); + SGP_READ, 0); if (error) { if (error == -EINVAL) error = 0; @@ -XXX,XX +XXX,XX @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset, error = -ENOMEM; else error = shmem_get_folio(inode, index, &folio, - SGP_FALLOC); + SGP_FALLOC, 0); if (error) { info->fallocend = undo_fallocend; /* Remove the !uptodate folios we added */ @@ -XXX,XX +XXX,XX @@ static int shmem_symlink(struct mnt_idmap *idmap, struct inode *dir, inode->i_op = &shmem_short_symlink_operations; } else { inode_nohighmem(inode); - error = shmem_get_folio(inode, 0, &folio, SGP_WRITE); + error = shmem_get_folio(inode, 0, &folio, SGP_WRITE, 0); if (error) goto out_remove_offset; inode->i_mapping->a_ops = &shmem_aops; @@ -XXX,XX +XXX,XX @@ static const char *shmem_get_link(struct dentry *dentry, return ERR_PTR(-ECHILD); } } else { - error = shmem_get_folio(inode, 0, &folio, SGP_READ); + error = shmem_get_folio(inode, 0, &folio, SGP_READ, 0); if (error) return ERR_PTR(error); if (!folio) @@ -XXX,XX +XXX,XX @@ struct folio *shmem_read_folio_gfp(struct address_space *mapping, int error; BUG_ON(!shmem_mapping(mapping)); - error = shmem_get_folio_gfp(inode, index, &folio, SGP_CACHE, - gfp, NULL, NULL, NULL); + error = shmem_get_folio_gfp(inode, index, &folio, SGP_CACHE, gfp, NULL, + NULL, NULL, PAGE_SIZE); if (error) return ERR_PTR(error); -- 2.39.2 Add large folio support for shmem write path matching the same high order preference mechanism used for iomap buffered IO path as used in __filemap_get_folio() with a difference on the max order permitted (being PMD_ORDER-1) to respect the huge mount option when large folio is supported. Use the __folio_get_max_order to get a hint for the order of the folio based on file size which takes care of the mapping requirements. Swap does not support high order folios for now, so make it order 0 in case swap is enabled. Signed-off-by: Daniel Gomez <da.gomez@samsung.com> --- mm/shmem.c | 66 ++++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 52 insertions(+), 14 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index XXXXXXX..XXXXXXX 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -XXX,XX +XXX,XX @@ static struct vfsmount *shm_mnt; /* Symlink up to this size is kmalloc'ed instead of using a swappable page */ #define SHORT_SYMLINK_LEN 128 +/* Like MAX_PAGECACHE_ORDER but respecting huge option */ +#define MAX_SHMEM_ORDER HPAGE_PMD_ORDER - 1 + /* * shmem_fallocate communicates with shmem_fault or shmem_writepage via * inode->i_private (with i_rwsem making sure that it has only one user at @@ -XXX,XX +XXX,XX @@ static struct folio *shmem_alloc_folio(gfp_t gfp, return folio; } +/** + * shmem_mapping_size_order - Get maximum folio order for the given file size. + * @mapping: Target address_space. + * @index: The page index. + * @size: The suggested size of the folio to create. + * + * This returns a high order for folios (when supported) based on the file size + * which the mapping currently allows at the given index. The index is relevant + * due to alignment considerations the mapping might have. The returned order + * may be less than the size passed. + * + * Like __filemap_get_folio order calculation. + * + * Return: The order. + */ +static inline unsigned int +shmem_mapping_size_order(struct address_space *mapping, pgoff_t index, + size_t size, struct shmem_sb_info *sbinfo) +{ + unsigned int order = ilog2(size); + + if ((order <= PAGE_SHIFT) || + (!mapping_large_folio_support(mapping) || !sbinfo->noswap)) + return 0; + else + order = order - PAGE_SHIFT; + + /* If we're not aligned, allocate a smaller folio */ + if (index & ((1UL << order) - 1)) + order = __ffs(index); + + order = min_t(size_t, order, MAX_SHMEM_ORDER); + + /* Order-1 not supported due to THP dependency */ + return (order == 1) ? 0 : order; +} + static struct folio *shmem_alloc_and_acct_folio(gfp_t gfp, struct inode *inode, - pgoff_t index, bool huge, unsigned int *order) + pgoff_t index, unsigned int order) { struct shmem_inode_info *info = SHMEM_I(inode); struct folio *folio; - int nr; - int err; - - if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) - huge = false; - nr = huge ? HPAGE_PMD_NR : 1U << *order; + int nr = 1U << order; + int err = shmem_inode_acct_block(inode, nr); - err = shmem_inode_acct_block(inode, nr); if (err) goto failed; - if (huge) + if (order == HPAGE_PMD_ORDER) folio = shmem_alloc_hugefolio(gfp, info, index); else - folio = shmem_alloc_folio(gfp, info, index, *order); + folio = shmem_alloc_folio(gfp, info, index, order); if (folio) { __folio_set_locked(folio); __folio_set_swapbacked(folio); @@ -XXX,XX +XXX,XX @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, return 0; } + order = shmem_mapping_size_order(inode->i_mapping, index, len, sbinfo); + if (!shmem_is_huge(inode, index, false, vma ? vma->vm_mm : NULL, vma ? vma->vm_flags : 0)) goto alloc_nohuge; huge_gfp = vma_thp_gfp_mask(vma); huge_gfp = limit_gfp_mask(huge_gfp, gfp); - folio = shmem_alloc_and_acct_folio(huge_gfp, inode, index, true, - &order); + folio = shmem_alloc_and_acct_folio(huge_gfp, inode, index, + HPAGE_PMD_ORDER); if (IS_ERR(folio)) { alloc_nohuge: - folio = shmem_alloc_and_acct_folio(gfp, inode, index, false, - &order); + folio = shmem_alloc_and_acct_folio(gfp, inode, index, order); } if (IS_ERR(folio)) { int retry = 5; @@ -XXX,XX +XXX,XX @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, if (folio_test_large(folio)) { folio_unlock(folio); folio_put(folio); + if (--order == 1) + order = 0; goto alloc_nohuge; } unlock: -- 2.39.2